ARB Research Seminar

This page updated July 26, 2013

Understanding the Origin of Trace Metals Emissions From Motor Vehicles

James J. Schauer, Ph.D., PE, University of Wisconsin-Madison

October 22, 2003
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA



The application of new analytical techniques for the analysis of trace metals in particulate matter samples has provided better tools to better understand the emissions of trace metals from motor vehicle roadways. The potential sources of metals emissions from roadways include tailpipes emissions, brake and tire wear, and resuspension of road dust. It has been recognized in the past that road dust if often contaminated with materials previously emitted from motor vehicles including tire wear, brake wear, engine oil, and exhaust treatment catalyst. However, the tools to quantitatively understand the contribution of these different sources to roadway emissions of PM10 and PM2.5 metals have not been presented in the past. To better understand the sources of the metals emitted from motor vehicle roadways, which will lead to a better understanding of impact of motor vehicles on urban air pollution and human health, trace metals source profiles have been developed for motor vehicle tailpipe emissions, brake wear, tire wear, and selected road dust samples. Trace metals were quantified using inductively coupled plasma mass spectrometry (ICPMS) techniques in the particulate emissions from more than 100 diesel and gasoline powered motor vehicles that were operated over different dynamometer driving cycles. To better understand the origin of the tailpipe metals emissions, lubricating oil samples from the vehicles were analyzed as from composite samples of the vehicles used for the dynamometer emissions tests. In addition, a series of brake wear emissions tests were conducted to develop source profiles for brake dust emissions and relate these emissions to the composition of the brake pads. These profiles were used to apportion the source of trace metals from roadway tunnel samples collected in Milwaukee, Wisconsin and are being used to understand the mechanism that lead to the emissions of trace metals from motor vehicles.

Speaker Biography

James Schauer is an Assistant Professor in the Environmental Chemistry and Technology Program and the Civil and Environmental Engineering Program at the University of Wisconsin-Madison, and serves as the Director of Air Chemistry at the Wisconsin State Laboratory of Hygiene. He received his Ph.D. in Environmental Engineering Science from the California Institute of Technology, his MS in Environmental Engineering from the University of California at Berkeley and his BS degree in Chemical and Petroleum Refining Engineering from the Colorado School of Mines. Dr. Schauer has previously worked in the chemical and petroleum refining industry as a Chemical Process Engineer and has helped commissioned and start-up large chemical facilities in Asia, Europe, North America, and Africa. Dr. Schauer currently leads an internationally recognized research team that employs advanced chemical analysis and air pollution sampling techniques to understand the chemical composition of source emissions and atmospheric pollutant concentrations. These methods are being used to understand the origin of impact of air pollutants in the urban atmosphere, human health, the ecosystems, and global climate change.

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