Preliminary Findings on Diesel and Coal Train Impact

UW Bothell Researcher Releases Preliminary Findings on Diesel and Coal Train Impact

November 4, 2013
Embargoed Until 6:30 p.m. on November 4
CONTACT: Lisa Hall, 425-352-5461,

BOTHELL, Wash. – University of Washington Bothell researcher Dan Jaffe, Ph.D., has released the preliminary results of a six-month study to investigate whether increased rail shipments of coal could have an adverse effect on air quality in the area. He will share his findings with the community and elected officials tonight at UW Bothell.

Jaffe is a professor of atmospheric and environmental chemistry in the School of Science, Technology, Engineering and Mathematics at UW Bothell. He is also an adjunct professor in the Department of Atmospheric Sciences at the University of Washington Seattle. The study has been submitted for publication to the online journal Atmospheric Pollution Research and is currently in peer review.

Jaffe’s study was conducted on a $24,000 budget over a six-month span. He was assisted by four undergraduate students from UW Bothell and UW Seattle. Jaffe’s group studied more than 450 freight, coal and passenger trains at two locations, the Columbia River Gorge and a private residence in Seattle’s Blue Ridge neighborhood, situated about 25 meters from a rail line.


  • Living very close to the tracks in the Blue Ridge neighborhood increases ones exposure to diesel PM by about 6.7 µgram/m3. This level of exposure is comparable to that in the most industrial parts of Seattle (Duwamish Valley).
  • A significant increase in large particles (>1 µm) in the air was found when coal trains passed by, compared with other train types. This result suggests that these trains are emitting coal dust into the atmosphere during transit.
  • An increase in train traffic will increase the DPM exposure for residents along the rail lines. A 50 percent increase in rail traffic will put some neighborhoods at risk of exceeding air quality standards.
  • We measured the diesel particulate matter emission from over 450 trains to get a mean value of 0.96 grams diesel particulate per kg of fuel burned.

Jaffe’s team recorded several thousand videos of passing trains in two locations. With each train, the team also measured concentrations of size-segregated particulate matter, which gives researchers information about diesel and coal particulates. Data analysis by the team confirms the diesel emissions and suggests release of coal dust.

“After the locomotive goes by, there is sometimes a second peak,” Jaffe says. “It’s definitely a component that has large particles, like dust. We don’t usually see that peak for freight trains.”

Jaffe cautions that this study was short in duration, far below the minimum three years of data required by the EPA to determine compliance with air quality. “Our one month of observations gives us an indication of whether the trains are a problem or not, but does not tell us about overall compliance with air quality standards.”

Jaffe performed the study in response to what he calls “significant information gaps,” as communities and policy makers consider whether to increase the rail shipments of coal in the region. After pursuing the usual routes to secure funding for the project, he almost gave up. But then he turned to the microfunding site Microryza, which was founded by two UW Seattle scientists. Within two weeks, Jaffe raised $24,000 to fund the study.

Jaffe conducted the study with a team of undergraduate students including Justin Putz of UW Bothell along with Sonya Malashanka, Jeffrey Thayer and Greg Hof of UW Seattle. The research team also included collaborators from Reed College and Colorado State University.

Jaffe will present his preliminary findings to the public.


Potential Impact of Coal Trains on Air Quality


Monday, November 4, 2013
6:30 p.m. Media Briefing – All information embargoed until 6:30 p.m.
7:00 p.m. Community Briefing
8:00 p.m. Q & A


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