Lexington Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Lexington (Lexington-Fayette, KY area) was June 28, 2023, when the daily AQI reached 167 (Unhealthy), set by fine particulate matter (PM2.5), in wildfire smoke season. Across 2,529 monitored days in 2019–2025, 1 of the 10 worst days was Unhealthy (AQI 151+) or worse; 6 of the 10 were driven by ground-level ozone and 4 by fine particulate matter (PM2.5), and 6 of them fell in 2023. The cleanest day was December 11, 2021 at AQI 6 (Good); the 10 best days span 2 different years.
Improve Indoor Air Quality
Even with good outdoor air in Lexington, indoor PM2.5, dust and allergens build up. A True-HEPA purifier keeps a bedroom or office consistently clean.
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When were Lexington's worst and best air quality days?
Worst: June 28, 2023, AQI 167 (Unhealthy, PM2.5). Best: December 11, 2021, AQI 6 (Good). Based on 2,529 EPA-monitored days in the Lexington-Fayette, KY area, 2019–2025.
- ✓1 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 100 (Moderate).
- ✓Ground-level ozone drove 6 of the 10 worst days.
- ✓2023 accounts for 6 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Lexington?▾
June 28, 2023: the Lexington-Fayette, KY area's daily AQI hit 167 (Unhealthy), driven by fine particulate matter (PM2.5), in wildfire smoke season. That is the highest of 2,529 monitored days in 2019–2025.
What was the best air quality day in Lexington?▾
December 11, 2021, with a daily AQI of 6 (Good). The daily AQI is the highest reading from any monitor in the area, so even the cleanest day reflects the area's worst monitor.
What was Lexington's worst air quality day in 2025?▾
September 19, 2025, AQI 100 (Moderate), set by ground-level ozone.
Which pollutant causes Lexington's worst air days?▾
Ground-level ozone set the AQI on 6 of the 10 worst days; fine particulate matter (PM2.5) on 4. The tables above list the defining pollutant for every day.
Lexington's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Lexington-Fayette, KY area (EPA AQS). The daily AQI is the highest reading from any monitor in the area that day.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2023 page) | 167 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 2 | (2023 page) | 128 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 3 | (2021 page) | 108 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) |
| 4 | (2022 page) | 106 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) |
| 5 | (2023 page) | 105 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 6 | (2021 page) | 101 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 7 | (2025 page) | 100 | Moderate | O3 — ground-level ozone |
| 8 | (2023 page) | 100 | Moderate | O3 — ground-level ozone, in peak ozone season |
| 9 | (2023 page) | 100 | Moderate | O3 — ground-level ozone, in peak ozone season |
| 10 | (2023 page) | 100 | Moderate | O3 — ground-level ozone, in peak ozone season |
Worst day of each year in Lexington
The single highest-AQI day in each year on record. Click a year for its full month-by-month statistics.
| Year | Worst day | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 2019 | 80 | Moderate | O3 — ground-level ozone, in peak ozone season | |
| 2020 | 86 | Moderate | PM2.5 — fine particulate matter (PM2.5) | |
| 2021 | 108 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) | |
| 2022 | 106 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) | |
| 2023 | 167 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2024 | 93 | Moderate | O3 — ground-level ozone, in peak ozone season | |
| 2025 | 100 | Moderate | O3 — ground-level ozone |
Lexington's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Lexington-Fayette, KY area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2021 page) | 6 | Good | NO2 — nitrogen dioxide |
| 2 | (2021 page) | 6 | Good | NO2 — nitrogen dioxide |
| 3 | (2021 page) | 7 | Good | NO2 — nitrogen dioxide |
| 4 | (2024 page) | 8 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 5 | (2021 page) | 8 | Good | NO2 — nitrogen dioxide |
| 6 | (2021 page) | 8 | Good | NO2 — nitrogen dioxide |
| 7 | (2021 page) | 9 | Good | NO2 — nitrogen dioxide |
| 8 | (2024 page) | 10 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 9 | (2021 page) | 10 | Good | PM10 — coarse dust (PM10) |
| 10 | (2024 page) | 13 | Good | PM2.5 — fine particulate matter (PM2.5) |
Right now in Lexington
The latest EPA AirNow observation puts Lexington's AQI at 32 (PM2.5). The days above are historical records, not today's reading.
View current Lexington air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Lexington-Fayette, KY), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.