Hospital admissions, especially for those with asthma, increase on smoggy days, and repeated exposure to smog may permanently injure lungs. Studies have linked smog to decreased lung function in healthy children. Fortunately, school districts, urged on by parents and educators, now have the option to choose cleaner school buses. While the 400,000 diesel school buses currently in use can be substantially improved through cleanup technologies, the greatest opportunity for improvement lies in new buses. Although diesel engine makers are required by law to produce cleaner bus engines in the future, cleaner diesel still provides far less health protection than other alternatives.
Buses powered by natural gas offer a big step forward.
Today, one in seven new school buses runs on natural gas. They emit 10 times less soot and 40 percent less smog-producing pollutants than their commercial diesel counterparts. While they cost more to buy than diesel buses, they cost less to run because fuel and maintenance expenses are lower. Electric school buses are the best choice of all, because they provide children with zero-pollution travel. The electricity that powers the buses is stored in batteries and, in the future, will be produced on board by fuel cell engines.