Minnesota · County air quality · 2025
Lake County, Minnesota
Median AQI 31 (Good). 85.9% of monitored days rated Good, direct from EPA Air Quality System stations.
- 31
- Median AQI
- 85.9%
- Good-air days
- 7
- Unhealthy days
- 72%
- Cleaner than US counties
Lake County's 2025 annual median AQI is 31 (Good), with 85.9% Good days
According to the U.S. EPA Air Quality System, Lake County, Minnesota posted a 2025 median AQI of 31 (Good) across 361 monitored days, with 85.9% rated Good and 7 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Lake County's 85.9% Good-day share places it cleaner than 72% of US counties in 2025.
- Closest median-AQI peer
- Athens County (83.4% Good, median AQI 31) is the closest nationwide median-AQI peer to Lake County.
- 2020–2025 trend
- Lake County's floor-qualifying Good-day share is worsening from 2020 to 2025 (94.2% → 85.9%).
- Median AQI
- Median AQI: 31
According to the 2025 EPA AQS county release on PlainAirData, Lake County, Minnesota ranks #100 of 951 by median AQI (31) and #269 by good-day share (85.9%). Ponce County, Puerto Rico is #1 of 951 by median AQI (3, 91.4% Good days) at good-day-share #159 ≠ largest of 7 at 100.0% Good days #1 by good-day share (100.0%, median AQI 9) at median-AQI #7.
Annual release change
What changed in the 2025 EPA annual release
- Lake County's peak single-day AQI rose from 110 to 191 between the 2024 and 2025 EPA annual releases, a change of +81 points.
- Lake County's Unhealthy-category days rose from 0 to 7 between the 2024 and 2025 EPA annual releases, a change of +7 days.
- Lake County's Good-day share fell from 90.2% to 85.9% between the 2024 and 2025 EPA annual releases, a change of -4.3 percentage points.
Data updated August 2026
- Good · 310 d · 85.9%
- Moderate · 36 d · 10.0%
- USG · 8 d · 2.2%
- Unhealthy · 7 d · 1.9%
How did Lake County's air break down in 2025?
Across 361 monitored days, 310 fell in the Good band (AQI 0–50) and 7 reached Unhealthy or worse. The worst single day peaked at AQI 191 (Unhealthy).
EPA AQS →Share of monitored days at AQI 0-50 (Good band).
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
Where Lake County sits nationally
COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. Lake County's Good-day share is 85.9% - cleaner than 72% of that comparison set.
Lake County Good-day share vs. every US county
Share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release
85.9% Cleaner than 72% higher than 72% of 951 US counties
Each bar is a band; taller bars hold more US counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Lake County.
- PM2.5 · 206 days · 57.1%
- Ozone · 155 days · 42.9%
2024 daily-monitor rhythm in Lake County
Month-by-month median AQI from EPA day-level county monitors (366 reported days in 2024). Apr posted the highest typical readings (median AQI 41, peak 75); Dec was cleanest at median 14. Summer months (Jun–Aug) averaged median AQI 39 vs 15 in Dec–Feb.
Five-year seasonal record
EPA day-level county files · 2020–20241,815 daily readings show a recurring local pattern: Jun has the highest matched-month median AQI (43), while Dec is lowest (18). Each cell is that month’s median daily AQI, not a current-air forecast.
Lower AQI is better. The colors summarize EPA AQI bands; gaps mean the county had no day-level record for that month.
Health Impact Assessment
Lake County's air quality is rated Good based on 85.9% good air days. There were 7 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 8 days reached "Unhealthy for Sensitive Groups" (AQI 101-150) and peak AQI reached 191. Sensitive groups should monitor real-time conditions at AirNow.gov.
The dominant pollutant is PM2.5, driving AQI on 206 of 361 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Lake County. Highest Good-day share: 2022 (95.8%, 342 of 357 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 344 | 21 | 0 | 0 | 34 | 71 |
| 2021 | 315 | 43 | 3 | 1 | 31 | 160 |
| 2022 | 342 | 15 | 0 | 0 | 31 | 78 |
| 2023 | 282 | 81 | 2 | 0 | 36 | 114 |
| 2024 | 330 | 35 | 1 | 0 | 32 | 110 |
| 2025 | 310 | 36 | 8 | 7 | 31 | 191 |
How does Lake County compare?
How Lake County compares
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Lake County, Minnesota · 2020–2025
Download this county's annual AQI row as CSV , with the same EPA fields and denominator shown on this page.
Every figure on PlainAirData is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.