The fleet of Public Works Department vehicles will continue to look and sound the same as they rumble up and down the streets. But there are some changes on the horizon that, while invisible, will help people breathe a little easier.

The Environmental Protection Agency [EPA] awarded $831,030 for Fairfield to cover the costs of retrofitted 39 vehicles -- from dump trucks to tractors -- with devices that will drastically reduce harmful emissions.

"You wouldn't notice it by looking at it," said Ed Boman, assistant director of Public Works.

In 2005, a push for cleaner air in Fairfield began when school buses were retrofitted with the devices. Last year, the town applied for the money for municipal vehicles did not receive it. Boman said that Fairfield will be the only municipality in Connecticut with both the town and school vehicles converted.

Federal guidelines have cut down harmful diesel emissions on vehicles, but passing a law and tightening regulations can be ineffectual, Boman said. New vehicles have to comply with the guidelines, but the older vehicles are still on the road. In Fairfield, these vehicles last often 20 to 30 years.

"Diesels don't wear out but they pollute," Boman said. "Now, they won't pollute and won't wear out."

The federal government hopes that the days when diesel trucks billowed out black smoke and other pollutants are on the decline due to heightened restrictions and improved technology. The reforms come on the heels of scientific research warning of the dangers of emissions from diesel engines.

"Diesel exhaust or diesel particulate matter (soot) is likely to cause lung cancer in humans," according to a report by the EPA. "Other health effects include aggravation of respiratory and cardiovascular disease, aggravation of existing asthma, acute respiratory symptoms, chronic bronchitis and decreased lung function."

The report added, "Emission reductions will prevent 8,300 premature deaths, more than 9,500 hospitalizations, and 1.5 million work days lost."

In Connecticut, particularly around the New York metropolitan area, the effect of poor air quality has been quantified.

According to the Connecticut Citizens Transportation Lobby, which advocates for mass transportation funding and programs to alleviate congestion on state highways, "One in 10 of Connecticut's school children suffer from asthma and the incidence of asthma has increased 75 percent in the last 10 years."

The process of adding diesel particulate filters to the town's vehicles is a relatively quick process. It may be completed by the end of the year. According to figures provided by the EPA, the filters are estimated to reduce particulate matter emissions by 1.7 tons, hydrocarbons by 2.6 tons and carbon monoxide by 7.9 tons over the vehicles' lifetimes.

Nationwide, $67 million has been awarded by the EPA through the 2010 National Clean Diesel Funding Assistance Program.

"Fewer diesel emissions will help those who suffer from asthma and other respiratory problems, said Curt Spaulding, regional administrator of the EPA's New England office in Boston. "These projects will help bring cleaner air to the residents of Connecticut."