Metro area air quality · 2025

Charleston-North Charleston, SC

Median AQI 47 (Good). 60.3% of monitored days rated Good across this metro's EPA monitoring network.

47
Median AQI
60.3%
Good-air days
0
Unhealthy days
26%
Cleaner than US metros

Charleston-North Charleston, SC posted a 2025 median AQI of 47 (Good) with 60.3% Good days

According to the U.S. EPA Air Quality System, the Charleston-North Charleston, SC CBSA recorded a median AQI of 47 across 365 monitored days in 2025, with 60.3% 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-North Charleston, SC CBSA's 60.3% Good-day share places it cleaner than 26% of US metros in 2025.
Closest median-AQI peer
Columbia, SC (58.1% Good, median AQI 47) is the closest nationwide median-AQI peer to Charleston-North Charleston, SC.
2020–2025 Good-day shift
Charleston-North Charleston, SC's Good-day share moved -11.9 points from 2020 to 2025 (median AQI +4).
Median AQI
Median AQI: 47

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

The verdict

Charleston-North Charleston, SC lands in the lower Good-day tercile (60.3% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 47 and 60.3% of 365 monitored days in the Good band.

47
median AQI · Good
60.3%
days rated Good
26%
cleaner than US metros
105
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-North Charleston, SC metro's Good-day share fell from 72.1% to 60.4% between the 2024 and 2025 EPA annual releases, a change of -11.7 percentage points.
  • Charleston-North Charleston, SC metro's peak single-day AQI rose from 90 to 105 between the 2024 and 2025 EPA annual releases, a change of +15 points.
  • Charleston-North Charleston, SC metro's median AQI rose from 44 to 47 between the 2024 and 2025 EPA annual releases, a change of +3 points.

Compared against 366 monitored days in 2024 and 364 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-North Charleston, SC lands in the lower Good-day tercile (60.3% Good), a thinner clean-air share than most CBSA peers here. Signature read: 60.3% Good-day share (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 47 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 220 Good (60%), 144 Moderate (39%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 60; the highest single-day reading hit 105 (USG).

Across 2020–2025, Good-day share shifted -11.9 points and median AQI moved +4 (worsening). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Columbia, SC (58.1% good, AQI 47); Corsicana, TX (59.2% good, AQI 47); Dayton, OH (57.0% good, AQI 47).

Health effects of air pollution →

Air Quality Summary

Median AQI

47

Good

Good Days

60.3%

220 of 365 days

Max AQI

105

USG

Health Grade

Moderate

90th pct: 60

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

220

60%

Moderate

144

39%

USG

1

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Charleston-North Charleston, SC metro area's air quality is rated Moderate based on 60.3% 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-North Charleston, SC metro compare?

How Charleston-North Charleston, SC compares

Good-day share worse than typical
Charleston-North Charleston, SC 60.3%
Columbia, SC 58.1%
Typical US metro 70.6%
Median AQI worse than typical
Charleston-North Charleston, SC 47
Columbia, SC 47
Typical US metro 41
Unhealthy days / yr better than typical
Charleston-North Charleston, SC 0
Columbia, SC 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Charleston-North Charleston, SC metro. Highest Good-day share: 2020 (72.3%, 264 of 365 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 264 101 0 43
2021 196 169 0 49
2022 206 159 0 48
2023 211 152 0 47
2024 264 102 0 44
2025 220 144 0 47

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Charleston-North Charleston, SC (47).

Columbia, SC

Median AQI 47 · 58.1% Good-day share

47

Corsicana, TX

Median AQI 47 · 59.2% Good-day share

47

Dayton, OH

Median AQI 47 · 57.0% Good-day share

47

Evansville, IN-KY

Median AQI 47 · 57.5% Good-day share

47

Farmington, NM

Median AQI 47 · 68.0% Good-day share

47

Glenwood Springs, CO

Median AQI 47 · 66.8% Good-day share

47

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Charleston-North Charleston, SC'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

How many unhealthy air days does Charleston-North Charleston, SC have? ▼
In 2025, the Charleston-North Charleston, SC metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 105.
What is the air quality in the Charleston-North Charleston, SC metro area? ▼
The Charleston-North Charleston, SC metro area has a median Air Quality Index (AQI) of 47, rated "Good." 60.3% of monitored days (220 out of 365) had good air quality in 2025.
Is air quality in Charleston-North Charleston, SC getting better or worse? ▼
Air quality in the Charleston-North Charleston, SC 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 72.3% (264 of 365 days). Lowest qualifying Good-day share: 2021 at 53.7% (196 of 365 days).
What does AQI 47 mean for health? ▼
An AQI of 47 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-North Charleston, SC compare to other metro areas? ▼
The Charleston-North Charleston, SC metro has 60.3% good air days. Similar metros: Columbia, SC (58.1% good), Corsicana, TX (59.2% good), Dayton, OH (57.0% good).
What is the 90th percentile AQI for Charleston-North Charleston, SC? ▼
The 90th percentile AQI for the Charleston-North Charleston, SC metro area is 60, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 105 (USG).

Data Sources

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