Air quality
Air quality in Louisville today
Updated
Good (US AQI 35) Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. Model estimate for Sun, Oct 25, 4:00 pm (20:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Louisville, Kentucky, United States, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 35 Good
- PM2.5
- 3.7 µg/m³ 0.2× WHO 24-h guideline
- PM10
- 3.7 µg/m³
- Ozone
- 131 µg/m³
- Dominant pollutant
- ozone sub-index 35
- Best hour today
- 4:00 pm AQI 35
- European AQI
- 66
Air quality in Louisville right now
Right now the modelled US Air Quality Index for Louisville, Kentucky, United States is 35, which falls in the "Good" band (up to 50). Air quality is satisfactory and poses little or no risk; a good time for outdoor activity.
The index is driven mainly by ozone, whose own sub-index is 35. Ozone usually peaks in the afternoon on sunny days and falls back after sunset.
PM2.5 is 3.7 µg/m³, within the WHO 24-hour guideline of 15 µg/m³; PM10 is 3.7 µg/m³ against a guideline of 45; ozone is 131 µg/m³ (above the WHO 8-hour level of 100); nitrogen dioxide is 0.5 µg/m³ (below the 24-hour guideline of 25).
Also this hour: UV index 2.1, carbon monoxide 141 µg/m³.
NASA FIRMS shows 125 fire hotspots within 300 km in the last day (nearest about 32 km), but particle levels are not elevated enough to point to smoke right now.
Louisville AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 35 around Sun 4:00 pm to 62 around Sun 9:00 pm, from "Good" at best to "Moderate" at worst.
The following day is expected to be worse, averaging about 60 against 51 for the next 24 hours.
| Local time (America/Kentucky/Louisville) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Sun 4:00 pm | 35 | Good | 3.7 | 4 | 131 |
| Sun 7:00 pm | 51 | Moderate | 6.8 | 7 | 101 |
| Sun 10:00 pm | 55 | Moderate | 12.8 | 13 | 61 |
| Mon 1:00 am | 41 | Good | 17.5 | 18 | 35 |
| Mon 4:00 am | 49 | Good | 18.7 | 19 | 27 |
| Mon 7:00 am | 53 | Moderate | 19.9 | 20 | 20 |
| Mon 10:00 am | 56 | Moderate | 16.7 | 17 | 50 |
| Mon 1:00 pm | 57 | Moderate | 6 | 6 | 116 |
| Mon 4:00 pm | 57 | Moderate | 4.4 | 5 | 137 |
| Mon 7:00 pm | 64 | Moderate | 7.3 | 7 | 93 |
| Mon 10:00 pm | 57 | Moderate | 13.6 | 14 | 50 |
| Tue 1:00 am | 58 | Moderate | 19.4 | 19 | 28 |
| Tue 4:00 am | 58 | Moderate | 23.3 | 24 | 19 |
| Tue 7:00 am | 60 | Moderate | 26.4 | 27 | 12 |
| Tue 10:00 am | 61 | Moderate | 24.2 | 24 | 56 |
| Tue 1:00 pm | 62 | Moderate | 7.4 | 7 | 118 |
| Tue 4:00 pm | 63 | Moderate | 6.7 | 7 | 136 |
Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.
Best time to be outside in Louisville today
Between 6 am and 9 pm local time, the cleanest air today is forecast around 4:00 pm (AQI 35, Good) and the worst around 9:00 pm (AQI 62). That is a swing of 27 points, so a run or walk around 4:00 pm is noticeably better.
Louisville vs the rest of United States
Across 619 United States cities we track, the average US AQI right now is 49 (Good). Louisville at 35 is 14 points cleaner than average.
It ranks 102 of 619 from cleanest to most polluted; the cleanest is Casper (16) and the most polluted Springfield, PA (131).
For context, the median across 3,556 cities worldwide is 58.
Air quality in cities near Louisville
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Columbus, IN | 106 km | 50 | Good | 2.7 |
| Lexington | 116 km | 37 | Good | 4.1 |
| Lexington-Fayette | 116 km | 37 | Good | 4.1 |
| Cincinnati | 145 km | 46 | Good | 5.6 |
| Evansville | 160 km | 35 | Good | 2.9 |
| Hamilton, OH | 164 km | 46 | Good | 5.6 |
| Oxford, OH | 165 km | 54 | Moderate | 6 |
| Indianapolis | 172 km | 54 | Moderate | 3.6 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Louisville, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.
Advice for sensitive groups
With the AQI at 35, there is no need for sensitive groups to change plans. People with asthma should still carry their reliever inhaler as usual.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for Louisville
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.