Median AQI
45
Good
Minnesota · County air quality · 2025
Hennepin County, Minnesota
Median AQI 45 (Good). 57.8% of monitored days rated Good, direct from EPA Air Quality System stations.
- 45
- Median AQI
- 57.8%
- Good-air days
- 6
- Unhealthy days
- 12%
- Cleaner than US counties
Hennepin County's 2025 annual median AQI is 45 (Good), with 57.8% Good days
According to the U.S. EPA Air Quality System, Hennepin County, Minnesota posted a 2025 median AQI of 45 (Good) across 365 monitored days, with 57.8% rated Good and 6 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Hennepin County's 57.8% Good-day share places it cleaner than 12% of US counties in 2025.
- Closest median-AQI peer
- Baltimore County (64.7% Good, median AQI 45) is the closest nationwide median-AQI peer to Hennepin County.
- 2020–2025 trend
- Hennepin County's floor-qualifying Good-day share is stable from 2020 to 2025 (56.3% → 57.8%).
- Median AQI
- Median AQI: 45
The verdict
According to EPA Air Quality System monitoring data, Hennepin County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 45 with 57.8% of 365 monitored days in the Good band, driven mainly by PM2.5.
- 45
- median AQI · Good
- 57.8%
- days rated Good
- PM2.5
- main pollutant
- 12%
- cleaner than US counties
6 days reached Unhealthy or worse; the worst single reading hit AQI 178.
Annual release change
What changed in the 2025 EPA annual release
- Hennepin County's Good-day share fell from 66.4% to 57.8% between the 2024 and 2025 EPA annual releases, a change of -8.6 percentage points.
- Hennepin County's Unhealthy-category days rose from 1 to 6 between the 2024 and 2025 EPA annual releases, a change of +5 days.
- Hennepin County's peak single-day AQI rose from 166 to 178 between the 2024 and 2025 EPA annual releases, a change of +12 points.
- Hennepin County's median AQI rose from 42 to 45 between the 2024 and 2025 EPA annual releases, a change of +3 points.
Data updated August 2026
- Good · 211 d · 57.8%
- Moderate · 144 d · 39.5%
- USG · 4 d · 1.1%
- Unhealthy · 6 d · 1.6%
How did Hennepin County's air break down in 2025?
Across 365 monitored days, 211 fell in the Good band (AQI 0–50) and 6 reached Unhealthy or worse. The worst single day peaked at AQI 178 (Unhealthy).
EPA AQS →Air quality data from EPA Air Quality System (2025). 365 days monitored. Median AQI: 45 (Good).
Insights: Hennepin County, Minnesota. EPA monitors recorded a median Air Quality Index of 45 across 365 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 211 (58%) fell in the Good band (AQI 0–50), 144 (39%) registered Moderate readings, and 4 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 71, while the worst single-day peak hit 178 (Unhealthy). Residents averaged about 17.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (284 days), Ozone (62 days), NO2 (14 days), PM10 (5 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by +1.5 points and the median AQI moved -3 points, placing the multi-year trajectory at stable. The annual record contains 6 days at Unhealthy or worse. On those days, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Anoka (74.1% good, AQI 38); Becker (74.0% good, AQI 38); Beltrami (79.1% good, AQI 36); Blue Earth (65.3% good, AQI 42); Carlton (82.8% good, AQI 33); Cass (82.7% good, AQI 28).
Air Quality Summary
Good Days
57.8%
211 of 365 monitored days
-17.2pp vs 75% target
Max AQI Recorded
178
Unhealthy
Health Grade
Moderate
90th-pct AQI 71
Hennepin County, Good days share 57.8%
National avg
Share of monitored days at AQI 0-50 (Good band).
Hennepin County, Unhealthy-or-worse share 16.4%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
211
58%
Moderate
144
39%
USG
4
1%
Unhealthy
6
2%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Hennepin County.
- PM2.5 · 284 days · 77.8%
- Ozone · 62 days · 17.0%
- NO₂ · 14 days · 3.8%
- PM10 · 5 days · 1.4%
Health Impact Assessment
Moderate
Hennepin County's air quality is rated Moderate based on 57.8% good air days. There were 6 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 4 days reached "Unhealthy for Sensitive Groups" (AQI 101-150) and peak AQI reached 178. Sensitive groups should monitor real-time conditions at AirNow.gov.
The dominant pollutant is PM2.5, driving AQI on 284 of 365 monitored days.
5-Year Air Quality Trend
Air quality is stable in Hennepin County. Highest Good-day share: 2022 (66.8%, 244 of 365 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 206 | 158 | 1 | 1 | 48 | 158 |
| 2021 | 213 | 149 | 0 | 3 | 45 | 157 |
| 2022 | 244 | 121 | 0 | 0 | 42 | 96 |
| 2023 | 173 | 175 | 14 | 3 | 52 | 187 |
| 2024 | 243 | 119 | 3 | 1 | 42 | 166 |
| 2025 | 211 | 144 | 4 | 6 | 45 | 178 |
How does Hennepin County compare?
How Hennepin County compares
Good-day share worse than typical
Hennepin County 57.8%
Baltimore County, Maryland 64.7%
Typical US county 76.0%
Median AQI worse than typical
Hennepin County 45
Baltimore County, Maryland 45
Typical US county 39
Unhealthy days / yr worse than typical
Hennepin County 6
Baltimore County, Maryland 0
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Hennepin County (45), not geographic neighbors.
Baltimore County, Maryland
Median AQI 45 · 64.7% Good-day share
Bell County, Texas
Median AQI 45 · 66.0% Good-day share
Box Elder County, Utah
Median AQI 45 · 64.7% Good-day share
Bronx County, New York
Median AQI 45 · 59.2% Good-day share
Catano County, Puerto Rico
Median AQI 45 · 60.6% Good-day share
Catron County, New Mexico
Median AQI 45 · 71.7% Good-day share
Same primary pollutant: PM2.5
PM2.5 led the AQI on the most monitored days here. These peers share that driver and the closest Good-day share (a second relationship type beyond median-AQI neighbors).
Clarke County, Georgia
57.8% Good-day share · median AQI 46
Hall County, Georgia
57.7% Good-day share · median AQI 46
Clark County, Indiana
58.1% Good-day share · median AQI 46
Richland County, South Carolina
58.1% Good-day share · median AQI 47
Sedgwick County, Kansas
57.5% Good-day share · median AQI 48
Gwinnett County, Georgia
58.3% Good-day share · median AQI 47
Minnesota counties on the map
Geographic containment only, other monitored counties in Minnesota, independent of AQI or pollutant match.
What Hennepin County's air means for you
On most days the air here is fine, but PM2.5 drives 6 unhealthy-or-worse days a year that sensitive groups should plan around.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 45 means for exposure. Health guidance
- See how Hennepin County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Hennepin County with its Minnesota neighbours before drawing a conclusion about the region. All of Minnesota
Based on 365 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
Keep exploring the annual AQI record
Air-quality reading list
Frequently Asked Questions
What is the air quality in Hennepin County, Minnesota? ▼
Hennepin County has a median Air Quality Index (AQI) of 45, rated "Good." 57.8% of monitored days (211 out of 365) had good air quality in 2025.
What is the main pollutant in Hennepin County? ▼
The primary pollutant in Hennepin County is Fine Particles (PM2.5), which was the main AQI driver on 284 days (78% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Hennepin County have? ▼
In 2025, Hennepin County recorded 6 unhealthy air days (6 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 178.
Is the air quality in Hennepin County getting better or worse? ▼
Air quality in Hennepin County is stable across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2022 at 66.8% (244 of 365 days). Lowest qualifying Good-day share: 2023 at 47.4% (173 of 365 days).
What does AQI 45 mean for health? ▼
Hennepin County's median AQI of 45 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Hennepin County compare to other counties in Minnesota? ▼
Hennepin County has 57.8% good air days. Nearby counties in Minnesota: Anoka (74.1% good), Becker (74.0% good), Beltrami (79.1% good), Blue Earth (65.3% good), Carlton (82.8% good), Cass (82.7% good).
What is the 90th percentile AQI in Hennepin County? ▼
The 90th percentile AQI for Hennepin County is 71, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 178 (Unhealthy).
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 Hennepin County, Minnesota · 2020–2025
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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.