The Hamilton County Department of Environmental Services, a local air agency covering the Greater Cincinnati Area in Southwest Ohio, has experienced many successes and failures obtaining grant money to fund school bus retrofits. However, seven years of persistent work has paid-off enormously.
The adverse health effects of diesel exhaust were making national headlines in the early 2000s. The U.S. Environmental Protection Agency’s (EPA) Health Assessment Document for Diesel Engine Exhaust (2002)1 concluded that “...diesel exhaust is likely to be carcinogenic to humans by inhalation.” In addition, diesel emissions reduction technologies were being introduced with a heavy emphasis on school bus installations. Also, EPA introduced the Clean School Bus USA program in 2003 to distribute grant funding to facilitate the installation of diesel emissions reduction technologies on school buses.
It was in March 2003 that the Hamilton County Department of Environmental Services staff witnessed a demonstration of a diesel particulate filter installed on a school bus and saw the significant reduction in diesel particulate emissions from the tailpipe of the retrofitted bus. This demonstration convinced us to start a school bus retrofit program in Southwest Ohio. A school bus retrofit program would significantly improve the air school children breathed both riding on school buses and waiting in line at school bus loading areas. Additionally, the Greater Cincinnati Area was classified as nonattainment for the annual PM2.5 standard (i.e., particles that are 2.5 micrometers in diameter and smaller), so any reduction in diesel particulate emissions would help the region toward compliance with the national standard.