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Characterization of Benzene Polycarboxylic Acids and Nitroaromatics in Atmospheric Aerosols and Vehicular Emitted Particulate Matter using UPLC-ESI-QqQ-MS
MAHMOUD YASSINE, Michal Suski, Ewa Dabek-Zlotorzynska, AAQS, AQRD, Environment Canada
Abstract Number: 93
Working Group: Carbonaceous Aerosol
Abstract
The impact of atmospheric PM2.5 in urban areas on human health, visibility degradation, and global climate change has prompted an increased scientific focus on identifying the components and sources of PM2.5 that are most directly responsible for such effects. Of great interest is the organic fraction, in particular, the water-soluble organic carbon (WSOC), which is composed of a multitude of individual polar oxygenated compounds generated from a variety of sources. Many studies on WSOC speciation have identified several classes of organic species, i.e., mono-, di-, and polycarboxylic acids along with additional functional groups, such as hydroxy-, methoxy-, and/or nitro-groups. Yet, improved molecular characteristics and distribution of WSOC constituents are critically important to gain insights into the sources and the underlying mechanisms of secondary organic aerosol formation and transformation.
This study describes an efficient and reliable ultrahigh pressure liquid chromatography-electrospray ionization-triple quadrupole mass spectrometry (UPLC-ESI-QqQ-MS) method for the simultaneous quantitative determination of 28 analytes distributed among three classes of compounds: (i) benzene polycarboxylic acids; (ii) nitroaromatic acids and (iii) nitrophenols (NPs) in urban PM2.5.and vehicular-emitted samples. Of all samples tested, the highest concentrations of both benzene polycarboxylic and nitroaromatic acids with much lower abundance of NPs were found in the diesel-emitted PM2.5. There were fewer target analytes observed in gasoline-emitted PM2.5. Clear differences in distribution of target species were observed between urban PM2.5 affected by the traffic and biomass burning emissions. This study also focuses on identifying potential compounds that may be used as tracers for specific sources.