School Bus Retrofits ‘Can Cut Emissions Up To 90%’

by | Nov 28, 2012

For between $9,000 and $15,000 each, older school buses can be fitted with tailpipe and crankcase filters that reduce soot emissions by up to 90 percent, according to an Environmental Defense Fund report.

This makes the old buses as clean as new ones for a fraction of the cost — a new bus costs between $75,000 and $80,000, EDF says.

In its new report, Review of Texas’ Clean School Bus Programs: How Far Have We Come and What Is Still Left to Do?, EDF recommends solutions for lower diesel-emitting buses that can be applied to fleets across the US.

Diesel engines power most of the 480,000 buses that carry 24 million American children to school every day, EDF reports. According to the California Air Resource Board, school bus trips can increase children’s daily exposure to black carbon up to 34 percent compared to passenger cars, and particle matter (PM) levels inside a school bus can be five to 10 times the levels outside the bus.

As of the 2010-2011 school year, about two-thirds of Texas’s school buses were over six years old, emitting at least 10 times as much PM as newer buses. (Editor’s note: EDF actually wrote that buses over six years old emit at least 10 times as much PM as “older buses,” which we assume is an error. UPDATE, Nov. 28, 10:24 CST: EDF has now confirmed this should read “newer.”)

This affects more than 700,000 children.

Texas has made progress with clean bus programs, however. Through the end of the 2011 calendar year, 7,068 buses were retrofitted, 700 buses were replaced and more than $38 million was spent on clean-fuel and idle-reduction projects, the report says.

In addition to replacing or retrofitting old buses, turning off engines when waiting can lower diesel emissions and save “countless” gallons of gas, EDF reports. When a bus remains idles for more than three minutes, emissions from the bus can increase more than 65 percent. By reducing idling, a 25-strong bus fleet can save thousands of dollars a year in fuel costs.

Under the Texas Clean School Bus Program, the Texas Commission on Environmental Quality is accepting applications for grants through Nov. 30. All public school districts and charter schools in Texas are eligible to apply for this grant, intended to reduce diesel emissions.

Additionally, EPA has launched a new rebate funding opportunity for school bus replacements under the Diesel Emissions Reduction Act. Applications will be accepted until Dec. 14.


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