Chris Frey

Futrell Distinguished University Professor

  • 919-515-1155
  • Fitts-Woolard Hall 3201

NOTE As of 2/1/2021 Dr. Frey is on leave from NCSU to serve in a leadership role at the U.S. Environmental Protection Agency.  On 1/4/2022 President Biden nominated Dr. Frey for Assistant Administrator of EPA’s Office of Research and Development. Dr. Frey’s nomination was approved and referred to the U.S. Senate by the Senate Environment and Public Works committee on 1/12/2022.  The U.S. Senate confirmed Dr. Frey’s nomination on 5/25/2022.

Dr. Frey is the Glenn E. and Phyllis J. Futrell Distinguished University Professor at North Carolina State University. His research includes measurement and modeling of human exposure to air pollution, measurement and modeling of vehicle emissions, probabilistic and sensitivity analysis methods, and probabilistic assessment of power generation environmental technologies. He has led over 70 research studies, published over 140 peer reviewed journal papers, and delivered over 180 invited talks nationally and internationally. He teaches courses on air pollution control, environmental exposure and risk assessment, and sustainable infrastructure.

Dr. Frey has worked extensively with the U.S. Environmental Protection Agency. His was a AAAS/EPA Environmental Science and Engineering Fellow at ORD’s National Center for Environmental Assessment in 1992 and served a one year IPA assignment as exposure modeling advisor in the National Exposure Research Laboratory from 2006 to 2007. He was a member of the EPA FIFRA Scientific Advisory Panel (2004 to 2006), a member of the EPA Clean Air Scientific Advisory Committee (CASAC) (2008 to 2012), chair of CASAC (2012 to 2015), and a member of the EPA Science Advisory Board (2012 to 2018). He chaired CASAC reviews of lead, nitrogen dioxide, and ozone, and has served on CASAC review panels for all criteria pollutants regulated under the National Ambient Air Quality Standards. He was a member of the CASAC Particulate Matter Review Panel that was dismissed in 2018: under his leadership, the panel reconvened as the Independent Particulate Matter Review Panel.

Dr. Frey has had numerous other science advising and expert roles, including serving on National Research Council (NRC) committees, on the NRC Board of Environmental Studies and Toxicology, on a World Health Organization (WHO) working group on uncertainty in exposure assessment, as a contributor to the U.S. Department of Transportation report to Congress on Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions, as a contributor to NARSTO reports on emission inventories and air quality management, and as an expert and lead author on uncertainty for the Intergovernmental Panel on Climate Change (IPCC) Guidelines on National Greenhouse Gas Emissions. He is a member of the Transportation and Air Quality Committee (ADC20) of the Transportation Research Board and the Publications and Critical Review committees of the Air & Waste Management Association. In 2018, he wrote and delivered the 48th Annual A&WMA Critical Review on “Trends in Onroad Transportation Energy and Emissions.”

Dr. Frey is a Fellow of the Air & Waste Management Association (A&WMA) and of the Society for Risk Analysis (SRA), served on the A&WMA Board of Directors (2015-2018), and was President of SRA in 2006. He received the Chauncey Starr Award from SRA in 1999, the Lyman A. Ripperton Award from A&WMA in 2012, and the Frank A. Chambers Award from A&WMA in 2019. He has a B.S. in mechanical engineering from the University of Virginia, a master of engineering in mechanical engineering from Carnegie Mellon University, and Ph.D. in engineering and public policy from Carnegie Mellon.


Ph.D. 1991

Engineering and Public Policy

Carnegie Mellon University

M.S. 1987

Mechanical Engineering

Carnegie Mellon University

B.S. 1985

Mechanical Engineering

University of Virginia

Research Description

Dr. Frey is interested in air pollution emissions, prevention and control; measurement and modeling of activity, energy use, and emissions of on-road and non-road vehicles; exposure and risk analysis; quantification of variability and uncertainty; modeling and evaluation of energy conversion and emission control technologies.

Honors and Awards

  • Nominated by President Biden and Confirmed by the U.S. Senate as Assistant Administrator of the Office of Research and Development at the U.S. Environmental Protection Agency, 2022
  • Alcoa Foundation Distinguished Engineering Research Award, 2020
  • Frank A. Chambers Excellence in Air Pollution Control Award from the Air & Waste Management Association, 2019
  • Excellence in Review Award from Environmental Science & Technology, 2017
  • Lyman A. Ripperton Environmental Educator Award from the Air & Waste Management Association, 2012
  • Fellow, Air & Waste Management Association, 2008
  • NCSU Alumni Association Outstanding Research Award, 2008
  • Fellow, Society for Risk Analysis, 2006
  • Chauncey Starr Award, Society for Risk Analysis, in recognition of exceptional contributions to the field of Risk Analysis, 1999


Challenges and opportunities for research supporting cumulative impact assessments at the United States environmental protection agency's office of research and development
Tulve, N. S., Geller, A. M., Hagerthey, S., Julius, S. H., Lavoie, E. T., Mazur, S. L., … Frey, H. C. (2024), Lancet Regional Health - Americas, 30.
Contribution of Cold Starts to Real-World Trip Emissions for Light-Duty Gasoline Vehicles
Hu, J., Frey, H. C., & Boroujeni, B. Y. (2023), ATMOSPHERE, 14(1).
Identifying emissions hotspots and strategies to reduce real-world fuel use and emissions for passenger rail: A spatially resolved approach
Rastogi, N., Frey, H. C., & Wei, T. (2023), SCIENCE OF THE TOTAL ENVIRONMENT, 896.
Redefining exposure science to advance research supporting cumulative impacts, environmental justice, and decision-making
Tulve, N. S., Guiseppi-Elie, A., Geller, A. M., Ward-Caviness, C. K., Paul, S. J., Lavoie, E. T., … Frey, H. C. (2023), Journal of Exposure Science and Environmental Epidemiology, 33(6), 843–845.
Simple Diesel Train Fuel Consumption Model for Real-Time Train Applications
Ahn, K., Aredah, A., Rakha, H. A., Wei, T., & Frey, H. C. (2023), ENERGIES, 16(8).
Fuel use and emission rates reduction potential for light-duty gasoline vehicle eco-driving
Intermodal comparison of tailpipe emission rates between transit buses and private vehicles for on-road passenger transport
Wei, T., & Frey, H. C. (2022), ATMOSPHERIC ENVIRONMENT, 281.
Microenvironment Tracker (MicroTrac) model to estimate time-location of individuals for air pollution exposure assessments: model evaluation using smartphone data
Breen, M. S. S., Xu, Y., Frey, H. C., Breen, M., & Isakov, V. (2022, December 16), JOURNAL OF EXPOSURE SCIENCE AND ENVIRONMENTAL EPIDEMIOLOGY, Vol. 12.
An illustrative case study of the contribution of commuting to PM2.5exposures in Hong Kong
Eluri, S., & Frey, H. C. (2021), Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA, 2021-June. Retrieved from
Characterizing Fuel Use and Emission Hotspots for a Diesel-Operated Passenger Rail Service
Rastogi, N., & Frey, H. C. (2021), ENVIRONMENTAL SCIENCE & TECHNOLOGY, 55(15), 10633–10644.

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