Louisville Air Quality in April
Across 2019–2025, Louisville's April air quality had a median AQI of 50 (Good) over 210 monitored days in the Louisville/Jefferson County, KY-IN area. 0.0% of April days (0 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 51.0% of days. The cleanest April on record here was 2022 (median AQI 47, 0 days above 100) and the worst was 2023 (median 55, 0 days above 100, peak AQI 100).
- Good: 51.0%
- Moderate: 49.0%
- Unhealthy for Sensitive Groups: 0.0%
- 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.
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How is the air in Louisville in April?
Good on a typical day: median AQI 50 across 2019–2025, with 0.0% of April days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓51.0% of April days were Good (AQI 0–50), 49.0% Moderate (51–100).
- ✓0 days of 210 reached AQI 101+; the April peak was 100.
- ✓Best April: 2022; worst April: 2023.
Frequently asked questions
What is the air quality like in Louisville in April?▾
Across 2019–2025, the median daily AQI in Louisville in April was 50 (Good). 51.0% of days were Good, 49.0% Moderate, and 0.0% 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 Louisville?▾
A typical April day in Louisville sits in the Good range (median AQI 50), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
Which pollutant causes Louisville's April air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 51.0% of April days in Louisville. The highest April AQI recorded in 2019–2025 was 100 (Moderate), in 2023.
Louisville April air quality, year by year
Louisville April 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 | 30 | 52 | 0 | 67 | O3 |
| 2020 | 30 | 55 | 0 | 77 | PM2.5 |
| 2021 | 30 | 54 | 0 | 74 | PM2.5 |
| 2022cleanest | 30 | 47 | 0 | 65 | PM2.5 |
| 2023worst | 30 | 55 | 0 | 100 | O3 |
| 2024 | 30 | 47 | 0 | 74 | O3 |
| 2025 | 30 | 48 | 0 | 67 | O3 |
What April air means in Louisville
A typical April day in Louisville sits in the Good range (median AQI 50), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
April's median AQI of 50 is below Louisville's whole-year median of 54, making it one of the area's cleaner periods. Nationally, the median April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Louisville runs above the national April norm; 0.0% of its April days topped AQI 100 versus 0.7% nationally (about the same).
April is part of Louisville's spring season (March, April, May); the spring page pools all three months.
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 month 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.