US Cities by Air Quality, 2026
Cleanest U.S. Cities by Year-Round Air Quality in 2026
The ranking compares U.S. metropolitan areas by year-round fine particle pollution, measured as annual PM2.5 design value in micrograms per cubic meter. Lower values indicate cleaner long-term particle exposure, a key signal for respiratory and cardiovascular risk, outdoor activity planning, public health analysis and environmental policy.
The 2026 snapshot is based on American Lung Association State of the Air 2026 tables, which use official EPA air quality data for 2022, 2023 and 2024. The ranking is not a live AQI table. Ozone, daily smoke spikes, monitor coverage and neighborhood-level exposure can change the practical experience of air quality inside the same metro area.
Bozeman, Montana leads at 3.2 µg/m³. The highest value inside this clean-air list is 6.2 µg/m³, shared by Gainesville-Lake City, Palm Bay-Melbourne-Titusville, Portland-Vancouver-Salem and Salinas.
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Summary: best U.S. cities for year-round PM2.5 air quality
The cleanest group is concentrated in smaller and mid-sized metro areas with low annual particle design values. Mountain West metros dominate the very top, Hawaii adds two high-ranking coastal island metros, and the Northeast appears through Vermont, Maine, Massachusetts and New York.
Bozeman, MT has the lowest annual PM2.5 design value in the cleanest-city table.
Four tied metros sit at 6.2 µg/m³ inside the cleanest-city table, not across all U.S. metros.
The source table is a Top 25 cleanest list, but ties at rank 23 create 26 metro entries.
Annual PM2.5 design value, ranked lower-to-higher. The monitored data window is 2022-2024.
Overview: why clean-air cities cluster by geography
Clean annual PM2.5 values tend to appear in places where persistent particle sources are limited or dispersed: lower industrial density, smaller urban footprints, stronger ventilation, less heavy traffic concentration and fewer long-duration smoke or stagnation episodes. That does not mean these places never experience poor air. Wildfire smoke, dust, winter inversions and short-term pollution spikes can still produce bad days even when the annual value remains low.
The cleanest list also separates long-term particle exposure from ozone performance. Bangor, Maine is notable because it appears among the cleanest places for year-round PM2.5 while also remaining clean for ozone and short-term particle pollution in the source report. Other cities can look strong on annual PM2.5 while having different risk profiles for summer ozone or episodic wildfire smoke.
Mountain West cities such as Bozeman, Casper, Cheyenne, Grand Junction, Colorado Springs and Pueblo sit high in the ranking. Hawaii’s Kahului-Wailuku and Urban Honolulu benefit from island geography and air movement. The Northeast appears through Burlington, Bangor, Elmira-Corning, Springfield and Syracuse, showing that clean year-round PM2.5 is not limited to one climate zone.
Top 10 cleanest U.S. cities by annual PM2.5
The Top 10 ranges from 3.2 to 5.0 µg/m³. The group includes Mountain West metros, two Hawaii metros, northern New England and Northeast metros, and Anchorage, Alaska.
| Rank | City / metro area | PM2.5 | Region / note |
|---|---|---|---|
| 1 | Bozeman, MT | 3.2 µg/m³ | Mountain West |
| 2 | Casper, WY | 3.4 µg/m³ | Mountain West |
| 3 | Kahului-Wailuku, HI | 4.0 µg/m³ | Pacific / Hawaii |
| 4 | Urban Honolulu, HI | 4.2 µg/m³ | Pacific / Hawaii |
| 5 | Burlington-South Burlington-Barre, VT | 4.3 µg/m³ | Northeast |
| 6 | St. George, UT | 4.4 µg/m³ | Mountain West |
| 7 | Anchorage, AK | 4.7 µg/m³ | Alaska |
| 7 | Cheyenne, WY | 4.7 µg/m³ | Mountain West |
| 9 | Grand Junction, CO | 4.9 µg/m³ | Mountain West |
| 10 | Bangor, ME | 5.0 µg/m³ | Northeast |
Values are annual PM2.5 design values from the State of the Air 2026 data tables. Lower values indicate cleaner year-round particle pollution.
Chart: Top 20 cleanest U.S. cities by annual PM2.5
Lower PM2.5 values are cleaner. The bars show concentration size, so shorter bars indicate cleaner year-round particle levels. The Top 20 runs from Bozeman at 3.2 µg/m³ to Syracuse-Auburn at 5.9 µg/m³.
Methodology
The ranking uses annual PM2.5 design value, a long-term fine particle concentration measure expressed in micrograms per cubic meter. The source table is from the American Lung Association State of the Air 2026 report, which ranks metropolitan areas using official EPA air quality data for 2022, 2023 and 2024.
What the metric measures
Annual PM2.5 measures fine particulate matter smaller than 2.5 micrometers. These particles can penetrate deep into the lungs and are linked to asthma attacks, cardiovascular stress, strokes, lung cancer risk and premature death.
Ranking direction
Lower values are better. The main table is sorted from the lowest annual PM2.5 design value to the highest value in the cleanest-city list.
Time period and snapshot logic
The 2026 label refers to the report cycle and publication snapshot. The underlying monitored air-quality years are 2022, 2023 and 2024, which are the quality-assured years used in the source report.
Metro-area calculation
Metropolitan areas are ranked by the highest annual PM2.5 design value among counties within the metro area, using the metropolitan definitions applied by the source report.
Rounding and ties
Values are shown to one decimal place in µg/m³, matching the source table. Equal values keep the same rank where the source table reports ties.
What the metric does not measure
Annual PM2.5 does not measure ozone days, short-term smoke spikes, indoor air, local street-level exposure, unmonitored neighborhoods or every source of environmental quality.
AQI and annual PM2.5 are different tools. AQI is a daily public communication index for pollutants such as ozone and particle pollution. Annual PM2.5 is a long-term concentration measure that fits a stable ranking, but it can understate short episodes from wildfire smoke, dust events or winter inversions. Readers comparing the cleanest U.S. cities by air quality should use annual PM2.5 for long-term exposure and daily AQI for immediate decisions.
Full ranking: cleanest U.S. metro areas by annual PM2.5
The full table includes all metro entries in the source Top 25 cleanest list for year-round particle pollution. Ties at rank 23 create 26 visible rows. The controls filter and sort existing HTML rows only; the table remains readable without JavaScript.
| Rank | City / metro area | PM2.5 | Region / note |
|---|---|---|---|
| 1 | Bozeman, MT | 3.2 µg/m³ | Mountain West |
| 2 | Casper, WY | 3.4 µg/m³ | Mountain West |
| 3 | Kahului-Wailuku, HI | 4.0 µg/m³ | Pacific / Hawaii |
| 4 | Urban Honolulu, HI | 4.2 µg/m³ | Pacific / Hawaii |
| 5 | Burlington-South Burlington-Barre, VT | 4.3 µg/m³ | Northeast |
| 6 | St. George, UT | 4.4 µg/m³ | Mountain West |
| 7 | Anchorage, AK | 4.7 µg/m³ | Alaska |
| 7 | Cheyenne, WY | 4.7 µg/m³ | Mountain West |
| 9 | Grand Junction, CO | 4.9 µg/m³ | Mountain West |
| 10 | Bangor, ME | 5.0 µg/m³ | Northeast |
| 11 | Colorado Springs, CO | 5.2 µg/m³ | Mountain West |
| 11 | Lubbock-Plainview, TX | 5.2 µg/m³ | South / Texas |
| 13 | Pueblo-Cañon City, CO | 5.4 µg/m³ | Mountain West |
| 13 | Sioux Falls, SD-MN | 5.4 µg/m³ | Upper Midwest |
| 15 | Wilmington, NC | 5.5 µg/m³ | Southeast |
| 16 | Elmira-Corning, NY | 5.6 µg/m³ | Northeast |
| 16 | Springfield-Amherst Town-Northampton, MA | 5.6 µg/m³ | Northeast |
| 18 | Duluth-Grand Rapids, MN-WI | 5.7 µg/m³ | Upper Midwest |
| 19 | Amarillo-Borger, TX | 5.8 µg/m³ | South / Texas |
| 20 | Syracuse-Auburn, NY | 5.9 µg/m³ | Northeast |
| 21 | Asheville-Waynesville-Brevard, NC | 6.1 µg/m³ | Southeast |
| 21 | Redding-Red Bluff, CA | 6.1 µg/m³ | West |
| 23 | Gainesville-Lake City, FL | 6.2 µg/m³ | Southeast |
| 23 | Palm Bay-Melbourne-Titusville, FL | 6.2 µg/m³ | Southeast |
| 23 | Portland-Vancouver-Salem, OR-WA | 6.2 µg/m³ | Pacific Northwest |
| 23 | Salinas, CA | 6.2 µg/m³ | West |
Source snapshot: American Lung Association, State of the Air 2026, Table 3b. The table uses official EPA air quality data for 2022, 2023 and 2024. Values are annual PM2.5 design values in µg/m³.
Insights from the 2026 clean-air ranking
Key Insight
Bozeman’s 3.2 µg/m³ value is roughly half of the 6.2 µg/m³ level seen at the bottom of the cleanest list. That gap matters because annual PM2.5 represents repeated exposure across the year, not a single bad day.
Notable Pattern
Mountain West metros hold six of the first eleven entries: Bozeman, Casper, St. George, Cheyenne, Grand Junction and Colorado Springs. Lower urban density and fewer persistent combustion sources may help explain part of the pattern, although wildfire smoke and winter inversions remain important risks.
Regional Concentration
The Northeast appears repeatedly below the very top, with Burlington, Bangor, Elmira-Corning, Springfield and Syracuse all inside the ranked group. Their values range from 4.3 to 5.9 µg/m³, showing consistent clean-air performance across several smaller and mid-sized metros.
Outlier
Bangor, Maine is the strongest all-around clean-air outlier because the source report identifies it as the only city remaining on all three cleanest lists: ozone, short-term particle pollution and year-round particle pollution.
What clean annual PM2.5 means for residents, businesses and policymakers
For residents, annual PM2.5 is a long-term exposure signal. Lower values may reduce chronic respiratory and cardiovascular burden, especially for children, older adults, outdoor workers and people with asthma, COPD or heart disease. The ranking should still be paired with daily AQI checks because smoke and ozone episodes can produce short-term risk even in cities with clean annual averages.
For employers and relocation teams, clean-air rankings can inform quality-of-life comparisons, office location decisions and employee wellbeing discussions. Air quality is not the only factor in city attractiveness, but it increasingly sits beside housing affordability, commute patterns, climate risk and access to healthcare.
For policymakers, the list highlights the value of long-term monitoring, smoke preparedness, transportation planning and industrial emissions control. A low annual PM2.5 value is not a reason to stop monitoring; it is a baseline to protect as wildfire risk, heat, population growth and regional emissions change.
FAQ: cleanest U.S. cities by air quality and PM2.5
Which U.S. city has the best air quality in this 2026 PM2.5 ranking?
Bozeman, Montana ranks first by year-round particle pollution in the source table, with an annual PM2.5 design value of 3.2 µg/m³. The ranking is based on metropolitan areas, not only municipal boundaries.
What metric is used for the ranking?
The table uses annual PM2.5 design value, measured in micrograms per cubic meter. PM2.5 refers to fine particles small enough to enter deep into the lungs, making it one of the most health-relevant long-term air pollution indicators.
Is PM2.5 the same as AQI?
No. AQI is a public communication index that changes daily and can cover several pollutants. Annual PM2.5 is a long-term concentration measure. A city can have a low annual PM2.5 value and still experience individual days with unhealthy AQI during smoke, dust, ozone or stagnation events.
Why can a clean annual PM2.5 city still have bad air days?
Annual values average conditions across a long period. A few severe wildfire smoke days may be diluted in the annual number, while daily AQI can still warn residents about immediate risk. Short-term particle pollution and ozone tables should be reviewed alongside annual PM2.5.
Does the ranking include ozone pollution?
No. The main ranking is specifically for year-round particle pollution. Ozone is a separate pollutant with different chemistry, seasonality and health effects. A metro area can perform well on annual PM2.5 while facing ozone problems during hot sunny periods.
Why does wildfire smoke matter for city air quality?
Wildfire smoke contains fine particles that can travel far from the fire source. Even if smoke episodes are short, they can raise daily PM2.5 and sometimes influence annual averages, especially in western and northern regions affected by repeated smoke transport.
Are city and metro area rankings the same?
No. This table uses metropolitan statistical areas. A metro ranking can include multiple counties, suburbs and surrounding communities. Local neighborhood exposure can differ from the metro-level value because monitors, traffic corridors and industrial sources are not evenly distributed.
How often should this clean-air ranking be updated?
The ranking should be refreshed when new quality-assured annual data and the next State of the Air cycle are available. For daily decisions, residents should use current AQI forecasts rather than annual rankings.
Sources
American Lung Association - State of the Air 2026 Report
Main source for the cleanest-city table, including Table 3b for year-round particle pollution and methodology notes on EPA data years, design values and metro-area ranking logic.
https://www.lung.org/getmedia/32f0646d-c5de-4501-b0ac-07cd63c974d4/State-of-the-Air-2026-Report.pdfAmerican Lung Association - Cleanest Cities
Public cleanest-city page explaining year-round particle pollution rankings and how they differ from ozone and short-term particle pollution lists.
https://www.lung.org/research/sota/city-rankings/cleanest-citiesEPA AirData / Outdoor Air Quality Data
Official EPA environment for outdoor air quality data collected by monitoring sites. Used as the underlying data system referenced by State of the Air.
https://www.epa.gov/outdoor-air-quality-dataAirNow - Air Quality Index Basics
Used to distinguish daily AQI interpretation from annual PM2.5 design values and to explain why a clean annual value does not replace daily air-quality alerts.
https://www.airnow.gov/aqi/
