Report Targets School Bus Pollution

California’s children are breathing unhealthful exhaust spewed by diesel school buses that are among the oldest and highest-polluting in the nation, according to a report to be released today by a Los Angeles environmental group.

The report, by the Coalition for Clean Air, urges Gov. Gray Davis’ administration to set tough emission standards for school buses and to provide tens of millions of dollars to help school districts replace their fleets with new buses powered by cleaner-burning alternative fuels.

About 17,000 diesel buses deliver children to school, including some 20-year-old models that spew dark clouds of noxious smoke. Diesel exhaust, a mix of soot and toxic gases, has been linked in health studies to lung cancer, asthma attacks, allergies and other respiratory illnesses.

Officials of the state Air Resources Board and the Los Angeles Unified School District agreed Wednesday that the current school bus fleet poses an environmental threat to children but have yet to decide on a strategy to deal with the problem. Diesel manufacturers said they are improving their engines and see no need for schools to switch to alternative technologies.

No one knows how much of a danger bus exhaust poses to schoolchildren--the amounts they breathe have not been measured and no studies have calculated their disease rates. In fact, for Californians on average, heavy-duty trucks pose a far greater health risk, with buses blamed for less than 1% of total diesel emissions, according to the California Air Resources Board.

Nevertheless, Air Resources Board Chairman Alan Lloyd, appointed this year by Davis, said the emissions, while relatively small, could be posing a serious health danger because tens of thousands of children come into direct contact with the bus exhaust every school day.

“We would agree with the coalition that the risk from diesel, particularly from school buses, should be reduced,” Lloyd said. “We’re trying to crack down on all sources of diesel.”

The report comes as the air board is preparing to unveil a controversial proposal in December that would set new state pollution standards for transit buses next year. That proposal, however, will exempt school buses because of the financial burden it would put on California’s already struggling school districts. Instead, Lloyd said the board’s staff in January will outline a separate strategy for getting cleaner buses at schools.

Buses powered by alternative technologies, predominantly compressed natural gas, are already available and are substantially cleaner than diesel buses. The price tag, however, for converting all of California’s school fleet to natural gas would exceed $1 billion, according to the environmental group’s calculations.

Antonio Rodriquez, transportation director at the Los Angeles Unified School District, said the district has been trying to clean up its fleet--it has gotten rid of its oldest buses and the rest meet current emission standards. Also, the district operates a small number powered by cleaner natural gas and hopes to buy more, but Rodriquez said money is the main obstacle because each one costs about 35% more than a diesel bus.

“We’re always interested in making sure our buses are as clean as possible,” he said. “Whatever we can do to clean the air helps our kids.”

Last year, the state air board declared diesel soot a cancer-causing air pollutant that could be causing 14,000 Californians alive today to contract cancer.

Medical experts say that children are especially vulnerable to the effects of diesel exhaust because they inhale large volumes of pollutants for their body weight and because their immune systems are still developing. Also, half a million asthmatic children live in California, and some medical experts say diesel exhaust can trigger attacks.

The environmental group reports that California ranks among the worst states--47th out of 50--in terms of the percentage of buses built before 1977. Pre-1977 diesel buses emit four times more particle soot and three times more smog-forming fumes than new natural gas buses, according to the air board.

About 69% of the states’s 24,372 buses are fueled by diesel and nearly 1,000, or 4%, predate 1977, according to data in the report compiled from three state agencies.

“Everyday, our children step aboard and ride a school bus that may intensify their exposure to diesel exhaust, a known human carcinogen,” the Coalition for Clean Air report says. “This exposure does not end with the bus ride, however. Exposure also occurs in and around the school grounds when school buses park and idle nearby or load and unload students.”

While other vehicles on California’s roads are the cleanest in the nation, school buses lag far behind.

Last year, the state air board resolved to promote alternative technologies for school buses and eliminate pre-1977 models. But little has been done to accomplish those goals. One of every five urban transit buses run on natural gas, compared with only 3% of school buses.

In its report, the Coalition for Clean Air urges the state to apply a new bus emission standard to schools. It also wants Davis and the Legislature to provide funds “exclusively earmarked” for non-diesel school buses. School districts, the group says, should adopt policies that phase out diesel buses, and parents should lobby for action.

The future of diesel--long considered the workhorse of America because it powers heavy-duty vehicles from trucks to trains--has been a recent focus of intense debate, especially in California.

Engine manufacturers, who oppose any efforts favoring alternative fuels over diesel, have spent millions of dollars researching ways to reduce emissions from diesel engines. They also question the reliability of health studies that find an increased cancer rate among workers exposed to high amounts of exhaust, and say there is no evidence that schoolchildren are breathing inordinate amounts.

“We’re very concerned about the health and safety of the people who use our products and of the environment, but there’s significant controversy at every level about the health effects,” said William Bunn, medical director of Navistar International, the largest manufacturer of bus engines in North America. “As we continue to determine what, if any, health effects there are, we are committed to the ‘green’ diesel approach.”

Diesel buses manufactured today already emit 90% less emissions than ones made a decade ago. Also, Navistar has developed soot traps that can make diesel buses cleaner than natural gas, and other companies are perfecting catalysts to cut smog-forming pollutants. The cleaner diesels, however, depend on the oil industry producing low-sulfur fuel, which would not be required until 2007 under a U.S. Environmental Protection Agency proposal expected next year.

Because switching to natural gas carries such a high cost, the manufacturers say it may be an unwise use of scarce public monies to require or subsidize them for buses.

“Would it make sense to convert to natural gas when we can achieve something very similar with diesel technology?” Bunn said.

At the Los Angeles Unified School District, 33 of the 2,600 buses that the district owns or contracts for run on natural gas. Rodriquez said they “have a very good track record” for performance and maintenance and he wants to buy six more. But, he said, the school district is reliant on special air-quality grants because each one costs roughly $30,000 more than a new diesel bus, which costs about $90,000.