Large amounts of diesel exhaust from the buses and trucks Downtown carry a significant cancer risk, according to a yearlong Carnegie Mellon University air toxics study.
The study, commissioned by the Allegheny County Board of Health to analyze the health risks of 38 air toxics at selected sites in the county, found elevated levels of 12 of the cancer-causing pollutants, including those found in diesel exhaust, benzene from coke production facilities in Clairton and Neville Island, and formaldehyde, which shows up countywide.
“But diesel dominates the risk, especially Downtown,” said Allen Robinson, a Carnegie Mellon engineering and public policy professor who presented the results to the health board yesterday. “The rest of the pollutants we measured show a risk profile similar to other cities, but it should be a high priority to reduce diesel particulates.”
When inhaled, the diesel-produced pollutants can lodge deep inside lungs, and can cause lung cancer, strokes, heart attacks and infant deaths and trigger asthma attacks and allergies. Locally, diesel exhaust causes thousands of asthma attacks and hundreds of heart attacks and shortens the lives of about 240 residents each year, according to a 2007 Clean Air Task Force study.
A final written report on the Carnegie Mellon study will be submitted to the health board within 10 days. Chairman Paul King said it will be reviewed by the board’s Air Quality Advisory Committee and could eventually lead to revisions of the county’s air toxic control guidelines.
The study was precipitated by residents’ concerns that emissions from coke, chemical and other industries on Neville Island are causing a public health risk. Researchers set up air pollution monitors nearby in Stowe and Avalon, and along the Ohio River, in Downtown Pittsburgh and in South Fayette, a more rural area used to measure background pollutant levels.
Formaldehyde was found at higher risk levels throughout the county, but compared with other urban areas in the United States, those levels were not out of the ordinary.
Found at high levels Downtown were several carcinogenic chlorinated compounds for which the researchers have not been able to identify a source or sources.
“The chlorinated compounds are associated with solvent use,” Dr. Robinson said. “They could be coming from the Allegheny County Sanitary Authority, dry cleaning operations or intermittent construction sites, but we don’t know for sure. We’re still looking at this.”
In a related matter, the board heard that the county’s School Bus Retrofit Program, which provides funding to school districts to install pollution controls that reduce exhaust by 90 percent, is woefully underutilized.
About $500,000 from the county Clean Air Fund is available. But a requirement that all but the poorest districts pay a 25 percent match to participate in the program is keeping most from doing so, said Rachel Filippini, executive director of the Group Against Smog and Pollution, a leader in the Allegheny County Partnership to Reduce Diesel Pollution.
Each filter installed in place of a bus muffler costs $5,000 to $7,000. The Penn Hills School District completed a $180,000 retrofit of its bus fleet in 2006, but the Deer Lakes and South Fayette school districts, after showing early interest, have backed away from participating in the program.
“Given the current economic climate and the dramatic rise in fuel prices in recent years, it may not be realistic to require the 25 percent match,” said Ms. Filippini, who urged the board to remove the school district funding match requirement.
“It sounds like something to consider if the school districts can’t do the match,” said Mr. King.