Sources of Particulate Matter and Its Precursors in the El Paso Area
SHIHAO ZHAI, Daniel Sung, Kyle Druckman, Kacper Przykaza, Lea El Khoury, David Sullivan, Pawel K. Misztal, Lea Hildebrandt Ruiz, University of Texas at Austin
Abstract Number: 379
Working Group: Urban Aerosols
Abstract
The region of El Paso, Texas, is frequently affected by haze, with particulate matter (PM) concentrations often exceeding established air quality standards, raising concerns about human exposure and public health. Emissions of particulate matter and its precursors have a variety of source categories in the region, including local and long-range transport of industrial emissions, local dust storms, vehicular emissions involving diesel trucks, and biomass burning emissions. Local meteorological conditions and geographical features can lead to higher frequency temperature inversion events and lower air exchange rates, which results in higher pollutant levels. Although recent data show a decline in the frequency of high ozone events, PM2.5 levels in the region continue to surpass the daily standard of 35 µg/m³. With the recent reduction of the National Ambient Air Quality Standards (NAAQS) for annual average PM2.5 down to 9 µg/m³, understanding the composition and sources of particulate matter has become crucial in avoiding non-attainment status.
During the field campaigns conducted in January and May 2025, we measured mixing ratios of volatile organic compounds (VOCs) and concentrations of fine particulate matter (<1 micron), using an electric mobile van equipped with a Vocus 2R Proton Transfer Reaction Time-of-Flight Mass Spectrometer (Vocus PTR-TOF-MS) and a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) in the El Paso area. Preliminary findings reveal hotspots for different pollutants from various source types and industries. For example, we observed elevated PM concentration near the US-Mexico border with wind from the western direction, suggesting sources from the nearby Mexican city of Juárez. Traffic emissions, mostly from diesel engines, contributed to sudden spikes in organic aerosol levels near major roads. We will present a comprehensive summary of the observations made and results from positive matrix factorization that provide insights into the sources of primary and secondary gas and particle-phase pollutants in the area.