The influence of oil and gas end-use activities on ambient air quality is complex and understudied, particularly in regions where intensive end-use activities and large biogenic emissions of isoprene coincide. In these regions, vehicular emissions of nitrogen oxides (NO≡NO + NO) modulate the oxidative fate of isoprene, a biogenic precursor of the harmful air pollutants ozone, formaldehyde, and particulate matter (PM). Here, we investigate the direct and indirect influence of the end-use emissions on ambient air quality.
View Article and Find Full Text PDFDespite declines in transportation emissions, urban North America and Europe still face unhealthy air pollution levels. This has challenged conventional understanding of the sources of their volatile organic compound (VOC) precursors. Using airborne flux measurements to map emissions of a wide range of VOCs, we demonstrate that biogenic terpenoid emissions contribute ~60% of emitted VOC OH reactivity, ozone, and secondary organic aerosol formation potential in summertime Los Angeles and that this contribution strongly increases with temperature.
View Article and Find Full Text PDFPrior studies have shown that people of color (POC) in the United States are exposed to higher levels of pollution than non-Hispanic White people. We show that the city of Denver, Colorado, displays similar race- and ethnicity-based air pollution disparities by using a combination of high-resolution satellite data, air pollution modeling, historical demographic information, and areal apportionment techniques. TROPOMI NO columns and modeled PM concentrations from 2019 are higher in communities subject to redlining.
View Article and Find Full Text PDFThe COVID-19 stay-at-home orders issued in the United States caused significant reductions in traffic and economic activities. To understand the pandemic's perturbations on US emissions and impacts on urban air quality, we developed near-real-time bottom-up emission inventories based on publicly available energy and economic datasets, simulated the emission changes in a chemical transport model, and evaluated air quality impacts against various observations. The COVID-19 pandemic affected US emissions across broad-based energy and economic sectors and the impacts persisted to 2021.
View Article and Find Full Text PDFNatural gas flaring is a common practice employed in many United States (U.S.) oil and gas regions to dispose of gas associated with oil production.
View Article and Find Full Text PDFEnviron Sci Technol
December 2023
The extent to which emission control technologies and policies have reduced anthropogenic NO emissions from motor vehicles is large but uncertain. We evaluate a fuel-based emission inventory for southern California during the June 2021 period, coinciding with the Re-Evaluating the Chemistry of Air Pollutants in CAlifornia (RECAP-CA) field campaign. A modified version of the Fuel-based Inventory of Vehicle Emissions (FIVE) is presented, incorporating 1.
View Article and Find Full Text PDFIncreasing trends in biomass burning emissions significantly impact air quality in North America. Enhanced mixing ratios of ozone (O) in urban areas during smoke-impacted periods occur through transport of O produced within the smoke or through mixing of pyrogenic volatile organic compounds (PVOCs) with urban nitrogen oxides (NO = NO + NO) to enhance local O production. Here, we analyze a set of detailed chemical measurements, including carbon monoxide (CO), NO, and speciated volatile organic compounds (VOCs), to evaluate the effects of smoke transported from relatively local and long-range fires on O measured at a site in Boulder, Colorado, during summer 2020.
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