Metro area air quality · 2025

Charleston, WV

Median AQI 39 (Good). 77.0% of monitored days rated Good across this metro's EPA monitoring network.

39
Median AQI
77.0%
Good-air days
0
Unhealthy days
61%
Cleaner than US metros

Charleston, WV posted a 2025 median AQI of 39 (Good) with 77.0% Good days

According to the U.S. EPA Air Quality System, the Charleston, WV CBSA recorded a median AQI of 39 across 365 monitored days in 2025, with 77.0% 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 Charleston, WV CBSA's 77.0% Good-day share places it cleaner than 61% of US metros in 2025.
Closest median-AQI peer
Bay City, MI (70.4% Good, median AQI 39) is the closest nationwide median-AQI peer to Charleston, WV.
2020–2025 Good-day shift
Charleston, WV's Good-day share moved -1.4 points from 2020 to 2025 (median AQI -2).
Median AQI
Median AQI: 39

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

The verdict

Charleston, WV's peak reading 69 stays in the lower max-AQI tercile on this extract. On the EPA scale the metro runs good, cleaner than the median US metro, with a median AQI of 39 and 77.0% of 365 monitored days in the Good band.

39
median AQI · Good
77.0%
days rated Good
61%
cleaner than US metros
69
worst single reading

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

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Charleston, WV metro's peak single-day AQI fell from 90 to 69 between the 2024 and 2025 EPA annual releases, a change of -21 points.

Compared against 364 monitored days in 2024 and 365 in 2025. These are arithmetic differences between two stored EPA annual summaries, not a cause claim or a live advisory.

National release changes Two-year CSV

Charleston, WV's peak reading 69 stays in the lower max-AQI tercile on this extract. Signature read: peak AQI 69 (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 39 over 365 measured days in 2025 (Good / Good). The monitored-day split lands at 281 Good (77%), 84 Moderate (23%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 55; the highest single-day reading hit 69 (Moderate).

Across 2020–2025, Good-day share shifted -1.4 points and median AQI moved -2 (stable). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Bay City, MI (70.4% good, AQI 39); Brainerd, MN (74.3% good, AQI 39); Cambridge, MD (86.0% good, AQI 39).

Understanding AQI →

Air Quality Summary

Median AQI

39

Good

Good Days

77.0%

281 of 365 days

Max AQI

69

Moderate

Health Grade

Good

90th pct: 55

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

281

77%

Moderate

84

23%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Charleston, WV metro area's air quality is rated Good based on 77.0% 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 Charleston, WV metro compare?

How Charleston, WV compares

Good-day share better than typical
Charleston, WV 77.0%
Bay City, MI 70.4%
Typical US metro 70.6%
Median AQI better than typical
Charleston, WV 39
Bay City, MI 39
Typical US metro 41
Unhealthy days / yr better than typical
Charleston, WV 0
Bay City, MI 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is stable in the Charleston, WV metro. Highest Good-day share: 2020 (78.4%, 287 of 366 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 287 79 0 41
2021 239 126 0 44
2022 253 100 0 41
2023 254 106 1 42
2024 283 81 0 40
2025 281 84 0 39

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Charleston, WV (39).

Bay City, MI

Median AQI 39 · 70.4% Good-day share

39

Brainerd, MN

Median AQI 39 · 74.3% Good-day share

39

Cambridge, MD

Median AQI 39 · 86.0% Good-day share

39

Dalton, GA

Median AQI 39 · 90.3% Good-day share

39

Harrisonburg, VA

Median AQI 39 · 80.0% Good-day share

39

Indiana, PA

Median AQI 39 · 74.8% Good-day share

39

Metros with similar unhealthy-day exposure

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

Aberdeen, SD

0 unhealthy-or-worse days · median AQI 27

27

Aberdeen, WA

0 unhealthy-or-worse days · median AQI 22

22

Adrian, MI

0 unhealthy-or-worse days · median AQI 41

41

Akron, OH

0 unhealthy-or-worse days · median AQI 45

45

Albany, GA

0 unhealthy-or-worse days · median AQI 46

46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

27

Frequently Asked Questions

What is the 90th percentile AQI for Charleston, WV? ▼
The 90th percentile AQI for the Charleston, WV metro area is 55, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 69 (Moderate).
How many unhealthy air days does Charleston, WV have? ▼
In 2025, the Charleston, WV metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 69.
What is the air quality in the Charleston, WV metro area? ▼
The Charleston, WV metro area has a median Air Quality Index (AQI) of 39, rated "Good." 77.0% of monitored days (281 out of 365) had good air quality in 2025.
Is air quality in Charleston, WV getting better or worse? ▼
Air quality in the Charleston, WV metro 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: 2020 at 78.4% (287 of 366 days). Lowest qualifying Good-day share: 2021 at 65.5% (239 of 365 days).
What does AQI 39 mean for health? ▼
An AQI of 39 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 Charleston, WV compare to other metro areas? ▼
The Charleston, WV metro has 77.0% good air days. Similar metros: Bay City, MI (70.4% good), Brainerd, MN (74.3% good), Cambridge, MD (86.0% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Charleston, WV, 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, Charleston, WV · 2020–2025