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No Escape From Diesel Exhaust: How to Reduce Commuter Exposure

Published: February 2007
File Size: 1,966 KB

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Every day, Americans are needlessly sickened from exposure to air pollution in the form of fine particles. Overall, health researchers estimate that fine particles, such as those found in diesel exhaust, shorten the lives of 70,000 Americans each year. Many more suffer the effects of particle-related respiratory and cardiovascular disease.

When during our day are we exposed to these particles? According to the California Air Resources Board, although we spend only about six percent of our day commuting to and from work, it is during that time when we receive over half of our exposure to utlrafine particles.

For the most part, the particles we breathe come from the diesel engines we encounter while driving or taking diesel-powered mass transit. According to the Transportation Research Board, one hundred and fifty million people.roughly half the to and from work in the U.S. daily. Most commuters drive, but many others take diesel-powered trains or city buses and ferries. Today's average commute lasts 25 minutes each way, and current trends indicate that our commutes, and therefore our exposures, are lengthening.

Legions of published, peer-reviewed studies have documented the increased exposure and resultant health risk from particles in and around nearby roadways. Using comparable instruments and research techniques as those employed by health researchers at major universities, Clean Air Task Force (CATF) investigated the exposure to diesel particles during typical commutes in four cities: Austin, Texas, Boston, Massachusetts, New York City, and Columbus, Ohio. In addition, CATF tested the air quality benefits due to emission control retrofits of transit buses in Boston and transit buses and garbage trucks in New York City.

CATF's investigation demonstrated that whether you commute by car, bus, ferry, train, or on foot, you may be exposed to high levels of diesel particles. Specifically, CATF documented diesel particle levels four to eight times higher inside commuter cars, buses, and trains than in the ambient outdoor air in those cities. In some cases, the ultrafine particle levels during the commutes were so high as to be comparable to driving with a smoker!

Several cities like Seattle, Boston and New York have purchased new cleaner transit buses and retrofitted many of their older buses and garbage trucks with effective emission controls. These emission controls are widely available today because U.S. EPA rules require them for new diesel engines starting this year. The only commutes where the researchers found little or no diesel exposure were commutes on electric-powered subways and commuter trains, on buses that have been retrofitted with diesel particulate filters or run on alternative fuels like compressed natural gas, and in cars traveling along routes with little or no truck traffic.

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