Right now: Louisville is at 44, good.
Is the air safe to breathe in Louisville today?
In Louisville, BreatheCheck reads 44 as Go. The cutoffs: go below 101, keep it short and easy from 101 to 150, move it indoors above 150. These are our own thresholds, drawn on the EPA bands — EPA itself classifies 101–150 as Unhealthy for Sensitive Groups and does not tell you how long to stay out.
Go AQI 0–100
Normal outdoor plans. No change needed.
Short & unloaded AQI 101–150
A 20-minute dog walk, not a 2.5-hour run. Keep it brief and easy.
Don’t go AQI 151+
Move it indoors. Above 200 that becomes everyone, not just sensitive groups.
Above 200 this stops being a personal call: everyone indoors.
Duration and intensity are two separate dials
| Under 20 min | 20–60 min | Over an hour | |
|---|---|---|---|
| Easy | Go | Go | Go |
| Moderate | Go | Go | Go |
| Hard | Go | Go | Go |
Go Every combination lands the same way at this reading — a hard hour is no different from an easy twenty minutes. The two dials separate above 80.
Where people actually draw the line
All the thresholds people reported, and who reported them
- 60 Asthmatic runnerone runner’s own 156-run log
- 75–100 Daycare / schoolparents and staff in one r/toddlers thread, Aug 2025 — not a published rule
- 100 Parentcommunity-reported, escalating at 150 and 200
- 110 Runnercommunity-reported
If you’re staying in, filter the room you’re actually in
Rubbertown, a valley lid, and a moderate ozone tag
Louisville’s air has a named industrial geography that few metros its size carry. Rubbertown is the chemical district on the west side along the Ohio. It took the name during the Second World War, when the federal government put synthetic rubber plants onto ground that had held a refinery since 1918, and around eleven large chemical plants still work there. Monitoring in the surrounding neighborhoods in 2000 and 2001 produced the West Louisville Air Toxics Risk Assessment Report in 2003, and the city answered that with the Strategic Toxic Air Reduction program, ratified by the Metro Air Pollution Control Board in June 2005.
The valley supplies the lid. Louisville sits in the Ohio River valley at the Falls of the Ohio, where air stagnates under winter inversions, and the same cap that holds an industrial release in place also holds exhaust from the interstate junctions cutting through the city.
The standing regulatory problem is a different pollutant. The Louisville KY-IN area, Jefferson, Bullitt and Oldham counties on the Kentucky side, is designated nonattainment for the 2015 eight-hour ozone standard, and was reclassified from marginal to moderate in 2022 after missing the marginal deadline. Kentucky asked to have the area redesignated to attainment; the EPA denied that request in a rule effective March 2026, so the label stands. Either way, a designation summarizes several years of measured summer data and says nothing about the reading on any given day.
Where this number sits
Of the 121 US metros reporting to us right now, Louisville is number 48 and the highest of the 2 we track in Kentucky. The pollutant driving it today is O3.
Nearby metros we also measure, and what they read at the same hour:
- Lexington, KY — 72 miles away, AQI 35
- Cincinnati, OH — 91 miles away, AQI 37
- Indianapolis, IN — 107 miles away, AQI 35
- Nashville, TN — 154 miles away, AQI 74
Where this reading comes from
AirNow’s Louisville reporting area, about 7 miles from the metro centre.
What has air quality in Louisville actually been?
0 of the 30 days we have recorded so far went above AQI 100.
| Date | Daily max AQI | EPA band | Hours read |
|---|---|---|---|
| 46 | Good | 22 | |
| 65 | Moderate | 23 | |
| 52 | Moderate | 23 | |
| 45 | Good | 23 | |
| 59 | Moderate | 23 | |
| 79 | Moderate | 23 | |
| 55 | Moderate | 23 | |
| 53 | Moderate | 23 | |
| 65 | Moderate | 23 | |
| 77 | Moderate | 23 | |
| 74 | Moderate | 23 | |
| 97 | Moderate | 24 | |
| 77 | Moderate | 23 | |
| 70 | Moderate | 23 | |
| 74 | Moderate | 23 | |
| 71 | Moderate | 23 | |
| 80 | Moderate | 23 | |
| 56 | Moderate | 22 | |
| 67 | Moderate | 23 | |
| 80 | Moderate | 23 | |
| 87 | Moderate | 23 | |
| 67 | Moderate | 24 | |
| 56 | Moderate | 23 | |
| 60 | Moderate | 23 | |
| 93 | Moderate | 23 | |
| 63 | Moderate | 23 | |
| 57 | Moderate | 23 | |
| 48 | Good | 23 | |
| 66 | Moderate | 26 | |
| 73 | Moderate | 7 — partial day |
Questions about Louisville
What is the air quality in Louisville right now?
Which monitor does this number come from?
How does Louisville compare with metros nearby?
Does this include pollen?
Put this number in context
Updated