Knoxville Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Knoxville (Knoxville, TN area) was October 21, 2022, when the daily AQI reached 162 (Unhealthy), set by fine particulate matter (PM2.5), in wildfire smoke season. Across 2,557 monitored days in 2019–2025, 2 of the 10 worst days were Unhealthy (AQI 151+) or worse; 7 of the 10 were driven by fine particulate matter (PM2.5) and 3 by ground-level ozone, and 5 of them fell in 2023. The cleanest day was October 30, 2025 at AQI 18 (Good); the 10 best days span 5 different years.
Extra Protection for Knoxville Homes
Air quality in Knoxville is moderate (AQI 61), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
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When were Knoxville's worst and best air quality days?
Worst: October 21, 2022, AQI 162 (Unhealthy, PM2.5). Best: October 30, 2025, AQI 18 (Good). Based on 2,557 EPA-monitored days in the Knoxville, TN area, 2019–2025.
- ✓2 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 113 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) drove 7 of the 10 worst days.
- ✓2023 accounts for 5 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Knoxville?▾
October 21, 2022: the Knoxville, TN area's daily AQI hit 162 (Unhealthy), driven by fine particulate matter (PM2.5), in wildfire smoke season. That is the highest of 2,557 monitored days in 2019–2025.
What was the best air quality day in Knoxville?▾
October 30, 2025, with a daily AQI of 18 (Good). The daily AQI is the highest reading from any monitor in the area, so even the cleanest day reflects the area's worst monitor.
What was Knoxville's worst air quality day in 2025?▾
March 21, 2025, AQI 156 (Unhealthy), set by ground-level ozone.
Which pollutant causes Knoxville's worst air days?▾
Fine particulate matter (PM2.5) set the AQI on 7 of the 10 worst days; ground-level ozone on 3. The tables above list the defining pollutant for every day.
Knoxville's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Knoxville, TN area (EPA AQS). The daily AQI is the highest reading from any monitor in the area that day.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2022 page) | 162 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 2 | (2025 page) | 156 | Unhealthy | O3 — ground-level ozone |
| 3 | (2021 page) | 150 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) |
| 4 | (2023 page) | 149 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 5 | (2023 page) | 140 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 6 | (2023 page) | 129 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 7 | (2022 page) | 115 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 8 | (2019 page) | 115 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) |
| 9 | (2023 page) | 114 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 10 | (2023 page) | 113 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
Worst day of each year in Knoxville
The single highest-AQI day in each year on record. Click a year for its full month-by-month statistics.
| Year | Worst day | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 2019 | 115 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) | |
| 2020 | 97 | Moderate | O3 — ground-level ozone, in peak ozone season | |
| 2021 | 150 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) | |
| 2022 | 162 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2023 | 149 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2024 | 105 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season | |
| 2025 | 156 | Unhealthy | O3 — ground-level ozone |
Knoxville's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Knoxville, TN area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2025 page) | 18 | Good | O3 — ground-level ozone |
| 2 | (2025 page) | 19 | Good | O3 — ground-level ozone |
| 3 | (2024 page) | 21 | Good | O3 — ground-level ozone |
| 4 | (2020 page) | 21 | Good | O3 — ground-level ozone |
| 5 | (2021 page) | 22 | Good | O3 — ground-level ozone, in peak ozone season |
| 6 | (2023 page) | 23 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 7 | (2021 page) | 23 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 8 | (2020 page) | 23 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 9 | (2024 page) | 24 | Good | O3 — ground-level ozone |
| 10 | (2021 page) | 24 | Good | PM2.5 — fine particulate matter (PM2.5) |
Right now in Knoxville
The latest EPA AirNow observation puts Knoxville's AQI at 61 (PM2.5). The days above are historical records, not today's reading.
View current Knoxville air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Knoxville, TN), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.