Charleston, SC Air Quality in October
Across 2019–2025, Charleston's October air quality had a median AQI of 41 (Good) over 217 monitored days in the Charleston-North Charleston, SC area. 0.0% of October days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 66.4% of days. The cleanest October on record here was 2019 (median AQI 37, 0 days above 100) and the worst was 2022 (median 48, 0 days above 100, peak AQI 63).
- Good: 73.7%
- Moderate: 26.3%
- Unhealthy for Sensitive Groups: 0.0%
- 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 is the air in Charleston in October?
Good on a typical day: median AQI 41 across 2019–2025, with 0.0% of October days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓73.7% of October days were Good (AQI 0–50), 26.3% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the October peak was 65.
- ✓Best October: 2019; worst October: 2022.
Frequently asked questions
What is the air quality like in Charleston in October?▾
Across 2019–2025, the median daily AQI in Charleston in October was 41 (Good). 73.7% of days were Good, 26.3% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is October a good time for outdoor exercise in Charleston?▾
A typical October day in Charleston sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.
Which pollutant causes Charleston's October air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 66.4% of October days in Charleston. The highest October AQI recorded in 2019–2025 was 65 (Moderate), in 2022.
Charleston October air quality, year by year
Charleston October air quality by year (Charleston-North Charleston, SC, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 31 | 37 | 0 | 55 | PM2.5 |
| 2020 | 31 | 41 | 0 | 63 | PM2.5 |
| 2021 | 31 | 45 | 0 | 64 | PM2.5 |
| 2022worst | 31 | 48 | 0 | 63 | PM2.5 |
| 2023 | 31 | 38 | 0 | 65 | PM2.5 |
| 2024 | 31 | 44 | 0 | 64 | PM2.5 |
| 2025 | 31 | 37 | 0 | 58 | O3 |
What October air means in Charleston
A typical October day in Charleston sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.
October's median AQI of 41 is below Charleston's whole-year median of 47, making it one of the area's cleaner periods. Nationally, the median October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Charleston runs in line with the national October norm; 0.0% of its October days topped AQI 100 versus 1.3% nationally (below average).
October is part of Charleston's fall season (September, October, November); the fall page pools all three months.
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 month 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.