As part of this program, new emission standards will begin to take effect in model year 2007 and will apply to heavy-duty highway engines and vehicles. These standards are based on the use of high-efficiency catalytic exhaust emission control devices or comparably effective advanced technologies. Because these devices are damaged by sulfur, we are also reducing the level of sulfur in highway diesel fuel by 97 percent by mid-2006. The program provides substantial flexibility for refiners, especially small refiners, and for manufacturers of engines and vehicles, to aid them in implementing the new requirements in the most cost-efficient manner. Background The pollution emitted by diesel engines contributes greatly to our nation's continuing air quality problems.
Exposure is widespread, particularly in urban areas.
Other health effects include aggravation of respiratory and cardiovascular disease, aggravation of existing asthma, acute respiratory symptoms, chronic bronchitis and decreased lung function. In some urban areas, the contribution is even greater. EPA's new program will result in PM and NOx emission levels that are 90 percent and 95 percent below today's levels, respectively. The results of this historic program are comparable to the advent of the catalytic converter on cars, as the standards will for the first time result in the widespread introduction of exhaust emission control devices on diesel engines. And, just as removing lead from gasoline enables the use of catalytic converters, this program removes sulfur from diesel fuel to enable the use of these advanced emission controls on diesel vehicles.