TY - JOUR AB - A mobile measurement system for complex characterization of particulate matter (PM) was developed together with the proposed methodology and applied in the subway system of Munich, Germany. The main objectives were to observe the spatio-temporal variability of PM, personal exposure, identify hot-spots and pollution sources. Particle mass (PMx) and number (PNC) concentrations, and equivalent black carbon (eBC) were measured at 0.1–1 Hz. On the U5 subway line, PM10, PM2.5 and PM1 concentrations at platforms ranged from 59 to 220, 27–80, and 9–21 μg m−3, respectively. During rides towards downtown, average PM10, PM2.5 and PM1 levels gradually increased from 8 to 220, 2 to 71 and 2–20 μg m−3, respectively, with a similar dynamic of decrease on the return journey. Spatial variability of PM was generally more important than temporal, and significant differences were observed between platforms. During the rides, air exchange between train and tunnel was high in both air-conditioned and old passively ventilated trains. Peak PM concentrations on platforms were associated with arriving/departing trains. Subway PNC were not significantly elevated, but a few cases of intake of traffic-related particles from outside were observed, otherwise air exchange was considered low. Generally, most of the aerosol mass was composed of iron corrosion products from rails and wheels (Fe up to 66 μg m−3 in PM2.5). The effective density of PM2.5 was 2.1 g cm−3. Particles were classified as 75.4% iron oxides, 5.35% metallic Fe, 1.23% aluminosilicates and 17% carbon and oxygen rich particles. The iron oxide particles consisted predominantly of Fe (63.4 ± 8.7 wt%) and O (36.2 ± 8.2 wt%). To effectively monitor subway PM and reduce overall PM exposure, we propose to identify hot-spots using our methodology and focus on improving their ventilation, as well as installing filters in air-conditioned wagons. AU - Bendl, J.* AU - Neukirchen, C.* AU - Mudan, A.* AU - Padoan, S. AU - Zimmermann, R. AU - Adam, T. C1 - 68541 C2 - 53575 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England TI - Personal measurements and sampling of particulate matter in a subway – Identification of hot-spots, spatio-temporal variability and sources of pollutants. JO - Atmos. Environ. VL - 308 PB - Pergamon-elsevier Science Ltd PY - 2023 SN - 1352-2310 ER - TY - JOUR AB - Background: In response to the COVID-19 pandemic, the Bavarian State government announced several COVID-19 mitigation measures beginning on March 16, 2020, which likely led to a reduction in traffic and a subsequent improvement in air quality. In this study, we evaluated the short-term effect of COVID-19 mitigation measures on NO2 concentrations in Munich, Germany. Methods: We applied two quasi-experimental approaches, a controlled interrupted time-series (c-ITS) approach and a synthetic control (SC) approach. Each approach compared changes occurring in 2020 to changes occurring in 2014-2019, and accounted for weather-related and other potential confounders. We hypothesized that the largest reductions in NO2 concentrations would be observed at traffic sites, with smaller reductions at urban background sites, and even small reductions, if any, at background sites. All hypotheses, as well as the main and additional analyses were defined a priori. We also conducted post-hoc analyses to ensure that observed effects were not due to factors other than the intervention. Results: Main analyses largely supported our hypotheses. Specifically, at the two traffic sites, using the c-ITS approach we observed reductions of 9.34 μg/m3 (95% confidence interval: -23.58; 4.90) and 10.02 μg/m3 (-19.25; -0.79). Using the SC approach we observed reductions of 15.65 μg/m3 (-27.58; -4.09) and 15.1 μg/m3 (-24.82; -9.83) at these same sites. We observed effects ranging from smaller in magnitude to no effect at urban background and background sites. Additional analyses showed that the effect was largest in the first two weeks following introduction of measures, and that a 3-day lagged intervention time also showed a larger effect. Post-hoc analyses suggested that at least some of the observed effects may have been attributable to changes in air quality occurring before the intervention, as well as unusually high concentrations in January 2020. Conclusion: We applied two quasi-experimental approaches in assessing the impact of the COVID-19 mitigation measures on NO2 concentrations in Munich. Taking the 2020 pre-intervention average concentrations as a reference, we observed reductions in NO2 concentrations of approximately 15-25% and 24-36% at traffic sites, suggesting that reducing traffic may be an effective measure to reduce NO2 concentrations in heavily trafficked areas by margins which could translate to public health benefits. AU - Burns, J.* AU - Hoffmann, S.* AU - Kurz, C.F. AU - Laxy, M. AU - Polus, S.* AU - Rehfuess, E.* C1 - 60633 C2 - 49509 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England TI - COVID-19 mitigation measures and nitrogen dioxide - a quasi-experimental study of air quality in Munich, Germany. JO - Atmos. Environ. VL - 246 PB - Pergamon-elsevier Science Ltd PY - 2021 SN - 1352-2310 ER - TY - JOUR AB - Pollen is indispensable for life. But, as it may trigger allergic reactions, it can become a biological pollutant, thus requiring monitoring. In urban ecosystems, this is usually done with sampling at rooftop level; exposure to allergenic pollen at ground level is largely unknown. Using the Hirst-type methodology, we explore here how the qualitative, quantitative and phenological features of airborne pollen change horizontally, in different sites of the urban environment, and vertically, when pollen sources are primarily local. We sampled for two years in Thessaloniki, Greece, at six near-ground stations (at 1.5 m) and one at rooftop-level (30 m high). There was a large variability in quantitative pollen features among stations, but Urticaceae, Cupressaceae, Platanus, Pinaceae, and Quercus were the five most abundantly represented taxa in the air, both near the ground and at rooftop level, exceeding there an annual pollen integral of 1000 grains m−3. We found height to have a clear effect on pollen concentration: near the ground, it was three times higher for the entire pollen spectrum and up to 11 times higher for individual taxa. Assuming an exponential decay of pollen with distance from the ground, we calculated pollen concentration for the entire spectrum to decline to half the near-ground value every 19 m and at higher rates for individual taxa. Pollen season also varied largely among stations; a semi-natural station, next to a peri-urban forest, differed from the purely urban stations in having higher pollen concentration and shorter pollen season. For only two taxa, Urticaceae and Cupressaceae, pollen concentrations exceeded thresholds associated with high risk for more than 5% of the year. We conclude that pollen is far from homogeneously distributed within the urban environment, and that height has a strong effect on the low-altitude vertical profile of pollen. At an applied level, this study provides necessary information for more efficient monitoring of airborne pollen and for designing and managing urban green spaces, particularly under the current climate change and the associated higher demand for urban green. AU - Charalampopoulos, A.* AU - Damialis, A. AU - Lazarina, M.* AU - Halley, J.M.* AU - Vokou, D.* C1 - 61227 C2 - 50102 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England TI - Spatiotemporal assessment of airborne pollen in the urban environment: The pollenscape of Thessaloniki as a case study. JO - Atmos. Environ. VL - 247 PB - Pergamon-elsevier Science Ltd PY - 2021 SN - 1352-2310 ER - TY - JOUR AB - Airborne pollen are the most important aeroallergens worldwide. Because of climate change, pollen seasonality and abundance have been altering significantly, raising the fundamental question: when and how much is the pollen exposure increasing? To answer this, we applied a multi-resolution study design, from bi-hourly to yearly scale, investigating the diversity, abundance and temporal occurrence of airborne pollen. The whole spectrum of airborne pollen concentrations was registered during 2015–2017, using a 7-day recording Hirst-type volumetric trap. Monitoring took place at ground-level, where we mostly commute and reside, and at the ‘gold-standard’ rooftop-level (12 m above ground level), at resolutions: A) bi-hourly, B) daily. The biodiversity and the relative abundance of all taxa were assessed, and the first pollen season calendars, along with circadian calendars, for Augsburg, Germany, were developed. More than 40 pollen types were identified, of which 13 were the most abundant (>0.5% relative abundance each, accounting for a total of 91.8%). Biodiversity did not present any striking differences between heights, with pollen from Urticaceae, Betula and Poaceae representing consistently more than half of the regional atmospheric biodiversity. At rooftop-level, pollen abundances often appeared to be higher, particularly for Betula, Picea and Quercus. The main pollen season extended from March to October, with the highest peak occurring April–May. At rooftop-level, the pollen seasons of most taxa were observed earlier and the overall seasons were longer. Within the day, higher pollen concentrations were observed either at midday to early afternoon (Urticaceae, Poaceae, Plantago and mostly taxa at ground-level) or night to early morning, frequently with multi-modal diurnal patterns (Betula, Fraxinus and mostly taxa at rooftop-level). Our findings reveal that generalisation of abundance and temporal distribution patterns between ground-level and ‘gold-standard’ rooftop-level pollen measurements should be intensively reconsidered. While the pollen diversity and abundance may be well represented within this height range, the temporal occurrence is not, with pollen vertical variability being more important than originally anticipated. Hence, we need to reassess when and how much the relevant pollen exposure is increasing. AU - Kolek, F. AU - Plaza, M.P. AU - Charalampopoulos, A.* AU - Traidl-Hoffmann, C. AU - Damialis, A.* C1 - 63255 C2 - 51409 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England TI - Biodiversity, abundance, seasonal and diurnal airborne pollen distribution patterns at two different heights in Augsburg, Germany. JO - Atmos. Environ. VL - 267 PB - Pergamon-elsevier Science Ltd PY - 2021 SN - 1352-2310 ER - TY - JOUR AB - In this study, we developed a novel land-use street view image random forest (LUSRF) model to estimate the equivalent black carbon (eBC) concentration based on land-use random forest (LURF) and street view imagery (SVI) models and compared their accuracy and precision in the urban city of Augsburg, Germany. The variables of the LUSRF model were constructed by combining LURF and SVI model variables (i.e., land-use, street scene, and meteorological factors). Stratified cross-validation (CV) was used to validate the model performance. Based on R2 and IA (Index of Agreement), LUSRF has superiority (average-R2: 0.73, average-IA: 0.91) compared to the LURF (average-R2: 0.52, average-IA: 0.81) and SVI model (average-R2: 0.68, average-IA: 0.89) in the urban city of Augsburg during the observed period. The main driving factors of the LUSRF model for BC estimation were different in heating and non-heating periods (i.e., elevation, the proportion of moving cars, and relative humidity for the non-heating period; and elevation, the proportion of building, and relative humidity for the heating period), which improves the estimation accuracy of eBC concentration and its sources. The model verification in other areas (i.e., suburban and small towns) further proved that the model has certain generalizability. Overall, the LUSRF model will provide insight for epidemiological studies in urban areas as a personal exposure assessment. AU - Liu, X. AU - Hadiatullah, H.* AU - Zhang, X.* AU - Schnelle-Kreis, J. AU - Lin, X.* AU - Cao, X. AU - Zimmermann, R. C1 - 63015 C2 - 51191 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England TI - Combined land-use and street view image model for estimating black carbon concentrations in urban areas. JO - Atmos. Environ. VL - 265 PB - Pergamon-elsevier Science Ltd PY - 2021 SN - 1352-2310 ER - TY - JOUR AB - Alnus pollen is one of the Northern Hemisphere's major aeroallergens. In Central Europe, the genus is represented by three species (Alnus glutinosa, Alnus incana, and Alnus viridis). The most common one, A. glutinosa (L.) Gaertn., is widespread in lowland riparian forests, swamps, and forest edges. However, to date is still unknown if all of them - in terms of pollen exposure - are clinically relevant for sensitized individuals. To investigate the associated pollen exposure, particularly also because of long-range transport of airborne pollen, we used backward air mass trajectories and tested this method for the year 2015, based on daily /thus pollen concentrations at 26 sites in Bavaria, Germany. A. glutinosa's main pollen season extends from February to March, but a six-day, post-season episode was additionally identified in June. For this episode and all sites, 72-h backward trajectories were calculated at 3-h intervals using high spatial and temporal resolution ERAS reanalysis data and the HYS-PLIT (hybrid single-particle Lagrangian integrated trajectory) model. This backward trajectory method identified air masses from the alpine region in Switzerland and Austria, where relevant areas of A. viridis (Chaix) DC as potential pollen sources exist. These may explain the post-season episode in June, as additionally confirmed by its unique spatial distribution, by a considerably later flowering period, and by repeated long-range transport events as observed in a 23-year pollen time series. AU - Ghasemifard, H.* AU - Ghada, W.* AU - Estrella, N.* AU - Lüpke, M.* AU - Oteros, J. AU - Traidl-Hoffmann, C. AU - Damialis, A. AU - Buters, J.T.M. AU - Menzel, A.* C1 - 59076 C2 - 48697 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England TI - High post-season Alnus pollen loads successfully identified as long-range transport of an alpine species. JO - Atmos. Environ. VL - 231 PB - Pergamon-elsevier Science Ltd PY - 2020 SN - 1352-2310 ER - TY - JOUR AB - Ambient air concentrations and bulk deposition of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/F) were monitored at three high Alpine stations in Germany (Schneefernerhaus/Zugspitze: 2650 m a.s.l.), Switzerland (Weissfluhjoch: 2663 m a.s.l.), and Austria (Sonnblick Observatory: 3106 m a.s.l.) from 2005 to 2018. High-volume active air samplers were selectively in operation on a daily basis according to predicted source-regions of air masses. Air concentrations showed only small differences between the three sites and were one or two orders of magnitude lower than in urbanized areas in central Europe. Calculation of source contribution revealed waste incineration, heating, and coal combustion as major sources of PCDD/F in ambient air. Air masses from the northeast were characterized by higher concentrations of PCDD/F than those from northwest and south. However, air masses from the northeast source region are significantly less frequent at the three Alpine stations than air masses from the other source regions. Only at Schneefemerhaus, the majority of congeners exhibit a clear decreasing temporal trend in ambient air concentrations. Deposition rates of PCDD/F measured at the three stations were almost as high as at monitoring stations in urban agglomerations. Despite lower precipitation rates in the central Alps, deposition of PCDD/F was higher at the Sonnblick Observatory than in the Northern Alps (Schneefemerhaus). Bulk deposition for Weissfluhjoch and Schneefemerhaus exhibit a decreasing temporal trend. AU - Kirchner, M. AU - Freier, K.P.* AU - Denner, M.* AU - Ratz, G.* AU - Jakobi, G. AU - Körner, W.* AU - Ludewig, E.* AU - Schaub, M.* AU - Schramm, K.-W. AU - Weiss, P.* AU - Moche, W.* C1 - 57705 C2 - 48004 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England TI - Air concentrations and deposition of chlorinated dioxins and furans (PCDD/F) at three high alpine monitoring stations: Trends and dependence on air masses. JO - Atmos. Environ. VL - 223 PB - Pergamon-elsevier Science Ltd PY - 2020 SN - 1352-2310 ER - TY - JOUR AB - The daily pollen forecast provides crucial information for allergic patients to avoid exposure to specific pollen. Pollen counts are typically measured with air samplers and analyzed with microscopy by trained experts. In contrast, this study evaluated the effectiveness of identifying the component pollens using the metabolites extracted from an air-sampled pollen mixture. Ambient air-sampled pollen from Munich in 2016 and 2017 was visually identified from reference pollens and extracts were prepared. The extracts were lyophilized, rehydrated in optimal NMR buffers, and filtered to remove large proteins. NMR spectra were analyzed for pollen associated metabolites. Regression and decision-tree based algorithms using the concentration of metabolites calculated from the NMR spectra outperformed algorithms using the NMR spectra themselves as input data for pollen identification. Categorical prediction algorithms trained for low, medium, high, and very high pollen count groups had accuracies of 74% for the tree, 82% for the grass, and 93% for the weed pollen count. Deep learning models using convolutional neural networks performed better than regression models using NMR spectral input, and were the overall best method in terms of relative error and classification accuracy (86% for tree, 89% for grass, and 93% for weed pollen count). This study demonstrates that NMR spectra of air-sampled pollen extracts can be used in an automated fashion to provide taxa and type-specific measures of the daily pollen count. AU - Klimczak, L.J.* AU - Ebner von Eschenbach, C. AU - Thompson, P.M.* AU - Buters, J.T.M. AU - Mueller, G.A.* C1 - 60002 C2 - 48945 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England TI - Mixture analyses of air-sampled pollen extracts can accurately differentiate pollen taxa. JO - Atmos. Environ. VL - 243 PB - Pergamon-elsevier Science Ltd PY - 2020 SN - 1352-2310 ER - TY - JOUR AB - The first part of the present study addresses meteorological and synoptic factors governing daily maximum 1-hour ozone (O-3) concentrations in the city of Augsburg in the months from March to September. In the second part statistical models are applied to assess the association between daily myocardial infarction (MI) frequencies and ozone exposure, under the additional consideration of climatic and synoptic factors. Daily maximum 1-hour ozone concentrations were increased with high air temperatures, low values of specific humidity and high ozone concentrations of the previous day. Besides, four weather types were connected with ozone, the weather type "U", which describes mainly low-flow conditions, being of particular importance. The daily maximum 1-hour ozone concentrations showed a notable non-linear relationship with MI frequencies in Augsburg. An enhanced MI risk occurred mainly at median to moderately high ozone concentrations. A piecewise linear regression up to the maximum relative risk at approximately the 75%-ozone percentile (116 mu g/m(3)) yielded a significant increase of 3.41% (95% confidence interval: [1.33%, 5.53%]) of the MI frequency per 10 pg/m 3 increase in ozone. At higher ozone concentrations a decrease of the MI risk occurred. Three weather types were selected as additional predictors in the statistical models. Most notable was the frequent weather type Anticyclonic (A), which is related to a reduction in MI frequencies. AU - Hertig, E.* AU - Schneider, A.E. AU - Peters, A. AU - von Scheidt, W.* AU - Kuch, B.* AU - Meisinger, C. C1 - 56934 C2 - 47436 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England TI - Association of ground-level ozone, meteorological factors and weather types with daily myocardial infarction frequencies in Augsburg, Southern Germany. JO - Atmos. Environ. VL - 217 PB - Pergamon-elsevier Science Ltd PY - 2019 SN - 1352-2310 ER - TY - JOUR AB - Background: Pollen is naturally emitted and is relevant for health, crop sciences and monitoring climate change, among others. Despite their relevance, pollen is often insufficiently monitored resulting in a lack of data. Thus, spatial modelling of pollen concentrations for unmonitored areas is necessary. The aim of this study was to develop an automatic system for calculating daily pollen concentrations at sites without regular pollen monitoring.Method: We used data from 14 pollen taxa collected during 2015 at 26 stations distributed across Bavaria, Germany. The proposed system was based on the Kriging interpolation method to spatially model pollen concentrations for unmonitored areas, in combination with regression of environmental parameters. The method also took into account weather effects on daily pollen concentrations.Results: An automatic system was developed for calculating current pollen concentrations at any location of the county. The results were displayed as daily pollen concentrations per m(3) in maps of 1 km(2) resolution. The models are trained automatically for every day by using the pollen and weather inputs. Automatic inputs will increase the usability of the model. In 50% of the cases, Gaussian Kriging was selected as the optimal model. An R-2 of 0.5 is reached in external validation without considering the effect of the weather. An R-2 of 0.7 is reached after considering the effect of daily weather parameters.Conclusions: A fully automatic pollen network (ePIN) was built in Bavaria during 2018 that delivers data on-line without delay. The proposed method allows for a comparably small number of automatic devices per study area, but still providing information on pollen on any location in the study area. AU - Oteros, J. AU - Bergmann, K.C.* AU - Menzel, A.* AU - Damialis, A. AU - Traidl-Hoffmann, C. AU - Schmidt-Weber, C.B. AU - Buters, J.T.M. C1 - 54898 C2 - 45925 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England SP - 435-442 TI - Spatial interpolation of current airborne pollen concentrations where no monitoring exists. JO - Atmos. Environ. VL - 199 PB - Pergamon-elsevier Science Ltd PY - 2019 SN - 1352-2310 ER - TY - JOUR AB - This work reports the first statistical analysis of multi-annual data on tropospheric aerosols from the German Ultrafine Aerosol Network (GUAN). Compared to other networks worldwide, GUAN with 17 measurement locations has the most sites equipped with particle number size distribution (PNSD) and equivalent black carbon (eBC) instruments and the most site categories in Germany ranging from city street/roadside to High Alpine. As we know, the variations of eBC and particle number concentration (PNC) are influenced by several factors such as source, transformation, transport and deposition. The dominant controlling factor for different pollutant parameters might be varied, leading to the different spatio-temporal variations among the measured parameters. Currently, a study of spatio-temporal variations of PNSD and eBC considering the influences of both site categories and spatial scale is still missing. Based on the multi-site dataset of GUAN, the goal of this study is to investigate how pollutant parameters may interfere with spatial characteristics and site categories. AU - Sun, J.* AU - Birmili, W.* AU - Hermann, M.* AU - Tuch, T.* AU - Weinhold, K.* AU - Spindler, G.* AU - Schladitz, A.* AU - Bastian, S.* AU - Löschau, G.* AU - Cyrys, J. AU - Gu, J. AU - Flentje, H.* AU - Briel, B.* AU - Asbach, C.* AU - Kaminski, H.* AU - Ries, L.* AU - Sohmer, R.* AU - Gerwig, H.* AU - Wirtz, K.* AU - Meinhardt, F.* AU - Schwerin, A.* AU - Bath, O.* AU - Ma, N.T.* AU - Wiedensohler, A.* C1 - 55436 C2 - 46156 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England SP - 256-268 TI - Variability of black carbon mass concentrations, sub-micrometer particle number concentrations and size distributions: Results of the German Ultrafine Aerosol Network ranging from city street to High Alpine locations. JO - Atmos. Environ. VL - 202 PB - Pergamon-elsevier Science Ltd PY - 2019 SN - 1352-2310 ER - TY - JOUR AB - Small-scale pellet boilers and stoves became popular as a wood combustion appliance for domestic heating in Europe, North America and Asia due to economic and environmental aspects. Therefore, an increasing contribution of pellet boilers to air pollution is expected despite their general high combustion efficiency. As emissions of primary organic aerosol (POA) and permanent gases of pellet boilers are well investigated, the scope of this study was to investigate the volatile organic emissions and the formation potential of secondary aerosols for this type of appliance. Fresh and aged emissions were analysed by a soot-particle aerosol time-of-flight mass spectrometry (SP-AMS) and the molecular composition of the volatile precursors with single-photon ionisation time-of-flight mass spectrometry (SPI-TOFMS) at different pellet boiler operation conditions. Organic emissions in the gas phase were dominated by unsaturated hydrocarbons while wood-specific VOCs, e.g. phenolic species or substituted furans, were only detected during the starting phase. Furthermore, organic emissions in the gas phase were found to correlate with fuel grade and combustion technology in terms of secondary air supply. Secondary organic aerosols of optimised pellet boiler conditions (OPT, state-of-the-art combustion appliance) and reduced secondary air supply (RSA, used as a proxy for pellet boilers of older type) were studied by simulating atmospheric ageing in a Potential Aerosol Mass (PAM) flow reactor. Different increases in OA mass (55% for OPT, 102% for RSA), associated with higher average carbon oxidation state and O:C, could be observed in a PAM chamber experiment. Finally, it was found that derived SOA yields and emission factors were distinctly lower than reported for log wood stoves. AU - Czech, H.* AU - Pieber, S.M.* AU - Tiitta, P.* AU - Sippula, O.* AU - Kortelainen, M.* AU - Lamberg, H.* AU - Grigonyte, J.* AU - Streibel, T. AU - Prévôt, A.S.H.* AU - Jokiniemi, J.* AU - Zimmermann, R. C1 - 50947 C2 - 42975 CY - Oxford SP - 236-245 TI - Time-resolved analysis of primary volatile emissions and secondary aerosol formation potential from a small-scale pellet boiler. JO - Atmos. Environ. VL - 158 PB - Pergamon-elsevier Science Ltd PY - 2017 SN - 1352-2310 ER - TY - JOUR AU - Czech, H.* AU - Schnelle-Kreis, J. AU - Streibel, T.* AU - Zimmermann, R. C1 - 51285 C2 - 43118 SP - 190-191 TI - New directions: Beyond sulphur, vanadium and nickel - About source apportionment of ship emissions in emission control areas. JO - Atmos. Environ. VL - 163 PY - 2017 SN - 1352-2310 ER - TY - JOUR AB - Ship emissions are known to cause severe impacts on human health, but are less restricted than land-based emissions. A regulation to improve air quality in coastal regions and frequented waterways is the limitation of fuel sulphur content to 0.1% in sulphur emission control areas (SECAs), which has caused a switch from heavy fuel oil (HFO) towards diesel-like marine gas oil (MGO) or marine diesel oil (MDO). The fraction of aromatic organic vapours in the exhaust from a marine engine, operating on HFO and MGO, was investigated by resonance-enhanced multi-photon ionisation time-of-flight mass spectrometry (REMPI-TOFMS). MGO with fuel sulphur content (FSC) below 0.1% and HFO with an average FSC of 2.7% denote representative marine fuels inside and outside SECAs, respectively. The obtained emission spectra were combined with data of previous REMPI-TOFMS studies of combustion engines and wood combustion in statistical analyses to derive marker substances for ship emissions inside and outside SECAs. A diagnostic ratio of C2-naphthalenes to methyl-naphthalenes was found to hold for a good discriminator between ship emissions on the one hand and road traffic and wood combustion on the other hand. Furthermore, random REMPI spectra from all emission sources were mixed with different proportions in a simulation to create a model based on partial least square (PLS) regression for the prediction of ship contribution to aromatic organic vapours. We point out that in particular PAHs with higher degree of alkylation are significant markers for primary ship emissions which may support source apportionment studies inside and outside SECAs to assess the benefits of fuel sulphur content regulation on air quality. AU - Czech, H.* AU - Stengel, B.* AU - Adam, T. AU - Sklorz, M. AU - Streibel, T. AU - Zimmermann, R. C1 - 51754 C2 - 43433 CY - Oxford SP - 212-222 TI - A chemometric investigation of aromatic emission profiles from a marine engine in comparison with residential wood combustion and road traffic: Implications for source apportionment inside and outside sulphur emission control areas. JO - Atmos. Environ. VL - 167 PB - Pergamon-elsevier Science Ltd PY - 2017 SN - 1352-2310 ER - TY - JOUR AB - Oxidative potential (OP) has been suggested as a health-relevant measure of air pollution. Little information is available about OP spatial variation and the possibility to model its spatial variability. Our aim was to measure the spatial variation of OP within and between 10 European study areas. The second aim was to develop land use regression (LUR) models to explain the measured spatial variation. OP was determined with the dithiothreitol (DTT) assay in ten European study areas. DTT of PM2.5 was measured at 16–40 sites per study area, divided over street, urban and regional background sites. Three two-week samples were taken per site in a one-year period in three different seasons. We developed study-area specific LUR models and a LUR model for all study areas combined to explain the spatial variation of OP. Significant contrasts between study areas in OP were found. OP DTT levels were highest in southern Europe. DTT levels at street sites were on average 1.10 times higher than at urban background locations. In 5 of the 10 study areas LUR models could be developed with a median R2 of 33%. A combined study area model explained 30% of the measured spatial variability. Overall, LUR models did not explain spatial variation well, possibly due to low levels of OP DTT and a lack of specific predictor variables. AU - Jedynska, A.* AU - Hoek, G.* AU - Wang, M.* AU - Yang, A.* AU - Eeftens, M.* AU - Cyrys, J. AU - Keuken, M.* AU - Ampe, C.* AU - Beelen, R.* AU - Cesaroni, G.* AU - Forastiere, F.* AU - Cirach, M.* AU - de Hoogh, K.* AU - de Nazelle, A.* AU - Nystad, W.* AU - Akhlaghi, H.M.* AU - Declercq, C.* AU - Stempfelet, M.* AU - Eriksen, K.T.* AU - Dimakopoulou, K.* AU - Lanki, T.* AU - Meliefste, K.* AU - Nieuwenhuijsen, M.* AU - Yli-Tuomi, T.* AU - Raaschou-Nielsen, O.* AU - Janssen, N.A.H.* AU - Brunekreef, B.* AU - Kooter, I.M.* C1 - 50059 C2 - 42155 CY - Oxford SP - 24-32 TI - Spatial variations and development of land use regression models of oxidative potential in ten European study areas. JO - Atmos. Environ. VL - 150 PB - Pergamon-elsevier Science Ltd PY - 2017 SN - 1352-2310 ER - TY - JOUR AB - An inventory of Sahara dust (SD) events at the Hohenpeiβenberg Global Atmosphere Watch station (Germany) is presented for the period 1997-2013. Based on daily in-situ measurements, high Ca2+-ion concentrations and large particle volume concentrations at diameters dp≈0.5-7μm are inferred as indicators for days influenced by SD. The resulting SD catalogue agrees with SD time series from Schneefernerhaus, Augsburg and Jungfraujoch stations. On average, SD occurs in 5-15 SD events (SDE) per year covering about 10-60 days/yr in the mixing layer. SDE exhibit a clear seasonality with spring and early autumn maxima, and typically last for 1-3 days. SDE are equally frequent but more significant at Alpine levels due to lower background. Wet deposition of Ca2+ at the surface is little correlated (R2=0.14) with particle Ca2+ on a daily basis and yields an average annual Ca2+ immission of 0.22±0.04g/m2yr, about 40% of which is due to SD. The majority of outstanding weekly Fe and Al depositions are associated with SDE. SD contributes about 0.5±0.1μg/m3 to the total particle mass with a decreasing trend from 6% to 4% (-0.1%/yr) in the 1997-2013 period. Except from one, all threshold exceedances according to European legislation (daily PM1050μg/m3) at Hohenpeiβenberg are due to SD. Implications are discussed with respect to SD-related circulation patterns, SD-induced temperature anomalies in weather forecast models and the capability of aerosol models to capture SDE. AU - Flentje, H.* AU - Briel, B.* AU - Beck, C.* AU - Collaud Coen, M.* AU - Fricke, M.* AU - Cyrys, J. AU - Gu, J. AU - Pitz, M.* AU - Thomas, W.* C1 - 43855 C2 - 36690 CY - Oxford SP - 87-96 TI - Identification and monitoring of Saharan dust: An inventory representative for South Germany since 1997. JO - Atmos. Environ. VL - 109 PB - Pergamon-elsevier Science Ltd PY - 2015 SN - 1352-2310 ER - TY - JOUR AB - Bulk deposition samples were collected at three elevated summits in different parts of the Alps from 2005 to 2010. Deposition samples were analyzed for a wide range of organochlorine pesticides (OCPs). HCHs, DDT, DDD, DDE, chlordanes, cis-heptachlor, HCB, dieldrin and endrin were found in all samples, only aldrin was found less frequently.Differences in the mean deposition rates between the three sites reflect the different amounts of precipitation at these sites. At the northern edge of the Alps with the highest annual total precipitations, mean annual deposition rates were at least twice those at the Swiss site for most of the investigated OCP. Average annual deposition of α-HCH amounted to 602, 461 and 216ngm-2year-1, the sum of DDT, DDD and DDE to 579, 210 and 144ngm-2year-1 and the sum of trans- and cis-chlordane to 35, 47, 16ngm-2 year-1at Zugspitze, Sonnblick, and Weissfluhjoch, respectively.A quite distinct seasonal pattern of OPC deposition was observed at all three locations. For most of the HCH isomers, higher deposition rates were observed in summer than in winter at all three sites, which may be caused by enhanced re-volatilization due to higher summer temperatures and the ongoing application of HCH-containing products in some regions as well. For the other investigated OCPs, higher summer deposition rates were found only at Weissfluhjoch. This site is more often affected by air masses crossing the river Po basin than the other two sites, an area exhibiting higher summer temperatures compared to other regions adjacent to the Alps. AU - Jakobi, G. AU - Kirchner, M. AU - Henkelmann, B. AU - Körner, W.* AU - Offenthaler, I.* AU - Moche, W.* AU - Weiß, P.S.* AU - Schaub, M.* AU - Schramm, K.-W. C1 - 42925 C2 - 35877 CY - Oxford SP - 158-165 TI - Atmospheric bulk deposition measurements of organochlorine pesticides at three alpine summits. JO - Atmos. Environ. VL - 101 PB - Pergamon-elsevier Science Ltd PY - 2015 SN - 1352-2310 ER - TY - JOUR AB - Less vegetated mountainous areas may provide better conditions for allergy sufferers. However, atmospheric transport can result in medically relevant pollen loads in such regions. The majority of investigations has focused on the pollen load, expressed as daily averages of pollen per cubic meter of air (pollen grains/m3); however, the severity of allergic symptoms is also determined by the actual allergen content of this pollen, its pollen potency, which may differ between high and low altitudes. We analysed airborne birch and grass pollen concentrations along with allergen content (birch: Bet v 1, grass: Phl p 5) at two different altitudes (734 and 2650 m a.s.l.) in the Zugspitze region (2009-2010). Back-trajectories were calculated for the high altitude site and for specific days with abrupt increases in pollen potency. We observed several days with medically relevant pollen concentrations at the highest site. In addition, a few days with pollen were not associated with allergens and vice versa. The calculated seasonal mean allergen release per pollen grain was 1.8-3.3 pg Bet v 1 and 5.7 pg Phl p 5 in the valley and 1.1-3.7 pg Bet v 1 and 0.7-1.5 pg Phl p 5 at the high altitude site. Back-trajectories revealed that high pollen potency at the higher site was generally associated with south-westerly to south-easterly (birch), or northerly (grass) wind directions. By investigating days with sudden increases in pollen potency, however, it was difficult to draw definitive conclusions on long- or short-range transport. Our findings suggest that people allergic to pollen might suffer less at higher altitudes and further indicate that a risk assessment relying on the actual concentration of airborne pollen does not necessarily reflect the actual allergy exposure of individuals. AU - Jochner, S.* AU - Lüpke, M.* AU - Laube, J.* AU - Weichenmeier, I. AU - Pusch, G. AU - Traidl-Hoffmann, C.* AU - Schmidt-Weber, C.B. AU - Buters, J.T.M. AU - Menzel, A.* C1 - 46905 C2 - 39023 SP - 83-93 TI - Seasonal variation of birch and grass pollen loads and allergen release at two sites in the German Alps. JO - Atmos. Environ. VL - 122 PY - 2015 SN - 1352-2310 ER - TY - JOUR AB - Gas phase emission samples of carbonyl compounds (CCs) were collected from a research ship diesel engine at Rostock University, Germany. The ship engine was operated using two different types of fuels, heavy fuel oil (HFO) and diesel fuel (DF). Sampling of CCs was performed from diluted exhaust using cartridges and impingers. Both sampling methods involved the derivatization of CCs with 2,4-Dinitrophenylhydrazine (DNPH). The CCs-hydrazone derivatives were analyzed by two analytical techniques: High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) and Gas Chromatography-Selective Ion Monitoring-Mass Spectrometry (GC-SIM-MS). Analysis of DNPH cartridges by GC-SIM-MS method has resulted in the identification of 19 CCs in both fuel operations. These CCs include ten aliphatic aldehydes (formaldehyde, acetaldehyde, propanal, isobutanal, butanal, isopentanal, pentanal, hexanal, octanal, nonanal), three unsaturated aldehydes (acrolein, methacrolein, crotonaldehyde), three aromatic aldehyde (benzaldehyde, p-tolualdehyde, m,o-molualdehyde), two ketones (acetone, butanone) and one heterocyclic aldehyde (furfural). In general, all CCs under investigation were detected with higher emission factors in HFO than DF. The total carbonyl emission factor was determined and found to be 6700 and 2300μgkWh-1 for the operation with HFO and DF respectively. Formaldehyde and acetaldehyde were found to be the dominant carbonyls in the gas phase of ship engine emission. Formaldehyde emissions factor varied from 3870μgkWh-1 in HFO operation to 1540μgkWh-1 in DF operation, which is 4-30 times higher than those of other carbonyls. Emission profile contribution of CCs showed also a different pattern between HFO and DF operation. The contribution of formaldehyde was found to be 58% of the emission profile of HFO and about 67% of the emission profile of DF. Acetaldehyde showed opposite behavior with higher contribution of 16% in HFO compared to 11% for DF. Heavier carbonyls (more than two carbon atoms) showed also more contribution in the emission profile of the HFO fuel (26%) than in DF (22%). AU - Reda, A. AU - Schnelle-Kreis, J. AU - Orasche, J. AU - Abbaszade, G. AU - Lintelmann, J. AU - Arteaga-Salas, J.M. AU - Stengel, B.* AU - Rabe, R.* AU - Harndorf, H.* AU - Sippula, O.* AU - Streibel, T. AU - Zimmermann, R. C1 - 44443 C2 - 36914 SP - 370-380 TI - Corrigendum: Gas phase carbonyl compounds in ship emissions: Differences between diesel fuel and heavy fuel oil operation. JO - Atmos. Environ. VL - 112 PY - 2015 SN - 1352-2310 ER - TY - JOUR AB - Gas phase emission samples of carbonyl compounds (CCs) were collected from a research ship diesel engine at Rostock University, Germany. The ship engine was operated using two different types of fuels, heavy fuel oil (HFO) and diesel fuel (DF). Sampling of CCs was performed from diluted exhaust using cartridges and impingers. Both sampling methods involved the derivatization of CCs with 2,4-Dinitrophenylhydrazine (DNPH). The CCs-hydrazone derivatives were analyzed by two analytical techniques: High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) and Gas Chromatography-Selective Ion Monitoring-Mass Spectrometry (GC-SIM-MS). Analysis of DNPH cartridges by GC-SIM-MS method has resulted in the identification of 19 CCs in both fuel operations. These CCs include ten aliphatic aldehydes (formaldehyde, acetaldehyde, propanal, isobutanal, butanal, isopentanal, pentanal, hexanal, octanal, nonanal), three unsaturated aldehydes (acrolein, methacrolein, crotonaldehyde), three aromatic aldehyde (benzaldehyde, p-tolualdehyde, m,o-molualdehyde), two ketones (acetone, butanone) and one heterocyclic aldehyde (furfural). In general, all CCs under investigation were detected with higher emission factors in HFO than DF. The total carbonyl emission factor was determined and found to be 6700 and 2300 mu g kWh(-1) for the operation with HFO and DF respectively. Formaldehyde and acetaldehyde were found to be the dominant carbonyls in the gas phase of ship engine emission. Formaldehyde emissions factor varied from 3870 mu g kWh(-1) in HFO operation to 1540 mu g kWh(-1) in DF operation, which is 4-30 times higher than those of other carbonyls. Emission profile contribution of CCs showed also a different pattern between HFO and DF operation. The contribution of formaldehyde was found to be 58% of the emission profile of HFO and about 67% of the emission profile of DF. Acetaldehyde showed opposite behavior with higher contribution of 16% in HFO compared to 11% for DF. Heavier carbonyls (more than two carbon atoms) showed also more contribution in the emission profile of the HFO fuel (26%) than in DF (22%). (C) 2015 Elsevier Ltd. All rights reserved. AU - Reda, A. AU - Schnelle-Kreis, J. AU - Orasche, J. AU - Abbaszade, G. AU - Lintelmann, J. AU - Arteaga-Salas, J.M. AU - Stengel, B.* AU - Rabe, R.* AU - Harndorf, H.* AU - Sippula, O.* AU - Streibel, T. AU - Zimmermann, R. C1 - 44862 C2 - 37162 CY - Oxford SP - 369 TI - Corrigendum to "Gas phase carbonyl compounds in ship emissions: Differences between diesel fuel and heavy fuel oil operation". JO - Atmos. Environ. VL - 112 PB - Pergamon-elsevier Science Ltd PY - 2015 SN - 1352-2310 ER - TY - JOUR AB - Limited information is available on the contribution of organic components in particulate matter to health effects related to fine particles. Spatial variability of specific fine particle organic components has not been assessed with consistent methods. The aim of this paper is to assess spatial variation of organic components of fine particles within and between European study areas. Highly standardized measurements of polycyclic aromatic hydrocarbons (PAH), hopanes/steranes, elemental/organic carbon (EC/OC) and levoglucosan were performed measured in ten study areas across Europe. In each study area, measurements were conducted at street, urban and regional background sites. Three two-week samples were taken per site and the annual average levels of pollutants were calculated using continuous measurements at one background site as a reference. Substantial variations within and between the study areas were found. EC/OC and hopanes/steranes concentrations were highest in southern European study areas and lowest in northern locations. PAH concentrations were lowest in London/Oxford and highest in Copenhagen, Rome and Athens. Concentrations at street locations were higher than at background locations in all study areas and for all components. However, these differences varied considerably between study areas and components. EC had the highest median street to urban background ratio (1.62), OC the lowest (1.32). EC was highly correlated with NOx and PM2.5 absorbance in all areas, with median r = 0.85 and r = 0.89, respectively. The correlation between OC and other components was variable, with a median correlation of 0.65 with PM2.5 mass and a weak (0.18) correlation with Σhopanes/steranes. ΣPAH correlated moderately with EC (r = 0.59) and weakly with ∑hopanes/steranes (r = 0.36). In conclusion, substantial variability was found in spatial patterns of atmospheric EC, OC, PAH and hopanes/steranes both within and between European study areas. The application of this highly standardized measurement approach across different locations will contribute to a consistent assessment of air pollutant levels and potentially contribute to understanding health effects associated with them. AU - Jedynska, A.* AU - Hoek, G.* AU - Eeftens, M.* AU - Cyrys, J. AU - Keuken, M.* AU - Ampe, C.* AU - Beelen, R.* AU - Cesaroni, G.* AU - Forastiere, F.* AU - Cirach, M.* AU - de Hoogh, K.* AU - de Nazelle, A.* AU - Madsen, C.* AU - Declercq, C.* AU - Eriksen, K.T.* AU - Katsouyanni, K.* AU - Akhlaghi, H.M.* AU - Lanki, T.* AU - Meliefste, K.* AU - Nieuwenhuijsen, M.* AU - Oldenwening, M.* AU - Pennanen, A.* AU - Raaschou-Nielsen, O.* AU - Brunekreef, B.* AU - Kooter, I.M.* C1 - 31236 C2 - 34234 SP - 239-248 TI - Spatial variations of PAH, hopanes/steranes and EC/OC concentrations within and between European study areas. JO - Atmos. Environ. VL - 87 PY - 2014 SN - 1352-2310 ER - TY - JOUR AB - Gas phase emission samples of carbonyl compounds (CCs) were collected from a research ship diesel engine at Rostock University, Germany. The ship engine was operated using two different types of fuels, heavy fuel oil (HFO) and diesel fuel (DF). Sampling of CCs was performed from diluted exhaust using cartridges and impingers. Both sampling methods involved the derivatization of CCs with 2,4-Dinitrophenylhydrazine (DNPH). The CCs-hydrazone derivatives were analyzed by two analytical techniques: High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) and Gas Chromatography-Selective Ion Monitoring-Mass Spectrometry (GC-SIM-MS). Analysis of DNPH cartridges by GC-SIM-MS method has resulted in the identification of 19 CCs in both fuel operations. These CCs include ten aliphatic aldehydes (formaldehyde, acetaldehyde, propanal, isobutanal, butanal, isopentanal, pentanal, hexanal, octanal, nonanal), three unsaturated aldehydes (acrolein, methacrolein, crotonaldehyde), three aromatic aldehyde (benzaldehyde, p-tolualdehyde, m,o-molualdehyde), two ketones (acetone, butanone) and one heterocyclic aldehyde (furfural). In general, all CCs under investigation were detected with higher emission factors in HFO than DF. The total carbonyl emission factor was determined and found to be 6050 and 2300μgMJ-1 for the operation with HFO and DF respectively. Formaldehyde and acetaldehyde were found to be the dominant carbonyls in the gas phase of ship engine emission. Formaldehyde emissions factor varied from 3500μgMJ-1 in HFO operation to 1540μgMJ-1 in DF operation, which is 4-30 times higher than those of other carbonyls. Emission profile contribution of CCs showed also a different pattern between HFO and DF operation. The contribution of formaldehyde was found to be 58% of the emission profile of HFO and about 67% of the emission profile of DF. Acetaldehyde showed opposite behavior with higher contribution of 16% in HFO compared to 11% for DF. Heavier carbonyls (more than two carbon atoms) showed also more contribution in the emission profile of the HFO fuel (26%) than in DF (22%). AU - Reda, A. AU - Schnelle-Kreis, J. AU - Orasche, J. AU - Abbaszade, G. AU - Lintelmann, J. AU - Arteaga-Salas, J.M. AU - Stengel, B.* AU - Rabe, R.* AU - Harndorf, H.* AU - Sippula, O.* AU - Streibel, T. AU - Zimmermann, R. C1 - 31597 C2 - 34655 CY - Oxford SP - 467-478 TI - Gas phase carbonyl compounds in ship emissions: Differences between diesel fuel and heavy fuel oil operation. JO - Atmos. Environ. VL - 94 PB - Pergamon-elsevier Science Ltd PY - 2014 SN - 1352-2310 ER - TY - JOUR AB - Radiocarbon (14C) measurement of water-soluble organic carbon (WSOC) in ambient aerosols is a quantitative tool for unambiguously distinguishing fossil and non-fossil sources. In this study, a fast and reliable method for measuring 14C in micro-scale (μg) WSOC aerosol samples is successfully developed, which includes three steps: (1) extraction (2) freeze drying, and (3) online 14C analysis of CO2 from WSOC combustion. Procedure blanks are carefully assessed by measuring high-purity water and reference materials. Accurate 14C results could be obtained for WSOC with only 10μgC, and thus the potential applications are substantially broadened because much less filter material is needed compared to previous reported methods. This method is applied to aerosols samples collected during winter from Switzerland and China. The results demonstrate that non-fossil sources are important if not dominant contributors of WSOC. These non-fossil components are consistently enriched in WSOC compared to bulk OC and water-insoluble OC for all samples, due to high water solubility of primary and secondary biomass burning aerosols. However, the presence of fossil WSOC is still considerable indicating a substantial contribution of secondary OC (SOC) formed from precursors emitted by fossil emissions. Larger fossil contributions to WSOC is found in China than in Switzerland and previously reported values in Europe, USA and South Asia, which may be attributed to higher fossil-derived SOC formation in China. AU - Zhang, Y.* AU - Liu, J.* AU - Salazar, G.A.* AU - Li, J.* AU - Zotter, P.* AU - Zhang, G.* AU - Shen, R.* AU - Schäfer, K.* AU - Schnelle-Kreis, J. AU - Prevot, A.S.H.* AU - Szidat, S.* C1 - 34380 C2 - 35545 SP - 1-5 TI - Micro-scale (μg) radiocarbon analysis of water-soluble organic carbon in aerosol samples. JO - Atmos. Environ. VL - 97 PY - 2014 SN - 1352-2310 ER - TY - JOUR AB - Estimating within-city variability in air pollution concentrations is important. Land use regression (LUR) models are able to explain such small-scale within-city variations. Transparency in LUR model development methods is important to facilitate comparison of methods between different studies. We therefore developed LUR models in a standardized way in 36 study areas in Europe for the ESCAPE (European Study of Cohorts for Air Pollution Effects) project. Nitrogen dioxide (NO2) and nitrogen oxides (NOx) were measured with Ogawa passive samplers at 40 or 80 sites in each of the 36 study areas. The spatial variation in each area was explained by LUR modelling. Centrally and locally available Geographic Information System (GIS) variables were used as potential predictors. A leave-one out cross-validation procedure was used to evaluate the model performance. There was substantial contrast in annual average NO2 and NOx concentrations within the study areas. The model explained variances (R2) of the LUR models ranged from 55% to 92% (median 82%) for NO2 and from 49% to 91% (median 78%) for NOx. For most areas the cross-validation R2 was less than 10% lower than the model R2. Small-scale traffic and population/household density were the most common predictors. The magnitude of the explained variance depended on the contrast in measured concentrations as well as availability of GIS predictors, especially traffic intensity data were important. In an additional evaluation, models in which local traffic intensity was not offered had 10% lower R2 compared to models in the same areas in which these variables were offered. Within the ESCAPE project it was possible to develop LUR models that explained a large fraction of the spatial variance in measured annual average NO2 and NOx concentrations. These LUR models are being used to estimate outdoor concentrations at the home addresses of participants in over 30 cohort studies. AU - Beelen, R.* AU - Hoek, G.* AU - Vienneau, D.* AU - Eeftens, M.* AU - Dimakopoulou, K.* AU - Pedeli, X.* AU - Tsai, M.-Y.* AU - Künzli, N.* AU - Schikowski, T.* AU - Marcon, A.* AU - Eriksen, K.T.* AU - Raaschou-Nielsen, O.* AU - Stephanou, E.* AU - Patelarou, E.* AU - Lanki, T.* AU - Yli-Tuomi, T.* AU - Declercq, C.* AU - Falq, G.* AU - Stempfelet, M.* AU - Birk, M. AU - Cyrys, J. AU - von Klot, S. AU - Nádor, G.* AU - Varró, M.J.* AU - Dedele, A.* AU - Grazuleviciene, R.* AU - Mölter, A.* AU - Lindley, S.* AU - Madsen, C.* AU - Cesaroni, G.* AU - Ranzi, A.* AU - Badaloni, C.* AU - Hoffmann, B.* AU - Nonnemacher, M.* AU - Krämer, U.* AU - Kuhlbusch, T.* AU - Cirach, M.* AU - de Nazelle, A.* AU - Nieuwenhuijsen, M.* AU - Bellander, T.* AU - Korek, M.* AU - Olsson, D.* AU - Strömgren, M.* AU - Dons, E.* AU - Jerrett, M.* AU - Fischer, P.* AU - Wang, M.* AU - Brunekreef, B.* AU - de Hoogh, K.* C1 - 23765 C2 - 31277 SP - 10-23 TI - Development of NO2 and NOx land use regression models for estimating air pollution exposure in 36 study areas in Europe - the ESCAPE project. JO - Atmos. Environ. VL - 72 PB - Pergamon-Elsevier Science PY - 2013 SN - 1352-2310 ER - TY - JOUR AB - Rainwater is not only a critical source of drinking and agricultural water but it plays a key role in the fate and transport of contaminants through their removal by wet deposition. Rainwater is a complex mixture of organic compounds yet despite its importance its spatial and temporal variability are not well understood and less than 50% of the organic matter has been characterized. In-depth analytical approaches were used in this study to characterize the seasonal variation in rainwater composition. Rainwater samples were collected over a one-year period in Scarborough, Ontario, Canada. The seasonal variation of atmospheric organic carbon (AOC) in rainwater was analyzed by excitation-emission matrix spectroscopy (EEMs), 1D and 2D NMR with compound identification by spectral database matching, GC-MS, FT-ICR-MS, and GC×GC-TOFMS. This combination of techniques provided four complementary datasets, with less than 10% overlap, of anthropogenic and biogenic AOC. NMR with database matching identified over 100 compounds, primarily carboxylic acids, carbohydrates, and nitrogen-containing compounds. GC×GC-TOFMS analysis identified 344 compounds in two rain events with 33% of the compounds common to both events. FT-ICR-MS generated a seasonally dependent profile of 1226-1575 molecular ions of CHO, CHOS, and CHON elemental composition. FT-ICR-MS and GC×GC-TOFMS datasets were compared using van Krevelen diagrams (H/C vs. O/C), the H/C ratio vs. mass/charge (m/z), and the carbon oxidation state/carbon number matrix. Fluorescence patterns were correlated with NMR results resulting in the identification one seasonally-dependent component of chromophoric dissolved organic matter (CDOM). This study demonstrated the importance of using of an integrated analytical approach to monitor the compositional variation of AOC. AU - Cottrell, B.A.* AU - Gonsior, M.* AU - Isabelle, L.M.* AU - Luo, W.* AU - Perraud, V.* AU - McIntire, T.M.* AU - Pankow, J.F.* AU - Schmitt-Kopplin, P. AU - Cooper, W.J.* AU - Simpson, A.J.* C1 - 26108 C2 - 32073 SP - 588-597 TI - A regional study of the seasonal variation in the molecular composition of rainwater. JO - Atmos. Environ. VL - 77 PB - Pergamon-Elsevier PY - 2013 SN - 1352-2310 ER - TY - JOUR AB - Source apportionment of ambient particulate matter (PM10) was carried out using daily chemical composition data collected in winter 2006/07 and winter 2007/08 in Augsburg, Germany. Six factors have been identified and were associated with secondary nitrate, secondary sulfate, residential and commercial combustion, NaCl, re-suspended dust and traffic emissions. Comparing the source profiles between winter 2006/07 and winter 2007/08 showed that they were similar for both winters, except the combustion and traffic emissions factors. The spatial variation of particulate sources was evaluated by analysis of data collected at eight sampling sites during a one-month intensive campaign in winter 2007/08. Secondary nitrate, secondary sulfate as well as residential and commercial combustion factors showed strong correlations and low coefficient of divergence (COD) values among eight sites, indicating that they are uniformly distributed in urban area. By contrast, traffic emissions factor and NaCl were highly heterogeneously distributed. These two factors were enhanced greatly at the traffic site and are the cause of elevated PM10 mass concentration at traffic site. It means that for some specific sources of particles showing pronounced spatial variability a central monitoring site could not assess the absolute concentrations across an urban area. Thus, cautions should be taken when approximating average human exposure to these particle sources in long-term epidemiological studies. AU - Gu, J. AU - Schnelle-Kreis, J. AU - Pitz, M. AU - Diemer, J.* AU - Reller, A.* AU - Zimmermann, R. AU - Soentgen, J.* AU - Peters, A. AU - Cyrys, J. C1 - 23273 C2 - 31019 SP - 131-139 TI - Spatial and temporal variability of PM10 sources in Augsburg, Germany. JO - Atmos. Environ. VL - 71 PB - Elsevier PY - 2013 SN - 1352-2310 ER - TY - JOUR AB - Exposure to allergens is pivotal in determining sensitization and allergic symptoms in individuals. Pollen grain counts in ambient air have traditionally been assessed to estimate airborne allergen exposure. However, the exact allergen content of ambient air is unknown. We therefore monitored atmospheric concentrations of birch pollen grains and the matched major birch pollen allergen Bet v 1 simultaneously across Europe within the EU-funded project HIALINE (Health Impacts of Airborne Allergen Information Network). Pollen count was assessed with Hirst type pollen traps at 10 I min(-1) at sites in France, United Kingdom, Germany, Italy and Finland. Allergen concentrations in ambient air were sampled at 800 I min(-1) with a Chemvol (R) high-volume cascade impactor equipped with stages PM > 10 mu m, 10 mu m > PM > 2.5 mu m, and in Germany also 2.5 mu m > PM > 0.12 mu m. The major birch pollen allergen Bet v 1 was determined with an allergen specific ELISA. Bet v 1 isoform patterns were analyzed by 2D-SDS-PAGE blots and mass spectrometric identification. Basophil activation was tested in an FC epsilon R1-humanized rat basophil cell line passively sensitized with serum of a birch pollen symptomatic patient. Compared to 10 previous years, 2009 was a representative birch pollen season for all stations. About 90% of the allergen was found in the PM > 10 mu m fraction at all stations. Bet v 1 isoforms pattern did not vary substantially neither during ripening of pollen nor between different geographical locations. The average European allergen release from birch pollen was 3.2 pg Bet v 1/pollen and did not vary much between the European countries. However, in all countries a >10-fold difference in daily allergen release per pollen was measured which could be explained by long-range transport of pollen with a deviating allergen release. Basophil activation by ambient air extracts correlated better with airborne allergen than with pollen concentration. Although Bet v 1 is a mixture of different isoforms, its fingerprint is constant across Europe. Bet v 1 was also exclusively linked to pollen. Pollen from different days varied >10-fold in allergen release. Thus exposure to allergen is inaccurately monitored by only monitoring birch pollen grains. Indeed, a humanized basophil activation test correlated much better with allergen concentrations in ambient air than with pollen count. Monitoring the allergens themselves together with pollen in ambient air might be an improvement in allergen exposure assessment. AU - Buters, J.T.M. AU - Thibaudon, M.* AU - Smith, M.* AU - Kennedy, R.* AU - Rantio-Lehtimaki, A.* AU - Albertini, R.* AU - Reese, G.* AU - Weber, B.* AU - Galan, C.* AU - Brandao, R.* AU - Antunes, C.M.* AU - Jager, S.* AU - Berger, U.* AU - Celenk, S.* AU - Grewling, L.* AU - Jackowiak, B.* AU - Sauliene, I.* AU - Weichenmeier, I. AU - Pusch, G. AU - Sarioglu, H. AU - Ueffing, M. AU - Behrendt, H. AU - Prank, M.* AU - Sofiev, M.* AU - Cecchi, L.* C1 - 8576 C2 - 30183 SP - 496-505 TI - Release of Bet v 1 from birch pollen from 5 European countries. Results from the HIALINE study. JO - Atmos. Environ. VL - 55 PB - Elsevier PY - 2012 SN - 1352-2310 ER - TY - JOUR AB - The ESCAPE study (European Study of Cohorts for Air Pollution Effects) investigates long-term effects of exposure to air pollution on human health in Europe. This paper documents the spatial variation of measured NO2 and NOx concentrations between and within 36 ESCAPE study areas across Europe. In all study areas NO2 and NOx were measured using standardized methods between October 2008 and April 2011. On average, 41 sites were selected per study area, including regional and urban background as well as street sites. The measurements were conducted in three different seasons, using Ogawa badges. Average concentrations for each site were calculated after adjustment for temporal variation using data obtained from a routine monitor background site. Substantial spatial variability was found in NO2 and NOx concentrations between and within study areas; 40% of the overall NO2 variance was attributable to the variability between study areas and 60% to variability within study areas. The corresponding values for NOx were 30% and 70%. The within-area spatial variability was mostly determined by differences between street and urban background concentrations. The street/urban background concentration ratio for NO2 varied between 1.09 and 3.16 across areas. The highest median concentrations were observed in Southern Europe, the lowest in Northern Europe. In conclusion, we found significant contrasts in annual average NO2 and NOx concentrations between and especially within 36 study areas across Europe. Epidemiological long-term studies should therefore consider different approaches for better characterization of the intra-urban contrasts, either by increasing of the number of monitors or by modelling. AU - Cyrys, J. AU - Eeftens, M.* AU - Heinrich, J. AU - Ampe, C.* AU - Armengaud, A.* AU - Beelen, R.* AU - Bellander, T.* AU - Beregszaszi, T.* AU - Birk, M. AU - Cesaroni, G.* AU - Cirach, M.* AU - de Hoogh, K.* AU - de Nazelle, A.* AU - de Vocht, F.* AU - Declercq, C.* AU - Dedele, A.* AU - Dimakopoulou, K.* AU - Eriksen, K.* AU - Galassi, C.* AU - Grauleviviene, R.* AU - Grivas, G.* AU - Gruzieva, O.* AU - Hagenbjörk Gustafsson, A.* AU - Hoffmann, B.* AU - Iakovides, M.* AU - Ineichen, A.* AU - Krämer, U. AU - Lanki, T.* AU - Lozano, P.* AU - Madsen, C.* AU - Meliefste, K.* AU - Modig, L.* AU - Mölter, A.* AU - Mosler, G.* AU - Nieuwenhuijsen, M.* AU - Nonnemacher, M.* AU - Oldenwening, M.* AU - Peters, A. AU - Pontet, S.* AU - Probst-Hensch, N.* AU - Quass, U.* AU - Raaschou-Nielsen, O.* AU - Ranzi, A.* AU - Sugiri, D.* AU - Stephanou, E.G.* AU - Taimisto, P.* AU - Tsai, M.-Y.* AU - Vaskövi, E.* AU - Villani, S.* AU - Wang, M.* AU - Brunekreef, B.* AU - Hoek, G.* C1 - 10842 C2 - 30398 SP - 374-390 TI - Variation of NO2 and NOx concentrations between and within 36 European study areas: Results from the ESCAPE study. JO - Atmos. Environ. VL - 62 PB - Elsevier PY - 2012 SN - 1352-2310 ER - TY - JOUR AB - The ESCAPE study (European Study of Cohorts for Air Pollution Effects) investigates relationships between long-term exposure to outdoor air pollution and health using cohort studies across Europe. This paper analyses the spatial variation of PM2.5, PM2.5 absorbance, PM10 and PMcoarse concentrations between and within 20 study areas across Europe. We measured NO2, NOx, PM2.5, PM2.5 absorbance and PM10 between October 2008 and April 2011 using standardized methods. PMcoarse was determined as the difference between PM10 and PM2.5. In each of the twenty study areas, we selected twenty PM monitoring sites to represent the variability in important air quality predictors, including population density, traffic intensity and altitude. Each site was monitored over three 14-day periods spread over a year, using Harvard impactors. Results for each site were averaged after correcting for temporal variation using data obtained from a reference site, which was operated year-round. Substantial concentration differences were observed between and within study areas. Concentrations for all components were higher in Southern Europe than in Western and Northern Europe, but the pattern differed per component with the highest average PM2.5 concentrations found in Turin and the highest PMcoarse in Heraklion. Street/urban background concentration ratios for PMcoarse (mean ratio 1.42) were as large as for PM2.5 absorbance (mean ratio 1.38) and higher than those for PM2.5 (1.14) and PM10 (1.23), documenting the importance of non-tailpipe emissions. Correlations between components varied between areas, but were generally high between NO2 and PM2.5 absorbance (average R2 = 0.80). Correlations between PM2.5 and PMcoarse were lower (average R2 = 0.39). Despite high correlations, concentration ratios between components varied, e.g. the NO2/PM2.5 ratio varied between 0.67 and 3.06. In conclusion, substantial variability was found in spatial patterns of PM2.5, PM2.5 absorbance, PM10 and PMcoarse. The highly standardized measurement of particle concentrations across Europe will contribute to a consistent assessment of health effects across Europe. AU - Eeftens, M.* AU - Tsai, M.Y.* AU - Ampe, C.* AU - Anwander, B.* AU - Beelen, R.* AU - Bellander, T.* AU - Cesaroni, G.* AU - Cirach, M.* AU - Cyrys, J.* AU - Hoogh, K.d.* AU - Nazelle, A.D.* AU - Vocht, F.d.* AU - Declercq, C.* AU - Dedele, A.* AU - Eriksen, K.* AU - Galassi, C.* AU - Grazuleviciene, R.* AU - Grivas, G.* AU - Heinrich, J. AU - Hoffmann, B.* AU - Iakovides, M.* AU - Ineichen, A.* AU - Katsouyanni, K.* AU - Korek, M.* AU - Krämer, U.* AU - Kuhlbusch, T.* AU - Lanki, T.* AU - Madsen, C.* AU - Meliefste, K.* AU - Mölter, A.* AU - Mosler, G.* AU - Nieuwenhuijsen, M.* AU - Oldenwening, M.* AU - Pennanen, A.* AU - Probst-Hensch, N.* AU - Quass, U.* AU - Raaschou-Nielsen, O.* AU - Ranzi, A.* AU - Stephanou, E.* AU - Sugiri, D.* AU - Udvardy, O.* AU - Vaskövi, E.* AU - Weinmayr, G.* AU - Brunekreef, B.* AU - Hoek, G.* C1 - 10852 C2 - 30388 SP - 303-317 TI - Spatial variation of PM2.5, PM10, PM2.5 absorbance and PMcoarse concentrations between and within 20 European study areas and the relationship with NO2 - results of the ESCAPE project. JO - Atmos. Environ. VL - 62 PB - Elsevier PY - 2012 SN - 1352-2310 ER - TY - JOUR AB - Measures must be undertaken to lower the transport sector's contribution to anthropogenic emissions. Vehicles powered by liquefied petroleum gas (LPG) are an option due to their reduced emissions of air pollutants compared to engines with conventional fuels. In the present study, ten different dual-fuel LPG/gasoline light duty vehicles were tested, which all complied with European emission level legislation EURO-4. Tests with LPG and gasoline were performed on a chassis dynamometer by applying the New European Driving Cycle (NEDC) and emission factors and ozone formation potentials of both kinds of fuels were compared. The components investigated comprised regulated compounds. CO(2), volatile hydrocarbons and carbonyls. On-line analysis of aromatic species was carried out by resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS). We demonstrate that utilization of LPG can entail some environmental benefits by reducing emissions. However, for dual-fuel LPG/gasoline vehicles running on LPG the benefits are less than expected. The main reason is that dual-fuel vehicles usually start the engine up on gasoline even when LPG is selected as fuel. This cold-start phase is crucial for the quality of the emissions. Moreover, we demonstrate an influence on the chemical composition of emissions of vehicle performance, fuel and the evaporative emission system of the vehicles. AU - Adam, T.W.* AU - Astorga, C.* AU - Clairotte, M.* AU - Duane, M.* AU - Elsasser, M. AU - Krasenbrink, A.* AU - Larsen, B.R.* AU - Manfredi, U.* AU - Martini, G.* AU - Montero, L.* AU - Sklorz, M.* AU - Zimmermann, R. AU - Perujo, A.* C1 - 6458 C2 - 28741 SP - 2842-2848 TI - Chemical analysis and ozone formation potential of exhaust from dual-fuel (liquefied petroleum gas/gasoline) light duty vehicles. JO - Atmos. Environ. VL - 45 IS - 17 PB - Elsevier PY - 2011 SN - 1352-2310 ER - TY - JOUR AB - Ambient PM10 concentration monitoring as well as dispersion calculations were conducted to determine the influence of emissions from domestic heating on ambient PM10 concentrations in Augsburg, Germany. Based on the Augsburg emission inventory for domestic heating an average emission factor for particulate emissions from the combustion of different solid fuels (wood logs, pellets, briquettes) in different types of stoves under various combustion conditions was found to be 120 mg/MJ energy input. Hence an emission model as well as a wind field model were created for dispersion calculation of the emitted PM from wood combustion within Augsburg. The results of the dispersion calculation concurred with the ambient PM10 monitoring data measured during the heating period 2007/2008. One result found that in residential areas with a high density of stoves the observed maximum concentration value of 9 μg/m3 from wood combustion was up to 50 % higher than in the city center. Ambient monitoring as well as dispersion calculation has shown a significant influence of wood combustion on ambient PM10 concentrations in Augsburg. Based on these results the impact of wood combustion in a city can be estimated. AU - Brandt, C.* AU - Kunde, R.* AU - Dobmeier, B.* AU - Schnelle-Kreis, J. AU - Orasche, J. AU - Schmoeckel, G.* AU - Diemer, J.* AU - Zimmermann, R. AU - Gaderer, M.* C1 - 4359 C2 - 28406 SP - 3466-3474 TI - Ambient PM10 concentrations from wood combustion - emission modeling and dispersion calculation for the city area of Augsburg, Germany. JO - Atmos. Environ. VL - 45 IS - 20 PB - Elsevier PY - 2011 SN - 1352-2310 ER - TY - JOUR AB - Positive matrix factorization (PMF) method was used to identify the sources of ambient particles (PM10) in Augsburg in winter 2006/07. The analyses were carried out separately with particulate chemical composition (PCC) data at an urban traffic site and with particle size distribution (PSD) data at an urban background site on daily and hourly base, respectively. For PCC data, six factors are identified and associated with NaCl (6.7% of PM10), secondary sulfate (13.0%), biomass burning (13.3%), secondary nitrate (30.5%), traffic emission (16.5%) and re-suspended dust (20.0%). For PSD data, seven factors are identified and are associated with fresh and aged traffic sources, secondary aerosols, stationary combustion, nucleation particles, re-suspended dust and long range transported dust. The two traffic factors were dominated by ultrafine particles (diameter < 100 nm), and accounted for 25% and 40% of total particle number concentration (NC). Stationary combustion factor, consisting of particles around 100 nm, accounted for 26% of total NC. Re-suspended dust was mainly composed of particles with diameters > 2.5 mu m. The two different approaches (PCC and PSD data) led to comparable results with strong correlations for secondary nitrate and sulfate/secondary aerosols (r = 0.92), which are considered to origin mainly from long range transport. Traffic emissions (r = 0.52) and re-suspended dust (r = 0.62) showed weaker correlation due to influences of local sources at the different sites. AU - Gu, J.W. AU - Pitz, M. AU - Schnelle-Kreis, J. AU - Diemer, J.* AU - Reller, A.* AU - Zimmermann, R. AU - Soentgen, J.* AU - Stoelzel, M. AU - Wichmann, H.-E. AU - Peters, A. AU - Cyrys, J. C1 - 5442 C2 - 28555 SP - 1849-1857 TI - Source apportionment of ambient particles: Comparison of positive matrix factorization analysis applied to particle size distribution and chemical composition data. JO - Atmos. Environ. VL - 45 IS - 10 PB - Elsevier PY - 2011 SN - 1352-2310 ER - TY - JOUR AB - Mediterranean ecosystems are large emitters of biogenic volatile organic compounds (BVOC), and recent studies illustrate how water stress can decrease these emissions even during hot summer. We present here a spatially explicit modelling experiment of BVOC emissions in a water-limited Mediterranean Region in Southern France dominated by Quercus ilex forests. Emission rates were estimated daily using a leaf-level emission model with appropriate up-scaling procedures. The model was based on Guenther's empirical equations, where we inserted effects for water limitation and seasonality observed from field measurements. Up-scaling from leaves to canopy was performed using Sellers' theory. For each grid cell, climate variables were interpolated daily from meteorological stations. Incoming solar radiation was measured at one site and extrapolated for the all region based on slope and aspect. Soil properties were derived from pedological maps as well as a digital elevation model, while soil water content was evaluated daily using a bucket-type model. We estimated monoterpene emissions from Q ilex woodlands to be 16 kt yr(-1) (on average), with most emissions occurring in the summer. When including the water-limitation module, yearly emissions were 50% of the initial estimates, with a significant decrease in the number of days with BVOC high emission peaks. This result highlights the importance of water control on determining air pollution peaks in Mediterranean areas and the need for scaling procedure in this area with its large range of strong emitter species. AU - Lavoir, A.V.* AU - Duffet, C.* AU - Mouillot, F.* AU - Rambal, S.* AU - Ratte, J.P.* AU - Schnitzler, J.-P. AU - Staudt, M.* C1 - 11324 C2 - 30612 SP - 2888-2897 TI - Scaling-up leaf monoterpene emissions from a water limited Quercus ilex woodland. JO - Atmos. Environ. VL - 45 IS - 17 PB - Elsevier PY - 2011 SN - 1352-2310 ER - TY - JOUR AB - Land use regression (LUR) models have been widely used to estimate traffic air pollution within cities taking into account spatial distributions. These prediction models are often built based on multiple linear models that regress concentrations measured at locations spread over the cities on land use characteristics of those locations. Land use variables, as for example total road length, are sometimes calculated in buffers of different radii that are then included simultaneously in the models to account for a distance gradient in the influence of sources. Some authors favour including disjoint concentric ring areas instead. Both approaches have their advantages, and adjacent concentric rings tend to make model interpretation more intuitive. The present paper shows that both approaches lead to identical models and the results achieved from one can be used to calculate the results of the other when absolute continuous exposure measures such as total length of roads are used. It is also shown that this holds as well for relative exposures such as area-weighted total length of streets, inhabitants per area, and % urban area, where the ;measure of interest is scaled by a constant factor. AU - von Klot, S. C1 - 6470 C2 - 28773 SP - 4108-4110 TI - Equivalence of using nested buffers and concentric adjacent rings as predictors in land use regression models. JO - Atmos. Environ. VL - 45 IS - 24 PB - Elsevier PY - 2011 SN - 1352-2310 ER - TY - JOUR AB - his paper synthesizes data on aerosol (particulate matter, PM) physical and chemical characteristics, which were obtained over the past decade in aerosol research and monitoring activities at more than 60 natural background, rural, near-city, urban, and kerbside sites across Europe. The data include simultaneously measured PM10 and/or PM2.5 mass on the one hand, and aerosol particle number concentrations or PM chemistry on the other hand. The aerosol data presented in our previous works (Van Dingenen et al., 2004; Putaud et al., 2004) were updated and merged to those collected in the framework of the EU supported European Cooperation in the field of Scientific and Technical action COST633 (Particulate matter: Properties related to health effects). A number of conclusions from our previous studies were confirmed. There is no single ratio between PM2.5 and PM10 mass concentrations valid for all sites, although fairly constant ratios ranging from 0.5 to 0.9 are observed at most individual sites. There is no general correlation between PM mass and particle number concentrations, although particle number concentrations increase with PM2.5 levels at most sites. The main constituents of both PM10 and PM2.5 are generally organic matter, sulfate and nitrate. Mineral dust can also be a major constituent of PM10 at kerbside sites and in Southern Europe. There is a clear decreasing gradient in SO42- and NO3- contribution to PM10 when moving from rural to urban to kerbside sites. In contrast, the total carbon/PM10 ratio increases from rural to kerbside sites. Some new conclusions were also drawn from this work: the ratio between ultrafine particle and total particle number concentration decreases with PM2.5 concentration at all sites but one, and significant gradients in PM chemistry are observed when moving from Northwestern, to Southern to Central Europe. Compiling an even larger number of data sets would have further increased the significance of our conclusions, but collecting all the aerosol data sets obtained also through research projects remains a tedious task. AU - Putaud, J.P.* AU - van Dingenen, R.* AU - Alastuey, A.* AU - Bauer, H.* AU - Birmili, W.* AU - Cyrys, J. AU - Flentje, H.* AU - Fuzzi, S.* AU - Gehrig, R.* AU - Hansson, H.C.* AU - Harrison, R.M.* AU - Herrmann, H.* AU - Hitzenberger, R.* AU - Hüglin, C.* AU - Jones, A.M.* AU - Kasper-Giebl, A.* AU - Kiss, G.* AU - Kousa, A.* AU - Kuhlbusch, T.A.J.* AU - Loschau, G.* AU - Maenhaut, W.* AU - Molnar, A.* AU - Moreno, T.* AU - Pekkanen, J.* AU - Perrino, C.* AU - Pitz, M. AU - Puxbaum, H.* AU - Querol, X.* AU - Rodriguez, S.* AU - Salma, I.* AU - Schwarz, J.* AU - Smolik, J.* AU - Schneider, J* AU - Spindler, G.* AU - ten Brink, H.* AU - Tursic, J.* AU - Viana, M.* AU - Wiedensohler, A.* C1 - 4554 C2 - 27687 SP - 1308-1320 TI - A European aerosol phenomenology-3: Physical and chemical characteristics of particulate matter from 60 rural, urban, and kerbside sites across Europe. JO - Atmos. Environ. VL - 44 IS - 10 PB - Elsevier PY - 2010 SN - 1352-2310 ER - TY - JOUR AB - Particulate matter (PM) has become a major research issue receiving increasing attention because of its significant negative impact on human health. There are main indicators that next to the morphological characteristics of the particle, also the chemical composition plays an important role in the adverse health effects of PM. In this context, the rather polar organic fraction of PM is expected to play a major role, and advanced analytical techniques are developed to improve the knowledge on the molecular composition of this fraction. One component class that deserves major attention consists of the oxygenated polycyclic aromatic hydrocarbons (PAHs). Those compounds are considered to be among the key compounds in PM toxicity. This paper presents a comprehensive review focusing on the analysis, fate and behavior of oxygenated PAHs in the atmosphere. The first part of the paper briefly introduces (i) the main sources and atmospheric pathways of oxygenated PAHs. (ii) available physical chemical properties and (iii) their health effects. The second and main part of this paper gives a thorough discussion on the entire analytical sequence necessary to identify and quantify oxygenated PAHs on atmospheric PM. Special attention is given to critical parameters and innovations related to (i) sampling, (ii) sample preparation including both extraction and clean-up, and (iii) separation and detection. Third, the state-of-the-art knowledge about the atmospheric occurrence of oxygenated PAHs is discussed, including an extended overview of reported concentrations presented as a function of sampling season and geographical location. A clear seasonal effect is observed with the median of the oxygenated PAHs concentrations during winter being a factor of 3-4 higher than during summer. However, the oxygenated PAH/parent PAH ratio is about 20 times higher during summer, indicating the importance of photochemical activity in the atmosphere. AU - Walgraeve, C.* AU - Demeestere, K.* AU - Dewulf, J.* AU - Zimmermann, R. AU - van Langenhove, H.* C1 - 5664 C2 - 27953 SP - 1831-1846 TI - Oxygenated polycyclic aromatic hydrocarbons in atmospheric particulate matter: Molecular characterization and occurrence. JO - Atmos. Environ. VL - 44 IS - 15 PB - Elsevier PY - 2010 SN - 1352-2310 ER - TY - JOUR AB - During the Pearl River Delta measurement campaign (Program of Regional Integrated Experiments of Air Quality over Pearl River Delta 2004, PRIDE-PRD2004, 4 October–5 November 2004), we measured aerosol light absorption and scattering (PM2.5) in urban Guangzhou, using a photoacoustic spectrometer and two integrating nephelometers (at ambient and dry humidity). In addition, 12-h averages of elemental carbon (ECa), organic carbon (OC), and inorganic species concentrations were determined. Aerosol concentrations in urban Guangzhou were extremely high, with average PM2.5, OC, and ECa concentrations of 103, 22.4, and 7.1 ?g m-3, respectively. The chemical composition of the aerosol was dominated by particulate organic matter, ECa, sulfate and ammonium. Elevated levels of potassium indicated significant contributions from biomass burning to the regional haze. The high average OC/ECa ratio of 3.6±1.1 resulted from a mixture of regional haze with high OC content and local emissions with low OC/ECa, mostly from vehicular sources. The average scattering and absorption coefficients for dry aerosol were 418 and 91 Mm-1 (?not, vert, similar540 nm), and the mean mass scattering and absorption efficiencies 4.2±1.0 and 0.78±0.19 m2 g-1. During some episodes resulting from the trapping of local emissions in a nocturnal boundary layer, extreme values of aerosol absorption were reached (up to 490 Mm-1). The average single scattering albedo (?0, ?not, vert, similar540 nm) at dry conditions was about 0.83, representing a mixture of fresh, strongly absorbing, urban pollution, and a more scattering regional haze. Because of the prevailing low humidity, the ambient ?0 was not significantly higher. The mass absorption efficiency of ECa was 7.7 m2 g-1; an additional contribution to absorption was associated with OC, either as a result of light absorption by OC or the effects of internal mixing. The observed diurnal trends of the optical and chemical properties are consistent with aged regional haze dominating during mid-day, enhanced traffic activity in the morning and evening hours, and the build-up of a shallow nocturnal boundary layer during night. AU - Andreae, M.O.* AU - Schmid, O. AU - Yang, H.* AU - Chand, D.* AU - Yu, J.Z.* AU - Zeng, L.-M.* AU - Zhang, Y.-H.* C1 - 2428 C2 - 25473 SP - 6335-6350 TI - Optical properties and chemical composition of the atmospheric aerosol in urban Guangzhou, China. JO - Atmos. Environ. VL - 42 IS - 25 PB - Elsevier PY - 2008 SN - 1352-2310 ER - TY - JOUR AB - Passive sampler concentration measurements of nitrogen dioxide (NO2) and ammonia (NH3) were performed in the framework of a transect study to investigate the impact of vehicle emissions on ecosystems dissected by highways. The concentrations of both gases decrease markedly with distance from highway to regional background pollution values. Modelling the functional form of the decay is of interest for reducing the amount of measurements, for exposure assessment, and for predicting background concentrations. Three modelling approaches are compared: the exponential decay function, the shifted power-law function, and the linear-logarithmic function. The models were fitted to four compound- and year-specific data sets from one transect, applying mixed-effects models for repeated-measurement designs. The goodness-of-fit did not differ consistently between the model classes. Combined data from four transects with different characteristics were analysed with the exponential decay model, allowing for transect-specific random coefficients. From the empirical point of view, none of the three model classes is consistently superior to the others. But for prediction beyond the observed distance range it is essential to consider a model with meaningful parameters. The final choice of a model depends on the amount of data and on the characteristics to be represented by the model. AU - Faus-Kessler, T. AU - Kirchner, M. AU - Jakobi, G. C1 - 2339 C2 - 25552 SP - 4589-4600 TI - Modelling the decay of concentrations of nitrogenous compounds with distance from roads. JO - Atmos. Environ. VL - 42 IS - 19 PB - Elsevier PY - 2008 SN - 1352-2310 ER - TY - JOUR AB - Studies have shown high concentrations of particulate matter (PM) in schools. Further insights into the sources and the composition of these particles are needed. During school hours for a period of 6 weeks, outdoor air and the air in two classrooms were sampled. PM was measured gravimetrically, and PM filters were used for the determination of the elemental and organic carbon, light absorbance, and 10 water-soluble ions. Some filters were further analyzed by scanning electron microscopy (SEM) and energy dispersive microanalysis (EDX). The median PM10 concentrations were 118.2 ?g m-3 indoors and 24.2 ?g m-3 outdoors; corresponding results for PM2.5 were 37.4 ?g m-3 indoors and 17.0 ?g m-3 outdoors. Using PM10 and PM2.5 data, we calculated the following indoor/outdoor ratios: 0.3 and 0.4 (sulfate), 0.1 and 0.2 (nitrate), 0.1 and 0.3 (ammonium), and 1.4 and 1.6 (calcium). Using the measured sulfate content on PM filters as an indicator for ambient PM sources, we estimated that 43% of PM2.5 and 24% of PM10, respectively, were of ambient origin. The composition of the classrooms' PM (e.g., high calcium concentrations) and the findings from SEM/EDX suggest that the indoor PM consists mainly of earth crustal materials, detrition of the building materials and chalk. Physical activity of the pupils leads to resuspension of mainly indoor coarse particles and greatly contributes to increased PM10 in classrooms. The concentration of fine particles caused by combustion processes indoors and outdoors is comparable. We conclude that PM measured in classrooms has major sources other than outdoor particles. Assuming that combustion-related particles and crustal materials vary in toxicity, our results support the hypothesis that indoor-generated PM may be less toxic compared to PM in ambient air. AU - Fromme, H.* AU - Diemer, J.* AU - Dietrich, S.* AU - Cyrys, J. AU - Heinrich, J. AU - Lang, W.* AU - Kiranoglu, M.* AU - Twardella, D.* C1 - 3059 C2 - 25734 SP - 6597-6605 TI - Chemical and morphological properties of particulate matter (PM10, PM2.5) in school classrooms and outdoor air. JO - Atmos. Environ. VL - 42 IS - 27 PB - Elsevier PY - 2008 SN - 1352-2310 ER - TY - JOUR AB - Outdoor leveis of fine particles (PM2.5; particles < 2.5 mu m) have been associated with cardiovascular health. Persons with existing cardiovascular disease have been suggested to be especially vulnerable. It is unclear, how well outdoor concentrations of PM2.5 and its constituents measured at a central site reflect personal exposures in Southern European countries. The objective of the study was to assess the relationship between outdoor and personal concentrations of PM2.5, absorbance and sulphur among post-myocardial infarction patients in Barcelona, Spain. Thirty-eight subjects carried personal PM2.5 monitors for 24-h once a month (2-6 repeated measurements) between November 2003 and June 2004. PM2.5 was measured also at a central outdoor monitoring site. Light absorbance (a proxy for elemental carbon) and sulphur content of filter samples were determined as markers of combustion originating and long-range transported PM2.5, respectively. There were 110, 162 and 88 measurements of PM2.5, absorbance and sulphur, respectively. Levels of outdoor PM2.5 (median 17 mu g m(3)) were lower than personal PM2.5 even after excluding days with exposure to environmental tobacco smoke (ETS) (median after exclusion 27 mu g m(3)). However, outdoor concentrations of absorbance and sulphur were similar to personal concentrations after exclusion of ETS. When repeated measurements were taken into account, there was a statistically significant association between personal and outdoor absorbance when adjusting for ETS (slope 0.66, p < 0.001), but for PM2.5 the association was weaker (slope 0.51, p = 0.066). Adjustment for ETS had little effect on the respective association of S (slope 0.69, p < 0.001). Our results suggest that outdoor measurements of absorbance and sulphur can be used to estimate both the daily variation and levels of personal exposures also in Southern European countries, especially when exposure to ETS has been taken into account. For PM2.5, indoor sources need to be carefully considered. AU - Jacquemin, B.* AU - Lanki, T.* AU - Sunyer, J.* AU - Cabrera, L.* AU - Querol, X.* AU - Bellander, T.* AU - Moreno, N.* AU - Peters, A. AU - Pey, J.* AU - Pekkanen, J.* C1 - 5886 C2 - 24582 SP - 1539-1549 TI - Levels of outdoor PM2.5, absorbance and sulphur as surrogates for personal exposures among post-myocardial infarction patients in Barcelona, Spain. JO - Atmos. Environ. VL - 41 PB - Elsevier PY - 2007 SN - 1352-2310 ER - TY - JOUR AB - Fine particulate matter (PM2.5) was sampled at 5 Spanish locations during the European Community Respiratory Health Survey II (ECRHS II). In an attempt to identify and quantify PM2.5 sources, source contribution analysis by principal component analysis (PCA) was performed on five datasets containing elemental composition of PM2.5 analysed by ED-XRF. A total of 4–5 factors were identified at each site, three of them being common to all sites (interpreted as traffic, mineral and secondary aerosols) whereas industrial sources were site-specific. Sea-salt was identified as independent source at all coastal locations except for Barcelona (where it was clustered with secondary aerosols). Despite their typically dominant coarse grain-size distribution, mineral and marine aerosols were clearly observed in PM2.5. Multi-linear regression analysis (MLRA) was applied to the data, showing that traffic was the main source of PM2.5 at the five sites (39–53% of PM2.5, 5.1–12.0 ?g m-3), while regional-scale secondary aerosols accounted for 14–34% of PM2.5 (2.6–4.5 ?g m-3), mineral matter for 13–31% (2.4–4.6 ?g m-3) and sea-salt made up 3–7% of the PM2.5 mass (0.4–1.3 ?g m-3). Consequently, despite regional and climatic variability throughout Spain, the same four main PM2.5 emission sources were identified at all the study sites and the differences between the relative contributions of each of these sources varied at most 20%. This would corroborate PM2.5 as a useful parameter for health studies and environmental policy-making, owing to the fact that it is not as subject to the influence of micro-sitting as other parameters such as PM10. African dust inputs were observed in the mineral source, adding on average 4–11 ?g m-3 to the PM2.5 daily mean during dust outbreaks. On average, levels of Al, Si, Ti and Fe during African episodes were higher by a factor of 2–8 with respect to non-African days, whereas levels of local pollutants (absorption coefficient, S, Pb, Cl) showed smaller variations (factor of 0.5–2). AU - Viana, M.* AU - Querol, X.* AU - Götschi, T.* AU - Alastuey, A.* AU - Sunyer, J.* AU - Forsberg, B.* AU - Heinrich, J. AU - Norbäck, D.* AU - Payo, F.* AU - Maldonado, J.A.* AU - Künzli, N.* C1 - 3629 C2 - 25178 SP - 1395-1406 TI - Source apportionment of ambient PM2.5 at five spanish centres of the european community respiratory health survey (ECRHS II). JO - Atmos. Environ. VL - 41 IS - 7 PB - Elsevier PY - 2007 SN - 1352-2310 ER - TY - JOUR AU - Hochadel, M. AU - Heinrich, J. AU - Gehring, U. AU - Morgenstern, V. AU - Kuhlbusch, T.* AU - Link, E.* AU - Wichmann, H.-E. AU - Krämer, U.* C1 - 1550 C2 - 23260 SP - 542-553 TI - Predicting long-term average concentrations of traffic-related air pollutants using GIS-based information. JO - Atmos. Environ. VL - 40 PY - 2006 SN - 1352-2310 ER - TY - JOUR AU - Keck, L. AU - Wittmaack, K. C1 - 4608 C2 - 23925 SP - 7106-7114 TI - Simplified approach to measuring semivolatile inorganic particulate matter using a denuded cellulose filter without backup filters. JO - Atmos. Environ. VL - 40 PY - 2006 SN - 1352-2310 ER - TY - JOUR AB - Measurements on hygroscopic properties of sub-micrometer atmospheric particles have been carried out using a tandem differential mobility analyser (TDMA). It measures the growth of initially dry monodisperse particles with sizes of 50,100,15050,100,150 and 250 nm at a relative humidity (RH) of 0.85. Measurements have been carried out at an urban, semi-urban and rural location in Bavaria (Germany) each during 1 week in winter, summer and fall. Two fractions of particles are found, hygroscopic and non-hygroscopic particles with mean growth factors of 1.37 and 1.03, respectively. Growth factors are nearly independent of location and season, but increased significantly with initial particle size from 1.31 to 1.47 for 50 and 250 nm particles, respectively. The mean number concentration of non-hygroscopic particles is strongly dependent on location and increases by a factor of 2.4 for the semi-urban site and by a factor of 9 for the urban site, compared to the rural location. The corresponding differences for hygroscopic particles are less than a factor of three, respectively. Individual measurements strongly differ in number concentration from each other. Assuming that the hygroscopic material is ammonium sulphate, the non-hygroscopic particles and the hygroscopic particles contain about 3% and 54% ammonium sulphate, respectively. For the hygroscopic particles the mean increase of ammonium sulphate was 38–74% for 50 and 250 nm particles, respectively. AU - Ferron, G.A. AU - Karg, E.W. AU - Busch, B. AU - Heyder, J. C1 - 5293 C2 - 22501 SP - 343-352 TI - Ambient particles at an urban, semi-urban and rural site in Central Europe: Hygroscopic properties. JO - Atmos. Environ. VL - 39 IS - 2 PY - 2005 SN - 1352-2310 ER - TY - JOUR AB - We sampled fine particles (PM2.5) over a 1-year period at 21 central urban monitoring sites in 20 cities of the European Community Respiratory Health Survey (ECRHS). Particle filters were then analysed for elemental composition using energy dispersive X-ray fluorescence spectrometry and reflectance (light absorption). Elemental analyses yielded valid results for 15 elements (Al, As, Br, Ca, Cl, Cu, Fe, K, Mn, Pb, S, Si, Ti, V, Zn). Annual and seasonal means of PM2.5, reflectance, and elements show a wide range across Europe with the lowest levels found in Iceland and up to 80 times higher concentrations in Northern Italy. This pattern holds for most of the air pollution indicators. The mass concentration of S did constitute the largest fraction of the analysed elements of PM2.5 in all locations. The crustal component varies from less than 10% up to 25% across these cities. Temporal correlations of daily values vary considerably from city to city, depending on the indicators compared. Nevertheless, correlations between estimates of long-term exposure, such as annual means, are generally high among indicators of PM2.5 from anthropogenic sources, such as S, metals, and reflectance. This highlights the difficulty to disentangle effects of specific sources or PM constituents in future health effect analyses using annual averages. AU - Götschi, T.* AU - Heinrich, J. C1 - 5533 C2 - 23383 SP - 5947-5958 TI - Elemental composition and reflectance of ambient fine particles at 21 European locations. JO - Atmos. Environ. VL - 39 IS - 32 PY - 2005 SN - 1352-2310 ER - TY - JOUR AB - During a 10-month sampling period, cellulose acetate-nitrate (CA), quartz fibre (QF), Teflon (Tf), and glass fibre (GF) filters were used to collect 19 ambient PM2.5 aerosol samples at mean temperatures between –10 and +25 °C. The standard procedure of sampling involved filters that were incorporated in monitor cassettes with cellulose support pads underneath. For comparison, measurements were carried out using a denuder-filter system. The samples were analysed for mass and major inorganic ions. At mean temperatures 〈T〉〈T〉 below 0 °C, CA, QF and Tf filters were found to properly collect particulate ammonium nitrate and chloride. At 〈T〉〈T〉 above 0 °C, the salts were lost from QF and Tf filters, more so the higher the temperature and with no significant difference between QF and Tf. The salts were lost completely from denuded QF filters above about 20 °C, from undenuded QF and Tf filters above about 25 °C. In contrast, the losses from CA filters were negligible or small up to 25 °C, but positive artefacts due to gas retention could occur at high concentrations of gaseous nitrate (and ammonia). The cellulose support pads collected evaporating equimolar ammonia and nitric acid quantitatively and also a small fraction of (pure) ambient gaseous ammonia. With the exception of GF, the filter face velocity had no significant effect on the PM concentrations measured on front filters. The observed sampling artefacts are in accordance with our recently reported gas retention efficiencies derived from laboratory studies. We conclude that, without additional means, inert QF and Tf filters are not suited for routine sampling of particulate ammonium nitrate and chloride at temperatures exceeding ∼0 °C. AU - Keck, L. AU - Wittmaack, K. C1 - 3088 C2 - 22760 SP - 4093-4100 TI - Effect of filter type and temperature on volatilisation losses from ammonium salts in aerosol matter. JO - Atmos. Environ. VL - 39 IS - 22 PY - 2005 SN - 1352-2310 ER - TY - JOUR AB - Retention efficiencies of nitric acid, hydrochloric acid and ammonia were measured for different filters, with particular emphasis on cellulose (CE) and cellulose acetate-nitrate (CA) materials. Gases were produced either by nebulising aqueous solutions or by a novel technique based on the desorption from ammonium salts deposited on quartz fibre (QF) filters. Efficiencies for pure acidic gases and ammonia on CE and CA ranged from very low (⩽3.6%) to low (∼10% for HNO3 on CE). In contrast, if acidic gases and ammonia were supplied in equimolar concentrations, they were retained (almost) completely on CE, with high efficiency on CA (60–80% for NH3+HNO3; 20–45% for NH3+HCl), also with high efficiency on glass fibre filter, but with very low efficiency on QF and Teflon (Tf) filters (<1%). For CA, retention efficiencies were found to increase with increasing relative humidity and to decrease with decreasing mean pressure at which the filters were exposed to the gases. Once retained on CA filters, the retained gases may be lost again during subsequent exposure to clean air. AU - Keck, L. AU - Wittmaack, K. C1 - 3089 C2 - 22761 SP - 2157-2162 TI - Laboratory studies on the retention of nitric acid, hydrochloric acid and ammonia on aerosol filters. JO - Atmos. Environ. VL - 39 IS - 11 PY - 2005 SN - 1352-2310 ER - TY - JOUR AB - A transect study consisting of air concentration and deposition measurements of nitrogen compounds was performed to estimate the potential influence of car emissions on the nitrogen input to ecosystems. Therefore, two transects each consisting of 4 plots, the first in a coniferous forest and the second one in an extensively farmed grassland, were installed perpendicular to a highway south of Munich (Bavaria). Both profiles were influenced mainly by car emissions and showed only small local influences caused by agricultural activities. In the framework of a pilot study based upon denuder measurements we found a strong temporal dependency of both nitrogen dioxide (NO2) and ammonia (NH3) concentrations on traffic density. In the main study air concentrations of NO2 and NH3 were measured by passive samplers; they used as the basis for the estimation of dry deposition. These estimations have been compared with the results of analyses from simultaneously conducted canopy throughfall deposition and open air bulk measurements of nitrate (NO3−) and ammonium (NH4+). Additionally, within the forest transect the variety of different soil vegetation species was recorded and quantified. We obtained a strong gradient of gas concentrations along both profiles. Whereas the bulk deposition remained quite constant along the non-forested transect, the nitrogen throughfall deposition rate diminished substantially with the distance from the highway. The deposition rate at the forest edge was twice of that inside. The nitrogen load estimated for the examined forest in the vicinity of the highway was comparable to other forest ecosystems situated near diffuse emission sources from agriculture. It could be shown that changes in soil composition and soil vegetation along the forest transect are caused by decreasing nitrogen deposition with distance from the highway. The application of road salt in winter leads to further impacts. AU - Kirchner, M. AU - Jakobi, G. AU - Feicht, E.A. AU - Bernhardt, M.* AU - Fischer, A.* C1 - 668 C2 - 22745 SP - 4531-4542 TI - Elevated NH₃ and NO₂ air concentrations and nitrogen deposition rates in the vicinity of a highway in Southern Bavaria. JO - Atmos. Environ. VL - 39 IS - 25 PY - 2005 SN - 1352-2310 ER - TY - JOUR AB - In this study, we describe the spatial variation of endotoxin across an urban setting using Geographic Information Systems (GIS) methods. We also identify potential sources of endotoxin that account for between-site variability and compare endotoxin levels in particulate matter with a 50% aerodynamic cut-off diameter of 2.5 μm (PM2.5) and of 10 μm (PM10). In 1999–2000, we collected PM2.5 and PM10 in Munich urban air and measured soluble endotoxin concentrations in both particle fractions. Using Teflon filters and Harvard impactors, PM2.5 was collected at 40 outdoor monitoring sites across Munich and PM10 at a subset of these sites (n=12n=12). Approximately four samples were collected at each site for a total of 158 PM2.5 samples and 48 PM10 samples. We visited and characterized the surrounding 100 m of each site for potential endotoxin sources. The geometric mean endotoxin concentration for all sites was 1.46 EU mg−1 PM2.5 (95% confidence intervals (CI): 1.21–1.77) and at the subset of the sites was 1.30 EU mg−1 PM2.5 (95% CI: 1.01–1.67 EU mg−1 PM2.5). Endotoxin levels in PM10 were higher, 3.91 EU mg−1 PM10 (95% CI: 3.03–5.03 EU mg−1 PM10), than in PM2.5 and were moderately correlated, r=0.51r=0.51. All endotoxin concentrations measured in this study were <5.5 EU m−3 and thus lower than the accepted thresholds for acute adverse health effects for occupational exposures. Sites with more potential sources (n⩾3n⩾3) had slightly higher mean endotoxin levels (MR: 1.30 for EU mg−1 PM2.5 and 1.13 for EU m−3 PM2.5) than sites with no identified sources. Based on the ranges of endotoxin levels at the different sites, we found very little spatial variation in ambient endotoxin concentrations across the metropolitan area of Munich using inverse distance weighting method (IDW) methods (R2=0.013R2=0.013 for EU mg−1 PM2.5 and R2=0.020R2=0.020 for EU m−3 PM2.5). Potential sources of endotoxin surrounding the sites only partly explained the variation seen. AU - Morgenstern, V. AU - Carty, C.L. AU - Gehring, U. AU - Cyrys, J. AU - Bischof, W.* AU - Heinrich, J. C1 - 1897 C2 - 23281 SP - 6931-6941 TI - Lack of Spatial Variation of Endotoxin in Ambient Particulate Matter across a German Metropolitan Area. JO - Atmos. Environ. VL - 39 IS - 36 PY - 2005 SN - 1352-2310 ER - TY - JOUR AB - Background: Ultrafine particles in urban air represent a potentially important health risk, and are not well characterized by mass concentrations like PM10 or PM2.5. The aerosol particle number concentration (PNC) is dominated by ultrafine particles, but urban PNC measurement campaigns have only recently started in many cities and missing data impedes much research. Hence, reliable estimation techniques are needed. Past estimations of ambient concentrations of particulate matter have focused on mass concentrations. This project developed city-specific models for estimating PNC using available data on other air pollutants and meteorological variables during a period when PNC was measured, and applied them retrospectively to predict daily PNC levels during the Health Effects of Air Pollution on Susceptible Subpopulations (HEAPSS) study period in order to enable epidemiological analyses. Methods: Monitoring of PNC began in April 2001 using condensation particle counters (3022A, TSI) in Augsburg, Barcelona, Helsinki, Rome, and Stockholm. Concurrent measurements of air pollutants and weather were used, as well as selected interactions between the two, to fit a regularized linear model (also called ridge regression). This technique is robust with respect to inclusion of irrelevant explanatory variables and can be modified to be highly tolerant of missing data, two highly beneficial features when there are many explanatory variables. Results: The most important predictor variables were the nitrogen oxides. The models appear to fit PNC data relatively well, with R2 of 0.77, 0.80, 0.58, 0.84, 0.81 respectively for the five cities. Split-halves analysis (modelling on half of the data with validation on the other half) indicates that the modelling process was fairly reliable. Conclusion: A statistical model can be applied to existing data on traffic-related air pollutants and weather variables in order to predict PNC levels. The retrospective prediction of PNC levels appears to be sufficiently reliable for use in epidemiological research. AU - Paatero, P.* AU - Cyrys, J. AU - Peters, A. C1 - 3131 C2 - 23133 SP - 2261-2273 TI - Estimating time series of aerosol particle number concentrations in the five HEAPSS cities on the basis of measured air pollution and meteorological variables. JO - Atmos. Environ. VL - 39 IS - 12 PY - 2005 SN - 1352-2310 ER - TY - JOUR AB - PM2.5 Particle-associated semi-volatile organic compounds (SVOC) were determined in the city of Augsburg, Germany. Daily samples were collected at a central monitoring station from late summer to late autumn 2002. The concentrations of polycyclic aromatic hydrocarbons (PAH), oxidized PAH (O-PAH), n-alkanes, hopanes and long chain linear alkylbenzenes were determined by direct thermal desorption-gas chromatography-time of flight mass spectrometry (DTD-GC-TOFMS). Additionally, PM2.5 particle mass and number concentrations were measured. The sampling campaign can be divided into two parts, distinguished by a lower temperature level in the second part of the campaign. The particulate mass concentration showed no significant changes, whereas most of the SVOC had significant higher mean and peak concentrations in the colder period. The analysis of the data showed an increased influence of non-traffic sources in the colder period, reflected by a weak shift in the PAH profile and a significant shift in the hopane pattern. Statistical analysis of the inter-group correlations was carried out. Eight clusters partly representing different sources of the aerosol have been identified. AU - Schnelle-Kreis, J.* AU - Sklorz, M.* AU - Peters, A. AU - Cyrys, J. AU - Zimmermann, R. C1 - 5228 C2 - 23061 SP - 7702-7714 TI - Analysis of particle-associated semi-volatile aromatic and aliphatic hydrocarbons in urban particulate matter on a daily basis. JO - Atmos. Environ. VL - 39 IS - 40 PY - 2005 SN - 1352-2310 ER - TY - JOUR AB - Brochosomes are excitingly shaped hollow spherical particles produced by leafhoppers (Cicadelliae), presumably to serve as a very efficient water-repellent protective surface coating. The spheroids have a diameter between 250 and 600 nm and are made of a network of protein–lipid rods, arranged in the form of hexagons and pentagons. Brochosomes in the atmosphere have been described only a few times and the reported concentrations were usually small. The cause of the apparently rare occurrence of these particles in ambient air is shown to be twofold. First, most of the brochosomes are airborne not as individual species, but in the form of rather large clusters containing up to 100,000 particles. Second, for high-efficiency collection of particles with aerodynamically complex morphology such as brochosomes (or agglomerates of carbon nanoparticles), size selective sampling with impactors turned out to be more efficient the higher the nozzle velocity. In a series of sampling campaigns brochosomes were found to be the most abundant bioaerosol particles in a semi-urban atmosphere during the warm season. Occasionally, brochosomes tended to react with other nanoparticle matter. As a result, the presumably freshly produced brochosomes became strongly distorted, rearranging in a variety of exotic forms, including perfect or distorted domes or even a spider web. AU - Wittmaack, K. C1 - 5052 C2 - 23054 SP - 1173-1180 TI - Brochosomes produced by leafhoppers-a widely unknown, yet highly abundant species of bioaerosols in ambient air. JO - Atmos. Environ. VL - 39 IS - 6 PY - 2005 SN - 1352-2310 ER - TY - JOUR AB - The follow-up of cohorts of adults from more than 20 European centres of the former ECRHS I (1989–1992) investigates long-term effects of exposure to ambient air pollution on respiratory health, in particular asthma and change of pulmonary function. Since PM2.5 is not routinely monitored in Europe, we measured PM2.5 concentrations in 21 participating centres to estimate ‘background’ exposure in these cities. Winter (November–February), summer (May–August) and annual mean (all months) values of PM2.5 were determined from measuring periods between June 2000 and November 2001. Sampling was conducted for 7 days per month for a year. Annual and winter mean concentrations of PM2.5 vary substantially being lowest in Iceland and highest in centres in Northern Italy. Annual mean concentrations ranged from 3.7 to 44.9 μg m−3, winter mean concentrations from 4.8 to 69.2 μg m−3, and summer mean concentrations from 3.3 to 23.1 μg m−3. Seasonal variability occurred but did not follow the same pattern across all centres. Therefore, ranking of centres varied from summer to winter. Simultaneously, NO2 concentrations were measured using passive sampling tubes. Annual mean NO2 concentrations range from 4.9 to 72.1 μg m−3 with similar seasonal variations across centres and constant ranking of centres between seasons. The correlation between annual NO2 and PM2.5 concentrations is fair (Spearman correlation coefficient rs=0.75), but when considered as monthly means the correlation is far less consistent and varies substantially between centres. The range of PM2.5 mass concentrations obtained in ECRHS II is larger than in other current cohort studies on long-term effects of air pollution. This substantial variation in PM2.5 exposure will improve statistical power in future multi-level health analyses and to some degree may compensate for the lack of information on within-city variability. Seasonal means may be used to indicate potential differences in the toxicity across the year. Across ECRHS cities annual NO2 might serve as a surrogate for PM2.5, especially for past exposure assessment, when PM2.5 is not available. AU - Hazenkamp-von Arx, M.E.* AU - Götschi, Th.* AU - Ackermann-Liebrich, U.* AU - Bono, R.* AU - Burney, P.* AU - Cyrys, J. AU - Jarvis, D.* AU - Lillienberg, L.* AU - Luczynska, C.* AU - Maldonado, J.A.* AU - Jaén, A.* C1 - 2442 C2 - 22055 SP - 1943-1953 TI - PM2.5 and NO2 assessment in 21 European study centres of ECRHS II: Annual means and seasonal differences. JO - Atmos. Environ. VL - 38 IS - 13 PY - 2004 SN - 1352-2310 ER - TY - JOUR AB - The current AOT40 concept for inferring risks in forest trees by ozone (O-3) injury is based on an accumulated external O-3 exposure rather than an internal O-3 dose or uptake rate. AOT40 assumes O-3 concentrations below 40 nl l(-1) and night-time exposure to be negligible. Hence, this concept is rather inconsistent with observed forest conditions. In contrast, the flux concept of cumulative O-3 uptake (CU) into the leaves has the potential of reflecting a physiologically meaningful internal O-3 dose experienced by trees. In this paper, we relate AOT40 to cumulative O-3 uptake into European beech (Fagus sylvatica), Norway spruce (Picea abies), European larch (Larix decidua) and cembran pine (Pinus cembra) trees differing in size, age and site conditions. We demonstrate that the flux concept can be extended to the tree and the stand level, making use of sap flow measurements through tree trunks. Although in both seedlings and adult trees AOT40 may show some linearity in correlations with average CU, the latter varies, at given AOT40, by 25 +/- 11% within and between species. This is because O-3 flux is primarily influenced by stomatal aperture, the latter being affected by climate, canopy position, leaf and tree age while varying between species. In particular, if weighed by detoxification capacity, we suggest, therefore, O-3 uptake related air quality indices to be promoted towards ecologically meaningful standards in forest protection, overcoming the shortcomings of exposure concepts. As O-3 injury results from the balance between O-3 uptake and detoxification in the leaf mesophyll, we conclude the flux concept in combination with measures of biochemical defence to have the capacity for predicting tree response to O-3 stress. AU - Matyssek, R.* AU - Wieser, G.* AU - Nunn, A.J.* AU - Kozovits, A.R.* AU - Reiter, I.M.* AU - Heerdt, C.* AU - Winkler, J.B. AU - Baumgarten, M.* AU - Häberle, K.-H.* AU - Grams, T.E.E.* AU - Werner, H.* AU - Fabian, P.* AU - Havranek, W.M.* C1 - 2457 C2 - 21771 SP - 2271-2281 TI - Comparison between AOT40 and ozone uptake in forest trees of different species, age and site conditions. JO - Atmos. Environ. VL - 38 IS - 15 PY - 2004 SN - 1352-2310 ER - TY - JOUR AB - Total air suspended particles (PM100) collected from an urban location near a traffic line in Wuhan, China, were examined for estrogen using a recombinant yeast bioassay. Wuhan, located at the central part of China, is the fourth biggest city in China with 7 million populations. Today, Wuhan has developed into the biggest city and the largest traveling center of central China, becoming one of the important bases of industry, education and research. Wuhan is right at the confluent point of Yangzi River, the third longest river in the world, and its largest distributary Hanjiang, with mountains and more than 100 lakes in downtown area. Therefore, by its unique landscape, Wuhan has formed clear four seasons with relatively long winter and summer and short spring and autumn. Foggy weather usually happen in early spring. The yeast line used in this assay stably expresses human estrogen receptor-alpha. Weak but clear estrogenic activities were detected in the organic phase of crude extracts of air particle materials (APM) in both sunny and foggy weather by 0.19–0.79 μg E2/g PM100 which were statistically significantly elevated relative to the blank control responding from 20% to 50% of the maximum E2 response, and the estrogenic activity was much higher in foggy weather than in sunny weather. The estrogenic activities in the sub-fractions from chromatographic separation of APM sampled in foggy days were also determined. The results indicated that the responses of the fractions were obviously higher than the crude extracts. Since there is no other large pollution source nearby, the estrogenic material was most likely from vehicle emissions, house heating sources and oil fumes of house cooking. The GC/MS analysis of the PM100 collected under foggy weather showed that there were many phenol derivatives, oxy-PAHs and resin acids which have been reported as environmental estrogens. These results of the analysis of estrogenic potency in sunny and foggy weather in a subtropical city of China indicate that further studies are required to investigate the actual risks for the associated health and atmospheric system. AU - Wang, J.* AU - Xie, P.* AU - Xu, Y.* AU - Kettrup, A. AU - Schramm, K.-W. C1 - 4646 C2 - 22110 SP - 6157-6166 TI - Differing estrogen activities in the organic phase of air particulate matter collected during sunny and foggy weather in a Chinese city detected by a recombinant yeast bioassay. JO - Atmos. Environ. VL - 38 IS - 36 PY - 2004 SN - 1352-2310 ER - TY - JOUR AB - Multiple, essentially identical samples of PM2.5, PM10 and TSP aerosol matter were collected on filters of cellulose acetate-nitrate membrane (CA), quartz fiber (QF) and glass fiber (GF) material. The samples were analyzed in terms of the gravimetric mass and the mass of nine inorganic ions. These parameters were also measured after step-wise thermodesorption of aerosol matter by 1-h heating in ambient air up to 350 °C. The observed thermograms of the analyzed ions were compared with results obtained using pure and mixed salts on filter. In summer the apparent mass concentration of aerosol matter collected on CA was always larger than on QF and GF filter. The excess mass on CA was found to be highly volatile, i.e. completely removable at 120 °C, and composed of both ionic and non-ionic matter. The apparent nitrate concentration sampled on QF and GF was almost an order of magnitude lower than on CA. The very pronounced nitrate losses from the fiber filters are attributed to volatilization of ammonium nitrate. In contrast, nitrate losses from CA were small or even negligible for two reasons, pile-up of aerosol matter predominantly on (rather than in) the filter (“cake” formation) and, more importantly, re-adsorption of volatilized ammonia and nitric acid in the filter. Sampling on GF filters was found to suffer from severe problems due to chemical reactions between Na+ of the glass and SO42− of the aerosol matter. A novel type of artifact was observed in sampling campaigns during fall. Presumably as a results of a high water content, the collected aerosol matter became liquefied and a large fraction of the water soluble components was driven through the filter into the support pad underneath. The negative “wetting artifact” was much more pronounced for the thin CA than for the relatively thick QF filters. The total amount of aerosol matter in the CA/pad and QF/pad combinations was the same, indicating that this kind of artifact can be corrected for. Ammonium nitrate-to-sulfate concentration ratios were low in summer (∼ 0.5 for PM2.5) but high in fall (⩾ 2). Furthermore, the ion fractions were low in summer (∼ 30%), but quite high in fall (⩾ 60%), and even higher in winter. AU - Wittmaack, K. AU - Keck, L. C1 - 2692 C2 - 22284 SP - 5205-5215 TI - Thermodesorption of aerosol matter on multiple filters of different materials for a more detailed evaluation of sampling artifacts. JO - Atmos. Environ. VL - 38 IS - 31 PY - 2004 SN - 1352-2310 ER - TY - JOUR AB - Objectives: We collected fine (PM2.5) and coarse (PM2.5−10) particulate matter fractions in two areas ∼80 km apart and measured soluble endotoxin concentrations in both particle fractions. Here we report on temporo-spatial variation of endotoxin content in the collected particles. Methods: Dichotomous Anderson samplers were used to collect 21 weekly samples of PM2.5 and PM2.5−10 in both towns from January to June 2002. Each Teflon filter was water extracted and endotoxin was measured by a chromogenic Limulus Amoebocyte Lysate method. Endotoxin concentrations were expressed per mg of fine or mg of coarse mass and per sampled air volume (m3). Results: For both cities, the mean endotoxin content in PM2.5 was 1.2 EU mg−1; however the endotoxin content in the coarse fraction was ∼10 times higher compared to the fine mass fractions. Although endotoxin content is highly variable over time, a good correlation was observed between the two town sites for both fine (r=0.85) and coarse PM (r=0.88). The fluctuations of weekly endotoxin means were high in both areas suggesting a strong temporal dependence on particle source and composition. The endotoxin content in particles collected during May and June were two to four times higher than concentrations measured during the winter and early spring weeks. Conclusions: Ambient airborne endotoxin concentrations were detected in coarse and fine particle fraction, but 10-fold higher in the coarse PM. The strong seasonality and the week to week fluctuation of endotoxin content in PM indicate different biologic PM properties which might affect results of time series studies on short-term effects as well as in vitro studies and human exposure studies. AU - Heinrich, J. AU - Pitz, M. AU - Bischof, W.* AU - Krug, N.* AU - Borm, P.J.A.* C1 - 8974 C2 - 21087 SP - 3659-3667 TI - Endotoxin in fine (PM2.5) and coarse (PM2.5-10) particle mass of ambient aerosols. A temporo-spatial analysis. JO - Atmos. Environ. VL - 37 IS - 26 PY - 2003 SN - 1352-2310 ER - TY - JOUR AB - Air quality in urban areas has considerably changed over time. Recent changes of particle emissions in Eastern Germany during the last 10 years provide a quick motion picture of a development which lasted several decades in Western countries. Size distributions of fine particles (<2.5 μm aerodynamic diameter) were measured during winters 1991/1992 through 2000/2001. Within these 10 years particle size distributions shifted strongly towards smaller sizes. This was mainly due to a twofold increase of the number concentration of 0.01–0.03 μm sized particles. In parallel, fine particle mass concentration decreased by 75%. Since the mass concentration of fine particles is considered most relevant for human health today, the observed substantially decreasing trend in Eastern Germany is a desirable development. It is, however, accompanied by an increase of the number concentration of ultrafine particles in the 0.01–0.03 μm size range for which most recently associations with health effects have been found. This development associated with rapid emission changes caused by the German unification may be considered as a time-lapsed development representing partially unrecorded temporal alterations of emissions in a large entity of Western industrialized urban environments over the last five decades. Thus, the worldwide policy to reduce only the mass concentration of ambient aerosols without controlling for the number concentration may not be sufficient to assess health effects associated with urban particles. AU - Kreyling, W.G. AU - Tuch, T. AU - Peters, A. AU - Pitz, M.* AU - Heinrich, J. AU - Stölzel, M.* AU - Cyrys, J. AU - Heyder, J. AU - Wichmann, H.-E. C1 - 8976 C2 - 21261 SP - 3841-3848 TI - Diverging long-term trends in ambient urban particle mass and number concentrations associated with emission changes caused by the German unification. JO - Atmos. Environ. VL - 37 IS - 27 PY - 2003 SN - 1352-2310 ER - TY - JOUR AB - Epidemiological studies suggest that exposure to sub-micrometer aerosol particles poses a health risk. In this study, we had the unique opportunity to investigate the comparability of the ambient aerosol measured at urban background stations in two cities located in one region. We compared particle number size distributions measured in Erfurt and Leipzig, Germany, over a 5-year period from February 1997 through August 2001. Our findings show that mean concentrations, size distributions and their diurnal variations of the ambient aerosol measured at urban background stations in two cities are very similar. Total particle number concentrations (10–800 nm) measured in Erfurt were only 9–20% higher compared to those measured in Leipzig. Average number concentrations in the size ranges 10–20, 20–50, 50–100, 100–200, and 200–800 nm differed by less than 50%. Diurnal variations in particle number distribution in summer and winter in Erfurt showed similar patterns to those in Leipzig. Evidence that the site in Erfurt was more influenced by local traffic compared to the site in Leipzig is the shifts in size distribution towards larger particles in Leipzig along with the 37–43% higher concentration of particles smaller than 30 nm in diameter and the two to three times elevated NO concentrations in Erfurt on workdays. Observed differences between Erfurt and Leipzig size distributions can be attributed to differences in horizontal distance to major roads, inlet heights, terrain, and climatic conditions. Our results suggest that the average urban background aerosol in two cities in the same region is similar if the major sources of the aerosol (traffic, domestic heating) in these two cities are similar. AU - Tuch, T.M.* AU - Wehner, B.* AU - Pitz, M.* AU - Cyrys, J. AU - Heinrich, J. AU - Kreyling, W.G. AU - Wichmann, H.-E. AU - Wiedensohler, A.* C1 - 8975 C2 - 21259 SP - 4687-4700 TI - Long-term measurements of size-segregated ambient aerosol in two German cities located 100km apart. JO - Atmos. Environ. VL - 37 IS - 33 PY - 2003 SN - 1352-2310 ER - TY - JOUR AB - Estrogenic activities of emission samples generated by fossil fuel combustion were investigated with human estrogen receptor (ER) recombinant yeast bioassay. The results showed that there were weak but clear estrogenic activities in combustion emissions of fossil fuels including coal, petroleum, and diesel. The estrogenic relative potency (RP) of fossil fuel combustion was the highest in petroleum-fired car, followed by coal-fired stove, diesel-fired agrimotor, coal-fired electric power station. On the other hand, the estrogenic relative inductive efficiency (RIE) was the highest in coal-fired stove and coal-fired electric power station, followed by petroleum-fired car and diesel-fired agrimotor. The estrogenic activities in the sub-fractions from chromatographic separation of emitted materials were also determined. The results indicated that different chemical fractions in these complex systems have different estrogenic potencies. The GC/MS analysis of the emission showed that there were many aromatic carbonyls, big molecular alcohol, PAHs and derivatives, and substituted phenolic compounds and derivatives which have been reported as environmental estrogens. The existence of estrogenic substances in fossil fuel combustion demands further investigation of their potential adverse effects on human and on the ecosystem. The magnitude of pollution due to global usage of fossil fuels makes it imperative to understand the issue of fossil fuel-derived endocrine activities and the associated health risks, particularly the aggregated risks stemmed from exposure to toxicants of multiple sources. AU - Wang, J.* AU - Wu, W.* AU - Henkelmann, B. AU - You, L.* AU - Kettrup, A. AU - Schramm, K.-W. C1 - 8973 C2 - 21079 SP - 3225-3235 TI - Presence of estrogenic activity from emission of fossil fuel combustion as detected by a recombinant yeast bioassay. JO - Atmos. Environ. VL - 37 IS - 23 PY - 2003 SN - 1352-2310 ER - TY - JOUR AB - Epidemiological studies of long-term air pollution effects have been hampered by difficulties in characterizing the spatial variation in air pollution. We conducted a study to assess the risk of long-term exposure to traffic-related air pollution for the development of inhalant allergy and asthma in children in Stockholm county, Munich and the Netherlands. Exposure to traffic-related air pollution was assessed through a 1-year monitoring program and regression modeling using exposure indicators. This paper documents the performance of the exposure monitoring strategy and the spatial variation of ambient particle concentrations. We measured the ambient concentration of PM2.5 and the reflectance of PM2.5 filters (‘soot’) at 40–42 sites representative of different exposure conditions of the three study populations. Each site was measured during four 14-day average sampling periods spread over one year (spring 1999 to summer 2000). In each study area, a continuous measurement site was operated to remove potential bias due to temporal variation. The selected approach was an efficient method to characterize spatial differences in annual average concentration between a large number of sites in each study area. Adjustment with data from the continuous measurement site improved the precision of the calculated annual averages, especially for PM2.5. Annual average PM2.5 concentrations ranged from 11 to 20 μg/m3 in Munich, from 8 to 16 μg/m3 in Stockholm and from 14 to 26 μg/m3 in the Netherlands. Larger spatial contrasts were found for the absorption coefficient of PM2.5. PM2.5 concentrations were on average 17–18% higher at traffic sites than at urban background sites, but PM2.5 absorption coefficients at traffic sites were between 31% and 55% increased above background. This suggests that spatial variation of traffic-related air pollution may be underestimated if PM2.5 only is measured. AU - Hoek, G.* AU - Meliefste, K.* AU - Cyrys, J. AU - Lewne, M.* AU - Bellander, T.* AU - Brauer, M.* AU - Fischer, P.* AU - Gehring, U. AU - Heinrich, J. AU - van Vliet, P.* AU - Brunekreef, B.* C1 - 22373 C2 - 21283 SP - 4077-4088 TI - Spatial variability of fine particle concentrations in three European areas. JO - Atmos. Environ. VL - 36 IS - 25 PY - 2002 SN - 1352-2310 ER - TY - JOUR AB - The processes occurring during the initial stages of size-selected sampling of atmospheric aerosol matter were explored by means of high-resolution scanning electron microscopy and energy dispersive X-ray spectrometry. The final four stages of a Berner impactor served to collect particles with aerodynamic diameters between 60 nm and I mum on polished silicon substrates at sampling times between 10s and 16 min. In the single-particle impact regime (fractional coverage below 5%), most of the particles produced circular black tracks, of which 15 to 30% contained cores of carbonaceous nanoparticles. At a fractional coverage above about 10%, initially generated deposits became increasingly active as centres of preferred aerosol collection. As a result, the number of black spots remained almost constant, but the area per spot increased rapidly. At this stage of fractional coverage, structured aerosol matter became visible within large black areas of random shape. The deposits showed clear evidence for the onset of phase separation between carbon nanoparticles and material rich in sulphur, probably a mixture of alkaline and alkaline earth sulphates. After some time of sample storage in air the low-coverage sulphate matter tended to attain a fractal pattern. At a fractional coverage of several hundred per cent, large amorphous or crystalline objects had grown, but 30% or more of the nominal impact area still did not contain any aerosol matter. Moreover, carbon nanoparticles were found to be phase separated from the newly grown, very uniform aerosol material. The observations imply that sub-micrometer aerosol matter collected in impactors has lost memory of the original particle morphology. AU - Wittmaack, K. C1 - 8977 C2 - 20438 SP - 3963-3971 TI - Impact and growth phenomena observed with sub-micrometer atmospheric aerosol particles collected on polished silicon at low coverage. JO - Atmos. Environ. VL - 36 IS - 24 PB - Elsevier PY - 2002 SN - 1352-2310 ER - TY - JOUR AB - Aerosol matter in the size range <2 μm was collected in a Berner impactor and subsequently analysed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectrometry. Owing to the low electron beam energy of 5 keV (occasionally 10 keV), analysis was restricted to elements with atomic numbers ⩽20 (Ca). Sub-micrometer aerosol matter was found to contain mostly S, O, and C as well as some K and Ca. Nitrogen appeared to escape detection, probably due to bombardment-induced sublimation of NO3 and NH4. During sampling at low to moderate relative humidity (<60%) the sulphur-rich fraction of the aerosol matter (most likely sulphates) regrew in the form of microcrystals with sizes up to 10 times larger than the mean aerodynamic diameter of the respective impactor stage. By contrast, when sampling during periods in course of which the relative humidity exceeded 70%, the aerosol matter regrew in the form of extended amorphous agglomerates. The aerosol deposits also contained large numbers of carbon nanoparticles, well separated from the regrown sulphate-rich matter. The nanoparticles were similar in size (∼20–40 nm), much smaller than the equivalent aerodynamic diameter of the impacting particles (63 nm–2 μm). Presumably, the carbon nanoparticles constituted the core of larger air-borne particles covered with sulphates (as well as with nitrates and organic carbon). The regrown microcrystals disappeared rapidly under electron bombardment at high current density, an observation that indicates high volatility at elevated temperatures. Aerosol matter collected in the size range between 1 and 2 μm contained large fractions of particles made of O, Si, P, K, and Ca (oxides). These particles were highly resistant to electron bombardment (hard) and showed little or no evidence for agglomeration or regrowth. After removing the soluble (acidic) material from the collected aerosol matter, only carbon nanoparticles and hard coarse particles were left behind. The observation of agglomerated or crystallized “soft” aerosol matter in combination with phase separation of carbon nanoparticles lends further support to the assertion that it is not possible to collect useful quantities of fine and ultrafine aerosol particles with as-suspended morphology. Some implications for health-related research are discussed. AU - Wittmaack, K. AU - Menzel, N. AU - Wehnes, H. AU - Heinzmann, U. C1 - 8978 C2 - 21164 SP - 5877-5886 TI - Phase separation and regrowth of aerosol matter collected after size fractionation in an impactor. JO - Atmos. Environ. VL - 36 IS - 39-40 PY - 2002 SN - 1352-2310 ER - TY - JOUR AB - The concentrations of the aromatic hydrocarbons benzene, toluene, ethylbenzene and the isomeric xylenes (BTEX) have been determined in the indoor air of 115 private non-smoker homes (similar to 380 individual rooms) situated in areas with an extreme traffic situation, i.e. in city streets (street canyons) with high traffic density and in rural areas with hardly any traffic at all. The influence of the traffic on the indoor concentration was apparent in the high traffic area. In order to identify other factors influencing the BTEX concentrations, the data and additional questionnaires were analyzed by univariate and multivariate analysis. The analysis was supplemented by some case studies. It is shown that meteorology (the seasons), the type of room (e.g. living room versus bedroom), the ventilation and, in particular, garages in the house strongly influence the indoor concentration of BTEX. Thus, the indoor BTEX level is significantly higher in winter than in summer. Moreover, garages with a connecting door to the living quarters lead to high indoor concentrations of aromatic hydrocarbons in these rooms. In addition, the storage of solvents and hobby materials, and also the presence of smoking guests increase the BTEX level. If rooms are directly heated by coal or wood, the BTEX level is higher compared to the use of gas healing. Surprisingly, no correlation was found between the building materials used and the BTEX level. Case studies were carried out for two homes with an integrated garage (and a connecting door to the living rooms) and for seven homes where redecoration work was carried out during sampling. In both instances, a pronounced increase was observed in the BTEX concentration. AU - Ilgen, E.* AU - Levsen, K.* AU - Angerer, J.* AU - Schneider, P. AU - Heinrich, J. AU - Wichmann, H.-E. C1 - 10341 C2 - 19880 SP - 1253-1264 TI - Aromatic hydrocarbons in the atmospheric environment : Part II. Univariate and multivariate analysis and case studies of indoor concentrations. JO - Atmos. Environ. VL - 35 IS - 7 PB - Elsevier Science Ltd. PY - 2001 SN - 1352-2310 ER - TY - JOUR AB - As part of a larger study, personal sampling of the aromatic hydrocarbons benzene, toluene, ethylbenzene and the isomeric xylenes (BTEX) was carried out by 55 nonsmoking volunteers for a period of 14 days. Thirty-nine persons lived in a rural area near Hannover (Germany) with hardly any traffic at all, while 16 persons lived in a high-traffic city street in Hannover. The personal exposure level of the persons in the rural area (some commuting to Hannover) was: 2.9, 24.8, 2.4 and 7.7 mug m(-3) for benzene, toluene, ethylbenzene and the sum of xylenes, respectively, while the corresponding data for the high traffic city streets were 4.0, 22.2, 2.8 and 9.7 mug m-3 (geometric means). Four microenvironments have been monitored which contribute to the total exposure to BTEX, i.e. the home, the outdoor air, the workplace and the car cabin. The most important microenvironment for non-working persons is the private home. The concentration of most BTEX in the private home is almost equal to the personal exposure level, demonstrating that the indoor pollution in the home makes by far the highest contribution to the total exposure. For working people (mostly office workers), the workplace is the second most important microenvironment contributing to the total BTEX exposure. Taking all working persons into consideration (independent of the location of their private home) the personal exposure level is higher by a factor of 1.2-1.4 than that of the workplace (for toluene this factor is 2.2). As already found by others, very high BTEX concentrations may be found in car cabins, in particular, if the engine is gasoline-driven. In the cabin of 44 cars in the rural/urban area average benzene concentrations (geometric mean) of 12/14 mug m(-3) and a maximum value of similar to 550 mug m(-3) were found. On average, the participating volunteers drove their car for 45 min day(-1) (i.e. 3% of the day). Nevertheless, the car cabin constitutes about 10% of the total benzene exposure. Refueling of the car during the 14-day sampling period has only a small effect on the personal exposure level. AU - Ilgen, E.* AU - Levsen, K.* AU - Angerer, J.* AU - Schneider, P. AU - Heinrich, J. AU - Wichmann, H.-E. C1 - 10342 C2 - 19879 SP - 1265-1279 TI - Aromatic hydrocarbons in the atmospheric environment. Part III: Personal monitoring. JO - Atmos. Environ. VL - 35 IS - 7 PB - Elsevier Science Ltd. PY - 2001 SN - 1352-2310 ER - TY - JOUR AB - Six aromatic hydrocarbons (benzene, toluene, ethylbenzene and the three isomeric xylenes) were monitored in the indoor and outdoor air of 115 private non-smoker homes ( similar to 380 rooms), about half of which were located in two city streets in Hannover (Northern Germany) with high traffic density, the other half in rural areas with hardly any traffic at all. This environmental monitoring was complemented by human biomonitoring (i.e. the determination of aromatic hydrocarbons in blood and exhaled air). Particular attention was paid to benzene as a result of its carcinogenicity. In the city streets with high traffic density, an average benzene concentration of 3.1 mug m(-3) and in the rural areas of 1.8 mug m(-3) was found in these non-smoker homes tall data = geometric means), which reflects the influence of the traffic (automobile exhaust) on the benzene level found indoors. Source identification is also possible by determining the indoor/outdoor (I/O) concentration ratio. For the rooms facing the city street, this I/O ratio is close to 1 for all aromatic hydrocarbons studied with the exception of toluene (I/O = 3.5), while in the rural areas I/O ratios for the individual compounds ranging in 6-9 were determined, with the exception of benzene where the I/O ratio is only 1.5. These I/O ratios in the city street with high traffic density indicate that an equilibrium between indoor and outdoor air is almost reached. Indoor sources prevail only in the case of toluene. In contrast, in the rural area, indoor sources dominate for all aromatic hydrocarbons except benzene, the indoor level of which is mainly influenced by the outdoor air even in areas of very low traffic density. However, weak indoor sources must exist also for this compound even in non-smoker homes. The internal exposure of the non-smoking inhabitants of these homes to benzene is very low. Depending on the living area, mean values of 61-67 ngl(-1) benzene in blood and 0.9-1.2 mug m(-3) in the exhaled air were found. AU - Ilgen, E.* AU - Karfich, N.* AU - Levsen, K.* AU - Angerer, J.* AU - Schneider, P. AU - Heinrich, J. AU - Wichmann, H.-E. AU - Dunemann, L.* AU - Bergerow, J.* C1 - 10343 C2 - 19881 SP - 1235-1252 TI - Aromatic hydrocarbons in the atmospheric environment : Part I. Indoor versus outdoor sources, the influence of traffic. JO - Atmos. Environ. VL - 35 IS - 7 PB - Elsevier Science Ltd. PY - 2001 SN - 1352-2310 ER - TY - JOUR AB - Concentrations of polycyclic aromatic hydrocarbons (PAH) and oxidised PAH (oxy-FAH) from outdoor air were determined. Size-fractionated aerosol samples were collected in the city of Munich (Germany). Twenty-four hour samples with six- and nine-stage Berner-type low-pressure impactors were collected between 1996 and 1998. Fluoranthene, pyrene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene and benzo[ghi]perylene were quantified by HPLC with fluorescence detection. The averaged sum of these PAH reached 1.24 ng m(-3) (range: 0.68-1.85 ng m (-3)) at the inner city site which was not directly influenced by any road nearby, whereas samples from two sites close to busy roads exhibited average PAH concentrations equal to 5.61 ng m(-3) (range: 3.65-6.65 ng m(-3)) and 5.74 ng m(-3) (range: 1.67-15.13 ng m(-3)). The PAH concentration observed at the northern outskirts of Munich ranged from 0.15 to 9.45 ng m(-3) (average, 2.4 ng m(-3)). Different distributions of the PAH in the investigated particle size fractions were observed. Close to the road (at about 1 m off), about 40% of the PAH were found in the particle fraction with diameters of 0.06-0.13 mum Similar distributions were observed at the second sampling site located close to a road when winds blew directly from this road. When winds blew from other directions, higher percents of PAH were present on larger particles. A bigger accumulation of PAH on particles ranging from 0.26 to 0.9 mum was also observed at the outskirts. Since the lung dose of particle-associated compounds is influenced by the distribution of the compounds within the particle size range, the observed differences in the distribution of PAH have implications on human exposure. AU - Schnelle-Kreis, J. AU - Gebefügi, I. AU - Welzl, G. AU - Jaensch, T. AU - Kettrup, A. C1 - 10340 C2 - 19816 SP - 71-81 TI - Occurrence of particle-associated polycyclic aromatic compounds in ambient air of the city Munich. JO - Atmos. Environ. VL - 35 IS - S PB - Elsevier Science Ltd. PY - 2001 SN - 1352-2310 ER - TY - JOUR AB - There is an ongoing debate on the question which size fraction of particles in ambient air may be responsible for human health effects observed in epidemiological studies. Since there is no single instrument available for the measurement of the particle-size distribution over the full range of the fine fraction (diameter <2.5 μm) of the atmospheric aerosol, two instruments, the mobile aerosol spectrometer (MAS) and the electrical aerosol spectrometer (EAS), have been tested in a side-by-side comparison measuring ambient aerosol for a time period of six weeks in spring 1996 in the city of Erfurt, Germany. Furthermore, total particle number concentration measured by a condensation particle counter (CPC) and mass concentrations PM10 and PM2.5 were determined. Both spectrometers, MAS and EAS, are based on electrical mobility measurements for particles <0.1 μm and <0.5 μm, respectively, while MAS applies optical particle spectrometry and EAS applies again electrical mobility analysis for particles up to 2.5 and 10 μm, respectively. Both instruments proved to be reliable during this comparison providing data availability of >94%. To compare the spectral data, particle numbers were integrated within three size ranges: 0.01 - 0.1, 0.1 - 0.5, 0.5 - 2.5 μm. Hourly mean number concentrations of each size range observed during the six week comparison was: 2.6 x 104 ± 19500 (2.48 x 104 ± 1.79 x 104), 3.1 x 103 ± 1.5 x 103 (4.1 x 103 ± 2.0 x 103), 50 ± 45 (1.9 x 102 ± 1.2 x 102) cm-3 for MAS (EAS), respectively. Both aerosol spectrometers followed the variations of the ambient aerosol in a similar manner and yielded almost identical results for particle number concentrations of particles with diameters smaller than 0.5 μm. Furthermore, the total particle number concentration derived from MAS and EAS measurements (29000 ± 20000; 29000 ± 19000 cm-3) is well comparable with the number concentration derived from an integral counting CPC (31100 ± 22000 cm-3). The results of this side-by-side comparison suggest that MAS and EAS together with PM2.5 measurements are suitable to reliably characterize size- distribution parameters of number and mass concentration of ambient aerosols. | There is an ongoing debate on the question which size fraction of particles in ambient air may be responsible for human health effects observed in epidemiological studies. Since there is no single instrument available for the measurement of the particle-size distribution over the full range of the fine fraction (diameter < 2.5 μm) of the atmospheric aerosol, two instruments, the mobile aerosol spectrometer (MAS) and the electrical aerosol spectrometer (EAS), have been tested in a side-by-side comparison measuring ambient aerosol for a time period of six weeks in spring 1996 in the city of Erfurt, Germany. Furthermore, total particle number concentration measured by a condensation particle counter (CPC) and mass concentrations PM10 and PM2.5 were determined. Both spectrometers, MAS and EAS, are based on electrical mobility measurements for particles < 0.1 μm and < 0.5 μm, respectively, while MAS applies optical particle spectrometry and EAS applies again electrical mobility analysis for particles up to 2.5 and 10 μm, respectively. Both instruments proved to be reliable during this comparison providing data availability of > 94%. To compare the spectral data, particle numbers were integrated within three size ranges: 0.01 - 0.1, 0.1-0.5, 0.5-2.5 μm. Hourly mean number concentrations of each size range observed during the six week comparison was: 2.6 × 104 ± 19500 (2.48 × 104 ± 1.79 × 104), 3.1 × 103 ± 1.5 × 103 (4.1 × 103 ± 2.0 × 103), 50 ± 45 (1.9 × 102 ± 1.2 × 102) cm-3 for MAS (EAS), respectively. Both aerosol spectrometers followed the variations of the ambient aerosol in a similar manner and yielded almost identical results for particle number concentrations of particles with diameters smaller than 0.5 μm. Furthermore, the total particle number concentration derived from MAS and EAS measurements (29000 ± 20000; 29000 ± 19000 cm-3) is well comparable with the number concentration derived from an integral counting CPC (31100 ± 22000 cm-3). The results of this side-by-side comparison suggest that MAS and EAS together with PM2.5 measurements are suitable to reliably characterize size-distribution parameters of number and mass concentration of ambient aerosols. AU - Tuch, T.H.* AU - Mirme, A.* AU - Tamm, E. AU - Heinrich, J. AU - Heyder, J. AU - Brand, P. AU - Roth, C. AU - Wichmann, H.-E.* AU - Pekkanen, J.J.* AU - Kreyling, W.G. C1 - 33165 C2 - 19435 SP - 139-149 TI - Comparison of two particle-size spectrometers for ambient aerosol measurements. JO - Atmos. Environ. VL - 34 IS - 1 PY - 2000 SN - 1352-2310 ER - TY - JOUR AB - Light scattering photometers are useful for in situ measurements of mass concentrations of environmental aerosols if certain requirements are fulfilled. For the determination of relative concentrations, the composition of the aerosol (particle size distribution, refractive index) has to be constant during the experiments. Absolute measurements of mass concentrations additionally require a calibration of the photometer in terms of gravimetric units. In the case of atmospheric aerosols special attention has to be paid to the relative humidity which has a strong effect on particle size. Preliminary measurements indicate that for atmospheric background aerosols with a dominating accumulation mode a fairly linear relationship between photometer response and mass (volume) concentration exists, a result, which is in agreement with theoretical predictions AU - Thomas, A. AU - Gebhart, J. C1 - 20210 C2 - 13392 SP - 935-938 TI - Correltations Between Gravimetry and Light Scattering Photometry for Atmospheric Aerosols. JO - Atmos. Environ. VL - 28 IS - 5 PY - 1993 SN - 1352-2310 ER - TY - JOUR AB - A mobile aerosol spectrometer (MAS) was used for in situ characterization of environmental aerosols in the size range between 10 nm and 25 μm. The device combines a differential mobility analyser with a laser and a white light aerosol spectrometer. Classification errors were estimated theoretically, considering the influence of the particles' refractive index and shape. Experimental intercomparison with a cascade impactor showed lower errors than predicted. A mechanism of error compensation is proposed to explain this discrepancy. In a 1-month field study in Frankfurt city the MAS has shown the capability of resolving fast changes in particle concentration and detecting periods of particle production. | A mobile aerosol spectrometer (MAS) was used for in situ characterization of environmental aerosols in the size range between 10 nm and 25 μm. The device combines a differential mobility analyzer with a laser and a white light aerosol spectrometer. Classification errors were estimated theoretically, considering the influence of the particles' refractive index and shape. Experimental intercomparison with a cascade impactor showed lower errors than predicted. A mechanism of error compensation is proposed to explain this discrepancy. In a 1-month field study in Frankfurt city the MAS has shown the capability of resolving fast changes in particle concentration and detecting periods of particle production. AU - Brand, P. AU - Ruos, K. AU - Gebhart, J. C1 - 40678 C2 - 38752 SP - 2451-2457 TI - Performance of a mobile aerosol spectrometer for an in situ characterization of environmental aerosols in Frankfurt city. JO - Atmos. Environ. VL - 26 A IS - 13 PY - 1992 SN - 1352-2310 ER - TY - JOUR AB - For the determination of regionally averaged fluxes and budgets of atmospheric trace constituents, the ultimate goal of the European Environment Research EUROTRAC, several ecosystems must be investigated, each representative of larger areas. One of the most wide-spread vegetation type is the coniferous forest, in which several compartments exist such as soil, trunk space, canopy and 'free' atmosphere above, which differ considerably in biology, chemistry and meteorology, but increase strongly by feedback processes caused by turbulent mixing and chemical reactions. To understand forest/atmosphere relations in detail, measurements are needed which provide concentrations, emission and deposition data of various chemical compounds as well as micrometeorological quantities. These measurements have to be carried out simultaneously in all storeys of a forest over extended periods and must be highly resolved with respect to time and space. In a first step detailed small-scale studies must be performed. This paper describes the scientific approach for integrated multi-disciplinary studies at Schachtenau, a research site in Central Europe's largest continuous forest, and presents first results from joint experiments. AU - Enders, G.* AU - Dlugi, R.* AU - Steinbrecher, R.* AU - Clement, B.* AU - Daiber, R.* AU - Eijk, J.v.* AU - Gäb, S. AU - Haziza, M.* AU - Helas, G.* AU - Herrmann, U.* AU - Kessel, M.* AU - Kesselmeier, J.* AU - Kotzias, D.* AU - Kourtidis, K.A.* AU - Kurth, H.H. AU - McMillen, R.T.* AU - Roider, G.* AU - Schürmann, W.* AU - Teichmann, U.* AU - Torres, L.* C1 - 40641 C2 - 12173 SP - 171-189 TI - Biosphere/Atmosphere interactions: Integrated research in a European coniferous forest ecosystem. JO - Atmos. Environ. VL - 26 IS - 1 PY - 1992 SN - 1352-2310 ER - TY - JOUR AB - The prototype of a new aethalometer was calibrated and tested in the laboratory by applying graphite, salt and iron oxide aerosol particles. It turned out that the response of the aethalometer was critical to the ratio of the mass of absorbing and non-absorbing materials. The aethalometer data from field measurements were compared with results gained by an optical absorption technique (Hanel's method). The correlations showed wide scattering, presumably due to different compositions of atmospheric particles. During field measurements the prototype was also compared with a commercial aethalometer of the 'Hansen-type'. The measured soot concentrations differed by about 50% on average. The results of the commercial aethalometer and the absorption technique agreed very well. | The prototype of a new aethalometer was calibrated and tested in the laboratory by applying graphite, salt and iron oxide acrosol particles. It turned out that the response of the acthalometer was critical to the ratio of the mass of absorbing and non-absorbing materials. The aethalometer data from field measurements were compared with results gained by an optical absorption technique (Hanel's method). The correlations showed wide scattering, presumably due to different compositions of atmospheric particles. During field measurements the prototype was also compared with a commercial aethalometer of the 'Hansen-type'. The measured soot concentrations differed by about 50% on average. The results of the commercial aethalometer and the absorption technique agreed very well. AU - Ruoss, K. AU - Dlugi, R. AU - Weigl, C. AU - Hänel, G. C1 - 40620 C2 - 38746 SP - 3161-3168 TI - Intercomparison of different aethalometers with an absorption technique: Laboratory calibrations and field measurements. JO - Atmos. Environ. VL - 26 A IS - 17 PY - 1992 SN - 1352-2310 ER - TY - JOUR AB - Air quality in the Athens basin is well known to be poor, damaging building materials and human health, but there is no information available on concentrations or the impact of oxidants on ecosystems in rural areas outside the basin. A short-term monitoring campaign, coupled with a survey using the O3 bioindicator Bel-W3 tobacco demonstrated that phytotoxic concentrations of O3 occurred throughout Attica, within a 75 km radius of the city. There was relatively little injury produced in the industrial centre of the city and maximum injury was found about 40 km to the SE. Visible lesions identical to those of O3 injury were found on Aleppo pine at all sites in the cooler months. In the summer the needles were very chlorotic, possibly due to photo-oxidation of chlorophylls mediated by heat or drought. This chlorosis may mask oxidant symptoms in the summer. NO2 diffusion tube data and needle analysis suggested that the effects of sulphur and NO2 are probably confined to the Athens basin. AU - Velissariou, D.* AU - Davison, A.W.* AU - Barnes, J.D.* AU - Pfirrmann, T. AU - MacLean, D.C.* AU - Holevas, C.D.* C1 - 40575 C2 - 38776 SP - 373-380 TI - Effects of air pollution on Pinus halepensis (Mill.): Pollution levels in Attica, Greece. JO - Atmos. Environ. VL - 26 IS - 3 PY - 1992 SN - 1352-2310 ER - TY - JOUR AB - A mobile aerosol spectrometer for automatic in situ evaluation of particle size and number concentration in environmental aerosols is described. The instrument is able to evaluate size distributions of ambient particles in the range 0.01-25 μm, and to detect alterations in these distributions with a time resolution of a few minutes, capabilities not at present offered by any single commercially available instrument. The satisfactory performance of the spectrometer was demonstrated in field trials at a rural site (Heligoland Island). Environmental aerosols at this site are usually characterized by a particle number concentration of about 5000 cm-3. During the passage of a warm air front, however, a 6-fold increase in this concentration was detected, resulting from enhanced particle production in the nucleation mode below 0.05 μm. | A mobile aerosol spectrometer for automatic in situ evaluation of particle size and number concentration in environmental aerosols is described. The instrument is able to evaluate size distributions of ambient particles in the range 0.01-25 μm, and to detect alterations in these distributions with a time resolution of a few minutes, capabilities not at present offered by any single commercially available instrument. The satisfactory performance of the spectrometer was demonstrated in field trials at a rural site (Heligoland Island). Environmental aerosols at this site are usually characterized by a particle number concentration of about 5000 cm-3. During the passage of a warm air front, however, a 6-fold increase in this concentration was detected, resulting from enhanced particle production in the nucleation mode below 0.05 μm. AU - Brand, P. AU - Gebhart, J. AU - Below, M. AU - Georgi, B. AU - Heyder, J. C1 - 40836 C2 - 11328 SP - 581-585 TI - Characterization of environmental aerosols on Heligoland Island. JO - Atmos. Environ. VL - 25 A IS - 3-4 PY - 1991 SN - 1352-2310 ER - TY - JOUR AB - Particle size analysis based on single particle observation in a sedimentation cell is investigated. The settling chamber consists of a 3 mm cylindrical channel in the centre of a copper block. The particles are illuminated with parallel laser light and examined by an ultramicroscope technique. Experiments are carried out with polystyrene latex spheres and a condensation aerosol of di 2 ethylhexyl sebacate (DES) in the size range between 0.3 and 5 μm. If, for particles of uniform size, the arithmetic mean value of the settling times is used, the Brownian motion has no influence on the size evaluation. For particles above ca. 1.5 μm, not only the median diameter, but the whole size distribution of the aerosol can be determined by the sedimentation method. The diameters derived from the settling velocity agree within a few per cent with results obtained by electron microscopy or optical size spectrometry. To achieve this accuracy about 100 single particles have to be counted for each size evaluation. The A value of the slip correction of polystyrene spheres is found to be: A = 1.34 ± 0.011. AU - Stahlhofen, W. AU - Armbruster, L. AU - Gebhart, J. AU - Grein, E. C1 - 42238 C2 - 38432 SP - 851-857 TI - Particle sizing of aerosols by single particle observation in a sedimentation cell. JO - Atmos. Environ. VL - 9 IS - 9 PY - 1975 SN - 1352-2310 ER -