The San Joaquin Valley Air Pollution Control District is soliciting public comment on a proposed rule to reduce emissions from diesel school buses.
Public workshops on the draft rule will be at the three District offices at 1:30 p.m. on April 27 and 28 and a 10:30 a.m. on April 29. The offices are located at 1990 E. Gettysburg in Fresno, 2700 M St., Suite 275 in Bakersfield and at 4230 Kiernan Ave., Suite 130 in Modesto.
Rule 9310 (School Bus Fleets) would apply to school bus fleets that transport k-12 students in both public and private schools.
"This new rule would reduce school children's exposure to toxic air pollutants," said Scott Nester, a planning manager for the Air District.
A study released in October. 2003 by the California Air Resources Board (ARB) showed that children riding diesel school buses are exposed to unhealthy levels of diesel exhaust on their way to and from school. Diesel exhaust is known to contain significant amounts of toxic air contaminants. The report estimated that riding a school bus for 13 years could increase a child's lifetime cancer risk by about 4 percent, and could increase respiratory symptoms by 6 percent.
Oxides of nitrogen, or NOx, reductions are needed as the San Joaquin Valley moves to the "extreme" non-attainment classification for the federal one-hour ozone standard.
Because the Air District is prohibited from setting tailpipe standards for "mobile sources," Rule 9310 would instead require school districts and other school bus operators to ensure their in-use fleets meet current state and federal tailpipe standards by 2015, and purchase only state-of-the-art school buses after Jan. 1, 2005.
The South Coast Air Quality Management District in Southern California and the ARB have adopted similar regulations for other types of fleets, including garbage and transit buses. Mobile sources include cars, trucks and other vehicles, and are the Valley's largest source of smog-forming emissions.
According to a recent survey, more than half of the Valley's diesel school buses will be at least 15 years old by the time this new rule would take effect. Cleaning up these older busses would provide the largest part of the total benefit from the rule. New diesel engine technology, coupled with new low-sulfer diesel fuel and exhaust controls, can achieve 85 percent lower particulate-matter emissions and 75 percent lower NOx emissions, compared to older buses.
Gasoline engines and engines fueled with compressed natural gas (CNG) emit fewer pollutants than diesel engines and would not be subject to the change-out provisions of Rule 9310. Nineteen school districts in the San Joaquin Valley have already switched some of their bus fleets to CNG; the Valley currently has 174 CNG school busses on the road.