At Risk: Particle Pollution

All too many people who live in areas with unhealthful ozone levels also face a second, even more dangerous threat: particle pollution. This American Lung Association report estimates that millions live in areas with unhealthful shortterm or year-round levels of particle pollution, including:

• 64.3 million people—more than 20 percent of the U.S. population—live in 71 counties with dangerous short-term levels, or spikes of particle pollution; and
• 53.1 million people—nearly one in five Americans—live in 68 counties with unhealthful levels of particle pollution day in and day out.

Those who are particularly vulnerable to ozone are also at greater risk from particles. Unfortunately, particle pollution also threatens two other large groups: people with cardiovascular diseases and people with diabetes. In total, millions of especially vulnerable people live in areas of the country where particle pollution levels place them at risk, including:

• 16.8 million children 18 and under live in areas with unhealthful short-term levels of particle pollution; 13.9 million live in areas with unhealthful yearround levels.
• 7.4 million adults 65 and older live in areas with unhealthful short-term levels of particle pollution; 6 million live in areas with unhealthful year-round levels.
• 3.9 million adults with asthma live in areas with unhealthful short-term levels of particle pollution; 3.2 million live in areas with unhealthful year-round levels.
• 1.4 million children with asthma live in areas with unhealthful short-term levels of particle pollution; 1.2 million live in areas with unhealthful yearround levels.
• 2 million people with chronic bronchitis live in areas with unhealthful shortterm levels of particle pollution; 1.6 million live in areas with unhealthful year-round levels.
• 763,000 adults with emphysema live in areas with unhealthful short-term levels of particle pollution; 627,900 live in areas with unhealthful year-round levels.
• 15.4 million people with cardiovascular diseases live in areas with unhealthful short-term levels of particle pollution; 12.7 million live in areas with unhealthful year-round levels.
• 3.2 million people with diabetes live in areas with unhealthful short-term levels of particle pollution; 2.7 million live in areas with unhealthful year-round levels.

Basis for the American Lung Association State of the Air Report

Because millions of people are exposed and millions more are at risk, the American Lung Association produces the American Lung Association State of the Air each year to alert individuals, families, business, industry and government leaders to the dangers inherent in the air we breathe.

In 2000, the American Lung Association initiated its State of the Air annual assessment to provide citizens with easy-to-understand summaries of the quality of the air in their communities. These annual assessments are based on concrete data and sound science. Counties are assigned grades ranging from A through F based on how often their air quality crosses into the “unhealthful” categories of EPA’s Air Quality Index for ground-level ozone (smog) pollution and short-term particle pollution.

The Air Quality Index is based on the national air quality standards. The air quality standard for ozone used as the basis for this report (0.08 parts per million averaged over an eight-hour period) was adopted by the EPA in 1997 based on the most recent health effects information. For particle pollution, the Air Quality Index is based on, but is more conservative than, the PM_2.5 24-hour national standard. Also adopted in 1997, the national standard for PM_2.5 24-hour levels is 65 µg/m³. However, EPA set the Air Quality Index for particles to acknowledge that levels below 65 µg/m³ are harmful to public health.⁸

The Lung Association has long urged the EPA to employ more protective standards to judge air quality. Thousands of studies completed in the years since EPA set its standards show clearly that air pollution harms millions of Americans at levels that were once considered safe. For that reason, the American Lung Association report uses a more conservative formula to grade than does EPA for ozone and short-term particle pollution.

To evaluate the year-round levels of particle pollution for any monitored county, the American Lung Association State of the Air 2006 uses the EPA’s own criteria for determining whether a county met or failed to meet the national air quality standards. A more detailed discussion of the methodology is contained in Appendix A.