# Counties in Oklahoma by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2018

All 25 values come from U.S. Environmental Protection Agency for 2018, so the places are comparable. 20 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/oklahoma-counties

| Rank | Place | % |
|---:|---|---:|
| 1 | Love County | 2.6 |
| 2 | Oklahoma County | 2.5 |
| 3 | Tulsa County | 2.2 |
| 4 | Dewey County | 1.9 |
| 4 | Jefferson County | 1.9 |
| 4 | Osage County | 1.9 |
| 7 | Canadian County | 1.7 |
| 8 | Cleveland County | 1.6 |
| 9 | Comanche County | 1.1 |
| 10 | Bryan County | 1 |
| 11 | McClain County | 0.9 |
| 12 | Carter County | 0.6 |
| 12 | Muskogee County | 0.6 |
| 14 | Adair County | 0.5 |
| 14 | Kay County | 0.5 |
| 16 | Mayes County | 0.4 |
| 17 | Creek County | 0.3 |
| 17 | Custer County | 0.3 |
| 17 | Ottawa County | 0.3 |
| 17 | Pittsburg County | 0.3 |
| 21 | Choctaw County | 0 |
| 21 | Le Flore County | 0 |
| 21 | Nowata County | 0 |
| 21 | Sequoyah County | 0 |
| 21 | Washington County | 0 |