by Matthew Holloway | Dec 1, 2025 | News
By Matthew Holloway |
The U.S. Environmental Protection Agency (EPA) has filed a motion in a federal appeals court to vacate a Biden-era rule on fine particulate matter air quality standards, which was set to affect air quality regulations in Arizona.
In the motion filed in the U.S. Court of Appeals for the D.C. Circuit, Department of Justice attorneys representing the EPA told the D.C. Circuit that the agency’s 2024 rule change on fine particulate pollution standards is both legally and scientifically flawed and must be vacated. The motion noted that the “supplement” to the EPA’s 2019 Assessment of the NAAQS, or National Ambient Air Quality Standards, for particulate matter, “did not represent [a] full multidisciplinary evaluation of evidence’ for the underlying air quality criteria.” It added that the agency “lacks statutory authority to revise standards absent a thorough review.”
The PM 2.5 rule, finalized on December 15, 2024, was purported to strengthen protections against fine particulate matter pollution, which the EPA stated was linked to respiratory and cardiovascular health risks. Implementation was set to begin in 2025, with full compliance deadlines extending to 2031. The final rule revising the NAAQS lowered the annual primary PM 2.5 standard from 12.0 micrograms per cubic meter to 9.0 micrograms per cubic meter. The rule also established a new 24-hour PM 2.5 standard of 35 micrograms per cubic meter. The rule remains in effect until the court comes to a decision.
The consolidated lawsuits involved petitioners including the Commonwealth of Kentucky, et al., the Arizona Legislature, and the Arizona Chamber of Commerce, along with 21 other states and business groups against the U.S. Environmental Protection Agency, et al. The states and business groups challenged the rule, arguing it would impose billions in compliance costs on states like Arizona, potentially halting construction projects and job growth in areas struggling to meet the stricter standards.
The petitioners contended that the new limits would classify more areas as being in a state of nonattainment, leading to economic restrictions under the Clean Air Act. Oral arguments in the case were heard on December 16, 2024.
Arizona Senate President Warren Petersen hailed the EPA’s motion on X on November 26, 2025, crediting EPA Administrator Lee Zeldin with what he called a “BIG WIN FOR ARIZONA!” He added that the EPA, “just filed a motion in federal court to throw out Biden’s unlawful PM 2.5 rule that made it nearly impossible for parts of Arizona to ever meet clean-air standards — a rule that would have crushed jobs, construction, and our economy with billions in costs. The AZ Legislature & the AZ Chamber sued the Biden admin to stop this job-killing regulation. Our lawsuit helped bring about this reversal. Thank you, President Trump, for keeping your promise to cut red tape and protect Arizona families!”
Adam R.F. Gustafson, Principal Deputy Assistant Attorney General, and Sarah I. Zafar, Trial Attorney in the DOJ Environment and Natural Resources Division, filed the EPA’s motion for vacatur. They wrote in part, “Implementation of the NAAQS is a complex process, which generates significant costs and reliance interests among States, local governments, and regulated parties.”
The DOJ attorneys also argued that the EPA, “should at least have considered the distinct costs associated with revising the NAAQS mid-cycle. EPA’s disregard of this relevant factor was arbitrary and capricious because it was unreasonable for EPA to read an exercise of discretionary authority as an invitation to ignore a relevant factor like cost.”
The case remains ongoing in the U.S. Court of Appeals for the D.C. Circuit.
Matthew Holloway is a senior reporter for AZ Free News. Follow him on X for his latest stories, or email tips to Matthew@azfreenews.com.
by Matthew Holloway | Dec 15, 2024 | News
By Matthew Holloway |
Following intervention from Congresswoman Debbie Lesko (R-AZ-08), the EPA has reportedly decided not to move forward with its decision to declare Maricopa County’s nonattainment status of ozone National Ambient Air Quality Standards (NAAQS) as ‘serious.’ Lesko publicly expressed concern that the change was motivated by the “upcoming administration change,” and not the law.
According to a press release from Lesko’s office, the Environmental Protection Agency (EPA) Administrator agreed to reconsider the decision to “prematurely reclassify” Maricopa County’s status of nonattainment as ‘serious.’
In her letter to the EPA, as previously reported by AZ Free News, Lesko warned, “If the EPA continues its expedited schedule in a rush to make their reclassification effective before the Trump Administration takes office, it will negatively impact Arizona and national security. The Taiwan Semiconductor Manufacturing Company (TSMC) was just awarded $6.6 Billion in CHIPS Act funding. This action by the EPA could jeopardize that funding and makes absolutely no sense.”
In her letter, Rep. Lesko expressed concern that the reclassification was not based upon law or environmental science but on politics. She wrote, “The reason for this change is not clear to me, but I am concerned tat this action was taken based upon the political reality of the upcoming administration change.”
She explained, “The law states that there is a 180-day window from August 3, 2024 for redesignation. The expedited timeline is set prior to the 180-day deadline.” She added, “It is crucial that the EPA and other federal agencies keep a consistent and stable regulatory environment where they do not expedite or change rulings based on the upcoming changes in executive power.”
As noted in our previous coverage, the arbitrary redesignation would lower Maricopa County’s emissions threshold from the current 100 tons to 50 tons for major sources of nitrogen oxides and volatile organic compounds, with said adjustments jeopardizing the operations of TSMC in Phoenix.
“TMSC’s new plant requires an air quality permit to proceed. The current major source threshold of 100 tons would allow TSMC to proceed without needing to acquire emission reduction credits (ERCs),” said Lesko.
“However, a redesignation to serious nonattainment would impose the 50-ton threshold, which is currently unfeasible due to the shortage of available ERCs, thus potentially delaying or halting this key project.”
Congresswoman Lesko posted to X on Friday to announce the result of her appeal to the EPA. She wrote, “Great news! Following my letter to the EPA sent earlier this week and after working with Senator Kelly and the governor’s office, our office has now heard from the EPA they will no longer move forward with the decision to prematurely reclassify Maricopa County to “serious” nonattainment status for their ozone National Ambient Air Quality Standards (NAAQS). This is wonderful news!”
Matthew Holloway is a senior reporter for AZ Free News. Follow him on X for his latest stories, or email tips to Matthew@azfreenews.com.
by Elizabeth Troutman | Mar 30, 2024 | News
By Elizabeth Troutman |
Arizona State Senate President Warren Petersen and House Speaker Ben Toma filed a lawsuit to stop the U.S. Environmental Protection Agency (EPA) from enacting a new air quality rule.
“The Biden administration should be rewarding American businesses for being the most environmentally friendly in the world,” Petersen said. “Instead, they are doubling down on their left-wing agenda. This rule is bad for Arizona, its citizens and our small businesses.”
Petersen and Toma filed the suit in the U.S. Court of Appeals for the D.C. Circuit on Monday.
The EPA rule, titled “Reconsideration of the National Ambient Air Quality Standards for Particulate Matter,” creates “unattainable” environmental goals for Maricopa, Pinal, and Santa Cruz counties, according to the news release.
The rule imposes strict regulations on fine particles within the air, also known as PM 2.5. Sources of PM 2.5 include smoke, vehicle exhaust, emissions from industrial facilities and energy sources, such as power plants.
Less than 20% of all coarse and fine particles combined come from power generation or other industrial activities. Wildfires are the largest source, accounting for 43% of all particulate matter in the air.
Petersen said the EPA should be focusing on mitigating wildfires, instead of imposing measures which economically harm Arizonans.
“This rule will create unnecessary hardships for job creators and hardworking Arizonans,” Petersen said. “It will detrimentally impact our power grid and create even more red tape for both small and large businesses. We have no choice but to ask the courts to provide relief from this tyrannical, arbitrary, and illegal move by the EPA.”
The United States already has some of the strictest air quality standards in the world, even more than the European Union. The Obama Administration first adopted them, and the Trump administration retained them.
But this new rule would be even more severe, causing new infrastructure construction that would improve safety and travel times for Arizonans to be halted and permits for new manufacturing facilities, especially in Maricopa, Pinal and Pima Counties, to be blocked.
Additionally, small businesses would be required to pay for expensive new equipment, and investments in new facilities will be sent to foreign countries with less stringent regulations, forcing jobs overseas and creating a greater reliance on adversary nations.
Up to eight additional counties within Arizona could be out of compliance, which could further threaten the state’s economic growth and prosperity.
Elizabeth Troutman is a reporter for AZ Free News. You can send her news tips using this link.
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