# Counties in Maine by highest daily Air Quality Index (US EPA), 2000

All 13 values come from U.S. Environmental Protection Agency for 2000, so the places are comparable. 3 counties have no value for that period and are not ranked.

- Indicator id: `aqi_max`
- Unit: index
- Definition: Highest daily Air Quality Index (AQI) value recorded in a US county during the year, from the EPA AirData annual summaries. Values above 500 are beyond the AQI scale and are published as EPA computes them.
- Source: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: highest daily AQI (https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual)
- Publisher page: https://invokely.ai/en/publishers/environmental-protection-agency
- Retrieved: 2026-10-12
- Citation: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
- Web page: https://invokely.ai/rankings/highest-daily-air-quality-index/maine-counties

| Rank | Place | index |
|---:|---|---:|
| 1 | Hancock County | 179 |
| 2 | York County | 159 |
| 3 | Sagadahoc County | 154 |
| 4 | Knox County | 147 |
| 5 | Cumberland County | 133 |
| 6 | Kennebec County | 115 |
| 7 | Penobscot County | 105 |
| 8 | Piscataquis County | 93 |
| 9 | Aroostook County | 90 |
| 10 | Oxford County | 84 |
| 11 | Washington County | 70 |
| 12 | Androscoggin County | 44 |
| 13 | Franklin County | 28 |