# Counties in Texas by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2025

All 45 values come from U.S. Environmental Protection Agency for 2025, so the places are comparable. 18 counties have no value for that period and are not ranked.

- Indicator id: `aqi_unhealthy_sensitive_or_worse_days_share`
- Unit: %
- Definition: Days with a daily Air Quality Index above 100 (unhealthy for sensitive groups, unhealthy, very unhealthy or hazardous) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; the counts are stored with each value.
- Source: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts (https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual)
- Retrieved: 2026-10-12
- Citation: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
- Web page: https://invokely.ai/rankings/unhealthy-air-quality-days-share/texas-counties

| Rank | Place | % |
|---:|---|---:|
| 1 | El Paso County | 17.3 |
| 2 | Harris County | 10.4 |
| 3 | Tarrant County | 8.2 |
| 4 | Collin County | 6.4 |
| 5 | Denton County | 5.2 |
| 6 | Bexar County | 3 |
| 6 | Dallas County | 3 |
| 8 | Parker County | 2.6 |
| 9 | Culberson County | 2.3 |
| 10 | Brazoria County | 2.2 |
| 10 | Cameron County | 2.2 |
| 10 | Galveston County | 2.2 |
| 10 | Montgomery County | 2.2 |
| 10 | Nueces County | 2.2 |
| 15 | Travis County | 1.6 |
| 16 | Webb County | 1.4 |
| 17 | Bell County | 1.1 |
| 17 | Hidalgo County | 1.1 |
| 17 | Hood County | 1.1 |
| 20 | Jefferson County | 0.8 |
| 20 | Kleberg County | 0.8 |
| 20 | McLennan County | 0.8 |
| 23 | Rockwall County | 0.7 |
| 24 | Ector County | 0.6 |
| 24 | Lubbock County | 0.6 |
| 26 | Kaufman County | 0.5 |
| 27 | Bowie County | 0.3 |
| 27 | Brewster County | 0.3 |
| 27 | Gregg County | 0.3 |
| 27 | Hunt County | 0.3 |
| 27 | Johnson County | 0.3 |
| 27 | Navarro County | 0.3 |
| 27 | Polk County | 0.3 |
| 34 | Atascosa County | 0 |
| 34 | Brazos County | 0 |
| 34 | Ellis County | 0 |
| 34 | Harrison County | 0 |
| 34 | Karnes County | 0 |
| 34 | Maverick County | 0 |
| 34 | Orange County | 0 |
| 34 | Potter County | 0 |
| 34 | Randall County | 0 |
| 34 | Smith County | 0 |
| 34 | Victoria County | 0 |
| 34 | Wilson County | 0 |