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Betito, G.* ; Catipay-Jamero, G.* ; Alas, H.* ; Birmili, W.* ; Cambaliza, M.O.* ; Cayetano, M.* ; Cohen, D.M.* ; Cruz, M.* ; Galvez, M.C.D.* ; Jagonoy, A.* ; Kecorius, S. ; Lorenzo, G.R.* ; Madueno, L.* ; Müller, T.* ; Pabroa, P.C.* ; Simpas, J.B.* ; Sorooshian, A.* ; Tamayo, E.G.* ; Vallar, E.A.* ; Weinhold, K.* ; Wiedensohler, A.*

Two approaches to mass closure analysis for carbon-rich aerosol in Metro Manila, Philippines.

Environ. Sci. - Atmospheres 5, 714-728 (2025)
Publ. Version/Full Text Research data DOI
Open Access Gold
Creative Commons Lizenzvertrag
In this paper, we investigate physico-chemical properties of particulate matter (PM) at an urban mixed site (UB) and two roadside (RS) sites during the 2015 Metro Manila Aerosol Characterization Experiment (MACE). Aerosol particle number size distributions (0.01-10 μm diameter) were measured using a combination of a mobility particle size spectrometer and aerodynamic particle size spectrometers. PM2.5 filter samples were analyzed for total mass, organic carbon (OC), elemental carbon (EC), water-soluble inorganic ions, and elemental species. Mass closure between the gravimetric mass, chemical composition, and mass concentration derived from the number size distribution was performed. We found that the bulk PM2.5 mass was dominated by carbonaceous materials, followed by secondary inorganic aerosols and crustal matter at all sites. The average OC/EC ratios at the RS sites (0.16-1.15) suggest that a major fraction of the aerosol mass at these sites derives from traffic sources, while the OC/EC ratio at the UB site (2.92) is indicative of a more aged aerosol, consistent with greater contribution from secondary organic carbon (SOC) formation. The ultrafine particles (UFPs, diameter < 100 nm) dominated (89-95%) the total particle number concentration at the three sites, highlighting the importance of such measurements in this region. However, UFPs have low mass contribution to PM2.5 (7-18%), while particles in the accumulation mode (diameter 100-1000 nm) accounted for most of the number-derived PM2.5 mass concentration (61-67%). On average, strong agreement between the chemically-derived mass and the gravimetric mass was found (slope = 1.02; r2 = 0.94). The number-derived mass concentration correlated well with the gravimetric PM2.5 mass (slope = 1.06; r2 = 0.81). These results highlight the need for more comprehensive PM characterization, particularly focusing on size-resolved chemical composition and particle number size distributions. The mass closure approach presented in this work provides a framework for a conversion between number size distributions and PM2.5 mass concentration in real time in an environment with similar characteristics.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Aerodynamic Diameter Measurements; Differential Mobility Analyzer; Particle-size Spectrometers; Particulate Matter; Source Apportionment; Organic-carbon; Chemical-characterization; Ultrafine Particles; Air-quality; Urban Air
ISSN (print) / ISBN 2634-3606
e-ISSN 2634-3606
Journal Environmental Science: Atmospheres
Quellenangaben Volume: 5, Issue: 6, Pages: 714-728 Article Number: , Supplement: ,
Publisher Royal Society of Chemistry (RSC)
Publishing Place Thomas Graham House, Science Park, Milton Rd, Cambridge Cb4 0wf, Cambs, England
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Institute of Epidemiology (EPI)
Grants NASA
DOST-Accelerated Science and Technology Human Resource Development Program (ASTHRDP) scholarship
ADMU Research Council
German Federal Ministry of Education and Research
Leibniz-Institut fur Tropospharenforschung e.V. (TROPOS)
Researchers for Clean Air, Inc.