# Counties in Idaho by share of days with good air quality (US EPA AQI), 2005

All 23 values come from U.S. Environmental Protection Agency for 2005, so the places are comparable. 8 counties have no value for that period and are not ranked.

- Indicator id: `aqi_good_days_share`
- Unit: %
- Definition: Days with a daily Air Quality Index of 0 to 50 (good) 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; both counts are stored with each value.
- Source: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: good days 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: good days 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/good-air-quality-days-share/idaho-counties

| Rank | Place | % |
|---:|---|---:|
| 1 | Butte County | 100 |
| 2 | Custer County | 99.1 |
| 3 | Bonneville County | 97.5 |
| 4 | Bonner County | 96.5 |
| 5 | Latah County | 95.2 |
| 6 | Bingham County | 92.3 |
| 7 | Nez Perce County | 89.1 |
| 8 | Idaho County | 86.9 |
| 9 | Boundary County | 84.9 |
| 10 | Bannock County | 84.7 |
| 11 | Twin Falls County | 78.5 |
| 12 | Benewah County | 75.7 |
| 13 | Franklin County | 74.8 |
| 14 | Elmore County | 68.4 |
| 15 | Valley County | 65.9 |
| 16 | Canyon County | 64.9 |
| 17 | Gem County | 63.3 |
| 18 | Lemhi County | 62.1 |
| 19 | Ada County | 61.9 |
| 20 | Boise County | 57.9 |
| 21 | Shoshone County | 51.4 |
| 22 | Power County | 50.4 |
| 23 | Kootenai County | 49.9 |