Metro area air quality · 2025

Somerset, KY

Median AQI 40 (Good). 81.4% of monitored days rated Good across this metro's EPA monitoring network.

Compiled by PlainAirData · August 23, 2026

40
Median AQI: 81.4%
Good-air days: 0
Unhealthy days: 70%
Cleaner than US metros

Somerset, KY posted a 2025 median AQI of 40 (Good) with 81.4% Good days

According to the U.S. EPA Air Quality System, the Somerset, KY CBSA recorded a median AQI of 40 across 365 monitored days in 2025, with 81.4% rated Good and 0 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 Somerset, KY CBSA's 81.4% Good-day share places it cleaner than 70% of US metros in 2025.
Closest median-AQI peer: Altoona, PA (76.9% Good, median AQI 40) is the closest nationwide median-AQI peer to Somerset, KY.
2020–2025 Good-day shift: Somerset, KY's Good-day share moved -5.6 points from 2020 to 2025 (median AQI +2).
Median AQI: Median AQI: 40

Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →

The verdict

Somerset, KY sits in the upper Good-day tercile among EPA CBSA metros on this site (81.4% of 365 monitored days). On the EPA scale the metro runs good, cleaner than the median US metro, with a median AQI of 40 and 81.4% of 365 monitored days in the Good band.

40
median AQI · Good: 81.4%
days rated Good: 70%
cleaner than US metros: 73
worst single reading

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

Somerset, KY metro's Good-day share rose from 79.8% to 81.4% between the 2024 and 2025 EPA annual releases, a change of +1.6 percentage points.

Somerset, KY sits in the upper Good-day tercile among EPA CBSA metros on this site (81.4% of 365 monitored days). Signature read: 81.4% Good-day share (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 40 over 365 measured days in 2025 (Good / Good). The monitored-day split lands at 297 Good (81%), 68 Moderate (19%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 54; the highest single-day reading hit 73 (Moderate).

Across 2020–2025, Good-day share shifted -5.6 points and median AQI moved +2 (worsening). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Altoona, PA (76.9% good, AQI 40); Beaver Dam, WI (72.3% good, AQI 40); Bismarck, ND (76.7% good, AQI 40).

Best and worst city air quality →

Air Quality Summary

Median AQI

Good

Good Days

81.4%

297 of 365 days

Max AQI

Moderate

Health Grade

Good

90th pct: 54

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

297

81%

Moderate

19%

USG

Unhealthy

Very Unhealthy

Hazardous

Health Impact Assessment

Good

The Somerset, KY metro area's air quality is rated Good based on 81.4% 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 Somerset, KY metro compare?

How Somerset, KY compares

Compare against

Good-day share better than typical

Somerset, KY 81.4%

Altoona, PA 76.9%

Typical US metro 70.6%

Median AQI better than typical

Somerset, KY 40

Altoona, PA 40

Typical US metro 41

Unhealthy days / yr better than typical

Somerset, KY 0

Altoona, PA 0

Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Somerset, KY metro. Highest Good-day share: 2020 (86.9%, 246 of 283 monitored days).

Year	Good	Moderate	Median AQI	Max AQI
2020	246	37	38	77
2021	229	131	45	101
2022	259	100	42	82
2023	232	129	45	120
2024	292	74	41	68
2025	297	68	40	73

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Somerset, KY (40).

Altoona, PA

Median AQI 40 · 76.9% Good-day share

Beaver Dam, WI

Median AQI 40 · 72.3% Good-day share

Bismarck, ND

Median AQI 40 · 76.7% Good-day share

Cape Coral-Fort Myers, FL

Median AQI 40 · 76.4% Good-day share

College Station-Bryan, TX

Median AQI 40 · 68.5% Good-day share

Fallon, NV

Median AQI 40 · 85.2% Good-day share

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Somerset, KY's 0 (independent of median AQI).

Aberdeen, SD

0 unhealthy-or-worse days · median AQI 27

Aberdeen, WA

0 unhealthy-or-worse days · median AQI 22

Adrian, MI

0 unhealthy-or-worse days · median AQI 41

Akron, OH

0 unhealthy-or-worse days · median AQI 45

Albany, GA

0 unhealthy-or-worse days · median AQI 46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

Frequently Asked Questions

How many unhealthy air days does Somerset, KY have? ▼

In 2025, the Somerset, KY metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 73.

What is the air quality in the Somerset, KY metro area? ▼

The Somerset, KY metro area has a median Air Quality Index (AQI) of 40, rated "Good." 81.4% of monitored days (297 out of 365) had good air quality in 2025.

Is air quality in Somerset, KY getting better or worse? ▼

Air quality in the Somerset, KY metro is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 86.9% (246 of 283 days). Lowest qualifying Good-day share: 2021 at 63.6% (229 of 360 days).

What does AQI 40 mean for health? ▼

An AQI of 40 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.

How does Somerset, KY compare to other metro areas? ▼

The Somerset, KY metro has 81.4% good air days. Similar metros: Altoona, PA (76.9% good), Beaver Dam, WI (72.3% good), Bismarck, ND (76.7% good).

What is the 90th percentile AQI for Somerset, KY? ▼

The 90th percentile AQI for the Somerset, KY metro area is 54, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 73 (Moderate).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Somerset, KY, 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, Somerset, KY · 2020–2025 Accessed 2026-07-06