Think Tank Takes: Air quality gains continue to grow

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.