Evaluating Chemical Mechanisms to Improve Understanding of Ozone Formation in Urban Regions

Abstract:

Due to advancements in automotive catalysis, engine efficiency, and control technology, the major volatile organic compound (VOC) precursors leading to urban ozone formation have shifted from the dominance of automotive-related VOCs to a mixture significantly impacted by volatile chemical products (VCPs). The atmospheric chemistry of VCP emissions has not been studied as rigorously as compounds emitted from mobile sources. Therefore, current models lack sufficient chemical detail to accurately model their ozone formation potential. Here, we update the chemical mechanisms of key VCP compounds such as, propylene glycol, glycerol, and isopropyl alcohol, in the Master Chemical Mechanism (MCM v3.3.1). We evaluate the impact of these changes using a 0-D box model designed to simulate ozone production observed during the 2018 New York Investigation of Consumer Emissions (NY-ICE) field study. The chemistry of these compounds is also refined in mechanisms used for 3D models, such as the Regional Atmospheric Chemistry Mechanism. We conduct sensitivity analyses to determine the impact these newly-implemented VCP mechanisms have on the formation of ozone and other photochemically-produced pollutants.