Louisville, KY Air Quality Index (AQI)
During a smoke episode the air over Louisville can shift hour to hour. This page uses EPA's NowCast — the same weighting AirNow uses — so the "current" number reflects fast changes instead of a stale 24-hour average. Wildfire smoke reaches here mostly as long-range haze from fires hundreds of miles away.
About air quality in Louisville
Louisville is one of the Kentucky cities we track, with a population of about 633,045, in Jefferson County.
A city this size carries its own year-round PM2.5 baseline from traffic, construction and industry, so wildfire smoke here arrives on top of an existing load rather than against clean background air. That matters for reading the number: a moderate AQI in Louisville on a smoke-free week is normal, and the same AQI during a plume means considerably more smoke than it would somewhere with a lower floor.
Smoke risk here concentrates in the summer months, driven by long-range transport from fires hundreds of miles away. Outside that window an elevated reading in Louisville is more likely to be local — traffic, dust, or a temperature inversion holding everyday pollution near the ground — than wildfire smoke, and the dominant pollutant shown above is what tells the two apart.
How local is this reading? The AQI above is reported for a monitoring area, not for a street address. The nearest city we track is Cincinnati, OH, about 89 miles away — far enough that conditions between the two can differ substantially, and worth checking both during an active plume.
Today & tomorrow
What each level means
| AQI | Level | What to do |
|---|---|---|
| 0–50 | Good | A great day to be active outside. |
| 51–100 | Moderate | Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors and watch for symptoms. |
| 101–150 | Unhealthy for Sensitive Groups | Sensitive groups should reduce prolonged or heavy exertion outdoors, take more breaks, and reschedule strenuous activities. |
| 151–200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should move activities indoors or reschedule. |
| 201–300 | Very Unhealthy | Everyone should avoid prolonged or heavy exertion and move activities indoors; sensitive groups should stay indoors and keep activity low. |
| 301–500 | Hazardous | Everyone should avoid all physical activity outdoors; stay indoors with clean air and keep activity low. |
Guidance paraphrased from EPA. Not medical advice — see disclaimer.
Nearby cities
All Kentucky cities · Smoke & your health · Can I go outside?
Louisville air quality FAQ
What is the air quality in Louisville right now?
The live AQI for Louisville, KY is shown at the top of this page, sourced from AirNow (U.S. EPA) and computed with the 2024 EPA standard, with the observation time and source labeled.
Is it safe to go outside in Louisville today?
It depends on the current AQI and whether you're in a sensitive group. At AQI 101–150 sensitive groups should cut back on prolonged outdoor exertion; at 151+ everyone should. Use our "Can I go outside?" tool for tailored guidance.
Why does Louisville's AQI here match AirNow?
Because AirNow is our display truth for US monitors — we show its reported number, never a self-computed value that disagrees with it for the same monitor.
When is wildfire smoke worst in Kentucky?
Smoke here is usually worst in summer when Canadian or Western wildfire plumes drift over the region.