Washington scores a "D" in bus pollution study
Schoolchildren still endangered by aging fleet
Diesel exhaust from the state’s aging fleet of school buses poses a major threat to children’s health, despite strides by the state in retrofitting buses to clean the exhaust, according to a report released Wednesday by the Union of Concerned Scientists.
The national public health advocacy group’s report graded all 50 states in the categories of soot pollution and smog pollution from school bus exhaust and the effectiveness of state programs to clean up the nation’s 505,000 school buses.
The state received a soot pollution grade of “D� and a smog pollution ranking of “poor,� largely based on the average age of the school bus fleet — 11 years old.
Here in Puget Sound, diesel exhaust from all vehicle and equipment contributes about 70 percent of the cancer risk posed by air toxins, according to state Department of Ecology studies.
Children are especially vulnerable because of the time they spend in school buses and they breathe more air per unit of body weight than adults do, Ecology senior toxicologist Harriet Ammann said.
The state school bus cleanup program received the second-highest grade in the nation, credited with reducing school bus soot by 7.3 percent, according to the report.
The 2003 state Legislature approved a five-year, $25 million program to retrofit some 5,000 of the roughly 9,000 school buses statewide with equipment that partially cleans exhaust before it leaves the tailpipe.
In a six-county region including Thurston and Mason counties, 334 of the 432 buses approved for retrofitting have been equipped, said Dan Nelson of the Olympic Regional Clean Air Agency.
“We’ve swept up all the buses that qualify for the program,� Nelson said.
The equipment, called diesel oxidation catalysts, work best on buses built from 1988 to 1995. The equipment fits on the exhaust system of the bus and reduces particle emissions by about 30 percent and toxic emissions by about 50 percent.
Diesel exhaust contains small particles and vapors that can include more than 40 toxic air contaminants, contributing to increased
incidences of asthma, hospitalizations and deficits in lung growth similar to second-hand smoke exposure.
“Despite the tremendous statewide progress, the average Washington school bus still releases 130 percent more soot pollution per mile than a big rig (tractor trailer),� said Patricia Monahan, author of the study and a senior clean vehicles analyst for the Union of Concerned Scientists.
The report calls on the federal government to beef up funding for retrofitting older buses and replacing older buses with newer ones with cleaner emissions.
“The federal government needs to boost funding to retrofit buses and replace fleets so schools don’t have to choose between textbooks and clean buses,� said Allan J. Jones, director of pupil transportation for the state Office of Superintendent of Public Instruction.
Other measures that would help include eliminating the practice of leaving school buses idling in front of schools or in bus yards in the mornings, converting to safer biodiesel fuel mixtures and placing filtration devices on bus crankcases, which are another source of air toxin emissions, Nelson said.
This article is republished courtesy of The Olympian:
Study flags risk from bus fumes
For more information about clean buses in Washington, and how you can take action, please visit the Breathable Bus Coalition website:
http://www.breathablebus.org/
