Chemical Characterization and Source Apportionment of Organic Aerosol in New York City Using FIGAERO-CIMS and HR-ToF-AMS as Part of 2023 NYC-METS Campaign

TIANCHANG XU, Ruizhe Liu, Yutong Liang, Taekyu Joo, Mitchell Rogers, Mitchell Alton, Anandi Williams, Jo Machesky, Mia Tran, Minguk Seo, Andrew Lambe, Drew Gentner, Nga Lee Ng, Georgia Institute of Technology

     Abstract Number: 371
     Working Group: Coast to Coast Campaigns on Aerosols, Clouds, Chemistry, and Air Quality

Abstract
The formation and evolution of organic aerosol (OA) are investigated as part of the summer 2023 NYC-METS (New York City metropolitan Measurements of Emissions and TransformationS) campaign from July to August 2023. We deploy two online instruments simultaneously to measure OA composition and concentrations: the high-resolution time-of-flight aerosol mass spectrometer (AMS) and the Filter Inlet for Gases and AEROsols coupled to a high-resolution time-of-flight iodide-adduct chemical ionization mass spectrometer (FIGAERO-CIMS). We conduct factorization analysis (PMF) of data obtained from both instruments to understand the sources of OA measured at the campaign. The speciated OA measurements by the FIGAERO-CIMS allow for additional new insights into the sources and composition determined from factor analysis on AMS data alone. Specifically, FIGAERO-CIMS data can aid in the determination of chemical oxidation reactions that lead to the formation of less-oxidized oxygenated OA (LO-OOA) and more-oxidized oxygenated OA (MO-OOA) because they offer molecular information of compounds, instead of fragments in AMS, that allows us to compare FIGAERO results directly with proposed reactants from different oxidation reactions. Both instruments capture aerosol formed from biomass burning events and at different oxidation states from LO-OOA to MO-OOA, but OA measured from FIGAERO-CIMS display a higher oxidation state due to the instrument’s measurement selectivity to highly oxidized compounds. In addition, the molecular and volatility information from FIGAERO-CIMS factorization analysis can also identify the types of reactions, such as oxidation of phenolic compounds in biomass burning events, that contribute to SOA formation. Results from this study highlight the importance and advanced technical capability of deploying both HR-ToF-AMS and FIGAERO-CIMS in OA measurements to gain new insights into the sources and reactions contributing to OA emissions and formation.