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Last month, the Ninth Circuit Court of Appeals denied a petition for review brought by environmental non-governmental organizations (ENGOs) challenging EPA’s conclusion that the Phoenix-Mesa, Arizona metropolitan area, which had been designated nonattainment for a National Ambient Air Quality Standard (NAAQS) for ozone, had met that standard by the applicable deadline.  Bahr v. Regan, No. 20-70092, 2021 U.S. App. LEXIS 22333 (9th Cir. July 28, 2021).  Failure to have met the standard would have had implications in terms of additional air emission controls required in the area.
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Continue Reading EPA’s Finding that Wildfires Did Not Preclude NAAQS Attainment is Upheld

As I have reported previously, the US Court of Appeals for the DC Circuit issued a significant decision in September 2019 on EPA’s implementation of the so-called “Good Neighbor Provision” of the federal Clean Air Act (CAA). That is the CAA’s principal provision addressing what is often termed “interstate transport,” the physical process in which emissions from cars, trucks, factories, power plants, and myriad other sources—and the resulting air pollution—are carried by prevailing winds across state borders. The main purpose of the Good Neighbor Provision (section 110(a)(2)(D)(i)(I) of the CAA) is to prevent “significant contribution” by “upwind” states’ emissions to violations of national ambient air quality standards (NAAQS) in “downwind” states. Although states have the principal responsibility to implement this provision, EPA periodically has invoked its CAA authority to impose requirements to curb interstate transport when it determines upwind states have not adopted adequate controls.
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Continue Reading Against a Backdrop of Litigation, EPA Prepares a New Rule to Address Interstate Air Pollution

A previous post, EPA Makes Room for State Flexibility in Addressing “Interstate Transport” Under the Clean Air Act, discussed the evolving policy of the US Environmental Protection Agency (EPA) regarding approval of state plans—required under the “Good Neighbor Provision” of the federal Clean Air Act—addressing “interstate transport” of air pollution. That article reviewed a series of guidance documents EPA issued in 2018 to allow states flexibility in addressing wind-borne emissions that can contribute to ground-level ozone pollution in other states located downwind. At stake are not only downwind states’ air quality objectives but the prospect of expensive additional emission controls on upwind states’ manufacturing facilities and power plants.

One of EPA’s 2018 guidance documents addresses the seemingly technical question of what “contribution threshold” to apply. That term refers to the quantity—measured in parts per billion (ppb) of ozone in the air at ground level—below which an upwind state’s impact on a downwind state’s ozone concentrations is small enough that any contribution would be considered essentially de minimis. Generally, a state will want its emission contributions to be deemed low enough that it would be clear that its emission sources would not need new control requirements.
Continue Reading EPA Acts on Clean Air Act “Interstate Transport” Plans

As we have discussed previously, the federal Clean Air Act (CAA) addresses what is often termed “interstate transport.” That is the phenomenon in which emissions from factories, power plants, motor vehicles and many other emission sources are transported by prevailing winds across state lines, sometimes over great distances. The CAA looks to states, first and foremost, to include control measures in implementation plans to reduce emissions that travel into other states. The statutory objective is to prohibit “significant contributions” by upwind states to violations of national ambient air quality standards (NAAQS) in downwind states. Although states have primary responsibility, EPA sometimes has invoked its CAA authority to establish federally enforceable requirements to address significant contributions when it concludes upwind states have not taken sufficient steps. In 2016, EPA adopted its most recent set of regulatory interstate transport controls in a rulemaking action called the “Cross-State Air Pollution Rule Update”—or the “CSAPR Update” for short. On September 13, the US Court of Appeals for the DC Circuit issued a decision in closely-watched litigation involving challenges to the CSAPR Update. (The case is Wisconsin v. EPA, No. 16-1406.) While upholding this EPA regulation in most respects, the court ruled in favor of a challenge that concerns the timing of upwind-state emission controls.
Continue Reading The DC Circuit Addresses EPA’s Latest Regulation on “Interstate Transport” Under the Clean Air Act

State environmental regulators are beginning to develop plans designed to meet more stringent air quality standards under the Clean Air Act (CAA), including standards to protect against unhealthful levels of ground-level ozone. In doing so, many states are looking more closely at a factor that contributes to their air quality problems but that they lack any authority to address: the phenomenon of air pollution carried by prevailing winds into their jurisdictions from emission sources located not only outside their own state borders but outside the US itself. The issue of international contributions to air quality concerns has gained currency in part due to the many challenges states face in meeting the stringent nationwide air quality standards for ground-level ozone that the US Environmental Protection Agency (EPA) adopted in 2015.
Continue Reading The Foreign Factor: Accounting for International Emissions in Air Quality Planning

The US National Ambient Air Quality Standards (NAAQS) are the centerpiece of the US Clean Air Act (CAA) and establish allowable concentration levels for six “criteria air pollutants”: ozone, particulate matter, lead, carbon monoxide, nitrogen dioxide, and sulfur dioxide. The CAA requires the US Environmental Protection Agency (EPA) to review and, as appropriate, revise the NAAQS at least every five years, and EPA has, since 1970, regularly adopted increasingly stringent standards. Whether those revisions have gone far enough or too far has become a predictably contentious issue, with each review involving debates over science, the role of EPA’s Clean Air Science Advisory Committee (CASAC), the discretion of the EPA Administrator, and the format of the review process itself, among many other issues.
Continue Reading The New NAAQS Review Process Begins to Take Shape

When an adverse party challenges final rules that are favorable to particular companies, those companies and their trade associations sometimes question whether it is worth their time and effort to intervene on EPA’s side to help the Agency defend its action. A recent D.C. Circuit decision shows that sometimes an argument made by a Respondent-Intervenor can be decisive. …
Continue Reading Why Should I Intervene?

The phrase “interstate transport” conjures images of planes, trains and trucks carrying people and goods cross-country. But, under the federal Clean Air Act (CAA), the term is often used to refer to interstate air pollution—emissions from factories, power plants, motor vehicles, refineries and other sources that are transported by prevailing winds across state lines, sometimes over hundreds of miles. The interstate transport phenomenon often has posed for the US Environmental Protection Agency (EPA) what the Supreme Court has called “a thorny causation problem: How should EPA allocate among multiple contributing upwind States responsibility for a downwind State’s excess pollution?” EPA v. EME Homer City Generation, L.P., 134 S. Ct. 1584, 1604 (2014). EPA’s efforts to address this issue have yielded, over the last two decades, a series of complex federal regulatory programs imposing increasingly stringent controls on emissions in most states in the eastern half of the country—first the “NOx SIP Call” rule in 1998, then the Clean Air Interstate Rule in 2005, followed by the Cross-State Air Pollution Rule (CSAPR) in 2011 and, most recently, the 2016 “CSAPR Update” rule. Now, however, EPA, while vigorously defending the CSAPR Update rule against pending litigation challenges, is signaling a fresh approach for potential future interstate transport regulation, an approach that may involve greater deference to states’ analyses and determinations and that may eschew additional broad regulatory mandates imposed by EPA.
Continue Reading EPA Makes Room for State Flexibility in Addressing “Interstate Transport” Under the Clean Air Act

In October 2015, EPA reduced the level of the National Ambient Air Quality Standards (“NAAQS”) for ozone from 75 parts per billion (“ppb”) to 70 ppb. What is happening concerning implementation of those NAAQS?

Although litigation over EPA’s decision to lower the ozone NAAQS remains in abeyance as the Trump Administration continues to consider whether the Agency should reconsider the rule or some part of it, the 2015 standard itself has not been stayed. Thus, the Clean Air Act requires that implementation of the standard proceed. One key step in implementation is promulgation by EPA of a list of areas where the standard is violated, including areas that contribute to standard violations in nearby areas. EPA’s identification of these “nonattainment” areas is a trigger for many of the Act’s control requirements.
Continue Reading What’s Up with Air Quality Standards for Ozone?