Investigating Sources of PM2.5 in Texas

Understanding the domestic and international sources of PM_2.5 in Texas is important for Federal Clean Air Act §179b demonstrations, exceptional event demonstrations, and other high-priority policy objectives. In this work, we investigated the sources of fine particulate matter (PM_2.5) pollution in Texas using a variety of models and data analysis techniques. Specifically, we (1) developed methods to rapidly flag sudden increases in hourly PM_2.5 measurements in Texas and evaluate the potential causes of the increase, (2) used positive matrix factorization (PMF) for a selection of sites to determine relative source contributions of five factors to total PM_2.5 observed between 2018 and 2021; and (3) investigated the impact of biomass burning smoke and mineral dust from regions outside the US on PM_2.5 concentrations in Houston, El Paso, and South Texas. Our study provides a framework for assessing sources of NAAQS-relevant anomalies in PM_2.5 which can be readily adapted to other health-relevant air pollutants.