We are currently working on several different projects:

We study emissions of volatile organic compounds (VOCs) in urban air and their chemical transformations with the ultimate goal of understanding ozone and organic aerosol formation. Towards these goals we conducted a field study in Los Angeles in the Summer of 2022.
We are interested in the disparities in air pollution exposure. We quantified the differences in NO2 and PM2.5 exposure across Denver and found significantly higher exposures for certain racial and ehnic groups.

We made measurements inside homes that were strongly impacted by smoke from the Marshall Fire in Boulder County in 2021. Some VOCs were enhanced inside these homes after the fire, and we found that their concentrations slowly decreased to more normal levels in 4-6 weeks.
A particular lack in our understanding of fire impacts at the wildland-urban interface are data on the release of VOCs from the burning of building materials. To fill this gap, we participated in a study at Colorado State University in Summer of 2023, where we measured these emissions in the laboratory.
We study wildfire emissions using satellite data from the TROPOMI instrument and found that the chemical composition changes as a fire progresses from more flaming to more smoldering conditions.

Indoor Air

The chemical composition of indoor air has received far less attention than pollution in the ambient atmosphere. We have made measurements inside different buildings on the campus of CU Boulder, including a classroom, art museum, and athletic center.
Our indoor air is now focusing more on the efficacy and side effects of air cleaners. We found that Germicidal UV lamps (GUV) form ozone indoors and are investigating the resulting chemistry when ozone reacts with indoor VOCs.

Oil and natural gas production are at all-time highs in the United States due to the development of horizontal drilling and hydraulic fracturing. We are studying the emissions associated with this industrial activity using data from TROPospheric Monitoring Instrument (TROPOMI). Trends in nitrogen oxide emissions were quantified in the context of the dramatic changes in drilling activity and production that this industry has seen in the past 2 decades. We found that formaldehyde in oil and gas regions is enhanced, mostly as a result of photochemical reactions that transform the emitted hydrocarbons into formaldehyde and other secondary compounds. Our current focus is on the emissions of methane in Colorado.

Nathan Sweet

CECA Member