The U.S. Environmental Protection Agency has issued a final rule that aims to give states more leeway in meeting a 2015 standard for ozone pollution, in part by accounting for emissions from sources as far away as Asia.
That long-awaited rule follows an April memorandum from President Donald Trump directing the agency to reduce "unnecessary impediments to new manufacturing and business expansion" as it implements the National Ambient Air Quality Standards, or NAAQS.
Ground-level ozone, or smog, is formed in the atmosphere through a reaction between sunlight, nitrogen oxides and volatile organic compounds emitted from sources such as cars, power plants, refineries and chemical plants. Exposure to ground-level ozone pollution is linked to a variety of significant cardiac and respiratory problems. The EPA in 2008 established a requirement for states to meet a 75 parts per billion ozone NAAQS and in 2015 lowered that standard to 70 ppb. The Clean Air Act requires states to submit to the EPA plans, known as state implementation plans, for meeting the NAAQS in nonattainment areas.
The 2008 and 2015 ozone standards, however, were challenged in the U.S. Court of Appeals for the District of Columbia Circuit by environmental groups and a coalition of states alike, with the EPA left defending the standards against both sides. Several of the key issues raised in the litigation are relevant to the EPA's rulemaking, which was dated Nov. 7 but announced by the agency Nov. 8.
In the same decision — South Coast Air Quality Management District v. U.S. EPA; No. 15-1115 — the D.C. Circuit partially upheld a complex challenge brought by environmental groups that essentially asked the court to review whether the EPA, when promulgating the 2008 NAAQS, improperly waived the obligation for states to meet the 1997 version of the rule. The EPA contended that the Clean Air Act allows the agency to revoke a previous standard when updating a rule if it establishes adequate anti-backsliding measures for nonattainment areas. But the D.C. Circuit vacated several provisions of the rule, finding that the agency failed to meet the anti-backsliding requirement.
Meanwhile, litigation over the 2015 ozone standard is ongoing. A coalition of states led by Arizona and Wisconsin challenged the rule on several grounds, including alleging that the EPA violated the Clean Air Act by failing to adequately address the effect of uncontrollable ozone emissions emanating from international sources. Environmental and industry groups also filed petitions for review, arguing that the 2015 standard is either overly restrictive or not restrictive enough. Oral arguments in that case — State of Arizona v. EPA (No. 15-1392) — are scheduled for Dec. 18.
The EPA also is proceeding with a streamlined approach to evaluate "whether to reconsider, modify, or maintain" the 2015 ozone standard by late 2020.
The Nov. 7 final rule did not address the D.C. Circuit's anti-backsliding rulings in South Coast v. U.S. EPA, however. The agency stated in the final rule that it intends to address any revocation of the 2008 ozone NAAQS and any potential anti-backsliding requirements in a separate future rulemaking.
