For 186 million Americans, that’s the message of the American Lung Association’s State of the Air 2009 report. That’s how many Americans live in areas with unhealthful levels of ozone or particulate air pollution. The ozone problem is much worse than the Association reported last year, primarily because EPA has tightened the ozone standard. But ozone pollution levels also have continued to climb in more than half of the cities with the worst ozone problems. The same is true for particulate pollution — although some of the most polluted cities have seen improvement, slightly more have gotten worse. The report identifies power plants, diesel exhaust, and oceangoing ships as key pollution sources needing tighter controls.