“State of the Air” 2026 finds that 75.9 million people living in 84 counties across 21 states have been exposed to year-round levels of particle pollution that do not meet the annual air quality standard. This is 9.1 million fewer than last year, but it is the third highest number in the history of the report, and a sobering reminder of the widespread, chronic nature of this deadly form of air pollution.
76 million people live in counties with failing grades for year-round particle pollution
When looking nationwide at all the counties with measurements for annual particle pollution, the average severity of this pollutant reached its lowest value in the history of the “State of the Air” report. However, there were 52 metro areas across the country whose worst county earned a failing grade. By its nature, the year-round measure of average particle pollution is not as changeable from year to year as the daily measure. Variations over time may look smaller, but because they typically represent recurring exposures over many days and weeks, seemingly minor differences can have a big impact on public health.
Annual particle pollution levels are most often highest in places that are subject to multiple sources of emissions all year long, such as from highways, oil and gas extraction, power generation and industry. The additional pollution load from wildfire smoke, though comparatively short-lived in any one location, can strongly influence that location’s annual average. In this year’s report, this influence can be found reflected in geographic shifts similar to those seen with short-term particle pollution.
Compared with last year’s report, the year-round average concentration of fine particle pollution generally improved in much of the United States, with about three-quarters of results showing improvement. In fact, increases in statewide annual particle pollution average values were observed in only six states—the greatest in Texas (also the state with the worst overall average) and Wyoming (which still has a low statewide average; only Hawaii’s is lower), but also in Arkansas, Louisiana, Mississippi and South Carolina.
In contrast, the states that saw the strongest improvement in year-round particle pollution compared to last year’s report were mainly in the eastern half of the country. Sixteen states, plus the District of Columbia and Puerto Rico, saw their year-round averages for particle pollution improve in every one of their counties graded for this measure. Five other states posted results that were either the same or better than last year’s in every county whose performance could be compared. Nineteen more states improved in the majority of their counties, even as at least one of their counties worsened.
In “State of the Air” 2026, of the worst 26 metropolitan areas for year-round particle pollution (26 because there was a four-way tie for 23rd place), 15 improved, 10 worsened and one stayed the same compared to last year’s report. Of those that worsened, only one, Brownsville-Harlingen-Raymondville, Texas, reported a new worst-ever value, falling from 16th worst in last year’s report to second worst in the nation. In contrast, of those that improved, seven reported new best-ever values for their worst counties: Fresno-Hanford-Corcoran, California and Los Angeles-Long Beach, California posted improvements (though still posting failing grades) and for a second year in a row, both recorded their lowest year-round averages of high particle pollution in the history of this report. In addition, Bakersfield-Delano, California, Cincinnati-Wilmington, OH-KY-IN, Pittsburgh-Weirton-Steubenville, PA-OH-WV, San Jose-San Francisco-Oakland, California, and Visalia, California, all newly posted their best-ever results.
Though 15 rankings on this list remained relatively stable, changing at most only three places compared with last year’s report, four changed more than ten places from their former position. The biggest change among the Worst 25 was San Diego-Chula Vista-Carlsbad, California’s leap from 59th worst in last year’s report to 5th worst; the other three were all in Texas: Austin-Round Rock-San Marcos, Texas (39th to 23rd), Brownsville-Harlingen-Raymondville, Texas (16th to 2nd), and McAllen-Edinburg, Texas (39th to 17th).
In addition to three of the four above cities having been added to the Worst 25 list for year-round particle pollution, three others were similarly newly listed: Dallas-Fort Worth, Texas-Oklahoma (30th to 22nd); Little Rock-North Little Rock, Arkansas-Texas (26th to 17th); and Philadelphia-Reading-Camden, PA-NJ-DE-MD (also 26th to 17th).
Again, these changes meant that five metro areas improved enough to leave the Worst 25 list. Two improved but still have failing grades: Missoula, Montana, and St. Louis-St. Charles-Farmington, Missouri-Illinois. Three others had been failing, but now pass: Sacramento-Roseville, California; Spokane-Spokane Valley-Coeur d'Alene, Washington-Idaho; and Yakima, Washington.
The geographical distribution of cities on the Worst 25 list for year-round fine particle pollution is more widespread than in previous years in some respects. Though California retains its position of being the state with the most metro areas on the list with seven of the 26 most-polluted cities, the other western states are limited to Oregon with two; then Alaska and Arizona, each with one. In the center of the country, Texas increases to six and Arkansas to one. Then, moving eastward, Illinois and Indiana each with one; finally, Michigan, Ohio and Pennsylvania each with two.