Knoxville Air Quality in April
Across 2019–2025, Knoxville's April air quality had a median AQI of 51 (Moderate) over 210 monitored days in the Knoxville, TN area. 1.4% of April days (3 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 62.4% of days. The cleanest April on record here was 2020 (median AQI 46, 0 days above 100) and the worst was 2021 (median 54, 1 day above 100, peak AQI 150).
- Good: 44.8%
- Moderate: 53.8%
- Unhealthy for Sensitive Groups: 1.4%
- Unhealthy or worse: 0.0%
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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How is the air in Knoxville in April?
Moderate on a typical day: median AQI 51 across 2019–2025, with 1.4% of April days above AQI 100. Ground-level ozone is the main driver.
- ✓44.8% of April days were Good (AQI 0–50), 53.8% Moderate (51–100).
- ✓3 days of 210 reached AQI 101+; the April peak was 150.
- ✓Best April: 2020; worst April: 2021.
Frequently asked questions
What is the air quality like in Knoxville in April?▾
Across 2019–2025, the median daily AQI in Knoxville in April was 51 (Moderate). 44.8% of days were Good, 53.8% Moderate, and 1.4% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is April a good time for outdoor exercise in Knoxville?▾
A typical April day in Knoxville is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 71 of April days (1.4%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Knoxville's April air quality problems?▾
Ground-level ozone set the daily AQI on 62.4% of April days in Knoxville. The highest April AQI recorded in 2019–2025 was 150 (Unhealthy for Sensitive Groups), in 2021.
Knoxville April air quality, year by year
Knoxville April air quality by year (Knoxville, TN, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 53 | 0 | 77 | O3 |
| 2020cleanest | 30 | 46 | 0 | 64 | O3 |
| 2021worst | 30 | 54 | 1 | 150 | PM2.5 |
| 2022 | 30 | 50 | 0 | 77 | O3 |
| 2023 | 30 | 52 | 1 | 105 | O3 |
| 2024 | 30 | 54 | 0 | 80 | O3 |
| 2025 | 30 | 51 | 1 | 105 | O3 |
What April air means in Knoxville
A typical April day in Knoxville is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 71 of April days (1.4%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
April's median AQI of 51 is in line with Knoxville's whole-year median of 52, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Knoxville runs above the national April norm; 1.4% of its April days topped AQI 100 versus 0.7% nationally (about the same).
April is part of Knoxville's spring season (March, April, May); the spring page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Knoxville
The latest EPA AirNow observation puts Knoxville's AQI at 61 (PM2.5). The figures above are multi-year month statistics, 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.