40 CFR 50 - NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS

This rule is being issued at this time as required by a court order governing the schedule for completion of this review of the air quality criteria and the national ambient air quality standards (NAAQS) for carbon monoxide (CO). Based on its review, the EPA concludes the current primary standards are requisite to protect public health with an adequate margin of safety, and is retaining those standards. After review of the air quality criteria, EPA further concludes that no secondary standard should be set for CO at this time. EPA is also making changes to the ambient air monitoring requirements for CO, including those related to network design, and is updating, without substantive change, aspects of the Federal reference method.

The EPA is proposing thresholds for classifying nonattainment areas for the 2008 ozone National Ambient Air Quality Standards (NAAQS) (the “2008 ozone NAAQS”) promulgated by the EPA on March 12, 2008. This proposal also addresses the timing of attainment dates for each classification. Finally, we are proposing to revoke the 1997 ozone NAAQS 1 year after the effective date of designations for the 2008 ozone NAAQS for transportation conformity purposes only.

The EPA is announcing the extension of the public comment period for the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Sulfur to October 10, 2011.

This rule is being issued at this time as required by a court order governing the schedule for completion of this review of the air quality criteria and the national ambient air quality standards (NAAQS) for carbon monoxide (CO). Based on its review, the EPA concludes the current primary standards are requisite to protect public health with an adequate margin of safety, and is retaining those standards. After review of the air quality criteria, EPA further concludes that no secondary standard should be set for CO at this time. EPA is also making changes to the ambient air monitoring requirements for CO, including those related to network design, and is updating, without substantive change, aspects of the Federal reference method.

The EPA is announcing a public hearing to be held for the proposed rule titled “Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Sulfur” which was published in the Federal Register on August 1, 2011. The hearing will be held in Arlington, Virginia on Thursday, August 25, 2011.

This proposed rule is being issued as required by a consent decree governing the schedule for completion of this review of the air quality criteria and the secondary national ambient air quality standards (NAAQS) for oxides of nitrogen and oxides of sulfur. Based on its review, EPA proposes to retain the current nitrogen dioxide (NO 2 ) and sulfur dioxide (SO 2 ) secondary standards to provide requisite protection for the direct effects on vegetation resulting from exposure to gaseous oxides of nitrogen and sulfur in the ambient air. Additionally, with regard to protection from the deposition of oxides of nitrogen and sulfur to sensitive aquatic and terrestrial ecosystems, including acidification and nutrient enrichment effects, EPA is proposing to add secondary standards identical to the NO 2 and SO 2 primary 1-hour standards and not set a new multi-pollutant secondary standard in this review. The proposed 1-hour secondary NO 2 standard would be set at a level of 100 ppb and the proposed 1-hour secondary SO 2 standard would be set at 75 ppb. In addition, EPA has decided to undertake a field pilot program to gather and analyze additional relevant data so as to enhance the Agency's understanding of the degree of protectiveness that a new multi-pollutant approach, defined in terms of an aquatic acidification index (AAI), would afford and to support development of an appropriate monitoring network for such a standard. The EPA solicits comment on the framework of such a standard and on the design of the field pilot program. The EPA will sign a notice of final rulemaking for this review no later than March 20, 2012.

On or about April 22, 2011, the EPA is making available for public review the documents titled, “Ozone National Ambient Air Quality Standards: Scope and Methods Plan for Health Risk and Exposure Assessment,” (REA Plan for the primary ozone NAAQS) and “Ozone National Ambient Air Quality Standards: Scope and Methods Plan for Welfare Risk and Exposure Assessment” (REA Plan for the secondary ozone NAAQS). These documents contain the plans for the risk and exposure analyses that EPA is preparing to conduct in support of the reviews of ozone NAAQS. EPA is also making available to the public the final document “Integrated Review Plan for the Ozone National Ambient Air Quality Standards” (IRP). This document contains the plans for the review of the air quality criteria and national ambient air quality standards (NAAQS) for ozone. The Ozone NAAQS provide for the protection of public health and the environment from ozone in ambient air.

The Office of Air Quality Planning and Standards (OAQPS) of EPA is announcing the availability of a final document titled, Policy Assessment for the Review of the Particulate Matter National Ambient Air Quality Standards (PA). The PA contains staff analyses of the scientific bases for alternative policy options for consideration by the Agency prior to rulemaking.

Based on its review of the air quality criteria and the national ambient air quality standards (NAAQS) for carbon monoxide (CO), EPA is proposing to retain the current standards. EPA is also proposing changes to the ambient air monitoring requirements for CO including those related to network design.

The Environmental Protection Agency (EPA, or Agency) is denying the petitions to reconsider the final revised primary national ambient air quality standard (NAAQS) for oxides of sulfur as measured by sulfur dioxide (SO 2 ) issued under section 109 of the Clean Air Act (CAA). The final revised SO 2 Primary NAAQS was published on June 22, 2010, and became effective on August 23, 2010. EPA has carefully reviewed all of the petitions and revisited both the rulemaking record and the Administrator's decision process underlying the final revised SO 2 Primary NAAQS in light of these petitions. EPA's analysis of the petitions reveals that the petitions have provided inadequate and generally irrelevant arguments and evidence that the underlying information supporting the final revised SO 2 Primary NAAQS is flawed, misinterpreted or inappropriately applied by EPA. The petitioners' arguments fail to meet the criteria for reconsideration under the Clean Air Act.