DeclineUpdated April 2026
Cities With Worsening Air Quality
10-year trends show declining air quality in these areas
Harrison, Ohio has the worst air quality trend at +6.3 AQI points per year over the past decade.
| # | Name | Metric | Change | Grade |
|---|---|---|---|---|
| 1 | Harrison, Ohio AQI 33 — trend +6.3/yr | 33 | +6.3 | B |
| 2 | Delta, Colorado AQI 44 — trend +4.1/yr | 44 | +4.1 | C |
| 3 | Johnson, Wyoming AQI 40 — trend +4.0/yr | 40 | +4 | C |
| 4 | Lincoln, Wyoming AQI 44 — trend +3.4/yr | 44 | +3.4 | C |
| 5 | Catano, Puerto Rico AQI 52 — trend +3.3/yr | 52 | +3.3 | D |
| 6 | Archuleta, Colorado AQI 35 — trend +3.0/yr | 35 | +3 | C |
| 7 | Sanders, Montana AQI 37 — trend +3.0/yr | 37 | +3 | D |
| 8 | Maricopa, Arizona AQI 72 — trend +2.9/yr | 72 | +2.9 | F |
| 9 | Valley, Idaho AQI 36 — trend +2.8/yr | 36 | +2.8 | D |
| 10 | SONORA, Country Of Mexico AQI 53 — trend +2.3/yr | 53 | +2.3 | D |
Harrison, Ohio has the worst air quality trend at +6.3 AQI points per year over the past decade.
Frequently Asked Questions
This report is auto-generated from real public data sources. Entities are ranked by their key metrics and the most notable changes and extremes are highlighted.
The underlying data is refreshed on a regular schedule. This report was generated from the most recent available data (last updated April 2026).
The primary metric varies by report type. It may represent a score, dollar amount, rate, or count depending on what the report is measuring.