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All Aboard the Carcinogen Express: Study Finds Red Line Commuters Exposed to Twice as Much Polluted Air Than on Gold Line

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Of Metro's Red Line subway and Gold Line light rail, which puts commuters at more of a risk of exposure to potentially hazardous air pollutants? A study conducted by the University of Southern California finds that Red Line riders are exposed to up to twice as much unhealthy air as those on the Gold Line.

The study was conducted by Constantinos Sioutas, Fred Champion professor of civil and environmental engineering in the USC Viterbi School of Engineering, who "measured the concentrations and chemical composition of fine and coarse particles in the air while riding on the Red Line and the Gold Line of the Los Angeles Metro using small carry-on suitcases equipped with portable air samplers," explains USC in a release. Sioutas used USC as a control site location to represent "typical urban air quality levels in LA."

The testing revealed the following:

The amount of particulate matter in the air on the Gold Line was similar to that in the air at the central USC, while the amount measured on the Red Line was significantly higher. Sioutas attributed the additional particulate matter in large part to the dust produced by the braking of trains approaching stations in the enclosed environment of the subway.
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The bottom line, however, is that the level of air pollutants on either transit line "pale in comparison to the levels of particulate matter that bombard commuters stuck in traffic on the freeways."

While Sioutas, a Gold Line rider himself, supports the use of public transit, particularly in terms of its environmental and health impacts on society, he says buses add to the problem of harmful air. The solution, according to Sioutas, is the expansion of light rail.

You can access the recently-published paper here.