EC-14. Emissions and Chemistry of Volatile Chemical Products in Los Angeles Basin

Volatile chemical products (VCPs) have emerged as the largest source of urban emissions in recent years. The magnitudes of VCPs emissions on urban ozone (O3) and particulate matter (PM) formation remain elusive, due to uncertainties in their emission amounts and atmospheric chemistry. Here, we analyze measurements at a ground site in Pasadena, CA during the SUNVEx (Southwest Urban NOx and VOC Experiment) study in 2020 summer. A wide range of analytical instruments were deployed, including a new Long-Time-of-Flight Mass Spectrometer using NH4+ as reagent ion (i.e., NH4-CIMS) to detect a variety of oxygenated organic compounds. Co-located CIMSs enable the evaluation of the novel NH4+ chemical ionization chemistry. Further, the extensive measurements of VOCs along with their oxidation products in SUNVEx provide insights into the critical roles of VCPs emissions in urban O3 and PM formation. Finally, we evaluate the long-term trend of air quality in Los Angeles Basin, by comparing SUNVEx measurements in 2020 to Calnex measurements in 2010.