Four health and environmental groups asked the 9th U.S. Circuit Court of Appeals Friday to reject a clean air plan submitted by the local anti-smog agency, claiming the plan allows polluters to escape strenuous regulations and leaves Angelenos breathing smoggy air.

The Sierra Club, Physicians for Social Responsibility-Los Angeles, the Natural Resources Defense Council and Communities for a Better Environment (CBE) petitioned the court to reject the U.S. Environmental Protection Agency’s approval of the plan and mandate that local, state and federal environmental agencies start over.

“The EPA approved a deficient smog plan for the L.A. region,” said Earth justice attorney Adrian Martinez, who is representing three of the four plaintiffs (not CBE). “We want to eliminate those loopholes.”

The South Coast Air Quality Management District, which approved the plan in December 2012 that was adopted by the California Air Resources Board in early 2013, defended its anti-smog blueprint.

“I don’t see any loopholes at all,” said Barbara Baird, SCAQMD chief deputy counsel. Baird said part of the plan relies on new technologies, such as battery-electric trucks being implemented in the region. If that doesn’t happen, the district must find equivalent reductions elsewhere that could be “Draconian,” she said.

The lawsuit was filed on the last day of smog season, which runs from May 1 to Oct. 31. This year, Southern California experienced 94 days above the new, 2008 federal standard for ozone, almost an additional week of bad air days as compared to 88 days in 2013, according to the plaintiffs. The last bad air day occurred Oct. 11.

Using the former, eight-hour ozone standard, the basin had 54 ozone days this year, according to Tina Cox, SCAQMD spokesperson.

Loopholes referred to by the environmental groups stem from a 1990 revision of the federal Clean Air Act for areas with extreme levels of air pollution. Instead of requiring plans to achieve one-hour and eight-hour ozone standards, clean-air agencies can work toward the goal of compliance by showing their best effort, and also are given longer.

Ozone is a colorless gas that is produced when oxides of nitrogen (NOx) and volatile organic compounds (VOCs) mix with sunlight and oxygen. Ground-level ozone causes lung damage and respiratory symptoms and can aggravate asthma conditions suffered by 1.1 million Southlanders. Ozone increases respiratory infections and leads to more doctor and emergency room visits by people with respiratory illnesses, according to the EPA.

According to the plan, 90 percent of NOx emissions and 60 percent of VOC emissions come from vehicles. Of the stationary sources, the largest contributors to air pollution are solvent processes, petroleum refineries, coatings, fuel combustion and waste disposal.

In order not to go over the 1997, eight-hour ozone standard of 80 parts per billion, it must reduce NOx emissions by 75 percent or between 150 tons and 185 tons per day. Instead, the plan estimates reductions of 35 tons per day after all regulations are in place by 2022.

“We are extremely disappointed to see this loophole was relied on again in the plan submitted by the air district,” said Evan Gillespie, director of the Sierra Club’s My Generation Campaign.

The EPA’s comments, contained in federal documents, say the SCAQMD plan does a good job in going after emissions needed to reduce ozone days. The south coast air basin, and the San Joaquin Valley, are the only two “extreme” nonattainment areas in the country.

The EPA said it would take “new commitments” by the SCAQMD, ramping up technology and a new commitment by the state agencies to meet emission reduction targets by Dec. 31, 2023 “(considering) the limited emissions remaining that can be regulated” since the basin has reduced emissions and smog by huge amounts in the past 30 years.

“The EPA is kicking the can down the road, as it has done for decades, turning a blind eye to the hundreds of thousands of people who need clean air because they have asthma and other chronic lung disorders,” Martinez said.

EPA Regional Administrator Jared Blumenfeld signed off on the plan May 5 and it was formally approved Sept. 3.

Gillespie said Southern California should have a plan that uses all available resources, such as electric cars and other less-polluting technologies.

“We have all the tools at our finger tips to solve this problem. It is really at this point not a technological problem but a political problem,” he said.

Martinez said it may take as long as two years for the court to hear the case. It may be heard in San Francisco or Pasadena, he said.

Baird said she will ask the air district’s governing board on Friday to intervene in the case and join the EPA in defending the plan in court.