Georgia received mixed grades for its air quality in a new report released Wednesday.

The Atlanta-Sandy Springs-Gainesville area dropped out of the Top 25 cities in the nation for ozone pollution, ranking No. 28 in the “State of the Air 2013” report from the American Lung Association.

But the same area tied for 18th in annual particle pollution, worse than last year’s ranking of 24th.

Macon-Warner Robbins-Fort Valley, in roughly the center of the state, tied for 14th among the most polluted cities in the nation for annual particle pollution.

Meanwhile, Brunswick and Savannah-Hinesville-Fort Stewart, close to the Atlantic Ocean, were recognized as having no unhealthy days of ozone pollution.

The Lung Association report found that overall, the nation’s air is getting healthier, as a result of reduced emissions from coal-fired power plants and the transition to cleaner diesel fuels and engines. The improvement is especially noticeable in the eastern United States, the report said.

The analysis used pollution data compiled by the EPA in 2009, 2010 and 2011 for ozone, or smog, and for particle pollution, also known as soot.

“The air in Georgia is healthier than when we started the ‘State of the Air’ report 14 years ago,” Martha Bogdan, president of the American Lung Association in Georgia, said in a statement. “We saw some significant improvements, but there are still many areas of the state with unhealthy levels of smog and soot.”

Several of the reporting Georgia counties received an “A” for high ozone days, while others, especially around Atlanta, received an “F.’’

June Deen, state director of the Lung Association, noted that the metro Atlanta area had a slight increase in both ozone and particle pollution in the latest data. “We’ll see if this trend continues,’’ she said.

Ozone and particle pollution, or soot, are the most widespread air pollutants — and among the most dangerous. Ground-level ozone, a main ingredient of smog, has harmful effects, especially on children, older adults and people with respiratory illnesses.

Air pollution, including particulate matter, is linked to respiratory and heart diseases, cancer, premature death, and reduced lung function in children.

Researchers are continuing to find an association between air pollution and a range of health effects, said Jeremy Sarnat, a research professor in the Department of Environmental Health at Emory’s Rollins School of Public Health.

He cited a study that found an association between exposure of pregnant women to pollution and pediatric cancers.

“Atlanta is still an area where a lot of improvements need to be made,’’ Sarnat said.

“I don’t think we’re driving less in Atlanta,’’ he told GHN.

But cutting back on driving, Sarnat said, “is the single greatest thing we can do to improve our air quality.’’