Cutting the Diesel Pollution Inside Texas School Buses

May 19th, 2006

School buses are the safest way for Texas children to get to school, but the vast majority of Texas’ 35,000 school buses runs on diesel fuel and emits tons of unhealthy pollution that can make its way into the bus cabin, where Texas children breathe it in.

Studies show that air pollution levels inside school buses can be greater than the ambient levels outside the bus. The elevated levels are attributed to emissions from the bus itself that intrude into the bus cabin. This “self-pollution” effect comes from sources of emissions: the tailpipe and the engine crankcase, which is vented to the air in most diesel engines.

Diesel emissions contribute to a laundry list of adverse health effects, including: dizziness, nausea, increased incidence and severity of asthma attacks, chronic bronchitis, and over a lifetime of exposure, increased risk of lung cancer.

Commercially available technologies can nearly eliminate all of the emissions that contribute to elevated pollution levels inside school buses. Crankcase filtration systems trap oil mists and reroute crankcase emissions back to the engine air intake, effectively eliminating those emissions. Diesel particulate filters can reduce tailpipe particulate emissions by 85%.

Of the many forms of air pollution we breathe, the diesel emissions in our school buses arguably should be the easiest to clean up:

• New buses are much cleaner than those they replace. Federal standards for new school bus emissions have been gradually tightened over recent years, and as buses are retired—usually after about 15 years—they are replaced with much cleaner ones. The 2007 models must meet standards that will make them more than 95% cleaner than the buses of two decades ago.

• Affordable pollution-cutting retrofits are available. Older buses scheduled to remain in service for a few more years can be retrofitted with filters that bring their tailpipe exhausts and crankcase emissions into line with new-bus emission standards.

• Revenues already collected are available to clean up buses. In recent years, the Texas Legislature imposed a series of fees and surcharges to generate revenue to help reduce emissions. Texans are paying this money to the state, but much of it is sitting unspent in the State Treasury. Legislators should use these funds to clean up air pollution as promised.

Contact your state representative and your state senator. [To find your legislators’ contact info online, visit] Tell them our children deserve to breathe healthy air. Urge them to use some of the emission-cutting funds sitting unspent in the State Treasury to help Texas school districts retrofit or replace older, polluting buses. If you’d like to help with the effort to clean up Texas school buses or for more information, contact Betin Santos: 713-942-5821,

A more detailed discussion about the need to clean up Texas school buses is available at: