23 June 2000

South Coast Air Quality Management District (SCAQMD) Chairman William A. Burke has proposed that the California Air Resources Board (ARB) and SCAQMD establish a joint project in Southern California to accelerate development of technologies to reduce particulate emissions from school buses.

Burke proposed that SCAQMD and the ARB rapidly establish a program in the Southland to test the durability of particulate traps and catalysts on diesel school buses. Once proven effective, Burke said, programs could be implemented to reduce children's exposure to diesel soot by retrofitting buses now in service with the devices. Burke envisions retrofits as part of a $50 million statewide program to reduce emissions from diesel school buses.

“While we at SCAQMD continue to pursue long-term replacement of school buses with cleaner, alternative-fueled models, we are also looking at other ways to address this urgent health need in the near term,”, Burke said.

Under the proposed testing project, three types of diesel pollution control devices would be tested on two buses each at participating schools. These six buses would be operated 24 hours a day for 50,000 miles over which the effectiveness and durability of the pollution control devices would be studied. The buses would operate on low sulfur diesel fuel.

The expected cost would be $40,000 to $70,000 per bus, including fuel, drivers, operation and maintenance, and data collection and record keeping. ARB and SCAQMD would split these costs under the proposal. The on-road test would be supplemented with dynamometer tests at the Los Angeles County Metropolitan Transportation Authority.

According to an SCAQMD estimate, diesel particulates are responsible for 70% of total cancer risk from toxic air pollution and about 0.6% of total cancer risk from all causes in the region. These SCAQMD figures are based on controversial assumptions that have not been widely adopted by the medical and epidemiological research community.

Source: SCAQMD