ALBUQUERQUE, N.M. - An environmental group has filed a petition with the U.S. Environmental Protection Agency to force 16 Western states to revise their air quality regulations in an effort to trim ozone pollution.

WildEarth Guardians said in its 25-page petition filed earlier this week that large cities throughout the West have already violated clean air standards limiting ozone and the problem is spreading to rural areas, including northwestern New Mexico and western Wyoming.

"The Western states are facing an unprecedented challenge in addressing the impacts of ozone air pollution. For the sake of public health, it is a challenge that must be met aggressively," Jeremy Nichols, WildEarth Guardian's climate and energy program director, wrote in the petition.

Ground-level ozone, a key component of smog, forms when emissions from tailpipes and smokestacks mix with sunlight. The colorless gas can irritate the respiratory system, reduce lung capacity and aggravate asthma.

WildEarth Guardians is asking the EPA to force New Mexico, Arizona, California, Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, North Dakota, Oklahoma, Oregon, South Dakota, Utah, Washington and Wyoming to revise their air quality regulations to strengthen ozone safeguards by 2013.

The group wants the agency to designate an interstate transport region for the West that would prioritize the development of regional solutions to ozone pollution. It also wants the EPA to create an interstate commission to assess the degree of ozone pollution transport and strategies to combat the problem.

According to the petition, all or portions of the 16 states are expected to exceed ozone pollution limits by 2018.

"With air quality projected to worsen throughout the West, we need regional solutions, not piecemeal plans or fingerpointing," Nichols said. "The Environmental Protection Agency can provide the leadership and direction needed to put the West on the path toward clean air."

The petition calls for the agency to act on the group's requests within 18 months.

EPA spokesman Jonathan Schrader in Washington, D.C., said this week that once the agency receives the petition it will be reviewed and the agency will respond appropriately.

The EPA earlier this year lowered the federal health standard for ozone from its previous level of 0.08 parts per million to 0.075 ppm.

The agency estimates that more than 300 counties nationwide will not be able to meet the new standard, although it is not expected to make official non-attainment designations until 2010.

WildEarth Guardians contends that the EPA has authority under the Clean Air Act to force states to revise their air quality regulations if the rules are found to be "substantially inadequate." Nichols argues that is the case - or soon will be - in the Western states.

WildEarth Guardians decided to petition the EPA now rather than wait for a new federal administration to take over, saying the problem needs to be addressed immediately.

"Filing it now really tees it up for the new EPA administrator to give it the priority attention it deserves," Nichols said. "… We are hopeful the next administrator will not just realize what's legally required, but what is the right thing to do from a public health and environment standpoint."