by Julie Rutherford
May 4th 2016
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A Portland State University (PSU) study published in the new edition of “Environmental Science & Technology,” found Portland cyclists can inhale up to twice the concentration of air pollution on high-traffic streets than on low-traffic streets.
The concentration of volatile organic compounds (VOCs) in cyclist breath after riding on streets with high vehicle traffic was 40 to 100 percent higher than on low-traffic routes. The ambient levels of VOCs on the high- traffic streets were 100 to 200 percent higher than on streets with less traffic.
The study found that separated bicycle paths and low-traffic routes can significantly reduce exposure concentrations. It also showed that cyclists can significantly reduce their pollution uptake by making even minor, one- to two-block detours from major arterials to parallel low-volume streets.
Alexander Bigazzi, who received his Ph.D. in civil engineering at PSU in 2014, did the project as part of his dissertation work with professors Miguel Figliozzi and James Pankow. Bigazzi is now an assistant professor in the Department of Civil Engineering and School of Community and Regional Planning at the University of British Columbia.
Bigazzi followed three volunteer research subjects who rode bicycles equipped with instruments to collect bicycle, rider, traffic and environmental data during morning rush hour on nine days in April through September 2013. Breath biomarkers were used to record the traffic-related VOCs present in each cyclist’s exhalations. Analysis of toxicants in exhalations closely correlates with concentrations present in an individual’s bloodstream.
Riders met for 30 minutes prior to their ride at Mt Tabor City Park, located approximately three miles from the city center, in an effort to bring blood concentrations toward an equilibrium with the environment. The subjects rode a variety of routes including bicycle lanes on primary and secondary arterials, bicycle boulevards, off-street paths and mixed-use roadways. They were told to ride at a pace and exertion level typical for utilitarian travel.
This research was funded by a grant from the National Institute for Transportation and Communities, a program of the Transportation Research and Education Center (TREC) at Portland State University. NITC is the U.S. Department of Transportation’s national center for livable communities and one of five U.S. DOT national university transportation centers.
More information about this study is available at Environmental Science and Technology, a journal of the American Chemical Society.