Metro area air quality · 2025
Marshall, MN
Median AQI 37 (Good). 77.0% of monitored days rated Good across this metro's EPA monitoring network.
- 37
- Median AQI
- 77.0%
- Good-air days
- 2
- Unhealthy days
- 61%
- Cleaner than US metros
Marshall, MN posted a 2025 median AQI of 37 (Good) with 77.0% Good days
According to the U.S. EPA Air Quality System, the Marshall, MN CBSA recorded a median AQI of 37 across 365 monitored days in 2025, with 77.0% rated Good and 2 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US metros
- The Marshall, MN CBSA's 77.0% Good-day share places it cleaner than 61% of US metros in 2025.
- Closest median-AQI peer
- Alexandria, LA (73.7% Good, median AQI 37) is the closest nationwide median-AQI peer to Marshall, MN.
- 2020–2025 Good-day shift
- Marshall, MN's Good-day share moved -7.8 points from 2020 to 2025 (median AQI +2).
- Median AQI
- Median AQI: 37
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
The Marshall, MN metro runs good on the EPA scale, cleaner than the median US metro, a median AQI of 37 with 77.0% of 365 monitored days in the Good band.
- 37
- median AQI · Good
- 77.0%
- days rated Good
- 61%
- cleaner than US metros
- 161
- worst single reading
2 days reached Unhealthy or worse across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Marshall, MN metro's Good-day share rose from 75.8% to 78.1% between the 2024 and 2025 EPA annual releases, a change of +2.2 percentage points.
- Marshall, MN metro's Unhealthy-category days rose from 0 to 2 between the 2024 and 2025 EPA annual releases, a change of +2 days.
- Marshall, MN metro's peak single-day AQI rose from 142 to 161 between the 2024 and 2025 EPA annual releases, a change of +19 points.
- Marshall, MN metro's median AQI fell from 40 to 37 between the 2024 and 2025 EPA annual releases, a change of -3 points.
Insights: Marshall, MN metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 37 over 365 measured days in 2025, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 281 Good days (77%), 77 Moderate (21%), and 5 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 65 while the highest single-day reading hit 161 (Unhealthy). Metro residents averaged roughly 23.1 clean-air days per 30-day window across the reporting year.
Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -7.8 points and the median AQI moved +2 points, which classifies the multi-year trajectory as worsening. The annual record contains 2 days at Unhealthy or worse. On those days, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Metros with comparable AQI profiles include Alexandria, LA (73.7% good, AQI 37); Athens, TN (78.2% good, AQI 37); Bennington, VT (83.6% good, AQI 37).
Air Quality Summary
Median AQI
37
Good
Good Days
77.0%
281 of 365 days
Max AQI
161
Unhealthy
Health Grade
Good
90th pct: 65
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
281
77%
Moderate
77
21%
USG
5
1%
Unhealthy
2
1%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Marshall, MN metro area's air quality is rated Good based on 77.0% good air days. There were 2 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 5 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 161. Sensitive groups should monitor real-time conditions at AirNow.gov.
How does the Marshall, MN metro compare?
How Marshall, MN compares
5-Year Air Quality Trend
Air quality is worsening in the Marshall, MN metro. Highest Good-day share: 2020 (85.8%, 309 of 360 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 309 | 51 | 0 | 35 | 80 |
| 2021 | 263 | 91 | 2 | 39 | 187 |
| 2022 | 303 | 51 | 2 | 38 | 172 |
| 2023 | 206 | 142 | 3 | 46 | 173 |
| 2024 | 276 | 88 | 0 | 40 | 142 |
| 2025 | 281 | 77 | 2 | 37 | 161 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Marshall, MN (37).
Alexandria, LA
Median AQI 37 · 73.7% Good-day share
Athens, TN
Median AQI 37 · 78.2% Good-day share
Bennington, VT
Median AQI 37 · 83.6% Good-day share
Blacksburg-Christiansburg-Radford, VA
Median AQI 37 · 94.4% Good-day share
Cadillac, MI
Median AQI 37 · 86.0% Good-day share
Chambersburg-Waynesboro, PA
Median AQI 37 · 91.5% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Marshall, MN's 2 (independent of median AQI).
Ardmore, OK
2 unhealthy-or-worse days · median AQI 45
Bridgeport-Stamford-Norwalk, CT
2 unhealthy-or-worse days · median AQI 44
Chattanooga, TN-GA
2 unhealthy-or-worse days · median AQI 49
Cincinnati, OH-KY-IN
2 unhealthy-or-worse days · median AQI 56
Columbus, GA-AL
2 unhealthy-or-worse days · median AQI 48
Davenport-Moline-Rock Island, IA-IL
2 unhealthy-or-worse days · median AQI 46
More Air Quality Data
Explore EPA air quality rankings and guides across U.S. metros and counties.
Cleanest Metro Areas
U.S. metros ranked by their share of Good air-quality days.
Worst Air Quality
Counties and metros with the most unhealthy air days.
All Metro Areas
Annual AQI by CBSA for every monitored U.S. metro area.
Best and Worst City Air
What drives urban air quality and how metro areas compare.
Air Quality Guides
Frequently Asked Questions
What is the air quality in the Marshall, MN metro area? ▼
How many unhealthy air days does Marshall, MN have? ▼
Is air quality in Marshall, MN getting better or worse? ▼
What does AQI 37 mean for health? ▼
What is the 90th percentile AQI for Marshall, MN? ▼
How does Marshall, MN compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. See our methodology for how AQI, median, and coverage figures are computed.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary files (metro-level) · 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.