Pittsburgh has the worst short-term particle pollution in the nation, surpassing Los Angeles in that category of the "State of the Air: 2008" report released Thursday by the New York-based American Lung Association (ALA). However, Los Angeles still has the highest level of year-round particle pollution and ozone pollution, the report finds.

The report found that Los Angeles, Houston and some other cities had made progress in reducing ozone levels, but others had fallen behind or stalled in efforts to control air pollution. ­Four out of five Americans — 42 percent — live in counties with unhealthy levels of ozone or particle pollution, according to the report.

ALA says stricter ozone standards recently adopted by the U.S. Environmental Protection Agency (EPA) will help lower levels of the pollutant. However, ALA is fighting changes to the Clean Air Act proposed by EPA that it says will weaken the act. ALA also is calling for increased efforts to clean up coal-powered power plants, cleaner diesel fuel and a requirement that all ships calling in U.S. ports use fuel that produces fewer emissions.

The entire report is available at http://www.stateoftheair.org/.