California and the nation achieved record-low air pollution levels in 2004. Yet despite this ongoing progress, the American Lung Association's "State of the Air" report continues to exaggerate air pollution levels and risks, fomenting unwarranted public fear.

Even places with clean air can get a failing air-quality grade from ALA. Orange County failed for ozone smog, yet the entire county complies with the federal government's tough new eight-hour ozone standard. Even in Los Angeles County, 60 percent of people breathe air that meets the standard, yet ALA counts everyone in its polluted-air tally. ALA contends 152 million Americans breathe air that exceeds federal standards, but the true number is only about one-third this amount.

ALA also exaggerates the amount of pollution in the air, claiming Los Angeles County averaged 57 days per year exceeding the federal ozone standard during 2001-2003. Inspection of the actual monitoring data shows the worst location, Santa Clarita, actually averaged 49 days, while the rest of the county averaged 10.

Despite ALA's phony numbers, tens of millions of Americans really do live in areas that exceed EPA's health standards for ozone, particulates or both. But that doesn't mean they all suffer serious harm as a result. In reality, nearly all potential benefits of reducing air pollution have already been achieved.

California's Air Resources Board (ARB) estimates that achieving statewide attainment of the federal ozone health standard would reduce total hospital admissions for respiratory disease by only 0.7 percent. ARB's Children's Health Study followed more than 1,000 children from ages 10 to 18 during the 1990s and reported no relationship between ozone levels and lung function, and also reported that asthma incidence was 30 percent lower in areas with the highest ozone levels.

Both activists and regulators claim current, historically low particulate levels are killing thousands each year, but they ignore weaknesses in studies supporting this conclusion and contrary evidence from other research. The American Cancer Society study, which provided the main support for the current federal particulate standard, reported that particulates kill men, but not women; those with no more than a high school education, but not those with at least some college; and former smokers, but not current or never smokers. These biologically implausible results suggest problems with the study's statistical methods, rather than real causal relationships. In contrast, a study of 50,000 veterans with high blood pressure reported no relationship between particulate levels and risk of death.

Environmentalists depend on public fear and outrage to keep the donations flowing and maintain support for increasingly costly regulations. Reality is far too benign to generate the desired level of anxiety, hence the scary statistics manufactured for reports like "State of the Air." The bottom line: Air pollution is at a historic low, and affects far fewer people, far less often and with far less severity than activists care to admit.

Joel Schwartz is a visiting fellow at AEI.