Charleston, SC Air Quality in 2025
In 2025, Charleston's air quality (Charleston-North Charleston, SC area) had a median daily AQI of 47 (Good) across 365 monitored days. 1 day (0.3%) reached Unhealthy for Sensitive Groups or worse, 220 were Good, and the year's peak AQI was 105 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 222 of those days. The cleanest month of 2025 was October (median AQI 37, 0 days above 100) and the worst was February (median 53, 1 day above 100, peak 105).
- Good: 60.3%
- Moderate: 39.5%
- Unhealthy for Sensitive Groups: 0.3%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Charleston
Today's main pollutant in Charleston is ground-level ozone (AQI 31). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How was Charleston's air quality in 2025?
Good on a typical day: median AQI 47, with 1 day above AQI 100 out of 365 monitored — the 6th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2025: 105 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 222 days.
- ✓Cleanest month: October; worst: February.
Frequently asked questions
What was the average AQI in Charleston in 2025?▾
EPA's Air Quality System puts Charleston's (Charleston-North Charleston, SC) median daily AQI for 2025 at 47, which is Good. 1 day were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 105.
Which month had the worst air quality in Charleston in 2025?▾
The cleanest month of 2025 was October (median AQI 37, 0 days above 100) and the worst was February (median 53, 1 day above 100, peak 105).
Was 2025 a good or bad year for Charleston's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 6th cleanest by days above AQI 100. 2025's median of 47 is in line with the area's typical annual median of 47.
Charleston month by month in 2025
Charleston air quality month by month, 2025 (Charleston-North Charleston, SC, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 46 | 0 | 58 | PM2.5 |
| Februaryworst | 28 | 53 | 1 | 105 | PM2.5 |
| March | 31 | 51 | 0 | 71 | O3 |
| April | 30 | 51 | 0 | 77 | PM2.5 |
| May | 31 | 49 | 0 | 77 | PM2.5 |
| June | 30 | 46 | 0 | 84 | PM2.5 |
| July | 31 | 45 | 0 | 56 | PM2.5 |
| August | 31 | 43 | 0 | 61 | PM2.5 |
| September | 30 | 41 | 0 | 67 | O3 |
| Octobercleanest | 31 | 37 | 0 | 58 | O3 |
| November | 30 | 49 | 0 | 62 | PM2.5 |
| December | 31 | 52 | 0 | 89 | PM2.5 |
How 2025 compares
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 6th cleanest by days above AQI 100.
2025's median of 47 is in line with the area's typical annual median of 47.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Charleston
The latest EPA AirNow observation puts Charleston's AQI at 31 (O3). The figures above are multi-year annual statistics, not today's reading.
View current Charleston air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Charleston-North Charleston, SC), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.