Poster sessions featured 59 posters of TSR&TP sponsored research

The Saturday session of the symposium began with presentations from last year's best poster winners, Wendy Hwang-Verslues of UC Riverside and Peter Bui of UC Los Angeles.

The TSR&TP's first best poster winner and the 2006 winner of the Best Publication Award, Julian Marshall, presented his research on vehicle emissions and air pollution. Marshall is an assistant professor of Civil Engineering at the University of Minnesota. As a graduate student at UC Berkeley, Marshall sought ways to determine the sources of air pollution that matter most to human health. He focused his research on intake fraction, a metric to summarize the relationship of emissions to inhalation. Intake fraction is the part of emissions that are inhaled, the mass of pollution that passes into our noses and mouths. The goal of the intake fraction approach is to understand the intake rate that results from the emissions rate. The main determinants are the number of people exposed, how close they are to the pollution, and how long they spend in that space. "It's a way of organizing information we have. We need other methods of gathering information so we can use intake fraction as a lens," explained Marshall. Intake fraction measurements are also a tool for prioritizing emissions sources in air quality management to help address environmental justice issues.

University of Minnesota Assistant Professor and former TSR&TP trainee Julian Marshall discovered that children riding diesel school buses inhale 20 times more pollutants than nearby cars.

Marshall discussed two case studies to illustrate his research. The first was carbon dioxide and benzene from motor vehicle emissions in the Southern California coast air basin surrounding the city of Los Angeles. One in 19 Americans live in this basin, and it's well known for air pollution issues. His results showed higher intake fractions in the winter rather than summer, due to more inversions and stagnant air. His second case study involved measuring school bus emissions by releasing a tracer gas into the tailpipe and measuring it onboard. The results were astounding. For every ton of emissions, kids are inhaling about 60g; people in nearby cars get 3g, and people in the general urban area get 9g. This suggests that diesel school buses have a strong relationship between emissions and exposures. "This way of comparing among sources of emissions is like finding a $20 bill on the sidewalk. The effectiveness of each dollar spent reducing diesel emissions is a factor of 4 in the case with school buses," explained Marshall.

Two sessions featuring 59 posters of TSR&TP funded research followed the morning's presentations. There was much lively interaction during the hour, and many participants commented that they would have liked more time to discuss their research. Rest assured, the schedule for the 2008 Symposium will include longer poster sessions.

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