“The picture we have in our mind of air pollution is black smoke billowing out of a smokestack or tailpipe,” said Gabriel Isaacman-VanWertz, assistant professor of civil and environmental engineering. “But the truth is that it is much more complicated.”

The atmosphere behaves like a giant chemical reactor driven by the sun, Isaacman-VanWertz explained, and major air pollutants like ozone and particulate matter are mostly products of this chemistry. Gases emitted from natural sources mix with emissions from human activities and “cook” in the atmosphere. Precipitation has the potential to wash out these gases before the chemistry produces ozone and particulate matter, but the process is not yet well understood, he said.

Isaacman-VanWertz received a National Science Foundation (NSF) CAREER Award and a Department of Energy Early Career Research Program grant to quantify the removal of those gases from the atmosphere, better understand how quickly this process occurs, and estimate its impacts on concentrations of air pollution around the globe. “We hope this will lead to improved models and better predictions of regional air quality,” he said. His research may also provide fundamental insights into the impact of different types of emissions on the chemistry of the atmosphere. 

These five-year grants are the top honors from these agencies awarded to early-career faculty to lead advances in education and research. 

Isaacman-VanWertz collaborated with researchers at MIT to establish a method for tracking reactions between air and carbon-based compounds. Photo provided by MIT.

Isaacman-VanWertz has been studying the way the atmosphere interacts with organic compounds for several years. In 2018, he was the lead scientist on a study published in Nature Chemistry that established a method of tracking reactions between air and carbon-based compounds. This was the first time this had been done by researchers and aimed to study pollution, smog, and haze in a way that was backed by data depicting a compound’s behavior over time. However, this project led him to wonder whether processes that couldn’t be easily captured in the lab, like rain-out from precipitation, happened fast enough or often enough to interrupt the sun-driven chemistry and reduce the amount of air pollution formed. He found that there was not much data on it so he envisioned a project to fill that gap by measuring the washing-out of gases in real-world and laboratory-generated rain storms. He also realized there was a network of measurements around the globe supported by the Department of Energy that might be useful to understand the global impacts of rain on pollutants.

Isaacman-VanWertz will measure concentrations of the reactive organic gases at an established forested field site and in Blacksburg that account for most of the reactivity of the atmosphere and have the most potential for aerosol formation. He will also build a chamber to simulate rain events and measure how they wash out gases. “As far as I know, this is something that has never been done before, but I have done a lot of modeling and reading to convince myself that it is possible,” he said. Using data from the Department of Energy Atmospheric Radiation Measurement network, he will estimate how fast these gases get washed out around the globe and model how this process affects the formation of pollution.

He hopes the research will contribute to scientific understanding across a range of disciplines, from ecology to public health to climatology. Furthermore, the goal is to translate the core scientific issues into a variety of materials to engage with the public. The NSF grant will support collaborations with regional partners to bring his science to the public and provide valuable opportunities for outreach and broad engagement.

“A major focus of my lab is to develop new methods and approaches for state-of-the-art instrumentation and lower-cost tools to make atmospheric measurements more available,” he said. Through the NSF grant, online educational materials and hands-on activities will be developed and shared through museum programming and on-campus events. He will be working with the Science Museum of Western Virginia to develop an exhibit for the museum floor about the chemistry of the atmosphere, as well as some virtual teaching materials.

“I hope this project will help the public develop a new picture of air pollution in their mind closer to reality, of gases and particles cooking together in the atmosphere,” Isaacman-VanWertz said. 

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