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).

51
Median AQI
Moderate
1.1%
Days above AQI 100
7 of 644 days
70
90th percentile AQI
worst 1 day in 10
156
Peak AQI
Unhealthy
O3
Main pollutant
59.5% of days
50.0%
Good days
322 of 644
  • Good: 50.0%
  • Moderate: 48.9%
  • Unhealthy for Sensitive Groups: 0.9%
  • Unhealthy or worse: 0.2%

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QUICK ANSWER

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)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
201992541115O3
2020cleanest9244064O3
2021worst92533150O3
20229250097O3
202392521105O3
20249251088O3
202592502156O3

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 61 (PM2.5). 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.