Around the World:
Air pollution is a major health risk and can contribute to stroke, heart disease, lung cancer, and a variety of respiratory diseases (especially asthma). For any country, the lower the levels of air pollution, both indoors and out, the better the cardiovascular and respiratory health of its citizens. About 92% of the world's population breathes unhealthy air on a daily basis and about 3 million premature deaths are caused by outdoor air pollution every year, with another three billion people at risk due to indoor air pollution. Whether it's by tobacco or wood smoke, car emissions, or industrial activity… air can quickly transition from an essential part of our lives to a dangerous one.

In the United States:
In the outdoors, the two greatest pollutants in the air you breathe are likely to be smog and particulates, generated from vehicle and industrial emissions as well as burning wood and other biomass. The best way to protect yourself from outdoor air pollution is to check air quality forecasts in your community daily and avoid exercising or working outdoors when air quality is poor. You can contribute to reducing outdoor air pollution by driving less as well as by using less electricity and fuel at home.

For most Americans, indoor rather than outdoor air pollution is more of a threat to individual health. Experts estimate that indoor air pollution can be 25-50% of the overall health risk that Americans face as a result of their environments. Reducing risk indoors is best done by avoiding secondhand tobacco smoke, ventilating whenever a paint stripper, paint, household cleaner, or other solvent is in use, and reducing the use of air fresheners and other scented products (including candles) in the home.