Most recent data available on the state of the nation's air quality showed significant improvement for every regulated air pollutant, according to a release by the EPA. Emissions of toxic air pollutants, such as benzene, have declined about 40 percent nationwide between 1990 and 2005, the agency said.

The report, Our Nation's Air, Status and Trends Through 2008, breaks down trends by pollutant (CO, ozone, Lead, NO₂, PM and SO₂), and also provides localized and national trend reports for those pollutants which the U.S. has established national air quality standards. Regulatory statistics are also provided.

Click here for read the trend report.