US daily air quality reports
Every afternoon we record the US AQI of every US city with a monitoring station reporting, and compare it with the day before. Each report stays online as a permanent record.
| Date | Most polluted | Cleanest | Median US AQI | Cities Unhealthy or worse |
|---|---|---|---|---|
| 18 October 2026 | Billings 84 | Concord 1 | 32 | 0 |
| 17 October 2026 | San Diego 87 | Concord 1 | 27 | 0 |
| 16 October 2026 | Tucson 307 | Findlay 1 | 31 | 4 |
| 15 October 2026 | Oxnard 136 | Findlay 1 | 36 | 0 |
| 14 October 2026 | Fresno 105 | Findlay 1 | 39 | 0 |
| 13 October 2026 | Birmingham 90 | Findlay 1 | 42 | 0 |