Louisville Air Quality in Spring
Across 2019–2025, Louisville's spring (March–May) air quality had a median AQI of 52 (Moderate) over 644 monitored days in the Louisville/Jefferson County, KY-IN area. 0.3% of spring days (2 of 644) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 58.5% of days. The cleanest spring on record here was 2025 (median AQI 47, 0 days above 100) and the worst was 2023 (median 55, 1 day above 100, peak AQI 101).
- Good: 47.2%
- Moderate: 52.5%
- Unhealthy for Sensitive Groups: 0.3%
- Unhealthy or worse: 0.0%
Extra Protection for Louisville Homes
Air quality in Louisville 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
As an Amazon Associate, we earn from qualifying purchases.
How is the air in Louisville in spring?
Moderate on a typical day: median AQI 52 across 2019–2025, with 0.3% of spring days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓47.2% of spring days were Good (AQI 0–50), 52.5% Moderate (51–100).
- ✓2 days of 644 reached AQI 101+; the spring peak was 108.
- ✓Cleanest month: April; worst month: May.
Frequently asked questions
What is the air quality like in Louisville in spring?▾
Across 2019–2025, the median daily AQI in Louisville in spring was 52 (Moderate). 47.2% of days were Good, 52.5% Moderate, and 0.3% 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 Louisville?▾
A typical spring day in Louisville is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of spring days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Louisville's spring air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 58.5% of spring days in Louisville. The highest spring AQI recorded in 2019–2025 was 108 (Unhealthy for Sensitive Groups), in 2023.
Louisville spring air quality, year by year
Louisville spring air quality by year (Louisville/Jefferson County, KY-IN, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 54 | 0 | 93 | PM2.5 |
| 2020 | 92 | 50 | 0 | 77 | PM2.5 |
| 2021 | 92 | 53 | 1 | 108 | PM2.5 |
| 2022 | 92 | 51 | 0 | 97 | PM2.5 |
| 2023worst | 92 | 55 | 1 | 101 | PM2.5 |
| 2024 | 92 | 48 | 0 | 97 | O3 |
| 2025cleanest | 92 | 47 | 0 | 77 | PM2.5 |
What spring air means in Louisville
A typical spring day in Louisville is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of spring days 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 52 is in line with Louisville's whole-year median of 54, 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 Louisville runs above the national Spring norm; 0.3% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).
Within the season, April is the cleanest month (median AQI 50, 0.0% of days above 100) and May the worst (median 51, 0.9% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Louisville
The latest EPA AirNow observation puts Louisville's AQI at 61 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Louisville air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Louisville/Jefferson County, KY-IN), 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.