Metro area air quality · 2025

Marshall, MN

Median AQI 37 (Good). 84.5% of monitored days rated Good across this metro's EPA monitoring network.

37
Median AQI
84.5%
Good-air days
0
Unhealthy days
75%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 181 monitored days. EPA AQS →

The verdict

The Marshall, MN metro runs good on the EPA scale, cleaner than most US metros, a median AQI of 37 with 84.5% of 181 monitored days in the Good band.

37
median AQI · Good
84.5%
days rated Good
75%
cleaner than US metros
140
worst single reading

No day crossed into the Unhealthy tier across the metro's monitors in 2025.

Insights: Marshall, MN metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 37 over 181 measured days in 2025, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 153 Good days (85%), 27 Moderate (15%), and 1 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 61 while the highest single-day reading hit 140 (USG). Metro residents averaged roughly 25.4 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -156 and the median AQI moved +2 points, which classifies the multi-year trajectory as stable. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Athens, TN (77.5% good, AQI 37); Bemidji, MN (88.8% good, AQI 37); Chambersburg-Waynesboro, PA (93.0% good, AQI 37).

Air Quality Summary

Median AQI

37

Good

Good Days

84.5%

153 of 181 days

Max AQI

140

USG

Health Grade

Good

90th pct: 61

AQI Day Breakdown (2025)

Distribution of 181 monitored days across EPA AQI categories.

Good

153

85%

Moderate

27

15%

USG

1

1%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Marshall, MN metro area's air quality is rated Good based on 84.5% good air days. No unhealthy air days were recorded in 2025.

Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.

How does the Marshall, MN metro compare?

How Marshall, MN compares

Good-day share better than US avg
Marshall, MN 84.5%
Athens, TN 77.5%
US average 71.3%
Median AQI better than US avg
Marshall, MN 37
Athens, TN 37
US average 41
Unhealthy days / yr better than US avg
Marshall, MN 0
Athens, TN 0
US average 1

5-Year Air Quality Trend

Air quality is stable in the Marshall, MN metro. Best year: 2020 (309 good days).

Year Good Moderate Unhealthy Median AQI
2020 309 51 0 35
2021 263 91 2 39
2022 303 51 2 38
2023 206 142 3 46
2024 276 88 0 40
2025 153 27 0 37

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Marshall, MN.

Athens, TN

AQI 37 · 77.5% good

37

Bemidji, MN

AQI 37 · 88.8% good

37

Chambersburg-Waynesboro, PA

AQI 37 · 93.0% good

37

Crestview-Fort Walton Beach-Destin, FL

AQI 37 · 92.7% good

37

Gainesville, FL

AQI 37 · 90.1% good

37

Grand Island, NE

AQI 37 · 80.2% good

37

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? ▼
The Marshall, MN metro area has a median Air Quality Index (AQI) of 37, rated "Good." 84.5% of monitored days (153 out of 181) had good air quality in 2025.
How many unhealthy air days does Marshall, MN have? ▼
In 2025, the Marshall, MN metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 140.
Is air quality in Marshall, MN getting better or worse? ▼
Air quality in the Marshall, MN metro is stable based on 5-year trends (2020-2025). Best year: 2020 with 309 good days. Worst year: 2025 with 153 good days.
What does AQI 37 mean for health? ▼
An AQI of 37 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for Marshall, MN? ▼
The 90th percentile AQI for the Marshall, MN metro area is 61, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 140 (USG).
How does Marshall, MN compare to other metro areas? ▼
The Marshall, MN metro has 84.5% good air days. Similar metros: Athens, TN (77.5% good), Bemidji, MN (88.8% good), Chambersburg-Waynesboro, PA (93.0% good).

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

Every figure on PlainAir 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.