Understanding Government

The Obama administration and environmentalists generally view public transportation as an environmentally wise mode of commuting.  However, a fleet of Chicago public transit trains exposes commuters to dangerous levels of diesel exhaust.

The Chicago Tribune’s Michael Hawthorne reports on the high level of diesel exhaust emitted from Chicago’s Metra trains and also floating in the atmosphere of the city’s main Metra train stations. More than a million people use Metra, which is part of the Regional Transit Authority, to commute between the city and suburbs. Metra commuters expose themselves to a level of soot 72 times higher than on Chicago’s streets.

“The U.S. Environmental Protection Agency considers diesel exhaust one of the most dangerous types of air pollution,” Hawthorne writes, noting that soot is linked to cancer, heart attacks and respiratory diseases. “Yet federal and state officials acknowledge they are woefully behind in assessing how breathing highly polluted air for short periods of time every day might affect a person’s health.”

The Tribune is investigating health risks to commuters and transit workers who are exposed daily to this soot from diesel engines, not how Metra affects Chicago’s overall air quality. Nonetheless, this is a major health problem — Hawthorne finds that even Metra’s rebuilt locomotives are not meeting EPA’s standards on the limits of soot emitted from diesel engines.

And air quality on Chicago’s commuter lines also isn’t expected to improve significantly any time soon. Rather than replacing its disco-era locomotives with newer, cleaner models, Metra is refurbishing a third of its aging fleet to keep them chugging for at least another two decades.

The closest thing the EPA has to a standard for diesel exhaust is 5 micrograms per cubic meter of air, which the agency defines as a level of average daily exposure that could trigger health problems later in life.

Yet EPA officials acknowledge the agency has done little to track whether people are breathing levels of diesel pollution that exceed that safety limit. Agency scientists also say they need to better understand the potential health effects of brief-but-intense exposures.

Rather than trying to enforce the safety limit for diesel exhaust, government officials set separate legal standards for overall air pollution across entire counties. Federal and state regulations require cleaner factories, power plants, engines and fuels to help meet the air quality standards.

Chicago and its suburbs are chronic violators of those broader pollution standards. The region fails to meet federal soot limits, and Chicago also is the nation’s only major metropolitan area that doesn’t meet tough new standards for smog-forming nitrogen oxide, an ingredient in diesel exhaust.