US EPA is proposing stricter health standards to date for smog. The agency want to set the “primary” standard, which protects public health, at a level between 0.060 and 0.070 parts per million (ppm) measured over eight hours. Children are at the greatest risk from ozone, because their lungs are still developing, they are most likely to be active outdoors, and they are more likely than adults to have asthma. Adults with asthma or other lung diseases, and older adults are also sensitive to ozone.
EPA is also proposing to set a separate “secondary” standard to protect the environment, especially plants and trees. This seasonal standard is designed to protect plants and trees from damage occurring from repeated ozone exposure, which can reduce tree growth, damage leaves, and increase susceptibility to disease.
In September 2009 Administrator Jackson announced that EPA would reconsider the existing ozone standards, set at 0.075 ppm in March 2008. As part of its reconsideration, EPA conducted a review of the science that guided the 2008 decision, including more than 1,700 scientific studies and public comments from the 2008 rulemaking process. EPA also reviewed the findings of the independent Clean Air Scientific Advisory Committee, which recommended standards in the ranges proposed today.
Depending on the level of the final standard, the proposal would yield health benefits between $13 billion and $100 billion. This proposal would help reduce premature deaths, aggravated asthma, bronchitis cases, hospital and emergency room visits and days when people miss work or school because of ozone-related symptoms. Estimated costs of implementing this proposal range from $19 billion to $90 billion.
Ground-level ozone forms when emissions from industrial facilities, power plants, landfills and motor vehicles react in the sun.
EPA will take public comment for 60 days after the proposed rule is published in the Federal Register. The agency will hold three public hearings on the proposal: Feb. 2, 2010 in Arlington, Va. and in Houston; and Feb. 4, 2010 in Sacramento.
More information: http://www.epa.gov/groundlevelozone