Buses take about 24 million children to school in the United States each year. The U.S. National Highway Traffic Safety Administration says they’re the safest way to get our children to school — eight times safer than riding in a passenger car. But most school buses also pollute the air with diesel exhaust, and that’s bad news for the kids on the bus.
The problem is that children are exposed to diesel exhaust when they play near idling school buses, or while they ride the bus, as fumes accumulate inside the vehicle. Studies show that over time, exposure to diesel fumes can cause serious health problems — one well-documented concern is that the particulate matter in diesel fumes can contribute to asthma and other respiratory illnesses, plus it’s been linked to increased risk of lung cancer.
But there’s also good news: A growing number of communities from around the country are working to make their school buses less polluting, and it’s surprisingly easy to do. Two organizations involved in these efforts are the nonprofit Union of Concerned Scientists and the Environmental Protection Agency’s Clean School Bus USA program. Both have online resources to help the public understand the issue. Some of the steps they recommend require buying new equipment; however, in many cases, government funding is available to help cash-strapped school districts replace or retrofit their buses.
“There’s federal funding, and a number of states also have cleanup programs,” says Patricia Monahan, deputy director for the Clean Vehicles Program at the Union of Concerned Scientists. “California, Washington and Ohio — all of these states have stepped up to provide funding for cleaner school buses.”
One of many success stories is the Puget Sound Clean Air Agency, which helped the Washington State Clean School Bus Program secure state funding to clean up more than 4,000 buses. “Our legislators have responded and I think others will also,” says Dennis McLerran, director of the Puget Sound Clean Air Agency.
There are several different ways to clean up school buses. Here are some of the best options:
Less Idling. A simple change that can make a big difference is to reduce idling by turning off the engine as soon as the bus is parked. Some communities have implemented voluntary “no idling” zones, which help keep the air cleaner for bus riders and everyone else.
Cleaner Fuels and Retrofits. Another option is to switch to cleaner burning fuels. One popular choice is B20, a blend of 20 percent biodiesel, 80 percent petrodiesel. This fuel has a price comparable to conventional diesel, and can be run in an unmodified diesel engine. According to the EPA, it reduces particulate matter by about 10 percent. Another clean fuel being used in school buses is compressed natural gas. Although this is a clean-burning fuel, it does require buying new buses.
Meanwhile, diesel fuel itself is getting cleaner. In 2006, most retailers began carrying a cleaner variety of diesel fuel, ultra-low sulfur diesel. This new fuel not only has much less sulfur, but case studies suggest it also reduces emissions of particulate matter by 5 percent to 9 percent. Even better, this fuel is designed to work with new particulate filters. Installing these filters is expensive, costing as much as $5,000 to $10,000, but together, the fuel and the filter reduce levels of pollutants by 60 percent to 90 percent.
Replace Older Buses. One of the best options for cleaning up buses is to replace older buses with newer, cleaner running models. Because emissions standards have changed significantly over the last 30 years, you can tell a lot about how much a bus pollutes simply by finding out how old it is. Buses produced after 1990 produce much lower particulate levels than older buses, and those produced in 1994 and later are even cleaner.