My research is focused on understanding the emissions and chemical transformation of volatile organic compounds (VOCs) in Earth's atmosphere. Specifically, I evaluate and quantify anthropogenic and natural emissions that lead to the formation of hazardous pollutants, such as ozone and secondary organic aerosol. I measure VOCs using a state-of-the-art proton-transfer-reaction mass spectrometer, which we deploy on aircraft and mobile laboratories to measure emissions from various sources. So far, we've targeted emissions from wildfire plumes, concentrated animal feed lots, oil and natural gas development, vehicle tailpipes, populated urban centers, and forested regions of the Western U.S.
Currently, I am studying the emissions from two understudied sources of pollution - wildfires and volatile chemical products.
(1) Wildfire Emissions
Biomass burning is a major source of particulate matter and volatile organic compounds (VOCs) to Earth's atmosphere. In the Western United states, the frequency and intensity of wildfires has increased, leading to higher incidents of hazardous air pollution in populated urban areas during the summer months. Since 2016, our lab has been studying the chemical complexity and atmospheric chemistry of wildfire emissions with an aim of understanding how these emissions lead to the formation of ozone and PM2.5, which are criterion pollutants that impact human health. Our work began with the Firelab 2016 campaign, which evaluated the the emissions and variability of VOCs and reactive nitrogen species, as well as the atmospheric chemistry of key VOCs emitted from fires, such as furanoids.
In summer 2019, we participated in the FIREX-AQ field campaign to characterize wildfire VOCs. We deployed our mass spectrometer onboard the NASA DC-8 aircraft and sampled smoke in and around large wildfire plumes to understand how much these emissions impact downwind air quality. We are currently analyzing these data in order to improve models used to simulate air quality. For more information about our work on wildfire chemistry, see our StoryMap.
(1) Volatile Chemical Products
Poor air quality impacts major cities across the world. For decades, vehicles emissions were the dominant source of air pollution in US cities. However, regulations and improvements in technology have drastically reduced vehicle pollution. For example, VOCs emitted from vehicle tailpipes have decreased by a factor of 100 from their 1960s levels in major cities like Los Angeles. Air in LA is much cleaner than it used to be, but there are still days in which air quality indices exceed acceptable levels considered to be healthy. Recent work has shown that, today, emissions from consumer products (e.g. personal care products, paints, and cleaners) are just as likely to contribute to urban air pollution as vehicle tailpipe emissions. For example, we have found that evaporation of deodorant and hair care products can lead to VOC emissions that are comparable to regional emission rates of certain pollutants from vehicle tailpipes.
Little is known about these emissions and how the lead to ozone and PM pollution. In 2018, we deployed our mass spectrometer on a mobile laboratory to measure consumer product emissions in New York City. Our recent work has shown that these emissions significantly contribute to urban ozone and can modulate the abundance of other atmospheric products. The upcoming AEROMMA field campaign will assess how these emissions, and other sources contribute, influence the modern urban atmosphere. For more information about our work on urban air quality, see our StoryMap.
Honors and Awards
- CIRES Outstanding Performance Award (2021)
- CIRES Administrator Award for FIREX-AQ (2021)
- NASA Group Achievement Award for FIREX-AQ (2021)
- CO-LABS Governer's Award for High Impact Research (Honorable Mention, 2019)
- CIRES Visiting Fellowship (2015)