The EPA's newest ozone pollution threshold has placed 26 national parks at non-compliant levels. But while the rest of the nation's communities must spend billions conforming to the new normal, the parks – including such gems as Sequoia and Rocky Mountain – may be off the hook. The National Park Service blames power plants for much of the problem. But scientists and officials from California say that car emissions – and the tourism that brings $15.7 billion per year to the parks -- are mostly to blame.

"Usually ozone pollution is caused by traffic rather than power plants," said Dr. Saewung Kim, an assistant professor of atmospheric chemistry at the University of California, Irvine. "Power plants have done a great job cleaning up their emissions and ozone-causing pollutants."

While the parks are a national treasure, the National Park Service says compliance with the ozone pollution threshold is a state issue. And just like with disastrous Animas River spill in August, the Environmental Protection Agency doesn't levy fines against itself, so the parks will continue to operate as usual unless the states somehow find a way to curtail the smog.

"States are responsible for implementing the provisions of the Clean Air Act," said Jeffrey Olson, chief of education and outreach at the National Park Service. "They will eventually have to put plans in place to show how they can come into compliance with violations of the ozone standard."

On Oct. 1, the ozone pollution standard was lowered from 75 to 70 parts per billion, thrusting 241 counties nationwide onto the non-compliance list – up from the 227 counties that were struggling to comply when the standard was still 75 ppb. The EPA estimates that compliance with the new standard will cost $1.4 billion annually .

Of the 26 parks that are not in compliance, the biggest violator is Dinosaur National Monument, home to 1,500 dinosaur fossils and a popular white-water rafting destination on the Colorado-Utah border. Its ozone level is 114 ppb. The runner-up at 90 ppb is the 631-square-mile Sequoia National Park in Northern California, a pristine forest boasting 3,200-year-old trees that are among the tallest in the world.

The Grand Canyon? It barely squeaks by at 69 ppb.

In all, 11 states have national parks that are in non-compliance with the new ozone standard: Arizona, 3; California, 9; Colorado, 2; Connecticut, 3; Illinois, 1; Maine, 1; Massachusetts, 1; Nevada, 1; New Jersey, 2; Pennsylvania, 1; and Utah, 2. Ozone levels are calculated over a three-year period.

Critics say that billions in product losses and compliance costs could make this the most costly regulation in history.

"The costs of compliance with this regulation would largely be borne by manufacturers, and the EPA can only identify a little more than a third of the controls we would need to install to comply. It calls the rest 'unknown controls,' because it simply cannot tell us what we will have to do," said Jay Timmons, president of the National Association of Manufacturers. "This regulation's strict mandates will force manufacturers to shut down, scrap or modify existing facilities. This means higher costs for consumers and lost jobs."

"Much of the pollution is from vehicles, but it also depends on the location of the park," said Dave Clegern, spokesperson for the California Air Resources Board. "Some of the recent pollution has been from wildfires, some drifts in from out of state."

Even though the National Park Service says power plants are mostly to blame, most of the non-compliant parks are located in the West, far from the coal-fired power plants dotting the eastern part of the country.

"I'm not talking about car or truck traffic but pollutants that are transported by prevailing winds," said Olson, of the National Parks Service. "For example, pollutants from a coal-fired electrical generating station are carried by prevailing winds long distances away from the plant and have an effect on air quality in a national park or other area downwind from that plant."

The scientific consensus on that is far from unanimous, however.

Scott Denning, a climate scientist at Colorado State University, says ozone forms "downwind of where it was created," and lists the ingredients as "unburned fuel from gasoline, nitrogen oxide and sunlight." He said it's understandable that Sequoia would have a level of 90 ppb because it's "between the L.A. basin on one end and the Bay Area on another – 20 million people can produce enough [pollution] and it's a sunny place and can cook it in the air and drift upwards."

California's governor and legislators have spent years enacting measures aimed at forcing residents to curtail driving, which is blamed for most if not all of its smog. The state has only four coal-burning plants.

Such evidence ought to be proof that Obama's focus on the power industry is misplaced, said Rep. Mike Kelly, R-Pa.

"The biggest offender is Mother Nature, with volatile organic compounds," he said. "It will get to the point where almost anything you do will have an effect on pollution."

Pennsylvania has 74 power plants run by either coal or petroleum and has spent decades struggling to comply with EPA measures. Approximately 40 percent of its manufacturing jobs have been lost since 1990, according to the Center for Regulatory Solutions.

"If your county or region is not meeting the standard, you are in non-attainment," said Kevin Sunday, government affairs director of the Pennsylvania Chamber of Commerce. "You have to spend whatever it takes or go buy emission credits."

A Pennsylvania study found that trying to reach the 65 ppb level would result in a $98 billion state product loss from 2017 to 2040, $109 billion in compliance costs and 101,182 lost jobs.

Response to the new 70 ppb standard will depend to a great degree on guidance from the EPA, as states and counties submit plans that will also include what to do about the national parks in their particular area.

"Until that guidance is available and states have produced plans identifying what measures are necessary to meet the standard, the National Park Service does not know its role," Olson said. But he was sure about one thing: "It is NOT safe to say ozone levels are worse because of tourists."