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 13 from 4 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Louisville, Kentucky is AQI 13 — Good and falling — with PM2.5 at 2.4 µg/m³, the median of 4 live PurpleAir sensors reading 0 to 16. 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
Pollen today in Louisville: weeds pollen is the strongest of the three at a high level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
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 16-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 | 13 | Good |
| 1.7 mi S | 16 | Good |
| 1.9 mi E | 0 | Good |
| 2.8 mi ENE | 13 | 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 | Moderate | ozone |
| Tomorrow | Moderate | ozone |
Southern Regions: Ozone was Good over the past weekend except for a few Moderates on the Kentucky side of Louisville yesterday. PM2.5 was Good except for one Moderate yesterday on the Kentucky side of Louisville. As of 12Z this morning, a large dome of surface high pressure is centered over the Great Lakes region. This high will shift to east throughout the day today and tonight. A warm front is expected to lift over the area from the southwest to northeast on early Tuesday, followed by a cold front Wednesday which stalls before reaching the southern counties of Indiana, leaving southern Indiana with an upcoming hot and dry forecast. Conditions today will be sunny and seasonal with highs around 80 to the lower 80's and dew points in the upper 50's. Winds will be east at 5 to 10 mph with mixing heights of 3000 ft. Tuesday will be sunny and hot with highs in the lower 90's and dew points around 70. Winds will be southeast at 5 to 10 mph with mixing heights of 4200 ft. For Wednesday it will also be sunny and hot with highs in the lower to mid-90's and dew points in the lower 70's. Winds will be southwest around 5 mph with mixing heights of 3200 ft. In terms of guidance, The Canadian is going Moderate through Wednesday for Ozone. The 06Z NOAA model is predicting Good straight through Wednesday for Ozone. Am inclined to go with the Canadian as persistence is showing some Moderates pop up yesterday in Kentucky. Think the area will see possibly a couple sites go over to Moderate with the steady easterly wind preventing them from going widespread, and then more sites on Tuesday and Wednesday as conditions start to get hot and the winds drop off, especially on Wednesday. As for PM2.5, the NOAA model is predicting Good for today and then Moderate for Tuesday/Wednesday which is possible for when conditions heat up and winds start to back off. So planning on going with exactly this, Good today and then Moderate the rest of the period.
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 2025 State of the Air report gave Jefferson County an F for ozone, citing an average of 8.2 unhealthy ozone days a year — the 29th worst count in the country and second worst in its region — alongside a D grade for short-term particle pollution and a failing grade for year-round particle levels. Advocacy Director Shannon Baker put it plainly: too many people in Louisville live with unhealthy ozone, and it's causing kids to have asthma attacks and making people who work outdoors sick.
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 September 14, 2026 at 8:09 AM EDT, the air quality in Louisville, Kentucky is AQI 13 — Good — with PM2.5 at 2.4 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 2025 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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