Abstract View
Secondary Organic Aerosol Formation in Regional Scales by Using Multiphase Reaction of Hydrocarbons
ZECHEN YU, Myoseon Jang, Soontae Kim, Jiwon Choi, Azad Madhu, Sanghee Han, Jinsoo Park, University of Florida
Abstract Number: 495
Working Group: Urban Aerosols
Abstract
Secondary organic aerosol (SOA) is one of the major components in ambient fine particulate matter. This SOA is formed through atmospheric oxidation of volatile organic compounds (VOCs) emitted from both anthropogenic and biogenic sources. To date, the prediction of SOA in regional and global scales is traditionally performed by using gas-particle partitioning models. SOA can also be formed by the heterogeneous reactions of semi-volatile organic compounds in aerosol phase. In particular, SOA formation increases via aqueous reactions in the presence of inorganic salted wet aerosols. However, the current air quality models have no features to process aqueous reactions of a variety of oxidized organic products from different hydrocarbons. Using the Unified Partitioning-Aerosol phase Reaction (UNIPAR) model, our research team recently launched the simulation of SOA formation by multiphase reaction of various hydrocarbons in the presence of inorganic aqueous salts under varying NOx, SO2, humidity, and temperature. In this work, the UNIPAR model is incorporated with the Comprehensive Air Quality Model with Extensions (CAMx) to predict the regional concentration of SOA under different urban atmospheres. The model parameters in UNIAPR are unified and optimized for various products originating from the oxidation of different precursors (i.e., aromatics, terpenes, and alkanes) and environmental conditions (i.e., NOx levels and aging). The CAMx-UNIPAR model simulates the air quality appeared during the Korean-United States Air Quality (KORUS-AQ) campaign between May and June in 2016. The predicted SOA is compared with field observations from ground sites and aircraft measurements in different meteorological conditions (dry to wet conditions for inorganic salts) to understand the significance of organic aqueous reactions. The contribution of biogenic emissions and automobile emissions on SOA formation is also evaluated by using CAMx-UNIPAR.