Effects of Emissions, Transport, and Chemistry on Prediction of Air Quality Impacts from Fires

Abstract:

Air quality forecasts using regional chemical models provide key information for affected communities and smoke management efforts, yet many models fail to accurately predict ozone (O₃) and particulate matter levels during fire events. Our research aims to improve process-level understanding and model representations of fire emissions, plume rise, and chemistry, with the aim of developing a better capability to predict air quality and weather in fire-affected regions. We simulate the 2019 U.S. fire season with the Weather Research and Forecasting with Chemistry (WRF-Chem) model. Simulated trace gas and aerosol fields are compared with aircraft and ground-based data from the NOAA/NASA Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field campaign, surface network observations, satellite retrievals, and regional smoke tracer simulations with the High Resolution Rapid Refresh – Smoke (HRRR-Smoke) system. Hourly fire emissions based on Geostationary Operational Environmental Satellite (GOES)-16/17 fire radiative power are implemented in WRF-Chem and compared with emissions estimates based on field measurements and satellite data. Emission factors and fuel types and loadings are updated based on laboratory and field observations. Uncertainties in plume injection heights in the model are quantified by comparison with aircraft- and satellite-based estimates. WRF-Chem simulations are used to quantify fire air quality impacts and examine formation and aging mechanisms for O₃ and secondary organic aerosol.