Hence Mr. Thomas promises to withhold sanctions if states merely devise plans to reduce ozone.

Reducing ozone lets more ultraviolet light to come through.

Instead of progressing toward the goal in the clean air law of reducing ozone to safe levels, the country appears to be losing ground.

The state's long-range goal, through tighter emission controls and other measures under way, is to reduce ozone to .09 parts per million on the worst days.

Denver's return to clean-air status has come largely through efforts to reduce ozone, carbon monoxide and soot.

Not only will reducing ozone provide public health benefits, but it will avoid damage to ecosystems and vegetation.

Air Quality Trends - Progress made in reducing ground-level ozone.

Reducing tropospheric, or bad ozone, is an issue that is addressed state by state.

The chief of the unit, Leonard Bruckman, said the state was starting initiatives to try to reduce ozone.

For information on ozone standards, sources, health effects, and programs to reduce ozone, please see www.epa.gov/airquality/ozonepollution/.