Anthropogenic VOCs in the Long Island Sound, New York, Airshed and Their Role in Ozone Production

For much of the Eastern U.S., and particularly in the New York-Connecticut region, surface ozone (O₃) concentrations are above the federally mandated 8-hour standard of 70 ppb. Past legislation has controlled both Volatile Organic Compounds (VOCs) and Nitrogen Oxides (NO_x), though most recently NO_x emissions have been the primary focus for decreasing surface O₃ concentrations. Isoprene, a dominant biogenic VOC, is a major precursor to O₃ formation over much of the Eastern U.S. during the summer months. Due to its short lifetime of a few hours, air decoupled from the influence of the terrestrial biosphere may quickly become isoprene depleted, resulting in longer-lived VOCs having a significant impact on tropospheric O₃ production. We expect these VOCs to be particularly important in large urban airsheds with considerable industrial hydrocarbons and other anthropogenic VOC sources, areas that lack sufficient vegetation, and regions over or near large bodies of water. Research aircraft observations acquired in 2017 by the University of Maryland suggest that select anthropogenic VOCs act as important, yet largely overlooked, contributors elevated levels of surface O₃. These data are analyzed to determine O₃ formation potential and the representation of these anthropogenic VOC species in air quality models. Finally, the important ramifications of our research for air quality policy will be discussed.