A report released by the American Lung Association on Tuesday ranks the Atlanta metropolitan area, which includes Gainesville, in the nation’s top 25 cities with air pollution problems.

The association’s State of the Air report notes that many cities, including the Atlanta area, have improved air quality over the past decade, but found that 6 in 10 Americans live in areas where air pollution levels are dangerous.

In 2008, Atlanta reported its best year-round particle pollution levels — a mixture of microscopic soot, diesel exhaust, chemicals, metals and aerosols — since the American Lung Association began tracking the pollutant.

Still, the Atlanta metropolitan statistical area, which included Gainesville and Sandy Springs, ranked 17th in the top 25 cities where people were most at risk for year-round particle pollution. The report states that breathing in particle pollution can increase the risk of early death, heart attacks, strokes and emergency room visits for asthma and cardiovascular disease.

The metropolitan area also ranks 23rd out of the report’s list of the nation’s 25 most ozone-polluted cities.

The association’s report gave Hall County a grade of C for particle pollution after particle pollutants were at high levels for three days in the research period.

Ozone pollutants were not recorded in Hall County for the study.