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Investigating the July 1st/2nd 2018, Pollution Event at Whiteface Mountain with Box Modeling and WRF-Chem
CHRISTOPHER LAWRENCE, Mary Barth, Sara Lance, Paul Casson, Dan Kelting, Elizabeth Yerger, University at Albany, SUNY
Abstract Number: 528
Working Group: Aerosol Chemistry
Abstract
Organic matter is an important constituent of aerosols, comprising 20-90% of aerosol mass. However, despite considerable research, the formation and composition of organic aerosol remain highly uncertain, mainly due to uncertainties related to secondary organic aerosols (SOA), formed from the oxidation of volatile organic compounds (VOCs) into less volatile compounds. The controlling factors for the composition and chemical aging of these VOCs are complicated and can be difficult to predict due to limited observational data, often requiring modeling to investigate. During July 1st/2nd 2018, a pollution event was identified by measurements of cloud water composition and air quality at the summit of Whiteface Mountain in Upstate New York. This pollution event was characterized by high concentrations of water soluble organic carbon, organic acids such as formic and acetic acids, and ammonium. To investigate this event and potentially important SOA precursor gases for this site, a combination of WRF-Chem and the chemical box model BOXMOX were used. WRF-Chem was used to create air-mass trajectories providing input data for BOXMOX which was run along the trajectory. Two chemical mechanisms were used within BOXMOX: the Model for Ozone and Related Chemical Tracers (MOZART) T1 mechanism, comprised of 151 gas-phase species and 352 reactions, and the Master Chemical Mechanism (MCM) 3.3.1., comprised of 143 VOC species and nearly 17,000 reactions. The formation and removal of important SOA gases such as glyoxal, methylglyoxal, formic acid, and acetic acid are compared between the two mechanisms to highlight the importance of reactions that may not be captured in WRF-Chem and MOZART-T1. Due to the similarity of their gas phase chemical mechanisms, outputs from both WRF-Chem and BOXMOX using the MOZART T1 scheme are also compared to investigate the importance of aerosol and aqueous chemistry on SOA precursors.