#1
Gillette, WY
PM2.5: 5.5 Unhealthy Days: 0.6% Trend: improving
Grade B
82.3
Score
Most Improved Air Quality Cities (5-Year Trend)
These cities show the strongest recent improvement signals in PM2.5 trends and Clean Air Score movement.
national improved 2026 ranking, generated from the latest CleanAirData city score dataset
How to read this ranking: Cities are ordered by trend score among places with improving air quality trends, highlighting the strongest recent improvement signals in the city score dataset. Want to know exactly how we calculate this? Read our full methodology.
Data note: Based on CleanAirData Clean Air Scores derived from EPA/AirNow PM2.5, unhealthy-day frequency, long-term trend, and data completeness fields available in the city score dataset.
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#2
Tukwila, WA
PM2.5: 6.9 Unhealthy Days: 0% Trend: improving
Grade B
78.5
Score
#3
Columbia, SC
PM2.5: 8.2 Unhealthy Days: 0.3% Trend: improving
Grade C
69.6
Score
#4
Cranston, RI
PM2.5: 6.4 Unhealthy Days: 0% Trend: improving
Grade B
81.1
Score
#5
Conway, SC
PM2.5: 7 Unhealthy Days: 0% Trend: improving
Grade B
78.1
Score
#6
New Albany, IN
PM2.5: 6.6 Unhealthy Days: 0% Trend: improving
Grade B
80.5
Score
#7
Chelsea, MA
PM2.5: 6 Unhealthy Days: 0% Trend: improving
Grade B
83.2
Score
#8
Fort Lee, NJ
PM2.5: 6.9 Unhealthy Days: 0.3% Trend: improving
Grade B
76.7
Score
#9
Springfield, OR
PM2.5: 5.5 Unhealthy Days: 0.3% Trend: improving
Grade B
84.8
Score
#10
East Chicago, IN
PM2.5: 7.9 Unhealthy Days: 0% Trend: improving
Grade B
72.8
Score
Related air quality data
Ranking FAQ
How is the most improved air quality ranking calculated?
Cities are ordered by trend score among places with improving air quality trends, highlighting the strongest recent improvement signals in the city score dataset.
What data source does this ranking use?
Based on CleanAirData Clean Air Scores derived from EPA/AirNow PM2.5, unhealthy-day frequency, long-term trend, and data completeness fields available in the city score dataset.
How do we rank cities?
Our Clean Air Score measures long-term air quality stability, factoring in annual PM2.5 levels, frequency of unhealthy days, and 5-year improvement trends. Data is sourced strictly from official EPA sensors.