The State of the Air: 2006 report finds that more than 150 million Americans still live in counties where they are exposed to unhealthful levels of air pollution. The report ranks the cities and counties with the dirtiest air, and provides county-by-county report cards on the two most pervasive air pollutants: particle pollution (more commonly called “soot”) and ozone (more commonly called “smog”). While air pollution is unsafe for everyone, some people are at increased risk because of their age or health situation. Those groups include people with asthma, adults over 65, children under 18, people with chronic obstructive pulmonary disease (COPD – chronic bronchitis and emphysema), people with cardiovascular disease, and those with diabetes.