According to the EPA, "Ground-level ozone forms when emissions from industrial facilities, power plants, landfills and motor vehicles react in the sun."
Under the proposed "primary" smog standard, emissions would be limited to between 0.060 and 0.070 parts per million (ppm) in eight hours. A separate "secondary" standard would vary with the seasons and protect plants and trees. The agency did not say what this standard would be.
The new smog standard replaces the 0.075 ppm limit the agency set in March 2008.
The agency estimates that implementing the new smog standard would cost industry $19 billion to $90 billion. But its benefits to human health would range from $13 billion to $100 billion, mainly from reduced premature deaths, aggravated asthma and bronchitis cases, and hospital and emergency room visits. Another benefit to society from the lower smog standard: fewer people missing work and school days because of ozone-related symptoms.
“Smog in the air we breathe poses a very serious health threat, especially to children and individuals suffering from asthma and lung disease. It dirties our air, clouds our cities, and drives up our health care costs across the country,” said EPA Administrator Lisa P. Jackson. “Using the best science to strengthen these standards is a long overdue action that will help millions of Americans breathe easier and live healthier.”
Children are at the greatest risk from ozone, the agency said, because their lungs are still developing, they are most likely to be active outdoors, and they are more likely than adults to have asthma.
The public may comment on the smog standards for 60 days after the proposal is published in the Federal Register.
According to the New York Times, under the current smog standard of 0.075 ppm,
322 counties of the 675 that monitor ozone levels are out of compliance. If the 0.070 limit is adopted, 515 counties would be out of compliance. Only 15 of the 675 monitored counties now meet the 0.060 standard.The Times reports that the agency expects to issue a final rule in August. The new rules would be phased in between 2014 and 2031.