Louisville, Kentucky Air Quality
Louisville air quality today — the AQI, the main pollutant, and whether it’s safe to exercise outside right now
Louisville, KY · Air quality right now
The air quality index in Louisville, KY is 45 (Good) right now — safe for outdoor activity.
Is it safe to be outside in Louisville today?
AQI 45 Yes — air quality is Good
Air is clean — great for outdoor activity.Main pollutant: PM2.5Observed 1:00 AM EDT
Pollutants right now
- PM2.57.9 µg/m³Main pollutantfine particles — smoke, exhaust, soot
- PM108.0 µg/m³coarse particles — dust, pollen, ash
- Ozone57 µg/m³smog — builds on hot, sunny days
- NO₂8.6 µg/m³nitrogen dioxide — traffic, combustion
ExerciseOK to run — no air-quality limits on outdoor exercise.
How to read Louisville’s air quality
Guides: The AQI Scale, Explained · Air Quality Alerts, Decoded · How to Read a Wildfire Smoke Map · Why Wildfire Smoke Travels 1,000 Miles.
Air quality over time in Louisville
Across the EPA’s county records from 2020 to 2025, Louisville’s cleanest year was 2025 (median AQI 49) and its most polluted was 2023 (median AQI 55); the typical (median) day has held roughly steady since 2020.
| Year | Median AQI | Unhealthy+ | Main pollutant | USG | Moderate | Good |
|---|---|---|---|---|---|---|
| 2020 | 52 | 0 | PM2.5 | 7 | 208 | 151 |
| 2021 | 54 | 0 | PM2.5 | 6 | 221 | 138 |
| 2022 | 53 | 0 | PM2.5 | 7 | 211 | 147 |
| 2023 | 55 | 1 | PM2.5 | 15 | 226 | 123 |
| 2024 | 50 | 1 | PM2.5 | 11 | 168 | 186 |
| 2025 | 49 | 1 | PM2.5 | 9 | 167 | 188 |
“USG” is Unhealthy for Sensitive Groups (AQI 101–150); “Unhealthy+” combines the Unhealthy, Very Unhealthy, and Hazardous days. In 2024 the EPA tightened the annual fine-particle (PM2.5) standard to 9 µg/m³ from the previous 12 µg/m³, so counties near the old limit read worse against the new one. Source: EPA AQS annual summaries, 2020–2025.
Frequently asked
- What was the worst year for air quality in Louisville?
- In the EPA's 2020–2025 county records, 2023 had the most days above AQI 100: 16 days (15 Unhealthy for Sensitive Groups, 1 Unhealthy or worse). It also had the highest median AQI, 55.
- How many unhealthy air days does Louisville have?
- Across 2020–2025, 3% of the days reported for Louisville's county had an AQI above 100 (58 of 2192), about 10 days a year. 2025 had 10 days.
- What's the main air pollutant in Louisville?
- PM2.5: it drove Louisville's county AQI on the most days in every year of the EPA's 2020–2025 records.