WASHINGTON -- Diesel fumes pose a major health risk to commuters, according to a new report by the non-profit Clean Air Task Force.

The Boston-based environmental research group reported that even though people spend only a tiny portion of our day commuting, it's during the commute that they receive more than half our overall exposure to deadly fine particle pollution.

"Exposure to diesel exhaust during commutes poses a serious public health risk that needs to be addressed," said George Thurston, Professor of Environmental Medicine at New York University's School of Medicine, who wrote the foreword to the report.

Fine particle pollution, including diesel exhaust, can cause lung cancer, stroke, heart attack and infant death. It also triggers asthma attacks and makes people more likely to become allergic.

Some health researchers have estimated that such fine particles are responsible for shortening the lives of at least 70,000 Americans each year.

The Task Force specifically investigated diesel exhaust levels during commutes in New York, Boston, Austin, Texas, and Columbus, Ohio. The Task Force documented diesel particle levels four to eight times higher inside commuter cars, buses, and trains than in the ambient outdoor air in those cities. These are examples of likely results during a commute anywhere in the country where there is significant diesel traffic.

The Task Force called on federal and state agencies to increase funding to clean up highly polluting buses and other existing diesel engines. It urged the U.S. Environmental Protection Agency to require that long-haul trucks clean up when their engines are rebuilt. It also urged the EPA to move ahead with plans to set new pollution standards for diesel trains and diesel-powered boats, including commuter ferries.