EPA's Efforts to Reduce Ground-level Ozone

To address ground-level ozone pollution, EPA has traditionally focused on local control strategies in areas of the country with high measured levels of ozone in the air. In recent years, EPA and the States have recognized the need for more aggressive programs to reduce ozone and other pollutants such as nitrogen oxides (NOx) that cause ozone problems hundred of miles away.

Additionally, increasingly stringent national controls continue to be implemented on mobile sources, such as cars and trucks.

National health-based air quality standards

In 1997 EPA revised the air quality standards for ozone to better reflect the new scientific health studies. These studies showed that longer-term exposures to moderate levels of ozone may cause irreversible changes in the lungs. EPA is continuing to collect air quality monitoring data to identify areas of the country that are routinely unable to meet the existing and new ozone air quality standards. For more information, visit EPA's Website.

Regional transport

Although many cities have made efforts to control ozone by reducing local emissions, incoming ozone transported from upwind areas also needs to be addressed. In 1998, EPA issued a rule that will significantly reduce regional emissions of nitrogen oxides (NOx) in 22 states and the District of Columbia, and in turn, reduce the regional transport of ozone. Some regional strategies for reducing ground-level ozone include:

• Reducing NOx emissions from power plants and industrial combustion sources
• Introducing low-emission cars and trucks using “cleaner” gasoline
• Improving vehicle inspection programs