Washington, DC - U.S. Senator Lisa Blunt Rochester (D-Del.), a member of the Senate Committee on Environment and Public Works, led seven of her colleagues in writing a letter to Environmental Protection Agency (EPA) Administrator Lee Zeldin requesting stronger oversight over Clean Air Act standards.

The letter addresses the agency's progress towards issuing area designations for the 2024 fine particulate matter (PM_2.5) national ambient air quality standard (NAAQS), as required by the Clean Air Act, and reports that the area designations may not be completed by the upcoming February 6, 2026, deadline. The Senators ask critical questions regarding the expected release of area designations, cause of delays, and agency staffing. In addition to Senator Blunt Rochester, the letter was signed by Senators Sheldon Whitehouse (D-R.I.), Chris Van Hollen (D-Md.), Chris Coons (D-Del.) Kirsten Gillibrand (D-N.Y.), Richard Blumenthal (D-Conn.), Ed Markey (D-Mass.), and Cory Booker (D-N.J.).

PM_2.5 are fine particles made of chemicals, solids, and liquids that when inhaled can cause serious health problems, especially for children, seniors, and pregnant people. Over 75 million people live in a county with PM2.5 pollution levels that do not comply with the 2024 standard, meaning that those tens of millions of people breathe air that EPA has deemed harmful to human health. In 2024, the EPA revised the PM_2.5 NAAQS, lowering the concentration threshold and requiring a reassessment of air quality standards, as directed by the Clean Air Act.

"We write to request an update on the Environmental Protection Agency (EPA)'s progress towards meeting the upcoming deadline to issue area designations for the 2024 fine particulate matter (PM_2.5) national ambient air quality standard (NAAQS)," the Senators wrote. "The Clean Air Act requires EPA to issue area designations within two years of setting a new standard or revising an existing standard. Recent reporting indicates that EPA may not meet this deadline. Finalizing these designations is critical because they represent EPA's legal determination of whether areas have clean or polluted air."

"Notably, although EPA has recently sought to backtrack on some legal issues pertaining to the 2024 standard," the Senators continued. "It has not retreated from its conclusion that the 2024 standard is rooted in strong scientific evidence…The area designations are key to ensuring that all people in the country can breathe clean air. EPA issuing the designations initiates the time-tested, commonsense process laid out in the Clean Air Act to clean up the air quality in those areas deemed legally unhealthy."

"We are concerned about EPA's apparent lack of progress towards the February 6th deadline," the Senators concluded. "To address our concerns about whether EPA is faithfully carrying out its legal responsibilities to protect public health by implementing the 2024 PM2.5 standard, we request that, by January 30, 2026, you update us on the status of and the anticipated timeline for completing the designations process."

"Trump and Zeldin's deregulatory agenda ignores scientific evidence and real-world harms to people's health and wellbeing in favor of doing what's best for polluters. They are turning their back on communities being hurt by dangerous pollution," said Earthjustice Action Senior Legislative Representative Liz Ruben. "National soot pollution standards protect public health and save lives. The law requires EPA to be working right now to implement the 2024 soot standard so areas with unhealthy air will take steps towards cleaning it up. We thank Senator Blunt Rochester and other Senators for their attention to this issue and for their leadership in urging EPA to carry out its legal responsibility to the American people."

The Senators' full letter can be found here and below.

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Dear Administrator Zeldin:

We write to request an update on the Environmental Protection Agency (EPA)'s progress towards meeting the upcoming deadline to issue area designations for the 2024 fine particulate matter (PM_2.5) national ambient air quality standard (NAAQS). The Clean Air Act requires EPA to issue area designations within two years of setting a new standard or revising an existing standard. EPA issued the revised 2024 PM_2.5 standard on February 7, 2024, and the deadline to issue designations is Friday, February 6, 2026.

Recent reporting indicates that EPA may not meet this deadline. Finalizing these designations is critical because they represent EPA's legal determination of whether areas have clean or polluted air-whether families, children, and workers across the United States are breathing in dangerous levels of toxic pollutants. PM_2.5 pollution is dangerous to human health, particularly for vulnerable populations, including children, seniors, pregnant people, and those in low-income and historically overburdened communities. It causes serious health harms, including cancers, chronic illnesses, heart attacks, and even death.

Over 75 million people live in a county with PM_2.5 pollution levels that do not comply with the 2024 standard, meaning that those tens of millions of people breathe air that EPA has deemed harmful to human health. And, consistent with numerous scientific studies, the demographics of the over 75 million people in polluted counties disproportionately consists of people of color. Notably, although EPA has recently sought to backtrack on some legal issues pertaining to the 2024 standard, it has not retreated from its conclusion that the 2024 standard is rooted in strong scientific evidence.

Air pollution affects our health, workforce, and economic productivity. Millions of workdays are lost each year due to air pollution, and millions of children miss school due to unhealthy air. Research shows that breathing unhealthy air negatively affects a student's development and academic success, and in the longer term, impacts their employment and earnings. Air pollution takes an immense health and financial toll on this country, with one report showing health costs exceeding $800 billion per year and rising.

The area designations are key to ensuring that all people in the country can breathe clean air. EPA issuing the designations initiates the time-tested, commonsense process laid out in the Clean Air Act to clean up the air quality in those areas deemed legally unhealthy. To meet the February 6, 2026, designations deadline, EPA would have had to make any notifications (typically called "120-day letters") by October 9, 2025. October 9, 2025, came and went, and as we understand, EPA has not sent any 120-day letters.

We are concerned about EPA's apparent lack of progress towards the February 6^th deadline. To address our concerns about whether EPA is faithfully carrying out its legal responsibilities to protect public health by implementing the 2024 PM_2.5 standard, we request that, by January 30, 2026, you update us on the status of and the anticipated timeline for completing the designations process, specifically including the following:

1. Whether all states have now submitted designations; if so, please share any that have not previously been publicly released; if not, please identify those that did not.
2. The number of exceptional event demonstrations that EPA received that are relevant to the designations process under the 2024 PM_2.5 standard; the number of such exceptional event demonstrations that EPA has determined require a response from EPA; and of the exceptional event demonstrations that EPA determined require an EPA response, the number of such demonstrations that EPA has reached a conclusion on.
3. Any communications EPA has had with state officials about its process for and progress toward issuing final designations.
4. Whether EPA intends or expects to send any 120-day letters to any states, and, if so, its anticipated timeline for doing so.
5. Whether EPA intends to provide a public comment period on the designations, as it has historically done.
6. The number of staff in the Office of State Air Partnerships and in each Regional Office, all broken out separately, who are working on completing the designations under the 2024 PM_2.5 standard.
7. EPA's anticipated timeline for completing the designations process under the 2024 PM_2.5 standard.

We look forward to receiving your prompt and detailed response.

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Senator Lisa Blunt Rochester represents Delaware in the United States Senate where she serves on the Committees on Banking, Housing, and Urban Affairs; Commerce, Science, and Transportation; Environment and Public Works; and Health, Education, Labor, and Pensions.