The U.S. Environmental Protection Agency is being urged to tighten its limits on allowable atmospheric levels of ozone, an invisible gas linked to lung damage and respiratory diseases.
The calls for stricter standards came at a public hearing, the third and final one before the EPA makes its decision on an often-delayed updated health standard addressing ozone, a major constituent of smog and other forms of air pollution.
The current standard for ozone of 75 parts per billion is insufficient to protect the public's health, says EPA Administrator Gina McCarthy, who has suggested a standard somewhere between 65 to 70 parts per billion.
In California, home to some of the country's smoggiest cities, environmentalists, doctors and religious leaders appearing before the EPA hearing in Sacramento argued for an even tighter standard, pressing for a standard as low as 60 parts per billion.
Business lobbyists and industry trade groups have opposed lower standards, arguing current standards are in fact reducing air pollution and warning stricter limits could result in American jobs going overseas where regulations are more lax.
"Manufacturing growth could slow or stop," said Lindsay Stovall of the trade group the American Chemistry Council.
Environmentalists suggested otherwise, pointing to years of improving air quality in California as evidence that business and industry can cut pollution output while still improving the economy.
Ann Rothschild, 71, a member of Sacramento's Trinity Episcopal Cathedral, told the hearing she was dismayed that some children in the area are told they can't play outdoors because of dangerous air pollution.
"If a standard does not protect the most vulnerable among us -- the children, the elderly and those with asthma -- then it's not protective enough," she said.
Although the EPA acknowledges that stricter limits on ozone could mean costs to industry of billions of dollars every year, it has contended those costs would be outweighed by the benefits of fewer missed work days, asthma attacks and emergency room visits, not to mention fewer premature deaths.
Stricter rules would be particularly hard on California, the smoggiest state in the nation.
Although it has seen dramatic improvements as a result of emission regulations, a full third of the state's residents live in areas with ozone levels that violate existing federal standards, state regulators say.
The EPA says that while it expects most of the U.S. would be able to meet any new stricter standards by 2025, California's smoggiest areas -- Southern California and the San Joaquin Valley -- would be given more time to comply, until 2037.
The EPA is working under a court-ordered deadline to come up with a final decision on new guidelines by October.
