Despite significant air-quality improvements in the nation’s most polluted cities, more than 40 percent of Americans still live in areas where air pollution is a threat to public health. That’s the conclusion of the American Lung Association (ALA) in its Annual State of the Air report issued last week.

The 2012 study focuses on air quality from 2008 through 2010. Still, many air pollution dangers remain, especially particle pollution. Short-term spikes in particle pollution are a continuing threat to more than 50 million Americans, the report says. “Particle pollution is the most dangerous and deadly widespread air pollutant in America,” says the report, noting that particle pollution can lead to early death, heart attacks, strokes and emergency room visits.

The study found that the five most-polluted cities for both short-term and year-round particle pollution were in California, with Bakersfield topping both lists. The year-round measurement was based on average results and gave a failing grade to annual concentrations averaging higher than 15µg/m(3). The short-term particle pollution scores used a weighted average based on the daily Air Quality Index. For more information check out http://www.stateoftheair.org/.

Numerous studies show that a high-efficiency air purifier can reduce indoor particle air pollution and help protect health. That’s a major reason why IQAir makes the county-by-county results of the State of the Air report available on its website. Visitors to the site can use the “What’s the State of Your Air” widget to check pollution levels in their own county, then use IQAir’s “Help Me Choose” tool to select the right IQAir air purifier to help protect their home against the dangers of air pollution. The 2012 State of the Air results are available now through the IQAir site.

Ultrafine particle pollution, which is the most widespread and most dangerous of all air pollution, is not measured by the U.S. Environmental Protection Agency standards used in the State of the Air report. “Air quality standards set by the EPA remain outdated,” Albert Rizzo, M.D., said in a State of the Air blog. Rizzo is the American Lung Association National Board Chair. “That means we’re not trying to clean up enough pollution, based on what current research says we should be doing to protect your family’s health,” Rizzo said.