Aerosol Formation from Oil and Gas Development in the Eagle Ford Shale
LEA EL KHOURY, Katarina Konon, Austin Turner, Evelyn Deveraux, Chou-Hsien Lin, Pearl Abue, Shihao Zhai, Albert Kyi, Mrinali Modi, Leif Jahn, Daniel C. Blomdahl, Pawel K. Misztal, Lea Hildebrandt Ruiz, University of Texas at Austin
Abstract Number: 413
Working Group: Coast to Coast Campaigns on Aerosols, Clouds, Chemistry, and Air Quality
Abstract
Oil and gas development (OGD) has grown substantially in the United States; yet, associated airborne emissions and air quality impacts are poorly characterized. Here we combine insights from three ambient measurement campaigns conducted in spring 2021 and spring and fall 2023 in Karnes City, Texas, located in the middle of the Eagle Ford Shale (EFS). We observed episodic high aerosol concentrations in all campaigns, with maximum hourly averaged PM1 (particulate matter with a diameter ≤1 µm) concentrations of 27 µg m-3 in spring 2021, 39 µg m-3 in spring 2023, and 12 µg m-3 in fall 2023. In fall 2023, organic aerosol dominated non-refractory PM1 (60% of the mass on average) while in spring 2021 sulfate and organics were present at similar levels. One of the sulfate sources in the spring was the shipping activity in the Gulf of Mexico southeast of the site. During plume periods in the fall, the organic aerosol formed up to 75% of PM1 and the wind direction was generally from the northeast, where oil and gas well density is higher. Positive matrix factorization analysis showed that the organic aerosol (OA) was primarily oxidized OA (OOA), consistent with the OA being primarily secondary organic aerosol (SOA) formed from volatile organic compound (VOC) oxidation. VOC plumes were followed by OA plumes and gas-phase measurements revealed elevated concentrations of these VOCs including large alkanes and BTEX (benzene, toluene, ethylbenzene, xylenes), which can result in the formation of SOA.
Thus, our measurements suggest that VOCs emitted from OGD result in substantial formation of organic aerosol. This is relevant to air quality within the EFS and other OGD regions, as well as downwind regions such as San Antonio, Texas, which will struggle to meet the new EPA standard for fine particulate matter.