The U.S. Environmental Protection Agency (EPA) recently proposed stricter limits be placed on ground level ozone, otherwise known as smog. The proposed National Ambient Air Quality Standards for Ozone would more adequately protect children and others "at risk" from the harmful effects of ground level ozone, which include reduced lung function, aggravation of lung and heart diseases, and increased risk of premature death in children and seniors.
The proposed EPA limits, if approved, will replace limits set in 2008 during the last year of George W. Bush's presidency. Those air quality limits were controversial because they were counter to scientific recommendations from the EPA’s panel of science advisers, the Clean Air Scientific Advisory Committee. In May 2008, states, environmental groups and industry groups filed petitions with the D.C. Circuit Court of Appeals for review of the 2008 ozone standards.
Proposed Air Quality Standards Would Protect Both Public Health and the Environment
Air quality management is mandated by the Clean Air Act for pollutants and emissions considered harmful to public health and the environment. National standards exist for six pollutants: ozone, particulate matter, nitrogen oxides, carbon monoxide, sulfur dioxide, and lead.
The EPA air quality proposal would strengthen the 8-hour “primary” ozone standard, designed to protect public health and it would also establish a distinct cumulative, seasonal “secondary” standard, designed to protect sensitive vegetation and ecosystems, including forests, parks, wildlife refuges and wilderness areas.
The Difference Between Atmospheric Ozone and Ground Level Ozone
Citizens are often confused about ozone because it can both be positive and negative for environmental health. Ozone is found in two regions of the Earth’s atmosphere – at ground level and in the upper regions of the atmosphere known as the stratosphere. Both types of ozone have the same chemical composition: O3. Upper atmospheric ozone forms a layer protecting Earth from the sun’s harmful rays, while ground level ozone is the main component of smog.
According to the EPA, the health effects associated with ozone exposure include respiratory health problems ranging from decreased lung function and aggravated asthma to increased emergency department visits, hospital admissions and premature death. The environmental effects associated with seasonal exposure to ground-level ozone include adverse effects on sensitive vegetation, forests, and ecosystems.
The EPA Will Accept Public Comment on the New Air Quality Standards
There are approximately 1,200 ozone monitors operating in the United States, with about 1,000 in urban areas and 200 in non-urban areas. The EPA estimates that about 270 new ozone monitors could be required to satisfy the new recommendations.
The EPA will take public comment on the proposed limits for ground level ozone for 60 days following publication of the proposal. The agency also will hold public hearings on the proposal in three locations, including Arlington, VA and Houston, TX on February 2, 2010 and Sacramento, CA on February 4, 2010.
Additional Resources
For more information, see Proposed Revisions to National Standards for Ground-Level Ozone on the epa.gov site for Regulatory Actions for Ground- Level Ozone.
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