Williams to study airborne gases, particles to determine sources of origin

When walking or driving in an urban area, you may catch smells of food cooking, but is the smell coming from food cooking at a restaurant or from a bus burning biodiesel fuel?

This illustration, drawn by Williams, describes the science approach of his lab.

Brent Williams, the Raymond R. Tucker Distinguished I-CARES Career Development Assistant Professor in the School of Engineering & Applied Science at Washington University in St. Louis, will use a five-year, $500,000 CAREER Award from the National Science Foundation to develop ways to track particles and gases in the air back to their original sources. His project is titled "Laboratory Studies on the Chemical Characterization of Atmospheric Emission Sources and their Oxidative Evolution using Novel Instrumentation."

The CAREER awards support junior faculty who model the role of teacher-scholar through outstanding research, excellent education and the integration of education and research within the context of the mission of their organization. Williams is the 27th faculty member in the School of Engineering & Applied Science to receive the award.

"Brent Williams is an integral member of the Center for Aerosol Science and Engineering (CASE) – a group of seven faculty who work with about 35 PhD students and other researchers," said Pratim Biswas, PhD, the Lucy and Stanley Lopata Professor and chair of the Department of Energy, Environmental & Chemical Engineering. "Brent is not only an active researcher, but has played a leading role in coordinating the efforts of the group. His work on unraveling the organic constituents of aerosols is noteworthy, and some of the instruments he has developed are widely used by researchers across the world to better understand particle formation and impacts on climate change. I have particularly benefited in my collaborative work with him, where we have unraveled the organic constituents of combustion emissions."

Williams' lab has developed new automated research tools that chemically characterize gases and particles from primary sources, or those that come directly from a tailpipe, a smokestack, a tree or food cooking, for example. The laboratory also is equipped to "age" a gas through photochemical oxidation, changing it chemically into a particle and mimicking what happens naturally in the atmosphere: When primary gases are oxidized in the atmosphere, they change their chemical makeup and can become secondary particles. His goal is to get a better understanding of the original sources of both natural and man-made gases and particles in the atmosphere, determine whether they are primary or secondary sources and develop an open-access database that can be used by other researchers and regulatory agencies as they study these particles and gases.

Currently, researchers have a limited understanding of the chemicals released from natural and man-made emission sources and an even more limited understanding of chemical transformations that occur in the atmosphere, said Williams, assistant professor in the Department of Energy, Environmental & Chemical Engineering.

"We need to understand more about the chemistry and oxidative evolution of material in the atmosphere," Williams said. "The limited information we do have from the past few decades is becoming outdated given the use of new fuels, foods, drugs, personal care and cleaning products, industrial and agricultural practices, and anything else you can smell. We also need to determine how these emissions change as they age in the atmosphere so that we can not only recognize them at the source, but also track how they continue to impact air quality and climate downwind of their release locations."

As part of the project, Williams will lead a peer mentoring pipeline program in collaboration with the university's Institute for School Partnership for grade 6-12 students in local schools, who will collect air samples at their schools, then come to his lab to work with undergraduate and graduate students to analyze the air samples for recognizable sources of particles and gases.

In addition, he will coordinate an undergraduate internship program with Aerodyne Research Inc. in Boston, a company where Williams worked to gain non-academic work experience. Engineering students in their junior years can take Williams' course on Atmospheric Science and Climate and work a semester in his lab, then go to Aerodyne Research for a summer internship.

"This gives them hands-on experience in industry and in academic research, helping them to judge which career path fits best," he said.

In 2013, Williams received a nearly $300,000 Early Career grant from the U.S. Environmental Protection Agency (EPA) to bring his expertise in measuring particles in the atmosphere to a national study of the climate trend in the southeastern United States as well as to the St. Louis area.

The School of Engineering & Applied Science at Washington University in St. Louis focuses intellectual efforts through a new convergence paradigm and builds on strengths, particularly as applied to medicine and health, energy and environment, entrepreneurship and security. With 88 tenured/tenure-track and 40 additional full-time faculty, 1,300 undergraduate students, more than 900 graduate students and more than 23,000 alumni, we are working to leverage our partnerships with academic and industry partners — across disciplines and across the world — to contribute to solving the greatest global challenges of the 21st century.