Principal Investigator

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Raymond R. Tucker Distinguished InCEES Career Development Associate Professor
Dept. of Energy, Environmental, and Chemical Engineering

B.S., Saint Cloud State University
PhD, University of California - Berkeley


Google Scholar

Professor Williams' research interests focus on the exploration of the composition, chemistry, and physical properties of Earth's atmosphere to determine the role of biogenic and anthropogenic gases and particles in Earth's climate system. Current projects include the study of particle formation from biomass combustion, secondary particle formation from photochemical aging, and novel instrumentation development.

Research and Teaching Award Highlights include:

  • NSF CAREER Award
  • U.S. EPA Early Career Award
  • Department Chair's Outstanding Teaching Award
  • Dean's Award for Excellence in Teaching

PhD Students


PhD Candidate
Energy, Environmental, and Chemical Engineering

B.S. Chemical Engineering '96, University of Arkansas
M.S. Chemical Engineering '99, University of Arkansas

After obtaining his Masters degree, Chris entered industry where he spent nearly 11 years in various engineering and supervisory roles. He resigned after those 11 years to entertain his dream of a PhD and a professorship. In 2011-2012, Chris taught Chemical Engineering classes as an adjunct professor confirming his path. The ACT laboratory welcomed Chris following the 2012-2013 academic cycle. His academic interests include transport phenomena and thermodynamics while his passions outside academia are spent as an avid cyclist and father.



PhD Candidate
Energy, Environmental, and Chemical Engineering

B.A. Chemistry ACS '13, Gustavus Adolphus College

Michael began working with the ACT lab during the summer of 2013 following his graduation from Gustavus Adolphus College. After participating in the East St. Louis field study, he officially joined the lab after his first semester in the EECE PhD program. His research interests revolve around studying the chemical composition of carbonaceous aerosols, and he will continue the development of the VAPS-AMS.


PhD Candidate
Energy, Environmental, and Chemical Engineering

B.S. Chemistry '14, College of William & Mary

Claire graduated from the College of William and Mary in the spring of 2014 and started working in the ACT lab the following summer. Her research interests include characterizing the oxidation chemistry of secondary organic and biomass burning aerosols. She will also be developing a more portable TAG system during her PhD studies at Washington University.

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PhD Candidate
Energy, Environmental, and Chemical Engineering

B.S. Physics, University of Nevada, Reno

Ben's current research focuses on fundamental radiative transfer properties of brown carbon aerosols emitted from smoldering wildfire fuels such as arctic peat. He continues to be involved in instrumentation development, including the construction of a 375 nm photoacoustic spectrometer and development and application of a new biomass burning chamber.  Ben is co-advised by Prof. Rajan Chakrabarty and also works in the AIR Lab at WashU.



PhD Candidate
Energy, Environmental, and Chemical Engineering

B.E. Chemical Engineering '14, Vanderbilt University

Audrey currently works on the development and deployment of lower-cost and portable air sampling instrumentation.  She has recently collaborated with WashU's Institute for Public Health and industry partners Aerodyne Research Inc. to deploy off-grid gas and particle monitors in Cap-Haitien, Haiti.  Audrey also collaborates with Prof. Jay Turner (WashU) on Haiti research and NIH-funded development of a portable volatile organic gas analyzer.

Raul Martinez

PhD Candidate
Energy, Environmental, and Chemical Engineering





graduate student ALUMNI

Yaping Zhang (Ph.D.)

Dhruv Mitroo (Ph.D.)

Peter Mellott (M.S.)

Mayura Patankar (M.Eng.)

Ruijie Yu (M.Eng.)

Xiaochen Zuo (M.Eng.)



Munkhbayar Baasandorj (2014):  Research Scientist

Wei Zhou (2016-2017):  Tsinghua University, School of Environment (Advisor:  Prof. Jingkun Jiang)

Qiongqiong Wang (2017-2018):  Hong Kong University of Science & Technology, Department of Chemistry & Division of Environment (Advisor: Prof. Jian Zhen Yu)


Undergraduate Researchers


Ashley Hesterberg

Riley Martell

Michelle Molina

Charlie Rapp

Skyler Simon

Pietro Vannucci



Blake Actkinson

Jin Hwan Choi

Emma Cotter

Karolina Cysneiros De Carvalho

Austin Darmawan

Steven Dhawan

Nathan Ferree

Ben Fu

William Geyer


David Hagan

Scarlett Li

Chunsoo Park

Julianna Portelli

Purushottam Kumar

Samantha Rosenthal

Taylor Smith

Ana Solorio

Andrew Spitz


Emma Streff

Eric Sussman

William Swanson

Jessica Ulan

Daniel Watson

Alec Wilcosky

Stone Yan

Ruijie Yu

Xiaochen Zuo