Problematic Exclusions: Analysis of the Clean Air Act’s Exceptional Event Rule Revisions

Abstract

In 2016 the EPA revised the Exceptional Events Rule of the Clean Air Act (CAA) making important changes to what types of air quality events are considered exceptional. The rule allows “exceptional” air quality events to be excluded from the dataset used to determine air quality violations, specifically attainment and nonattainment. These exclusions allow air quality levels to remain above standards, yet simultaneously appear safe. This policy analysis focuses on the revisions and asks two questions. What are the negative consequences in how the rule defines exceptional events? Does this rule support the primary goal of the CAA? The paper analyzes four exclusion criteria, focuses in on air pollution from dust storms, and draws on a case study of Lamar, Colorado. It returns to the original questions to argue, first, that the rule allows common events to be excluded from the dataset, and second, works against the ultimate goal of the CAA.

Keywords:

• Air quality
• dust
• environmental hazards—risk and health
• environmental impact
• environmental regulation
• policy and law

Acknowledgments

I am grateful for the helpful feedback from William Travis, Lisa Dilling, Laura Nash, and Justin Latici and wish to thank the three anonymous reviewers whose thoughtful commentary improved the manuscript. This analysis was made possible with support from the Babbitt Dissertation Fellowship from the Lincoln Institute of Land Policy and the Western Water Assessment.

Notes

1 The EPA defines particulate matter “the term for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope” (Environmental Protection Agency 2020).

2 The Federal Register states that the revisions were made “to address certain substantive issues raised by state, local and tribal co-regulators and other stakeholders and to increase the administrative efficiency of the Exceptional Events Rule criteria and process” (Treatment of Data Influenced by Exceptional Events 2016, 68220).

3 For example, in the comments, the Western Governors Association wrote “the term ‘reasonable controls’ has not been defined by EPA and has been inconsistently applied” (Mead and Bullock 2015, 1).

4 Agency Docket: EPA-HQ-OAR-2015-0229.

5 As indicated in the Federal Register.

6 Specifically, PM₁₀.

7 Even by December 2019, Colorado had no public designations under the new rule due to the long review process.