Knoxville Air Quality in Spring
Across 2019–2025, Knoxville's spring (March–May) air quality had a median AQI of 51 (Moderate) over 644 monitored days in the Knoxville, TN area. 1.1% of spring days (7 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 59.5% of days. The cleanest spring on record here was 2020 (median AQI 44, 0 days above 100) and the worst was 2021 (median 53, 3 days above 100, peak AQI 150).
- Good: 50.0%
- Moderate: 48.9%
- Unhealthy for Sensitive Groups: 0.9%
- Unhealthy or worse: 0.2%
Reduce Indoor Ozone in Knoxville
Today's main pollutant in Knoxville is ground-level ozone (AQI 29). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Knoxville in spring?
Moderate on a typical day: median AQI 51 across 2019–2025, with 1.1% of spring days above AQI 100. Ground-level ozone is the main driver.
- ✓50.0% of spring days were Good (AQI 0–50), 48.9% Moderate (51–100).
- ✓7 days of 644 reached AQI 101+; the spring peak was 156.
- ✓Cleanest month: May; worst month: April.
Frequently asked questions
What is the air quality like in Knoxville in spring?▾
Across 2019–2025, the median daily AQI in Knoxville in spring was 51 (Moderate). 50.0% of days were Good, 48.9% Moderate, and 1.1% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is spring a good time for outdoor exercise in Knoxville?▾
A typical spring 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 91 of spring days (1.1%) 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 spring air quality problems?▾
Ground-level ozone set the daily AQI on 59.5% of spring days in Knoxville. The highest spring AQI recorded in 2019–2025 was 156 (Unhealthy), in 2021.
Knoxville spring air quality, year by year
Knoxville spring air quality by year (Knoxville, TN, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 54 | 1 | 115 | O3 |
| 2020cleanest | 92 | 44 | 0 | 64 | O3 |
| 2021worst | 92 | 53 | 3 | 150 | O3 |
| 2022 | 92 | 50 | 0 | 97 | O3 |
| 2023 | 92 | 52 | 1 | 105 | O3 |
| 2024 | 92 | 51 | 0 | 88 | O3 |
| 2025 | 92 | 50 | 2 | 156 | O3 |
What spring air means in Knoxville
A typical spring 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 91 of spring days (1.1%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Spring'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 Spring AQI across every EPA metro area (307,196 metro-days, 2019–2025) is 43, so Knoxville runs above the national Spring norm; 1.1% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).
Within the season, May is the cleanest month (median AQI 50, 0.9% of days above 100) and April the worst (median 51, 1.4% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Knoxville
The latest EPA AirNow observation puts Knoxville's AQI at 29 (O3). The figures above are multi-year season 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.