Single-Particle Perspective on Aerosol Sources and Aging in New York City and a Downwind Coastal Site during NYC-METS

KAYLEIGH REILLY, Emily Costa, Yao Xiao, Tiantian Zhu, Xena Mansoura, Zezhen Cheng, Nurun Nahar Lata, Swarup China, Drew Gentner, Rachel O'Brien, Andrew Ault, University of Michigan

     Abstract Number: 660
     Working Group: Coast to Coast Campaigns on Aerosols, Clouds, Chemistry, and Air Quality

Abstract
Understanding the sources and aging of atmospheric aerosols is critical to evaluating their impacts on climate and health. Single-particle analysis can determine the sources of atmospheric aerosols near the point of emission and their evolution through multiphase chemistry (i.e., aging) during transport in the atmosphere. The July-August 2023 New York City metropolitan Measurements of Emissions and TransformationS (NYC-METS) campaign provided a unique opportunity to explore the physicochemical properties of individual particles within a diverse and evolving population at both an urban site and downwind at a coastal Connecticut site. NYC-METS is a part of a larger comprehensive field effort known as AEROMMA, which is an investigation into urban areas to study air quality, atmospheric interactions at the marine-urban interface, and climate change with the ultimate goal of improving our understanding of air pollution. Herein, computer-controlled scanning electron microscopy with energy dispersive x-ray spectroscopy (CC-SEM-EDX) was used to analyze both morphology and elemental compositions of sub- and super-micron aerosol particles at both sites. Additionally, transmission electron microscopy (TEM) was used to gain further insight into morphology of sub-micron aerosol particles. Using these techniques we observe an increased number of sea spray aerosols (SSA) at the coastal site compared to NYC, with a significant fraction showing chloride depletion due to aging. There is also clear evidence of atmospheric processing between the two sites based on the morphology and composition of soot particles. These observations between combustion and marine aerosols provided important contexts to the sources and aging occurring during this campaign. This comparison between the urban and downwind coastal sites is helping to shed light on air pollution sources and evolution, along with its effect on air quality in a highly populated region.