Data for 10 years show remarkable improvement in U.S. air quality.(1984 to 1993)

The U.S. Environmental Protection Agency (EPA) recently reported the air quality trends for six pollutants for which it has issued National Ambient Air Quality Standards (Naaqs).

The analyses are based on data from some 4,000 air pollution monitors throughout the U.S. The 1993 data disclose changes for the 1984-93 period and indicate significant improvements in the concentrations of all pollutants tested:

* Ground-level ozone decreased 12%.

* Lead decreased 89%.

* Sulfur dioxide (SO2) dropped 26%.

* Carbon monoxide (CO) declined 37%.

* Nitrogen dioxide (NO2) levels fell 12%.

* Particulate matter smaller than 10 m (PM-10) has decreased 20% since 1988.

The report, titled "National Air Quality and Emissions Trends Report, 1993," also reveals that 1993 was the second consecutive year in which no U.S. cities violated the NO2 standard.

Nonattainment areas

When the Clean Air Act Amendments of 1990 were passed, 140 million Americans were living in areas out of attainment for groundlevel ozone. That number has since fallen to 43 million.

Of the 91 areas designated "nonattainment" for smog in 1990, 48 now meet the standard. In addition, 28 of the original 38 areas designated nonattainment for CO now meet that standard.

The EPA says these areas "are eligible for redesignation to attainment status." To date, however, only a handful of areas have …