John Beale, Post-Gazette Peter Reba of International Truck & Engine Co., left, and Dr. Bruce Hill, a senior scientist for Clean Air Task Force, use a handkerchief to cover the tailpipe of a Plum Borough School District bus to show how little particulate matter is coming from the exhaust. Plum has retrofitted some of its buses with tailpipe filters that reduce the amount of diesel pollution. Click photo for larger image.

It wasn't a white-glove test, but it came close.

Dr. Bruce Hill, senior scientist with the Clean Air Task Force, used a white handkerchief yesterday to prove how little soot puffed from tailpipes of 23 Plum Borough School District buses retrofitted with diesel particulate filters.

When he held a hanky over a retrofitted bus tailpipe, it remained white. But when he held it over a regular bus tailpipe, it came away soiled with a black circle of pollution.

Using a meter, he showed that particulates from the retrofitted bus were below levels already in the air and 1,000 times lower than levels spewing from a regular bus.

The point of the demonstration: The anti-pollution technology works without affecting fuel efficiency.

Ten environmental and public health organizations held a news conference and demonstration yesterday at Plum's O'Block Junior High School to announce plans to reduce diesel pollution throughout Allegheny County.

Plum is key. It represents the first school district in the county to install the filters on 23 of its 60 buses through a $200,000 "Clean Buses for Kids" federal grant.

Diesel soot is one of the most serious health threats to local residents, the groups said. But as Plum is proving, technology exists that all but eliminates particulate pollution from diesel-powered engines and vehicles.

Two thousand diesel-powered buses crisscross Allegheny County each school day, spewing pollution with significant health effects.

"It is estimated that because of diesel emissions [from all vehicles], 237 local residents face premature death each year, in addition to causing hundreds of heart attacks and thousands of asthma attacks," said Rachel Filippini, executive director of Group Against Smog and Pollution.

Local cancer risk from diesel exhaust is almost 400 times the federal goal, she said. It also contributes to global warming.

"It's time for our region to tackle this serious air pollution problem," she said.

But there are 13 million diesel engines operating in America that "burn dirty," Ms. Filippini said.

Particulates from diesel fuel are a known health risk, said Dr. Robbie Ali of the University of Pittsburgh School of Public Health. Those risks include asthma, heart disease, high blood pressure, diabetes and cancer.

"These vehicles put toxic materials in your lungs," he said, noting the soot contains dangerous particulates, metals and hydrocarbons.

Federal regulations will mandate that, beginning in October, cleaner diesel fuel be used in on-road vehicles to reduce emissions. Diesel particulate filters are not required by law but will become standard equipment on new diesel engines next year, Ms. Filippini said.

But local environmental and health organizations recommend that all school districts in Allegheny County install filters on buses that can use the technology.

Myron Arnowitt, Western Pennsylvania director of Clean Water Action, said a multistate partnership has adopted a national platform to reduce diesel pollution by 40 percent by 2012 and 70 percent by 2020. The hope is to save 90,000 lives nationally in the next generation, he said.

The partnership recommends that all Port Authority buses be retrofitted with filters and the federal government budget $50 million to help local communities with diesel cleanup programs. It also encourages Allegheny County to extend legislation that prohibits idling of on-road vehicles to include off-road diesel engines, including construction equipment and tractors.

"We are grateful that the Plum school district is working to protect its kids," Mr. Arnowitt said.

Tom Zeminski, Plum's supervisor of transportation, said his district also is using ultra low-sulfur diesel fuel which costs 56 cents per gallon more than regular diesel fuel.

Retrofitting each school bus with filters costs up to $8,000 per vehicle, he said. District buses travel 750,000 miles each year.

While the cost may seem sizable, Ms. Filippini said, the cost of doing nothing is greater when health care costs and lost school and work days are considered.