Characteristics of Size - Resolved Organic Aerosols Using Offline Aerosol Mass Spectrometry: NYC-METS, Part of the 2023 AEROMMA Campaign
XU HE, Corin Tyler, Yao Xiao, Emily Costa, Delaney Schulteiss, Kayleigh Reilly, Ruizhe Liu, Athena Xu, Nga Lee Ng, Drew Gentner, Andrew P. Ault, Rachel O'Brien, University of Michigan
Abstract Number: 169
Working Group: Aerosol Chemistry
Abstract
Urban areas often suffer from high ozone and PM events, both of which can have detrimental effects on human health. New York City has periods of high particulate matter (PM) concentrations each summer, much of which is formed through secondary processes. There is a wide range of biogenic and anthropogenic sources, including volatile chemical products (VCPs), that contribute to volatile organic compound (VOC) emissions. Their contribution to the formation of secondary organic aerosols (SOA) in urban environments is not well characterized. To improve our understanding of the changes in the composition and size distribution of urban organic aerosols (OA), aerosol particles were collected at a ground site in Manhattan during the summer of 2023 as part of the Atmospheric Emissions and Reactions Observed from Megacities to Marine Areas (AEROMMA) campaign. The chemical composition and concentration of the aerosols as a function of particle size were analyzed using offline high-resolution time of flight aerosol mass spectrometry (HR-ToF-AMS) and with liquid chromatography (LC)-Orbitrap mass spectrometry. Combining organic family fragment group information obtained from HR-TOF-AMS with the molecular distribution from LC-Orbitrap enabled a detailed characterization of organic aerosol composition across the full-size distribution (56 nm to 5.6 um). Comparison of aerosol composition and organic mass loading under different weather conditions is used to examine the influence of sources on SOA formation. 12 and 24-hour size resolved samples are compared to online data sets collected during the campaign. Both qualitative and quantitative comparison provide insights into characteristics OA mass that are retained during offline analysis. Overall, these results investigating chemical composition, concentration, and urban aerosol size distribution will improve our understanding of OA composition and possible sources within megacities as VOC emissions changes.