Mobile Source Emissions

Mobile source emissions, or emissions from motor vehicles and non-road engines, account for almost a third of the air pollution in the United States. Routine aging and deterioration of vehicles, poor state of tune, and emission system tampering all increase emissions.

These emissions, primarily hydrocarbons and nitrogen oxides, contribute to the formation of ground level ozone, a noxious pollutant considered this country’s most pressing urban air quality problem.

To reduce vehicle emissions, the U. S. Environmental Protection Agency (EPA) has enacted several new standards that will phase in nationwide between 2004 and 2008. Low sulfur gasoline and diesel fuels will also be introduced during this period. These standards address emissions from passenger cars, light trucks, and heavy-duty diesel and gasoline-powered vehicles. In addition, EPA recently began to address emissions from non-road equipment and is developing emission standards comparable to those for cars and trucks. These new standards will, in time, favorably impact air quality throughout the United States.

What the EPA is doing about Diesel Emissions from Trucks and Buses

• Hot Spot Analysis For Indirect Sources, size 2.5 MB, PDF