Audit, Compliance and Risk Blog

EPA Promulgates “Back-to-Basics” Process for Reviewing Air Quality Standards

Posted by Jon Elliott on Tue, Jun 26, 2018

SmogOn May 9, Environmental Protection Agency (EPA) Administrator Chris Pruitt issued a policy memo recasting his agency’s basic approach to review and revision of national ambient air quality standards (NAAQSs) – EPA’s broadest and most basic targets for national pollution levels. He entitles it a “Back-to-Basics” Process for Reviewing [NAAQSs]”, echoing the phrase he used last year to recalibrate the agency’s relationships with the public and its various stakeholders. (I blogged about this general policy here).

This new NAAQS policy contains five general “principles” intended to guide EPA’s formal review of NAAQSs. As with any generalized policy and political pronouncements, the memo and its principles are subject to a wide variety of interpretations that can be evaluated once EPA acts. In the context of Administrator Pruitt’s actions to date, however, there is ample reason to believe that this recalibration will reduce regulated entities’ costs and the public’s protections.

What is EPA’s Responsibility to Establish and Administer NAAQSs?

The Clean Air Act (CAA) requires EPA to identify and list “conventional” air pollutants that meet the following conditions:

  • Emissions of the pollutant cause or contribute to air pollution, which may reasonably be anticipated to endanger public health or welfare.

  •  Presence of the pollutant in ambient air results from “numerous or diverse mobile or stationary sources”.

  • EPA intends to issue air quality criteria for the pollutant.

EPA evaluates atmospheric concentrations that would lead to unacceptable health and environmental impacts, and sets NAAQSs for atmospheric (ambient air) concentrations. EPA sets NAAQSs (primary and secondary standards) for carbon monoxide (CO), lead, nitrogen dioxide (literally NO2, which is typically measured as nitrogen oxides or NOX), ozone, particulates (measured separately as PM-10 (particles with an aerodynamic diameter less than or equal to a nominal 10 microns) and as PM-2.5 (less than or equal to 2.5 microns)), and oxides of sulfur (typically measured as sulfur dioxide (SO2)). NAAQSs must “accurately reflect the latest scientific knowledge useful in indicating the kind and extent of all identifiable effects on public health or welfare….” CAA requires EPA to re-evaluate each NAAQS at least every 5 years, and to determine whether to change acceptable concentrations; EPA frequently misses these deadlines.

What Principles Does this Memo Expound?

The memo emphasizes that EPA will make NAAQS decisions with technical support from its independent Clean Air Scientific Advisory Committee (CASAC). Roles and priorities are changing; most noticeably, EPA claims to be ensuring the distinction between scientific and policy evaluations, and seems to be reducing the relative importance of science.

  • Principle 1: Meet Statutory Deadlines

The memo points out that EPA has frequently failed to meet its 5-year review cycle requirement. Accordingly, the memo calls for “efficiencies” to narrow and expedite reviews, beginning with its next review of the ozone NAAQS (due to be completed by 2020), For the next review of the ozone NAAQS, EPA will replace the rulemaking’s kick-off workshop with a “more robust request for information,” and will consider combining its integrated science, risk and exposure, and policy assessment into a single review. CASAC’s wider role may end up diffusing its traditional scientific focus.

  • Principle 2: Address All CAA Provisions for NAAQS Reviews

EPA notes that CASAC has traditionally been used to provide scientific reviews and advice regarding NAAQS, but that CAA also directs CASAC to prepare advice on any “adverse social, economic, or energy effects related to NAAQS.” EPA now intends to remedy this shortfall by directing CASAC to expand the scope of its activities to include these neglected issues. EPA intends to provide a standardized set of key questions to CASAC to frame NAAQS reviews, addressed to:

  • Any scientific evidence developed since the last review indicating that the primary or secondary NAAQS should be revised.

  • Any need for “additional knowledge” in order to properly evaluate a NAAQS.

  • Assessment of relative contributions to ambient concentrations from natural vs. human activities

  • “[A]ny adverse public health, welfare, social, economic, or energy effects which may result from various strategies for attainment and maintenance of such NAAQS”.

  • Whether “key studies … properly addressor characterize uncertainty and causality.”

In doing so, EPA acknowledges a U.S. Supreme Court decision (American Trucking Associations v. Whitman) ruling that CAA does not allow EPA to consider implementation costs when setting NAAQS, but emphasizes that the Supreme Court did not attack the provision cited in the paragraph above. Furthermore, EPA emphasizes that “…CAA does not require the Administrator to establish a primary NAAQS at a zero-risk level or at background concentration levels, but rather at a level that reduces risk sufficiently so as to protect public health with an adequate margin of safety. The selection of any particular approach to providing an adequate margin of safety is a policy choice left specifically to the Administrator's judgment.”

  • Principle 3: Streamline and Standardize the Process for Development and Review of Key Policy-Relevant Information

This Principle commits EPA to identify and implement “more efficient” ways to conduct thorough scientific assessments, and to focus on “policy-relevant” information that will help Administrator Pruitt decide whether to retain or revise NAAQSs. It notes that he may wish to make minor adjustments “both above and below” existing standards, suggesting that existing NAAQSs may be loosened as well as tightened.

  • Principle 4: Differentiate Science and Policy Considerations in NAAQS Review Process

This Principle makes the clearest statement that “scientific” considerations may be distinguished from – and perhaps subordinated to – other “policy considerations: “The Agency should establish a clearer distinction between the purely scientific findings of [EPA’s Integrated Science Assessment as part of the NAAQS review] and the wider range of policy concerns that the Administrator must consider in making judgments about requisite standards.” However, the memo does not provide details.

  • Principle 5: Issue Timely Implementation Regulations and Guidance

In the past, NAAQSs adjustments have not always been accompanied by necessary compliance and implementation guidance, leading to uncertainties and delays while interested parties awaited such guidance. This Principle states that EPA will attempt to provide contemporaneous guidance.

What’s Next?

Within the memo, Administrator Pruitt notes that the ozone and particulate matter NAAQSs are due for review, and sets targets to complete both by December 2020. As these reviews proceed, stakeholders will learn how to interpret the Principles provided in the memo, including whether they are consistent with the directions that Pruitt is pushing his agency.

Self Assessment Checklist

Does the organization conduct activities that emit conventional pollutants subject to NAAQSs?

If so, are any of these activities characterized as “major sources” that are subject to the most extensive permit requirements?

Where Do I Go For More Information?

Specialty Technical Publishers (STP) provides a variety of single-law and multi-law services, intended to facilitate clients’ understanding of and compliance with requirements. These include:

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About the Author

Jon Elliott is President of Touchstone Environmental and has been a major contributor to STP’s product range for over 25 years. He was involved in developing 13 existing products, including Environmental Compliance: A Simplified National Guide and The Complete Guide to Environmental Law.

Mr. Elliott has a diverse educational background. In addition to his Juris Doctor (University of California, Boalt Hall School of Law, 1981), he holds a Master of Public Policy (Goldman School of Public Policy [GSPP], UC Berkeley, 1980), and a Bachelor of Science in Mechanical Engineering (Princeton University, 1977).

Mr. Elliott is active in professional and community organizations. In addition, he is a past chairman of the Board of Directors of the GSPP Alumni Association, and past member of the Executive Committee of the State Bar of California's Environmental Law Section (including past chair of its Legislative Committee).

You may contact Mr. Elliott directly at:



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Tags: Environmental risks, Environmental, Greenhouse Gas, ghg, CAA, mact