TY  - JOUR
AB  - Recent advancements in single-particle mass spectrometry (SPMS) have enabled the detection of aromatic hydrocarbons at the individual particle level in conjunction with inorganic/refractory particle components. However, the laser desorption (LD) of organic material from particles prior to their ionization in a two-step process necessitates pulsed infrared lasers with adequate pulse energy that can be irregularly triggered on detected particles. Pulsed CO2 lasers with a 10.6 µm wavelength have been traditionally utilized, yet these lasers are bulky and costly and require regular maintenance, including gas exchange or a continuous laser gas supply. In this study, we present the application of a prototype solid-state laser based on an erbium-doped yttrium aluminum garnet (Er:YAG) crystal, emitting long pulses of 200 µs at 3 µm wavelength as a compact, cost-effective, and user-friendly alternative for LD. We directly compared the new laser with a commonly used CO2 laser and found similar performance in LD for both laboratory particles and ambient air experiments. With the exception of slightly increased fragmentation observed with the CO2 laser due to its beam profile, no qualitative differences were noted in the resulting mass spectra. Additionally, we compared a novel two-step ionization (LD-REMPI–LDI) with the conventional single-step LDI regarding the potential to detect polycyclic aromatic hydrocarbons (PAHs) and inorganics in laboratory and field experiments. The combined methods demonstrated superior performance in the detection of PAHs, for both the CO2 and the new Er:YAG laser. In addition to its higher sensitivity and lower fragmentation for PAHs when compared to single-step LDI, it is less dependent on the particle matrix, sharing the benefits of traditional two-step methods but extending its capability to combine PAH measurements with the LDI-based detection of inorganic particle compounds.
AU  - Schmidt, M.
AU  - Hakkim, H.
AU  - Anders, L.
AU  - Kalamašņikovs, A.
AU  - Kröger-Badge, T.
AU  - Irsig, R.*
AU  - Graf, N.*
AU  - Kelnberger, R.*
AU  - Passig, J.
AU  - Zimmermann, R.
C1  - 74914
C2  - 57658
CY  - Bahnhofsallee 1e, Gottingen, 37081, Germany
SP  - 2425-2437
TI  - A solid-state infrared laser for two-step desorption–ionization processes in single-particle mass spectrometry.
JO  - Atmos. Meas. Tech.
VL  - 18
IS  - 11
PB  - Copernicus Gesellschaft Mbh
PY  - 2025
SN  - 1867-1381
ER  - 

TY  - JOUR
AB  - The chemical composition of aerosol particles is a key parameter for human health and climate effects. Single-particle mass spectrometry (SPMS) has evolved to a mature technology with unique chemical coverage and the capability to analyze the distribution of aerosol components in the particle ensemble in real time. With the fully automated characterization of the chemical profile of the aerosol particles, selective real-time monitoring of air quality could be performed, e.g., for urgent risk assessments due to particularly harmful pollutants. For aerosol particle classification, mostly unsupervised clustering algorithms (ART-2a, K-means and their derivatives) are used, which require manual postprocessing. In this work, we focus on supervised algorithms to tackle the problem of the automatic classification of large amounts of aerosol particle data. Supervised learning requires data with labels to train a predictive model. Therefore, we created a labeled benchmark dataset containing °1/424000 particles with eight different coarse categories that were highly abundant at a measurement in summer in Central Europe: elemental carbon (EC), organic carbon and elemental carbon (OC-EC), potassium-rich (K-rich), calcium-rich (Ca-rich), iron-rich (Fe-rich), vanadium-rich (V-rich), magnesium-rich (Mg-rich) and sodium-rich (Na-rich). Using the chemical features of particles, the performance of the following classical supervised algorithms was tested: K-nearest neighbors, support vector machine, decision tree, random forest and multi-layer perceptron. This work shows that despite the entrenched position of unsupervised clustering algorithms in the field, the use of supervised algorithms has the potential to replace the manual step of clustering algorithms in many applications, where real-time data analysis is essential. For the classification of the eight classes, the prediction accuracy of several supervised algorithms exceeded 97%. The trained model was used to classify °1/449000 particles from a blind dataset in 0.2s, taking into account also a class of "unclassified"particles. The predictions are highly consistent with the results obtained in a previous study using ART-2a.
AU  - Wang, G.*
AU  - Ruser, H.*
AU  - Schade, J.*
AU  - Passig, J.
AU  - Adam, T.
AU  - Dollinger, G.*
AU  - Zimmermann, R.
C1  - 70012
C2  - 55360
CY  - Bahnhofsallee 1e, Gottingen, 37081, Germany
SP  - 299-313
TI  - Machine learning approaches for automatic classification of single-particle mass spectrometry data.
JO  - Atmos. Meas. Tech.
VL  - 17
IS  - 1
PB  - Copernicus Gesellschaft Mbh
PY  - 2024
SN  - 1867-1381
ER  - 

TY  - JOUR
AB  - The portable microAeth® MA200 (MA200) is widely applied for measuring black carbon in human exposure profiling and mobile air quality monitoring. Due to it being relatively new on the market, the field lacks a refined assessment of the instrument's performance under various settings and data post-processing approaches. This study assessed the mobile real-time performance of the MA200 to determine a suitable noise reduction algorithm in an urban area, Augsburg, Germany. Noise reduction and negative value mitigation were explored via different data post-processing methods (i.e., local polynomial regression (LPR), optimized noise reduction averaging (ONA), and centred moving average (CMA)) under common sampling interval times (i.e., 5, 10, and 30ĝ€¯s). After noise reduction, the treated data were evaluated and compared by (1) the amount of useful information attributed to retention of microenvironmental characteristics, (2) the relative number of negative values remaining, (3) the reduction and retention of peak samples, and (4) the amount of useful signal retained after correction for local background conditions. Our results identify CMA as a useful tool for isolating the central trends of raw black carbon concentration data in real time while reducing nonsensical negative values and the occurrence and magnitudes of peak samples that affect visual assessment of the data without substantially affecting bias. Correction for local background concentrations improved the CMA treatment by bringing nuanced microenvironmental changes into view. This analysis employs a number of different post-processing methods for black carbon data, providing comparative insights for researchers looking for black carbon data smoothing approaches, specifically in a mobile monitoring framework and data collected using the microAeth® series of Aethalometer.
AU  - Liu, X.
AU  - Hadiatullah, H.*
AU  - Zhang, X.*
AU  - Hill, L.D.*
AU  - White, A.H.A.*
AU  - Schnelle-Kreis, J.
AU  - Bendl, J.
AU  - Jakobi, G.
AU  - Schloter-Hai, B.
AU  - Zimmermann, R.
C1  - 62781
C2  - 51059
CY  - Bahnhofsallee 1e, Gottingen, 37081, Germany
SP  - 5139-5151
TI  - Analysis of mobile monitoring data from the microAeth® MA200 for measuring changes in black carbon on the roadside in Augsburg.
JO  - Atmos. Meas. Tech.
VL  - 14
IS  - 7
PB  - Copernicus Gesellschaft Mbh
PY  - 2021
SN  - 1867-1381
ER  - 

TY  - JOUR
AB  - Ships are among the main contributors to global air pollution, with substantial impacts on climate and public health. To improve air quality in densely populated coastal areas and to protect sensitive ecosystems, sulfur emission control areas (SECAs) were established in many regions of the world. Ships in SECAs operate with low-sulfur fuels, typically distillate fractions such as marine gas oil (MGO). Alternatively, exhaust gas-cleaning devices (“scrubbers”) can be implemented to remove SO2 from the exhaust, thus allowing the use of cheap high-sulfur residual fuels. Compliance monitoring is established in harbors but is difficult in open water because of high costs and technical limitations. Here we present the first experiments to detect individual ship plumes from distances of several kilometers by single-particle mass spectrometry (SPMS). In contrast to most monitoring approaches that evaluate the gaseous emissions, such as manned or unmanned surveillance flights, sniffer technologies and remote sensing, we analyze the metal content of individual particles which is conserved during atmospheric transport. We optimized SPMS technology for the evaluation of residual fuel emissions and demonstrate their detection in a SECA. Our experiments show that ships with installed scrubbers can emit PM emissions with health-relevant metals in quantities high enough to be detected from more than 10 km distance, emphasizing the importance of novel exhaust-cleaning technologies and cleaner fuels. Because of the unique and stable signatures, the method is not affected by urban background. With this study, we establish a route towards a novel monitoring protocol for ship emissions. Therefore, we present and discuss mass spectral signatures that indicate the particle age and thus the distance to the source. By matching ship transponder data, measured wind data and air mass back trajectories, we show how real-time SPMS data can be evaluated to assign distant ship passages.
AU  - Passig, J.
AU  - Schade, J.*
AU  - Irsig, R.*
AU  - Li, L.*
AU  - Li, X.*
AU  - Zhou, Z.*
AU  - Adam, T.
AU  - Zimmermann, R.
C1  - 62260
C2  - 50755
CY  - Bahnhofsallee 1e, Gottingen, 37081, Germany
SP  - 4171-4185
TI  - Detection of ship plumes from residual fuel operation in emission control areas using single-particle mass spectrometry.
JO  - Atmos. Meas. Tech.
VL  - 14
IS  - 6
PB  - Copernicus Gesellschaft Mbh
PY  - 2021
SN  - 1867-1381
ER  - 

TY  - JOUR
AB  - Detailed characterization and classification of precipitation is an important task in atmospheric research. Line scanning 2-D video disdrometer devices are well established for rain observations. The two orthogonal views taken of each hydrometeor passing the sensitive area of the instrument qualify these devices especially for detailed characterization of nonsymmetric solid hydrometeors. However, in case of solid precipitation, problems related to the matching algorithm have to be considered and the user must be aware of the limited spatial resolution when size and shape descriptors are analyzed. Clarifying the potential of 2-D video disdrometers in deriving size, velocity and shape parameters from single recorded pictures is the aim of this work. The need of implementing a matching algorithm suitable for mixed- and solid-phase precipitation is highlighted as an essential step in data evaluation. For this purpose simple reproducible experiments with solid steel spheres and irregularly shaped Styrofoam particles are conducted. Self-consistency of shape parameter measurements is tested in 38 cases of real snowfall. As a result, it was found that reliable size and shape characterization with a relative standard deviation of less than 5 % is only possible for particles larger than 1 mm. For particles between 0.5 and 1.0 mm the relative standard deviation can grow up to 22 % for the volume, 17 % for size parameters and 14 % for shape descriptors. Testing the adapted matching algorithm with a reproducible experiment with Styrofoam particles, a mismatch probability of less than 3 % was found. For shape parameter measurements in case of real solid-phase precipitation, the 2-DVD shows self-consistent behavior.
AU  - Bernauer, F.
AU  - Hürkamp, K.
AU  - Rühm, W.
AU  - Tschiersch, J.
C1  - 46673
C2  - 37674
CY  - Gottingen
SP  - 3251-3261
TI  - On the consistency of 2-D video disdrometers in measuring microphysical parameters of solid precipitation.
JO  - Atmos. Meas. Tech.
VL  - 8
IS  - 8
PB  - Copernicus Gesellschaft Mbh
PY  - 2015
SN  - 1867-1381
ER  - 

TY  - JOUR
AB  - Source apportionment and characterization of primary and secondary aerosols remains a challenging research field. In particular, the organic composition of primary particles and the formation mechanism of secondary organic aerosols (SOAs) warrant further investigations. Progress in this field is strongly connected to the development of novel analytical techniques. In this study an off-line aerosol mass spectrometric technique based on filter samples, a hyphenated thermal-optical analyzer photo-ionization time-of-flight mass spectrometer (PI-TOFMS) system, was developed. The approach extends the capability of the widely used particulate matter (PM) carbon analysis (for elemental / organic carbon, EC / OC) by enabling the investigation of evolved gaseous species with soft and selective (resonance enhanced multi-photon ionization, REMPI) and non-selective photo-ionization (single-photon ionization, SPI) techniques. SPI was tuned to be medium soft to achieve comparability with results obtained by the electron ionization aerosol mass spectrometer (AMS). Different PM samples including wood combustion emission samples, smog chamber samples from the reaction of ozone with different SOA precursors, and ambient samples taken at Ispra, Italy, in winter as well as in summer were tested. The EC / OC-PI-TOFMS technique increases the understanding of the processes during thermal-optical analysis and identifies marker substances for the source apportionment. Composition of oligomeric or polymeric species present in PM can be investigated by the analysis of the thermal breakdown products. In the case of wood combustion, in addition to the well-known markers at m/z ratios of 60 and 73, two new characteristic masses (m/z 70 and 98) have been revealed as potentially linked to biomass burning. All four masses were also the dominant signals in an ambient sample taken in winter time in Ispra, Italy, confirming the finding that wood burning for residential heating is a major source of PM in winter at this location. The summer sample from the same location showed no influence of wood burning, but seems to be dominated by SOAs, which was confirmed from the comparison with chamber experiment samples. The experiments conducted with terpenes as precursors showed characteristic masses at m/z 58 and 82, which were not observable in any other emission samples and could serve as a marker for SOA from terpenes.
AU  - Diab, J.*
AU  - Streibel, T.
AU  - Cavalli, F.*
AU  - Lee, S.C.*
AU  - Saathoff, H.*
AU  - Mamakos, A.*
AU  - Chow, J.C.*
AU  - Chen, L.W.A.*
AU  - Watson, J.G.*
AU  - Sippula, O.*
AU  - Zimmermann, R.
C1  - 46664
C2  - 37683
CY  - Gottingen
SP  - 3337-3353
TI  - Hyphenation of a EC / OC thermal-optical carbon analyzer to photo-ionization time-of-flight mass spectrometry: An off-line aerosol mass spectrometric approach for characterization of primary and secondary particulate matter.
JO  - Atmos. Meas. Tech.
VL  - 8
IS  - 8
PB  - Copernicus Gesellschaft Mbh
PY  - 2015
SN  - 1867-1381
ER  - 

TY  - JOUR
AB  - The monosaccharide anhydrides (MAs) levoglucosan, galactosan and mannosan are products of incomplete combustion and pyrolysis of cellulose and hemicelluloses, and are found to be major constituents of biomass burning (BB) aerosol particles. Hence, ambient aerosol particle concentrations of levoglucosan are commonly used to study the influence of residential wood burning, agricultural waste burning and wildfire emissions on ambient air quality. A European-wide intercomparison on the analysis of the three monosaccharide anhydrides was conducted based on ambient aerosol quartz fiber filter samples collected at a Norwegian urban background site during winter. Thus, the samples' content of MAs is representative for BB particles originating from residential wood burning. The purpose of the intercomparison was to examine the comparability of the great diversity of analytical methods used for analysis of levoglucosan, mannosan and galactosan in ambient aerosol filter samples. Thirteen laboratories participated, of which three applied high-performance anion-exchange chromatography (HPAEC), four used high-performance liquid chromatography (HPLC) or ultra-performance liquid chromatography (UPLC) and six resorted to gas chromatography (GC). The analytical methods used were of such diversity that they should be considered as thirteen different analytical methods. All of the thirteen laboratories reported levels of levoglucosan, whereas nine reported data for mannosan and/or galactosan. Eight of the thirteen laboratories reported levels for all three isomers. The accuracy for levoglucosan, presented as the mean percentage error (PE) for each participating laboratory, varied from g'63 to 20%; however, for 62% of the laboratories the mean PE was within ±10%, and for 85% the mean PE was within ±20%. For mannosan, the corresponding range was g'60 to 69%, but as for levoglucosan, the range was substantially smaller for a subselection of the laboratories; i.e. for 33% of the laboratories the mean PE was within ±10%. For galactosan, the mean PE for the participating laboratories ranged from g'84 to 593%, and as for mannosan 33% of the laboratories reported a mean PE within ±10%. The variability of the various analytical methods, as defined by their minimum and maximum PE value, was typically better for levoglucosan than for mannosan and galactosan, ranging from 3.2 to 41% for levoglucosan, from 10 to 67% for mannosan and from 6 to 364% for galactosan. For the levoglucosan to mannosan ratio, which may be used to assess the relative importance of softwood versus hardwood burning, the variability only ranged from 3.5 to 24 . To our knowledge, this is the first major intercomparison on analytical methods used to quantify monosaccharide anhydrides in ambient aerosol filter samples conducted and reported in the scientific literature. The results show that for levoglucosan the accuracy is only slightly lower than that reported for analysis of SO42-(sulfate) on filter samples, a constituent that has been analysed by numerous laboratories for several decades, typically by ion chromatography and which is considered a fairly easy constituent to measure. Hence, the results obtained for levoglucosan with respect to accuracy are encouraging and suggest that levels of levoglucosan, and to a lesser extent mannosan and galactosan, obtained by most of the analytical methods currently used to quantify monosaccharide anhydrides in ambient aerosol filter samples, are comparable. Finally, the various analytical methods used in the current study should be tested for other aerosol matrices and concentrations as well, the most obvious being summertime aerosol samples affected by wildfires and/or agricultural fires.
AU  - Yttri, K.E.*
AU  - Schnelle-Kreis, J.
AU  - Maenhaut, W.*
AU  - Abbaszade, G.
AU  - Alves, C.A.*
AU  - Bjerke, A.*
AU  - Bonnier, N.*
AU  - Bossi, R.*
AU  - Claeys, M.*
AU  - Dye, C.*
AU  - Evtyugina, M.G.*
AU  - García Gacio, D.*
AU  - Hillamo, R.E.J.*
AU  - Hoffer, A.G.*
AU  - Hyder, M.*
AU  - Iinuma, Y.*
AU  - Jaffrezo, J.L.*
AU  - Kasper-Giebl, A.*
AU  - Kiss, G.*
AU  - López-Mahía, P.L.*
AU  - Pio, C.*
AU  - Piot, C.*
AU  - Ramirez-Santa-Cruz, C.*
AU  - Sciare, J.*
AU  - Teinilä, K.*
AU  - Vermeylen, R.*
AU  - Vicente, A.M.*
AU  - Zimmermann, R.
C1  - 43101
C2  - 36033
CY  - Gottingen
SP  - 125-147
TI  - An intercomparison study of analytical methods used for quantification of levoglucosan in ambient aerosol filter samples.
JO  - Atmos. Meas. Tech.
VL  - 8
IS  - 1
PB  - Copernicus Gesellschaft Mbh
PY  - 2015
SN  - 1867-1381
ER  - 

TY  - JOUR
AB  - The aerosol light absorption coefficient is an essential parameter involved in atmospheric radiation budget calculations. The Aethalometer (AE) has the great advantage of measuring the aerosol light absorption coefficient at several wavelengths, but the derived absorption coefficients are systematically too high when compared to reference methods. Up to now, four different correction algorithms of the AE absorption coefficients have been proposed by several authors. A new correction scheme based on these previously published methods has been developed, which accounts for the optical properties of the aerosol particles embedded in the filter. All the corrections have been tested on six datasets representing different aerosol types and loadings and include multi-wavelength AE and white-light AE. All the corrections have also been evaluated through comparison with a Multi-Angle Absorption Photometer (MAAP) for four datasets lasting between 6 months and five years. The modification of the wavelength dependence by the different corrections is analyzed in detail. The performances and the limits of all AE corrections are determined and recommendations are given.
AU  - Coen, M.C.*
AU  - Weingartner, E.*
AU  - Apituley, A.*
AU  - Ceburnis, D.*
AU  - Fierz-Schmidhauser, R.*
AU  - Flentje, H.*
AU  - Henzing, J.S.*
AU  - Jennings, S.G.*
AU  - Moerman, M.*
AU  - Petzold, A.*
AU  - Schmid, O.
AU  - Baltensperger, U.*
C1  - 5364
C2  - 27619
SP  - 457-474
TI  - Minimizing light absorption measurement artifacts of the Aethalometer: Evaluation of five correction algorithms.
JO  - Atmos. Meas. Tech.
VL  - 3
IS  - 2
PB  - Copernicus
PY  - 2010
SN  - 1867-1381
ER  -