As government agencies across the country tighten the emission levels on aged school buses, many school districts are being faced with a decision to either retro-fit the diesel engines on their fleet or replace them with engines that are powered by natural gas or compressed natural gas (CNG). One example of the upcoming regulations on emissions is the requirement by California Air Resources Board which mandates that school districts add emission controls such as filters to older diesel powered school buses by the year 2018 to reduce the emission of soot and other pollutants. Buses that aren’t retro-fitted by that time must be removed from service.
Retro-fitting older school buses is a far less expensive proposal than buying new ones and can reduce emissions substantially, but there are arguments against these types of emission controls as well. The arguments against retro-fitting include additional maintenance expenses and the fact that, even with drastic reductions in emissions, schoolchildren are still breathing a cocktail of soot and pollutants when they ride on older school buses. Further arguments against retro-fitting are that 1980’s era school buses are so dirty that filters would have to be replaced so often that school buses would be in the garage more than they would be on the road.
The other option for school districts is to replace old diesel engines with natural gas or CNG powered engines that will likely cost more initially but provide savings over time with lower fuel costs (when measured by present day prices) as well as less frequent and less expensive maintenance requirements than retro-fitted engines. The other big advantage of these replacement fuels is that children would travel in a much healthier environment, which is hard to put a price on.
