The reduction in air pollution continues to be the most successful domain of pollution reduction since the first Earth Day in 1970. Since the first edition of this Almanac of Environmental Trends two years ago, reductions in air pollution have been astonishing. ...

» Virtually the entire nation has achieved clean air standards for four of the six main pollutants regulated under the Clean Air Act (carbon monoxide, sulfur dioxide, nitrogen oxides, and lead). The only pollutant where the clean air standard is still widely exceeded is ozone.

» In the case of ozone and particulates, the areas of the nation with the highest pollution levels have shown the greatest magnitude of improvement. The average ambient declines in pollution on the national scale that are reported here understate the magnitude of improvement in the worst areas.

On the flip side, the [Environmental Protection Agency's] regulatory structure systematically overstates the number of Americans exposed to unhealthy air.

» The chief factor in the reduction in air pollution has been technological improvement, mostly in "process efficiency" such as more complete fuel combustion, but also in control technologies that capture emissions, such as power plant "scrubbers" and catalytic converters on automobiles.

Regulatory mandates played a prominent role in prompting some of these technological changes, but many were the result of market forces and economic growth, as can be seen by the fact that air pollution began dropping in the U.S. in the mid-1960s -- before the passage of the first Clean Air Act.

» The long-term trend of improving air quality is certain to continue. Government air quality models project significant decreases in emissions over the next 20 years as technology improvement and equipment turnover continue. At the present time, however, reductions in air pollution are occurring more rapidly than the EPA's models have forecast. - Steven Hayward, Pacific Research Institute