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
group, and computer
laboratory are available in the links
above. [link to CCEE department webpage
for Dr. Frey]
Follow Dr. Frey on LinkedIn and on ResearchGate.
Dr. Frey is available to the media to discuss the Volkswagen light
duty diesel vehicle excess emissions scandal. Dr. Frey’s group is measuring the
real world emissions of VW diesel cars using portable emission measurement
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 is
expected to announce the final ozone rule on October 1, 2015.
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)
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:
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