High diesel emissions call for replacement school bus fleets, says ‘Pollution Report Card’

A new school report analysing diesel emissions from US school bus fleets have awarded either the lowest grade, or have 'failed' 21 states for the condition of their vechicles. The report grades states - A through to D - in accordance to their levels of diesel emissions from school buses, snd none of the states 'even came close' to receiving the top 'A' grade for lowest emissions. Only six states and the District of Columbia are ranked as having lower than average diesel emissions.

The new report Pollution Report Card: Grading America’s School Bus Fleets, from the Union of Concerned Scientists (UCS), is the first nationwide analysis of pollution from these vehicles in the US.

School bus fleets in the US release 3,000 tonnes of soot, 95,000 tonnes of smog-forming pollutants and 11 million tonnes of greenhouse gas emission annually, says the report. Older buses – those built before 1990 and 1991, constituting one third of those on the road – are the main contributors to these pollution levels. These emit six times more toxic soot and nearly three times more smog-forming nitrogen oxides than more modern models.

The report recommends cleaner alternatives to standard diesel fuel, claiming natural gas-run school buses can reduce toxic soot 83% compared to new model diesel powered buses and 93% in comparison to older diesel buses. Smog-forming nitrogen oxides are reduced about 48% with natural gas compared to today’s diesel and 78% compared to diesel buses built before 1990. In the last decade on in five transit buses on order are powered by natural gas, they have a proven record of success, says the report.

The UCS have welcomed the Environment Protection Agency’s new emissions standards for a 97% reduction in the sulphur content of diesel fuel in vehicles built after 2007 (see related story). However, the organisation wishes to see federal recognition of cleaner fuels. They are currently campaigning for a US$300 million grant under the Senate Energy Bill, which they would hope to replace 2000 or more of the dirtiest buses across America.

The exhaust from diesel fuel has been proven to aggravate a number of health problems including asthma and other respiratory problems; it is also thought to be responsible for 70% of California’s state cancer risk. There are concerns in particular for children’s health, whose immature lungs are particularly susceptible to the dangers of diesel emissions. “Going to school should not be hazardous to our kids’ health,” says Michelle Robinson, Senior Advocate for Clean Vehicles at UCS.

“The large gap in performance between standard diesel buses and natural gas buses shows that even the ‘cleanest’ state fleet has room for improvement,” says the report author Patricia Monahan. The UCS hope that a federal investment of US$300 million would start the ball rolling towards an eventual pollution free transportation system and act as an important down payment on the health of children across the country.

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