Is the air you breathe killing you?

The air we breathe is becoming increasingly polluted and poses a health threat to millions, experts say.

According to a new study, an estimated 2.1 million deaths occur each year due to human-caused increases in fine particulate matter – tiny particles suspended in the air that can lodge deep in the lungs, causing cancer and other respiratory diseases. Additionally, approximately 470,000 people die annually because of the increase in ozone levels.

To determine their estimate, researchers from the University of North Carolina and the Environmental Protection Agency (EPA), used an array of climate models to simulate the concentrations of air pollution in the year 1850 as compared to year 2000. The study also compared the results from a range of earlier mathematical models on deaths from air pollution.

“Our estimates make outdoor air pollution among the most important environmental risk factors for health,” said study co-author Jason West, in a news release. “Many of these deaths are estimated to occur in East Asia and South Asia, where population is high and air pollution is severe.”

Although developing nations are the worst affected areas, those in developed countries are also at risk of air pollution and its dangers, study leaders said.

Almost 45 million Americans live in areas burdened by year-round particle pollution, according to the American Lung Association’s annual “State of the Air.” This year’s report gave an “F” to both Cook and Lake Counties in Illinois on the “Ozone Grade,” and Cook County also received a failing grade in “Particle Pollution.”

While it may be impossible to completely avoid air pollution, there are steps you can take to reduce your exposure. The best thing to do is increase your awareness of air quality reports, according to Gary Shellenberger, manager of respiratory services at Advocate Condell Medical Center, Libertyville, Ill.

“An area’s air quality index for the day is available online, in newspapers and usually on television weather reports,” says Shellenberger. “On days when air quality is poor, it’s best to avoid outside activity.”

If staying indoors is not possible, Shellenberger suggests trying to plan activities in the morning or late evening when ozone levels are typically lower.