Temperature Dependence of Gas-Phase Precursors of Secondary Organic Aerosol During Summertime in New York City

MIA TRAN, Mitchell Alton, Anita Avery, Minguk Seo, Jo Machesky, Taekyu Joo, Manjula Canagaratna, Jordan Krechmer, Andrew Lambe, Drew Gentner, Yale University

     Abstract Number: 473
     Working Group: Aerosol Processes and Properties in Changing Environments in the Anthropocene

Abstract
Fine mode particulate matter (PM_2.5) is an important criteria pollutant with significant health impacts. Approximately 80-83% of PM_2.5 is organic aerosol, 73-76% of that is secondary organic aerosol (SOA), which is formed via the chemical processing of anthropogenic and biogenic emissions of gas-phase organic compounds in the atmosphere. Previous PM_2.5 measurements in New York City have demonstrated that there is a positive correlation between SOA concentration and ambient temperature, emphasizing the importance of better understanding the influence of temperature on reactive volatile organic compound (VOC) precursor emissions in the context of increasing temperatures and more frequent heat waves. To quantify and further understand the temperature dependence of VOC precursors and their sources in NYC, a suite of VOCs, as well as intermediate volatility organic compounds (IVOCs) and semi-volatile organic compounds (SVOCs), were measured using proton transfer reactor-time of flight mass spectrometry (PTR-ToF-MS) during the NYC-METS (New York City metropolitan Measurements of Emissions and TransformationS) ground campaigns of summer 2022 and 2023. These intensives were associated with the larger AEROMMA (Atmospheric Emissions and Reactions Observed from Megacities to Marine Areas) and AGES+ (AEROMMA+CUPiDS, GOTHAAM, EPCAPE, STAQS) collaborative projects. PTR-ToF-MS data was collected at 4 Hz alongside temperature, wind speed, and wind direction data with a collocated sonic anemometer. The high temporal resolution and broad scope of compounds measured was used to examine temperature dependencies for a diverse range of compounds, while also considering other influential variables, such as population density, source distributions, meteorology, and photochemistry. Additionally, source apportionment via positive matrix factorization (PMF) was performed to identify source factors and their temperature dependence for comparison to individual VOCs.