Details

Part of the Hixon Center's Climate and Environmental Sciences Colloquium (CLES199)

Shifting patterns of emissions have reduced the importance of anthropogenic fuel-related volatile organic compounds (VOCs) in forming urban pollution, increasing the relative significance of "novel" (i.e., previously underappreciated) sources. These novel VOC emissions include oxygenated organics from personal care products and cooking activities, as well as terpenoids from both anthropogenic and biogenic sources. Such compounds are often poorly represented in air quality and climate models, making it difficult to diagnose their individual effects on atmospheric outcomes of interest.

Kelvin Bates, assistant professor of air quality at University of Colorado Boulder, combines field observations, targeted laboratory experiments and atmospheric modeling to determine the chemistry and the impacts of these compounds. His research team uses mass spectrometric techniques to identify gas-phase tracers of individual emission sources in major U.S. cities. After quantifying their emissions, they replicate the chemistry of VOCs from individual sources in environmental chamber experiments, which enables them to diagnose the atmospheric fates of compounds from each source. They incorporate the chemistry elucidated by their experiments into GEOS-Chem, a global atmospheric chemistry model, and show that organic emissions from cooking, personal care products and urban vegetation are all major contributors to modern U.S. urban air pollution. Moreover, these sources are sufficiently strong and widespread to change atmospheric composition at regional to global scales, with important implications for climate-chemistry feedbacks.