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Major industry bodies voice concern over ozone standards

Hydrocarbon Engineering,

In response to a draft letter on CASAC’s review of the EPA’ second drat policy assessment for the review of the ozone national ambient air quality standards, a group of industry bodies voiced their concerns in a letter to the CASAC chair. Below are some extracts.

Background information

‘The draft CASAC letter states that ‘the second draft PA is not clear as to how background estimates might impact the primary and secondary standards and whether these impacts may differ regionally.’ EPA’s analysis indicates that the impact could be quite large and, therefore, background ozone levels need to be more fully considered.’

‘Also, EPA’s models have shown that decreasing anthropogenic sources of ozone could actually lead to increased ozone in some areas (because nitrogen oxides both form and destroy ozone). By controlling human sources of ozone to achieve lower standards, many parts of the country may not be able to meet current ozone standards, partially because of naturally formed ozone. In addition, in recent years, scientists have measured increasing amounts of air pollution coming to the US from overseas. The impacts of international emissions on ozone levels in the US, however, have not been fully considered during the current review of the ozone NAAQS. Given these issues, EPA should calculate risks that would occur with ozone exposure above background, and should not set standards for which some areas will be out of attainment as a result of background ozone.’

Mode of action

‘CASAC’s discussion of mode of action (MoA) in the draft CASAC letter seems to relate primarily to issues with how the MoA is communicated. CASAC should more carefully evaluate whether EPA’s analysis of ozone’s MoA was sufficient, particularly whether the discussed MoAs could occur at exposures below the current NAAQS. This MoA analysis is critically important because it could impact the presumed casual associations in the draft policy assessment.’

‘Finally, the policy assessment is based on the Integrated Science Assessment, the Health Risk and Exposure Assessment (HREA), and the Welfare Risk and Exposure Assessment (WREA). CASAC has brought up several issues with the second draft HREA and, perhaps more importantly, EPA has indicated that it will conduct additional analyses before finalising the HREA.’


‘In closing, we maintain that there is no new significant evidence since the last review indicating that the ozone standard should be lowered below 75 ppb. Moreover, CASAC should include 75 bbp in any range that it considers. We urge CASAC to consider addressing the issues discussed herein as it finalises its letter to EPA n the second draft policy assessment for the review of the ozone national ambient air quality standards.’

Industry bodies who submitted the letter

  • American Chemistry Council
  • American Forest & Paper Association
  • American Petroleum Institute
  • American Wood Council
  • American Iron and Steel Institute
  • Corn Refiners Association
  • Council of Industrial Boiler Owners
  • National Oilseed Processors Association
  • Portland Cement Association
  • Treated Wood Council
  • US Chamber of Commerce
  • Utility Air Regulatory Group

Adapted from letter by Claira Lloyd

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