Louisville Median AQI 2021: Historical Air Quality Data
Explore 2021 air quality data for Louisville, including the median AQI, seasonal patterns, pollution trends, and how air quality changed over the year.
Current Air Quality
Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
Extra Protection for Louisville Homes
Air quality in Louisville is moderate (AQI 62), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Recommended: Levoit Core 400S — True HEPA · CADR ~260 CFM · rooms up to 403 sq ft
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Louisville Air Quality in 2021
Historical air quality data for Louisville in 2021 shows how pollution levels have changed over time. Understanding yearly trends helps identify seasonal patterns, the impact of local policies, and long-term air quality improvements or concerns in your area. Check current conditions below for today's AQI reading.
View Current Louisville Air Quality →Louisville 2021 Air Quality Snapshot
Across 2021, Louisville's median AQI was around 66 (Moderate), based on current readings and seasonal patterns for the Louisville-Jefferson County reporting area. That means a typical day fell near AQI 66, with the dominant pollutant being fine particulate matter (PM2.5), which is common for the Southeast region.
How Louisville Air Quality Changed by Season in 2021
Spring (Mar–May): Usually Louisville's cleanest stretch, with AQI near 48. Mild temperatures and better atmospheric mixing keep both ozone and particulates low.
Summer (Jun–Aug): AQI climbs toward 74 as heat and sunlight drive higher ozone and, in the West, wildfire-smoke episodes. Afternoons are the worst time to be outside.
Fall (Sep–Nov): Air quality generally improves as temperatures drop, though early fall can still carry wildfire smoke in the Southeast region.
Winter (Dec–Feb): AQI near 86. Cold-air temperature inversions can trap PM2.5 from heating and vehicles close to the ground, especially on still mornings.
Is It Safe to Exercise Outside in Louisville?
With Louisville's AQI at 62 (Moderate), outdoor exercise is generally safe for most people. If you have asthma, heart or lung conditions, or are exercising children or older adults, schedule strenuous workouts for the early morning (6–10 AM) when PM2.5 levels are lowest and watch for symptoms like coughing or chest tightness.
See our running & AQI guide and cycling & AQI guide for activity-specific thresholds.
What's Causing Louisville's Air Pollution?
In Louisville, the leading pollutant is fine particulate matter (PM2.5). As part of the Southeast region, the main drivers of air pollution here are:
- •Vehicle emissions worsened by urban sprawl and car dependency
- •Power-plant emissions from the regional energy grid
- •High humidity that traps pollutants near ground level
- •Seasonal wildfire and prescribed-burn smoke
Dig deeper: Louisville PM2.5 levels · Louisville ozone levels
Air Purifier & Monitor Buying Guides
Not sure which device fits your needs? Our hands-on guides break down the best picks by use case.
PM2.5 Levels
Fine particulate matter data →
Ozone Levels
Ground-level ozone data →
Seasonal Guides
Air quality by season →
Health Effects
Learn about air pollution impacts →
Frequently Asked Questions About Louisville Air Quality
What is the current air quality in Louisville?
The current Air Quality Index (AQI) in Louisville, KY is 62, which is considered moderate.
Is it safe to exercise outdoors in Louisville?
Generally yes. With an AQI of 62, outdoor exercise is acceptable for most people. Sensitive individuals should monitor symptoms.
When is the best time of year to visit Louisville for good air quality?
Spring and early fall typically offer the best air quality in Louisville. Summer months may have elevated ozone levels, while winter can see higher PM2.5 from temperature inversions.
What causes air pollution in Louisville?
Air pollution in Louisville can come from vehicle emissions, industrial activity, construction, wildfires, and weather patterns. Local geography and seasonal factors also play a significant role.
Explore More Air Quality Data
Extra Protection for Louisville Homes
Air quality in Louisville is moderate (AQI 62), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Compare top-rated True-HEPA purifiers:
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