Description: Description: Description: Description: image005.jpg 



H. Christopher Frey


Glenn E. Futrell Distinguished University Professor

Description: Description: Description: Description: image001.jpg

Department of Civil,

Construction, and

Environmental Engineering


North Carolina State University
Raleigh, NC 27695-7908

Telephone: (919) 515-1155

Email:  frey (at)

Research Interests



Current and Recent Projects

Past Projects

Computer Laboratory

Frey Research Group

Professional Activities

Real-World Vehicle Emissions

My interests are broadly in energy and environmental systems, including:  modeling and evaluation of advanced energy conversion (e.g.,combustion, gasification) and environmental control systems; measurement and modeling of real-world fuel use and emissions of onroad and nonroad vehicles; development and application of methods for quantification of variability and uncertainty and for sensitivity analysis in systems models; and exposure and risk analysis.  Air pollutant emissions of interest include criteria pollutants, hazardous air pollutants (“air toxics”), particulate matter, and greenhouse gases.  More details on my teaching, current and past research activities, publications, professional advisory activities, research group, and computer laboratory are available in the links above.  [link to CCEE department webpage for Dr. Frey]


Follow Dr. Frey on LinkedIn, ResearchGate, ORCID, Scopus, Google Scholar and ReachNC.


Latest News:


·         PhD student Maryam Delavarrafiee, advised by Dr. Frey, won a Student Merit Award from the Exposure Assessment Specialty Group of the Society for Risk Analysis.  Ms. Delavarrafiee will receive the award at the SRA Annual Meeting in Arlington, VA during Dec 7-10, where she will present a paper on “Empirical Comparison of Fine Particulate Matter Exposure Concentrations in North Carolina State University Campus Buses and a Personal Passenger Car.”

·         Research from Dr. Frey’s group was featured in the latest summary of “Highlights from the Coordinating Research Council’s 25th Real-World Emissions Workshop,” published November 2015 in the “EM” Magazine of the Air & Waste Management Association.  Research on locomotive emissions, modeling of traffic emissions from light duty vehicles, and measurement of refuse truck emissions, are depicted in the article.

·         Dr. Frey is quoted in an article by NC Health News regarding the scientific basis for the new Ozone National Ambient Air Quality Standard announced by the U.S. Environmental Protection Agency on October 1, 2015.  Dr. Frey chaired the EPA Clean Air Scientific Advisory Committee and CASAC’s Ozone Review Panel.  CASAC advised the EPA Administrator on the scientific basis for revising the ozone standard. 

·         Dr. Frey spoke as an invited lecturer in the 2015 Warren Lecture Series at the University of Minnesota on October 16, 2015.  His lecture regarding “Measurement and Modeling of Real-World Onroad Vehicle Activity and Emissions” is available as a YouTube video.

·         Dr. Frey, who chaired the EPA Clean Air Scientific Advisory Committee (CASAC) and the CASAC Ozone Review Panel, answers some of the most frequently asked questions about the scientific review completed in 2014 of the National Ambient Air Quality Standard for Ozone.  EPA Administrator Gina McCarthy announced the final ozone rule on October 1, 2015.

·         Dr. Frey and others co-hosted a tour of the NCDOT rail yard during the June 2015 annual meeting of the Air & Waste Management Association.  This tour featured methods and results from 8 years of research by NCSU on emissions from NCDOT owned and Amtrak operated railroad locomotives.

·         Research by Dr. Frey’s group is featured in an article about the role of the NC State Department of Civil, Construction, and Environmental Engineering at the June 2015 Annual Meeting of the Air & Waste Management Association.

·         Many of Dr. Frey’s current and recent students were active participants and presenters at the June 2015 Annual Meeting of the Air & Waste Management Association, held at the Raleigh Convention Center.  Dr. Frey was chair of the Student Program for this meeting.

·         Dr. Frey’s research on the effect of biofuels on emissions from diesel railroad locomotives was featured in CCEE News.

·         Dr. Frey shared a best paper award at the 2015 Annual Meeting of the Transportation Research Board.

·         Dr. Frey and colleagues developed a new modeling framework for estimating the effect of transportation infrastructure, traffic control measures, and traffic operations on vehicle emissions.

·         Five recently published journal papers:

1.    Che, W., H.C. Frey, and A.K.H. Lau, “Comparison of Sources of Variability in School Age Children Exposure to Ambient PM2.5,” Environmental Science and Technology, 49(3):1511–1520, DOI: 10.1021/es506275c (2015)

2.    Liu, B., and H.C. Frey, “Quantification and Application of Real-World Light Duty Vehicle Performance Envelope for Speed and Acceleration,” Transportation Research Record, 2503:128-136.  DOI: 10.3141/2503-14 (2015)

3.    Liu, B., and H.C. Frey, “Variability in Light Duty Gasoline Vehicle Emission Factors from Trip-Based Real-World Measurements,” Environmental Science & Technology, “Just Accepted” publication, published online September 24, 2015.  10.1021/acs.est.5b00553 (2015)

4.    Salamati, K., N.M. Rouphail, H.C. Frey, B. Liu, and B.J. Schroeder, “A Simplified Method for Comparing Emissions at Roundabouts and Signalized Intersections,” Transportation Research Record, 2517:48-60.  DOI: 10.3141/2517-06 (2015)

5.    Zhou, X., S. Tanvir, H. Lei, J. Taylor, B. Liu, N.M. Rouphail, and H.C. Frey, Integrating a Simplified Emission Estimation Model and Mesoscopic Dynamic Traffic Simulator to Efficiently Evaluate Emission Impacts of Traffic Management Strategies, Transportation Research – Part D, 37(2015):123-136 doi:10.1016/j.trd.2015.04.013

More publications

News Archive



Portions of this web site are based upon work supported by the
National Science Foundation under Grant No. 9701502.

Any opinions, findings, and conclusions or recommendations expressed in this web site
are those of the author(s) and do not necessarily reflect the views of the
National Science Foundation.