Space-based Views on the Photochemical Environment Shaping Air Pollution along Urban-to-rural transects over the Northeastern U.S.A. (Invited Presentation)

Despite impressive progress in reducing the highest air pollution concentrations over the United States, many regions face major challenges to attain tighter health-based National Ambient Air Quality Standards (NAAQS) for ozone and fine particles. Over the Northeastern United States, a quantitative understanding of the relative contributions of local nitrogen oxide (NO_x) and volatile organic compound (VOC) emissions to producing the highest ozone events is lacking. We present examples from ongoing work, including under the NASA Health and Air Quality Applied Sciences Team (HAQAST) Tiger Team (“Analysis to support air quality and health TEMPO applications for surface ozone”) that investigate the information content of satellite products for describing the near-surface photochemical environment during high-ozone events. We focus on applications using tropospheric column nitrogen dioxide (NO₂, a component of NO_x) and formaldehyde (HCHO, a proxy for VOC) retrieved from the TROPOMI (afternoon overpass, launched in 2017) and/or TEMPO (staring at North America throughout daylight hours, launched in 2023) satellite instruments. Drawing on a suite of ground-based in situ and remotely sensed measurements available during the summer 2018 Long Island Sound Tropospheric Ozone Study (LISTOS) field campaign in the New York City metropolitan area, we examine spatial and temporal relationships between tropospheric column and surface concentrations of NO₂ and HCHO, and interpret their relevance to the products retrieved from satellite instruments. A preliminary analysis of multiple TROPOMI products (aerosol layer height, CO, in addition to HCHO and NO₂) during a high-ozone event when smoke from distant fires was transported into the region indicates promise for characterizing ozone-forming chemical conditions associated with smoke plumes. We will highlight throughout how analysis of satellite products alongside models and suborbital datasets can inform the implementation of effective air quality policy. Disclaimer: The views expressed in this abstract are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency.