ChE Seminar – “Measurement and Modeling of Onroad Vehicle Air Pollutant Emissions and Exposure” by Dr. H. Christopher Frey (North Carolina State University)

Host: Drs. David Allen and Lea Hildebrandt Ruiz; Paul Hollingsworth Lectureship in Engineering


There are over 1.3 billion onroad vehicles globally.  Vehicle operation contributes significantly to global energy use and emissions of greenhouse gas, criteria, and mobile source air toxic air pollutants.  Vehicle emissions lead to adverse effects on human health, including approximately 200,000 premature deaths globally.  The objective of this work is to quantify the real-world energy use and emissions from onroad transport, to quantify the sensitivity of emissions to infrastructure, vehicle technology, fuels, and operator behavior, and to quantify exposures to transportation-related emissions in near-road and on-road microenvironments.  Measurements of vehicles energy use and tailpipe exhaust emissions were made under real-world operating conditions using portable emission measurement systems (PEMS).  Vehicle emissions are highly sensitive to second-by-second speed trajectories, which leads to spatial variation in emission source strength.  Implications for near road air quality and human exposure to traffic-related air pollution are discussed.


Dr. Frey is the Glenn E. and Phyllis J. Futrell Distinguished University Professor at North Carolina State University.  As a member of the environmental engineering group in the Department of Civil, Construction, and Environmental Engineering, he conducts research on measurement and modeling of the activity, energy use, and emissions of onroad and nonroad vehicles, and regarding human exposure to air pollution.  He chaired the Clean Air Scientific Advisory Committee of the U.S. Environmental Protection Agency and served on the EPA Science Advisory Board.  He has also served in expert and advisory roles for the National Research Council, the World Health Organization, and the Inter-Governmental Panel on Climate Change, and contributed to a report to the U.S. Congress on Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions.  He was the 2018 Critical Review author and speaker for the Air & Waste Management Association on trends in onroad transportation energy and emissions.  He is a Fellow of the A&WMA and a Fellow and past president of the Society for Risk Analysis.  He is a recipient of the AWMA Ripperton Award and the SRA Chauncey Starr Award.  He is an adjunct professor in the Division of Environment and Sustainability at the Hong Kong University of Science and Technology.  His degrees include B.S. Mechanical Engineering from the University of Virginia, Master of Engineering in Mechanical Engineering from Carnegie Mellon University, and PhD in Engineering and Public Policy from Carnegie Mellon University.

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