By Valerie Volcovici
WASHINGTON, Nov 25 (Reuters) - The U.S. Environmental Protection Agency is proposing more stringent air quality standards for ground-level ozone, the main culprit in smog, the agency's chief said on Wednesday.
Under deadline to release its proposal by Monday, the agency said it will seek a National Ambient Air Quality Standard between 65 and 70 parts per billion concentration of ozone, and take comment on standards within a 60-75 ppb range, EPA administrator Gina McCarthy said.
Current standards, set under then-President George W. Bush in 2008, are set at 75 ppb.
The EPA must finalize the rule by October 2015.
The standards would "clean up our air, improve access to crucial air quality information, and protect those most at-risk -- our children, our elderly, and people already suffering from lung diseases like asthma," McCarthy wrote in an editorial.
The proposal, which will apply not only to power plants but to cars and oil and gas facilities, is expected to face opposition from industry groups.
The tougher standards would be closer to the proposal drafted in 2011 by former EPA Administrator Lisa Jackson, which was withdrawn by President Barack Obama before its release because of cost concerns amid the nation's economic recovery.
Although Obama had directed the EPA to come up with a new proposal, the agency did not take action, prompting the American Lung Association and green groups Earthjustice, the Sierra Club, the Environmental Defense Fund and the Natural Resources Defense Council to sue and get a court-ordered deadline.
Health and environment groups say the new standards can lower the risk of early deaths, asthma and other respiratory illnesses from the pollutant.
"President Obama is not up for re-election. This should be a centerpiece of his environmental legacy," said Terry Maguire, the Sierra Club's Washington representative on smog pollution.
He said the coalition of green and health groups had been pressing for a standard of 60 ppb, but added he could support the 60-70 ppb range recommended by EPA scientists.
For months, industry groups had been preparing for the release of a standard as low as 60 ppb, estimating a price tag of $270 billion a year, according to the National Association of Manufacturers.
Howard Feldman, regulatory affairs director at the American Petroleum Institute, said air quality would still improve without regulatory change and attaining EPA's proposed standards would be "extremely difficult" for most of the country.
(Reporting by Valerie Volcovici; Editing by Peter Cooney and Susan Heavey)