EPA Proposes Rule to Revise National Ozone Standard

The U.S. Environmental Protection Agency (EPA) announced on Thursday its proposed revisions to the National Ambient Air Quality Standards (NAAQS) for ozone (O₃).¹  EPA seeks to revise the existing ozone standard of 0.075 parts per million (ppm) that was previously set in March 2008 during the Bush Administration.  The rulemaking would tighten the 2008 standard by setting the 8-hour primary standard for ozone at a level between 0.060 and 0.070 ppm.  EPA also proposes to add a secondary ozone standard that is intended to “protect the public welfare”² and safeguard plants and trees from damage from repeated ozone exposure.  

Ground-level ozone is the primary component of smog.  It occurs as a result of a chemical reaction of oxides of nitrogen (NO_X) and volatile organic compounds (VOC) in the presence of sunlight.  The majority of man-made NO_X and VOC emissions that contribute to ozone formation in the United States come from three types of sources:  mobile sources, industrial processes (which include consumer and commercial products), and the electric power industry.³  Although the proposed rule will not result in direct regulations on businesses from EPA, the new standard, if adopted, would trigger state action to implement increased control techniques for various pollution sources related to NO_X and VOC emissions.  In California, the current state ambient air quality standard for ozone (0.070 ppm) is more stringent than the existing 2008 federal standard for ozone.  EPA’s proposed rule could bring the federal standard in line with California’s, or it could result in the federal standard exceeding the California standard.  

EPA estimates that the costs of implementing the more stringent ozone standard could range from $19 billion to $90 billion as industrial facilities, power plants, landfills, motor vehicles, and other industries face heightened regulations to meet the new air quality requirements.  

The proposed rule reflects EPA’s concern that the existing ozone standard does not adequately protect public health.  Exposure to ozone has been demonstrated to result in negative health effects that can lead to an increased occurrence of asthma and other respiratory-related conditions.  EPA estimates that the proposal could yield health benefits between $13 billion and $100 billion.  

EPA will take public comment on the proposed rule for 60 days.  The agency will hold three public hearings on the issue:  February 2, 2010, in Arlington, Virginia and Houston, Texas; and February 4, 2010, in Sacramento, California. 

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