Breathing Easier in the Penn Hills School District

More in this Section

Hotline, Winter 2004

by Suzanne Seppi, GASP Executive Director

Several months ago, GASP initiated a meeting with Dr. Dixon, Director of the Allegheny County Health Department. We also invited to the meeting some experts from Cummins Bridgeway LLC (distributors of Cummins Engines), as well as representatives from Allegheny County Port Authority who kindly agreed to participate. The goal was to create a model project to decrease diesel emissions in Allegheny County. Dr. Dixon was enthusiastic about supporting a school bus retrofit program and quickly took the lead to introduce this proposal to the Board of Health. The proposal was then sent to the Air Quality Advisory Committee and back to the Board of Health for its consideration. The Education Subcommittee, along with Sam Schlosberg and Tom Lattner of the Health Department, worked hard to develop the idea and prepare it for approval by the Board of Health.

Happily, on January 7, 2004, the Board of Health approved the request for an expenditure of $184,500 from the Allegheny County Clean Air Fund as a grant to create a demonstration school bus retrofit program at Penn Hills School District. County Executive Dan Onorato still must approve the grant. And what is a retrofit program, anyway? Retrofit refers to tailpipe equipment installed to decrease pollutants from the diesel vehicles.

Up to 75 buses owned by the Penn Hills School District are to be fitted with diesel oxidation catalysts (DOC). DOCs use a chemical process to break down pollutants in the exhaust stream into less harmful components. A typical DOC is a stainless steel canister installed in the exhaust system much like a muffler. The canister contains a honeycomb structure that is coated with catalytic metals such as platinum. There are no moving parts in the canister, but as exhaust gases pass through the honeycomb structure, pollutants and particulate matter are chemically oxidized into harmless gases.

A DOC can remove 20%-50% of the particulate matter, 70% of hydrocarbons, and 90% of the carbon monoxide that each bus generates. While a DOC can operate on regular higher sulfur diesel fuel with 500 parts per million (ppm) sulfur, it works best when operating on ultra low sulfur fuel (15 ppm). The Health Department was able to locate ultra low sulfur diesel fuel at 30 ppm, and the premium cost of this fuel will be covered by the grant. Starting in 2006, by regulation, highway diesel fuel sold as ultra low sulfur diesel will be 15 ppm, and will be required to be generally available at the retail level.

Penn Hills School District was chosen for the demonstration project because it is a district that owns its buses and is interested in reducing school bus emissions, but needs financial help to do so. Recently, the EPA also gave a grant to North Allegheny School District for a similar retrofit program. Hopefully these projects will encourage other school districts and bus contractors to clean up their existing fleets of buses. There will likely be additional funding available through the EPA and possibly through the Department of Environmental Protection in Pennsylvania.

Controlling diesel emissions is especially important because there are few other sources of air pollution that are so widespread and toxic. Diesel emissions include 40 hazardous air pollutants listed under the Clean Air Act, 15 of which are known or probable carcinogens. As much as 20% of diesel particulate matter is comprised of ultrafine particulates that are so small they can invade lung tissue and enter the bloodstream. Additionally, while children make up only 25% of the population, they represent about 40% of all asthma cases. Research shows a correlation between air pollutants such as diesel exhaust and exacerbation of asthma among children.

By approving a grant for this initiative, the Allegheny County Board of Health has put the Clean Air Fund to work in the community, reducing toxic emissions, especially for children.