Emissions Regulations

All engines – diesel, gasoline, propane, and natural gas – produce exhaust gas containing carbon monoxide, hydrocarbons, and nitrogen oxides. These emissions are the result of incomplete combustion. Diesel engines also produce particulate matter. As more focus is placed on health and environmental issues, governmental agencies throughout the world are enacting more stringent emissions laws.

Because so many diesel engines are used in trucks, the U.S. Environmental Protection Agency and its counterparts in Europe and Japan first focused on setting emissions regulations for the on-road market. While the worldwide regulation of non-road diesel equipment came later, the pace of cleanup and rate of improvement have been more aggressive for non-road equipment than for on-road engines.

Non-road emissions reductions:

Tier 3/Stage III A emissions regulations required an approximate 65 percent reduction in PM and a 60 percent reduction in NOx from 1996 levels.
Interim Tier 4/Stage III B regulations require a 90 percent reduction in PM along with a 50 percent drop in NOx.
Final Tier 4/Stage IV regulations, which will be fully implemented by 2015, will take PM and NOx emissions to near-zero levels.