Grade F Air Quality Cities
4 cities with poor air quality
Grade F means poor air quality with persistent unhealthy conditions and worsening trends. These cities are scored using EPA Air Quality System data spanning 10 years of daily AQI readings.
All Grade F Cities
| City | State | 5yr Avg AQI | Trend | Worst Pollutant |
|---|---|---|---|---|
| San Bernardino, California | CA | 82 | Improving | Ozone |
| Inyo, California | CA | 57 | Worsening | Ozone |
| BAJA CALIFORNIA NORTE, Country Of Mexico | MX | 81 | Worsening | PM2.5 |
| Maricopa, Arizona | AZ | 90 | Worsening | Ozone |
Frequently Asked Questions
Grade F (Poor) indicates poor air quality with persistent unhealthy conditions and worsening trends. The grade is based on 5-year average AQI (40%), trend direction (30%), unhealthy days per year (20%), and worst pollutant severity (10%).
4 of 1,020 monitored US cities currently have a Grade F Air Quality rating, representing 0.4% of all tracked areas.
Grade F cities experience regular periods where air quality poses health risks, especially for children, the elderly, and people with respiratory conditions. Checking daily AQI readings is recommended.
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