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, ResearchGate, ORCID, Scopus, Google Scholar and ReachNC.
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)
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