Distributions and Correlations of Volatile Organic Compounds (VOCs) during AEROMMA 2023

Volatile organic compounds (VOCs) have both natural and anthropogenic sources and are ingredients for ground level ozone and particle formation, both of which degrade air quality and adversely impact human health. Long-term reductions in urban VOC sources, such as motor vehicles emissions, have resulted in volatile chemical products (VCPs) becoming the dominant anthropogenic VOC source sector in densely populated areas. VCPs include personal care products, paints, adhesives, cleaning agents, and more. VCP emissions are not well understood in part due to the diverse product composition and usage.

The summer 2023 Atmospheric Emissions and Reactions Observed from Megacities to Marine Areas (AEROMMA) campaign utilized multiple airborne and stationary platforms outfitted with a large suite of gas and aerosol instrumentation in order to investigate urban and marine emissions with a focus on how tropospheric composition, including VCPs, impacts air quality and climate over North America. A full suite of VOCs was measured on board the NASA DC-8 research aircraft via the NOAA integrated Whole Air Sampling System with offline analysis vis gas chromatography mass spectrometry (iWAS/GC-MS) and several on-line chemical ionization mass spectrometers. Over 2000 iWAS samples were collected during AEROMMA including 536 for New York City, 510 for Los Angeles, and 524 for Chicago.

This presentation focuses on NASA DC-8 airborne measurements highlighting VOC distributions and emission characterization over major North American cities. We found that during AEROMMA eastern cities were impacted by biomass burning. Additionally, Los Angeles had higher mixing ratios of iso-octane and 1,3-diclorobenzene compared to eastern cites indicative of mobile sources and pesticide usage, respectively. We will also compare AEROMMA iWAS data to mobile and ground data including the 2021 SUNVEX campaign in Los Angeles, CA and 2024 USOS campaign in Salt Lake City, UT.