EPA Administrator Lee Zeldin has launched a broad restructuring of the Regional Haze Program, a federal initiative that for decades has driven pollution reductions to protect visibility at national parks and wilderness areas. Conservationists say the changes, combined with lenient state plan approvals and a temporary halt to park air-quality monitoring, threaten to reverse hard-won gains in air clarity at some of the country’s most visited public lands. The stakes extend across 36 states and tribal lands, where pollution from power plants and industrial sources drifts into protected areas that millions of Americans visit each year.
Zeldin Reframes the Haze Program’s Purpose
In 2025, Zeldin announced the EPA would pursue a restructuring of the Regional Haze Program, arguing the program had been stretched beyond its original intent. “The program’s purpose is to improve visibility, not to shut down American energy,” Zeldin said in the official release, framing the overhaul as a correction rather than a rollback. That same announcement signaled the agency would reconsider how it evaluates state compliance plans and what pollution controls it expects from coal-fired power plants and heavy industry.
The restructuring did not arrive in isolation. Zeldin also announced that the agency would seek to undo dozens of existing rules, placing the haze program within a much larger deregulatory agenda. The framing matters: conservationists and public health advocates argue that casting the Regional Haze Program primarily as an economic burden rather than a public-interest safeguard could give states political cover to propose weaker controls on emissions that drift into protected areas.
Under the Clean Air Act, the haze program has long been treated as a visibility-focused complement to health-based standards for fine particulate matter. But conservationists and public health advocates note that the same tiny particles that cloud park vistas can also be inhaled and are associated with respiratory and other health concerns. They warn that narrowing the program’s scope to scenery alone downplays the broader benefits of cutting sulfur dioxide, nitrogen oxides and other pollutants from major sources. That shift in emphasis, they argue, is already showing up in how the EPA reviews and approves state plans.
West Virginia Approval Sets a New Template
The clearest example of this shift came when the EPA approved West Virginia’s Regional Haze State Implementation Plan under what the agency called a “commonsense” approach. The approval eased pollution control expectations for sources in a state that upwind-transport and regional-haze advocates say can contribute to pollution affecting some of the East Coast’s most treasured protected areas, including Shenandoah National Park and the Great Smoky Mountains region.
Conservation groups see the West Virginia decision as a template that other coal-heavy states will follow. According to conservationists quoted by the Associated Press, the about-face in West Virginia is just one example of the administration clearing the way for states to weaken controls at parks and tribal reservations across 36 states. The concern is not hypothetical: haze pollution travels hundreds of miles, so a single state’s decision to relax standards can degrade visibility in parks well beyond its borders. Eastern national parks are especially vulnerable because they sit downwind of densely clustered coal plants and industrial facilities across Appalachia and the Ohio River Valley.
Industry groups in West Virginia and elsewhere have welcomed the new approach, arguing that earlier haze requirements forced costly retrofits on plants that already comply with other federal air standards. They contend that further controls would deliver only marginal visibility gains at a steep economic price. Environmental advocates counter that the Clean Air Act requires states to adopt all “reasonable” measures to improve visibility, and they see the West Virginia approval as redefining “reasonable” in a way that prioritizes short-term economic interests over long-term environmental commitments.
What the Program Protects and How Visibility Is Tracked
The Regional Haze Program covers Class I areas that include national parks and wilderness areas across the country. These sites receive the highest level of air-quality protection under the Clean Air Act, and the program’s goal is to return them to natural visibility conditions. Sulfate particles from coal combustion, nitrates from vehicle exhaust, and organic carbon from wildfires all contribute to the milky haze that can shrink a 100-mile vista to a fraction of that distance.
The National Park Service tracks these changes through the IMPROVE monitoring network, which uses optical instruments and filter-based samplers at sites inside and near parks to measure fine particulate matter and its effect on how far visitors can see. The data collected through this network has documented significant visibility improvements over the past two decades, gains directly tied to emission reductions required under the haze program and related clean air rules.
Those improvements have been especially notable on the haziest days of the year, when past pollution levels routinely obscured iconic vistas. In many parks, the frequency of extremely poor-visibility days has dropped, and average conditions have brightened. Scientists use the long-term IMPROVE record to track trends, assess whether state plans are working and determine whether additional controls are needed to stay on track toward the program’s long-range goals.
Monitoring Pause Clouds the Picture
That monitoring infrastructure itself is now at risk. The Trump administration temporarily paused some national-park air-quality monitoring, according to Associated Press reporting and separate reporting by The Washington Post, which described the decision as not publicly disclosed at the time. Without continuous data collection, scientists and regulators lose the ability to detect whether relaxed state plans are allowing haze to creep back into protected areas. The suspension also creates a gap in the long-term data record that researchers rely on to distinguish between natural variability and policy-driven changes in air quality.
Park advocates say the timing of the monitoring halt is particularly troubling. With the EPA simultaneously approving weaker state plans, the absence of fresh data makes it harder for watchdog groups and the public to hold regulators accountable. If visibility worsens in a given park, it may be impossible to say whether the decline stems from new emissions, wildfire smoke, or simply a lack of recent measurements.
Federal officials have portrayed the pause as a temporary step driven by budget constraints and a broader review of monitoring priorities. But critics argue that suspending measurements at the very moment when policy is in flux amounts to turning off the headlights while changing course. They are pressing for rapid restoration of the full network and for public disclosure of any internal analyses that informed the decision to halt data collection.
Why Weaker Plans Hit Eastern Parks Hardest
Most coverage of the haze program treats all protected areas as equally affected, but the geography of pollution transport creates sharply uneven risk. Western parks like the Grand Canyon sit in relatively isolated airsheds, where a single upwind source can be identified and controlled. Eastern parks face a far more complex problem: emissions from dozens of facilities across multiple states mix and accumulate before settling over ridgelines in Virginia, Tennessee and North Carolina.
That interconnection means the “commonsense” approach to state plan approvals carries outsized consequences in the East. When West Virginia relaxes controls on its coal plants, the sulfate haze does not stop at the state line. It drifts into Shenandoah, the Great Smokies and other Class I areas that have seen their vistas gradually clear over the past 20 years. Similar decisions in neighboring states could compound the effect, eroding progress that took decades of coordinated regulation to achieve.
Eastern parks also tend to sit closer to population centers and major highways, adding vehicle emissions to the mix. On humid summer days, these pollutants interact in the atmosphere to form fine particles that scatter light and tint the horizon a bluish-gray. Scientists warn that small increases in sulfur and nitrogen emissions from power plants can have disproportionate visibility impacts in such conditions, making stringent regional controls especially important.
What Comes Next for Regional Haze
Legal and political battles over the Regional Haze Program are likely to intensify as more states submit plans under the restructured framework. Conservation groups are already weighing challenges to approvals they view as inconsistent with the Clean Air Act’s visibility goals, arguing that the statute leaves limited room for the kind of broad discretion the EPA is now asserting. Industry and state officials, by contrast, are expected to defend the new approach as a needed correction to what they see as overreach by prior administrations.
For park visitors, the stakes may be less abstract. The difference between a clear and a hazy day at a national park can determine whether distant peaks, canyons or city skylines are visible at all. Advocates say that protecting those views requires not only strong state plans, but also transparent monitoring and timely public reporting. Without those elements, they warn, the country could slowly slide back toward the murky conditions that first prompted Congress to act on regional haze decades ago.
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*This article was researched with the help of AI, with human editors creating the final content.
