Modeling SOA Formation from Phenols Using an Updated Gas-Phase Mechanism and Revised SOA Parameters

JIA JIANG, Samiha Binte Shahid, Yanyu Zhang, David R. Cocker III, William P. L. Carter, Kelley Barsanti, University of California, Riverside

     Abstract Number: 654
     Working Group: Aerosol Chemistry

Abstract
The increasing frequency and intensity of wildfires, driven by climate change and human activities, have significant implications for tropospheric chemistry and air quality due to the emission of volatile organic compounds (VOCs). Among these VOCs, phenolic compounds (phenols) are key constituents of wildfire emissions and play a crucial role in atmospheric reactions. Accurate representation of the chemistry of phenols is critical for modeling secondary organic aerosol (SOA) formation when these compounds contribute significantly to emissions. In this study, we present an updated detailed mechanism for phenolic compounds under atmospheric conditions. The reaction schemes integrate existing experimental and theoretical data with estimations derived using the SAPRC Mechanism Generation System (MechGen). This new mechanism was evaluated against data from environmental chamber experiments using the F0AM box modeling framework, with an SOA model based on AERO in CMAQ. The volatility basis set (VBS) parameters were updated to reflect the generally higher SOA yields of phenolics relative to non-oxygenated aromatic compounds. The updated mechanism demonstrates improved accuracy in simulating the oxidation reactions of phenol and substituted phenols, including cresols compared to previous mechanisms, improving predictions of ozone levels and SOA formation.