Metro area air quality · 2025

Vermillion, SD

Median AQI 37 (Good). 82.6% of monitored days rated Good across this metro's EPA monitoring network.

37
Median AQI
82.6%
Good-air days
0
Unhealthy days
71%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 167 monitored days. EPA AQS →

The verdict

The Vermillion, SD metro runs good on the EPA scale, cleaner than the median US metro, a median AQI of 37 with 82.6% of 167 monitored days in the Good band.

37
median AQI · Good
82.6%
days rated Good
71%
cleaner than US metros
74
worst single reading

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

Insights: Vermillion, SD metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 37 over 167 measured days in 2025, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 138 Good days (83%), 29 Moderate (17%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 57 while the highest single-day reading hit 74 (Moderate). Metro residents averaged roughly 24.8 clean-air days per 30-day window across the reporting year.

Across the 2022–2025 trend window, good days shifted by -182 and the median AQI moved -1 points, which classifies the multi-year trajectory as worsening. 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

82.6%

138 of 167 days

Max AQI

74

Moderate

Health Grade

Good

90th pct: 57

AQI Day Breakdown (2025)

Distribution of 167 monitored days across EPA AQI categories.

Good

138

83%

Moderate

29

17%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Vermillion, SD metro area's air quality is rated Good based on 82.6% 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 Vermillion, SD metro compare?

How Vermillion, SD compares

Good-day share better than US avg
Vermillion, SD 82.6%
Athens, TN 77.5%
US average 71.3%
Median AQI better than US avg
Vermillion, SD 37
Athens, TN 37
US average 41
Unhealthy days / yr better than US avg
Vermillion, SD 0
Athens, TN 0
US average 1

5-Year Air Quality Trend

Air quality is worsening in the Vermillion, SD metro. Best year: 2022 (320 good days).

Year Good Moderate Unhealthy Median AQI
2022 320 45 0 38
2023 244 103 3 43
2024 289 75 0 39
2025 138 29 0 37

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Vermillion, SD.

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 Vermillion, SD metro area? ▼
The Vermillion, SD metro area has a median Air Quality Index (AQI) of 37, rated "Good." 82.6% of monitored days (138 out of 167) had good air quality in 2025.
How many unhealthy air days does Vermillion, SD have? ▼
In 2025, the Vermillion, SD metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 74.
Is air quality in Vermillion, SD getting better or worse? ▼
Air quality in the Vermillion, SD metro is worsening based on 5-year trends (2022-2025). Best year: 2022 with 320 good days. Worst year: 2025 with 138 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 Vermillion, SD? ▼
The 90th percentile AQI for the Vermillion, SD metro area is 57, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 74 (Moderate).
How does Vermillion, SD compare to other metro areas? ▼
The Vermillion, SD metro has 82.6% 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.