Air Quality in Louisville, Kentucky — Live
Live readings from PurpleAir sensors across Louisville — with free alerts when ozone action days or west Louisville air toxics spike.
AQI 37 from 4 PurpleAir sensors · Trending up · data from PurpleAir
As of , the air quality in Louisville, Kentucky is AQI 37 — Good and rising — with PM2.5 at 6.7 µg/m³, the median of 4 live PurpleAir sensors reading 3 to 39. Canairy's verdict: Breathe easy.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
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Live PurpleAir sensor map for Louisville and St. Matthews, Shepherdsville, New Albany, IN, Jeffersonville, IN. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Louisville
The sensors Canairy reads in Louisville agree right now — all 4 sit in the Good band, a 36-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.4 mi SW | 37 | Good |
| 1.7 mi S | 39 | Good |
| 1.9 mi E | 3 | Good |
| 2.8 mi ENE | 36 | Good |
Louisville's air isn't a wildfire-smoke story the way it is out West — most winters and springs the readings are unremarkable. What defines it instead is a stubborn ozone problem every summer and one of the country's most studied environmental-justice fights over industrial air: the Rubbertown corridor on the city's west side, where eleven chemical plants have shaped a neighborhood's air for generations. Add in the region's June-through-September Ozone Action Days and the thick, hazy stillness that Ohio Valley humidity produces most summer afternoons, and Louisville's air quality is a real year-round variable — just not a fire-driven one.
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What the air in Louisville is doing next
| When | Expected air quality | Main pollutant |
|---|---|---|
| Today | Good | PM2.5 |
Southern Regions: Ozone levels were a mix of good and moderate Wednesday and Thursday and PM2.5 levels were moderate. A weak cold front is going to move through the region as of Friday morning. This is only bringing mostly sunny to partly cloudy conditions with high level clouds and a wind shift to the NE. Despite this, generally warm and dry conditions are forecast to prevail in the mid to upper 70's. Clouds increase on Saturday with partly to mostly cloudy conditions as rain is possible Halloween night into Sunday due to increasing moisture from the SW and a weak system at the surface. The tropical moisture is actually the remnants of Tropical system Vance. Scattered showers are possible with mostly cloudy conditions. Sunday the cooler weather pattern will begin with low clouds and rain possible. Monday night a strong upper low and surface cold front are forecast to move through with chances of rain and cloudy conditions. Temperatures are forecast to be upper 70's Friday, mid to low 70's Saturday, mid-60's Sunday and upper 60's Monday. Dewpoints are forecast to be in the 50's Friday, around 50 degrees Saturday, 60's Sunday and Monday. Winds are forecast to be calm Friday morning with ENE winds 0-5 MPH Friday afternoon, ESE 0-10 MPH Saturday, SSE 5-15 MPH Sunday and Monday. The NOAA 06Z BC model for PM2.5 forecasts good levels Friday through Sunday for SE and moderate for SW. The Canadian model shows mostly good levels for that entire forecast period. I think moderate is possible for SW today, but beyond that a mix seems more possible. Moderate is not out of the question with the tropical moisture and southerly flow with higher RH and low wind speeds. Due to all this, thinking moderate for both Friday with moderate possible for SW before the rain and a mix of good and moderate for SE. Logic behind this choice is the flow of moisture, frontal angle and precipitation chances; I think a fresh air mass Monday with new air flow with drop levels back to good. The NOAA 06Z BC model for ozone predicts moderate ozone for SW Friday with otherwise good ozone for Friday through Sunday for all. The Canadian model forecasts moderate for SW and good for SE Friday and good levels for all beyond that. Moderate ozone seems possible today for perhaps both SE and SW depending on the angle and timing of the cold front. tomorrow more good levels through the weekend due to the cold front, building cloud cover, and rain chances. Mixing heights are forecast around 3,700 ft. Friday and 1,800 ft. Saturday.
Forecast from EPA AirNow for the Louisville reporting area. Canairy watches the live sensors against it and tells you when the air actually crosses your threshold, rather than leaving you to check.
Rubbertown and the fight over west Louisville's air
Along the Ohio River on Louisville's west side sits Rubbertown, an industrial corridor of eleven chemical plants — synthetic rubber, solvent, and chemical manufacturers that trace back to a World War II buildup of wartime rubber production. A federal West Louisville Air Toxics Study, run with the University of Louisville from 2000 to 2005, found 17 hazardous air pollutants at levels high enough to justify action. In 2005 Louisville Metro responded with the Strategic Toxic Air Reduction (STAR) program, one of the strictest local air-toxics ordinances of its kind in the country, tightening emissions limits on Rubbertown's plants specifically.
The story hasn't stopped there. In 2024 the EPA and the University of Louisville's Envirome Institute launched the Rubbertown Air Toxics and Health Action (RATHA) project, a three-year, roughly $1 million effort to expand air monitoring and study health effects in neighborhoods like Shawnee that sit closest to the plants. Researchers pointed to elevated rates of liver, lung, and stomach cancer in Jefferson County, disproportionately among Black residents — echoing an older, well-documented case at a former B.F. Goodrich plant in Rubbertown, where vinyl chloride exposure caused rare liver cancers in workers decades ago. In 2025 the Trump EPA terminated the RATHA grant and rejected the district's appeal, leaving the expanded monitoring in limbo even as Rubbertown keeps operating.
Ozone Action Days run June through September
Louisville's other recurring problem is ground-level ozone, formed when summer heat and sunlight react with vehicle exhaust, industrial emissions, and vapors from everyday sources like printing shops, auto body shops, and lawn equipment. The Kentuckiana Ozone Prevention Coalition calls an Ozone Action Day whenever conditions favor that reaction, and Louisville Metro's Air Pollution Control District — using data from the regional KAIRE monitoring network — posts an updated Air Quality Index four times a day on weekdays specifically because ozone here is common enough to need routine tracking, not just occasional smoke-season vigilance.
The American Lung Association's 2026 State of the Air report gave Jefferson County an F for ozone, with an average of 10.7 unhealthy ozone days a year, the worst count in Kentucky and up from 8.2 in the 2025 report. That moved the Louisville metro from 29th to 22nd worst in the country for ozone, out of 226 metro areas. Jefferson County earned a C for short-term particle pollution, and its year-round particle levels improved enough to pass. Advocacy Director Shannon Baker put it plainly: too many people in the Louisville metro area are living with unhealthy levels of ozone and particle pollution.
Why Louisville's summer sky turns hazy and white
On humid afternoons Louisville's sky can turn a milky white instead of blue, and WAVE 3 meteorologist Tawana Andrews explained why in a July 2026 interview with Louisville Public Media: once relative humidity climbs past 60 to 70 percent, water vapor starts merging with airborne particles — pollen, dust, and especially sulfate aerosols formed when industrial sulfur dioxide reacts with oxygen and moisture in the air. Those droplets scatter sunlight instead of letting it pass straight through, whitening the sky and turning sunsets a deeper red and orange.
Canadian wildfire smoke has become part of that same summer haze in recent years, drifting into the Ohio Valley without ever being the main event the way it is farther north. That's worth knowing because a hazy-looking sky over Louisville isn't automatically a health emergency — the sulfate haze itself isn't harmful at typical concentrations — but the ozone and particle levels underneath it can be, which is exactly why the number matters more than what the sky looks like.
Louisville air quality FAQ
What is the air quality in Louisville right now?
As of November 2, 2026 at 10:11 AM EST, the air quality in Louisville, Kentucky is AQI 37 — Good — with PM2.5 at 6.7 µg/m³, the median of 4 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does west Louisville have worse air than the rest of the city?
West Louisville sits closest to Rubbertown, an industrial corridor of eleven chemical plants along the Ohio River. A 2000-2005 federal study found 17 hazardous air pollutants at elevated levels there, which led to Louisville's Strategic Toxic Air Reduction (STAR) program in 2005 and, more recently, an EPA-funded health study focused on neighborhoods like Shawnee.
Why does Louisville get so many Ozone Action Days in summer?
Ground-level ozone forms when sunlight and summer heat react with vehicle exhaust, industrial emissions, and everyday vapors from sources like auto body shops and lawn equipment. The Kentuckiana Ozone Prevention Coalition calls an Ozone Action Day whenever conditions are right for that reaction, common enough from June through September that the American Lung Association gave Jefferson County an F for ozone in its 2026 State of the Air report.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 4 curated PurpleAir sensors Canairy tracks in and around Louisville, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
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