LOS ANGELES -- The Southland ranks among the worst metropolitan areas in the nation for fine-particle, or soot, pollution, according to a report released Thursday by a statewide environmental group.

Environment California released "Plagued by Pollution," an analysis of fine particle data from environmental agencies across the country. The study ranks the Los Angeles-Long Beach-Santa Ana area as the third-worst metropolitan area in the nation.

"Los Angeles has some of the worst soot pollution in the nation and our kids and senior citizens suffer asthma attacks and other serious health programs as a result," said Winston Vaughan, Environment California campaign director.

The American Lung Association has blamed soot pollution for aggravating respiratory and cardiovascular conditions.

The Riverside-San Bernardino-Ontario area ranked as the nation's worst for soot pollution among large metropolitan areas. Pittsburgh ranked second-worst on the list.

The report, released at news conferences Thursday in Los Angeles and Long Beach, ranked California as the nation's most soot-polluted state.

"California is the worst state but it also has the worst particle-polluted cities as well," Sarah Jane Vaughan of Environment California said.

Bakersfield, Salt Lake City and the Visalia-Porterville area took the top three spots, respectively, for mid-size metropolitan areas with the highest particle pollution.

The metropolitan areas were ranked by micrograms of pollution per cubic meter, or soot in the air. Using the data, several mid-size areas across the nation had higher soot pollution than larger regions. Bakersfield, which ranked worst among mid-size cities with a maximum average of 18.92 micrograms per cubic meter, had worse pollution than the large metro areas of Atlanta- Sandy Springs-Marietta, Ga., with 17.58, and Cleveland-Elyria-Mentor, Ohio, with 17.53.

The small cities with the worst soot level was Hanford-Corcoran in central California with 17.45.

"California tops all three worst categories - large, medium and small cities," Winston Vaughan said.

He said the state's power plants and large numbers of diesel trucks, cars and ships in ports cause most of its air pollution. And despite gains in environmental policy, population seems to be boosting pollution.

"While our individual cars may be cleaner, we need cleaner fuel technology," he said.

Soot particles are often released from fossil fuel combustion; exhaust from diesel trucks, buses and heavy equipment; and emissions from coal-fired power plants or factories. Particulates are sometimes carried by the wind, according to the Environmental Protection Agency.