The report, "Latest Findings on National Air Quality: 2002 Status and Trends," shows that since 1970, emissions of the six principle air pollutants have been cut 48 percent. Acid rain data released at the same time demonstrates the cap and trade program's success in reducing harmful sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions from power plants.
According to the data, SO2 emissions from power plants were 10.2 million tons in 2002, 9 percent lower than in 2000 and 41 percent lower than 1980. NOx emissions from power plants also continued a downward trend, measuring 4.5 million tons in 2002, a 13 percent reduction from 2000 and a 33 percent decline from 1990 emissions levels.
The annual Trends Report summarizes air quality information and facility emissions data for the six principal, or criteria, air pollutants: carbon monoxide (CO), lead (Pb), nitrogen dioxide (NO2), ozone (O3), particulate matter (PM) and sulfur dioxide (SO2). The report, based on monitoring at thousands of locations across the country, focuses primarily on national trends for the 20-year period between 1983-2002 and the 10-year period between 1993-2002.