Chemistry of Volatile Organic Compounds in a Changing Atmosphere by Joost de Gouw
Light refreshments will be served after the talk in Room 340.
Volatile organic compounds (VOCs) in the atmosphere can react to form important pollutants such as ozone and secondary organic aerosol, and can also have direct effects on human health. In this seminar, I will present several new insights into the sources and chemistry of VOCs in urban air, from oil and natural gas production and in biomass burning emissions.
Emissions of VOCs from motor vehicles have strongly declined for decades, and as a result, other emission sources such as from the use of volatile chemical products (e.g. cleaners, glues, coatings, solvents and personal care products) have become more important in urban air. I will show how measurements in urban air can be used to determine emissions of reactive VOCs, despite the fact that they can be removed and/or formed in between the time of emission and sampling. As many volatile chemical products are used inside buildings, I will show how measurements of indoor air can be used to determine emissions.
Electric power generation by wind and solar is expanding rapidly, but the use of natural gas power plants to make up demand will likely remain in the foreseeable future. The production of natural gas in the United States is currently at an all-time high. Methane emissions associated with this activity have received much attention because they offset the climate benefits of this lower-carbon fuel. Less attention has been paid to the emissions of air pollutants such as VOCs and nitrogen oxides (NOx). Using results from airborne measurements during the NOAA SONGNEX campaign, I will show that a significant fraction of VOC emissions over the lifecycle of oil and natural gas takes place during production. Using remote sensing measurements made from the Ozone Monitoring Instrument onboard the NASA Aura satellite, I will show that both the drilling of new wells as well as the extraction of fossil fuels that follows contribute to emissions of NOx.
Wildfires in the United States have become more frequent and extensive during a longer wildfire season. Due to the complexity of fuel composition and burning conditions, biomass burning emissions are among the most challenging to analyze chemically, which makes it difficult to describe the atmospheric fate and health effects. Measurements of VOCs from biomass burning emissions were made at the Fire Sciences Laboratory in Missoula, MT during the NOAA FIREX study. I will show how different processes such as distillation and pyrolysis can explain the composition of VOC emissions for different fuels and phases of a burn. I will also show the results from laboratory experiments aimed at elucidating the chemistry of functionalized aromatic compounds that are common from biomass burning.
Finally, I will briefly discuss the development and characterization of new instrumentation for VOC measurements that will likely lead to new discoveries in our science.
Joost de Gouw received a PhD in Physics from the University of Utrecht in the Netherlands in 1994. He is a Senior Research Scientist and Fellow with the Cooperative Institute for Research in Environmental Sciences at the University of Colorado in Boulder, and an Adjoint Professor in the Department of Chemistry and Biochemistry. His research over the past two decades has focused on the sources and chemical transformations of organic compounds in the atmosphere, the formation of ozone and secondary organic aerosol, and the impact that these processes have on air quality, climate change, and human health.