Louisville, KY · US EPA Air Quality Index · as of 8:00 PM UTC
Air in Louisville is Moderate today (US AQI 52).
Moderate
Acceptable. Unusually sensitive people should consider limiting prolonged outdoor exertion.
- Good 0–50
- Moderate 51–100
- Unhealthy for sensitive groups 101–150
- Unhealthy 151–200
- Very unhealthy 201–300
- Hazardous 301–500
Air data: Google Air Quality API, updated hourly. Index: US EPA Air Quality Index. Guidelines: WHO 2021 air quality guidelines.
What is in the air right now
Each reading against the World Health Organization guideline for that pollutant.
- PM2.5
- 6.7µg/m³
1.4× the guideline
WHO annual guideline 5 µg/m³
- PM10
- 19.7µg/m³
1.3× the guideline
WHO annual guideline 15 µg/m³
- Ozone
- 104.3µg/m³
1.7× the guideline
WHO peak season guideline 60 µg/m³
- NO₂
- 15.8µg/m³
1.6× the guideline
WHO annual guideline 10 µg/m³
Who should take care today
Advice from the index provider for each group.
If you start to feel respiratory discomfort such as coughing or breathing difficulties, consider reducing the intensity of your outdoor activities.
The last seven days
| Day | Max | Average | Band |
|---|---|---|---|
| 2026-09-23 | 38 | 37 | Good |
| 2026-09-24 | 39 | 37 | Good |
| 2026-09-25 | 33 | 27 | Good |
| 2026-09-26 | 44 | 31 | Good |
| 2026-09-27 | 49 | 46 | Good |
| 2026-09-28 | 50 | 46 | Good |
| 2026-09-29 | 51 | 46 | Moderate |
Outdoor air comes indoors
Outdoor air comes indoors: studies find indoor PM2.5 tracks outdoor levels at roughly half to three-quarters of their concentration in homes without filtration.
US EPA, “Indoor Particulate Matter”, 2024
What the Sans Air Purifier is tested to capture
Independently tested on particles down to 0.3 µm, the size class of PM2.5 and smoke. These are the figures behind the claim.
- Particles ≥ 0.3 µm99.97%HEPA filtration standard
- Clean air delivery420 m³/hrCADR, Sans Air Purifier
- Coverage1,854 sq ftCleaned every hour
Figures are the laboratory’s own, measured under test conditions in a sealed chamber.