Charleston, SC Air Quality in Spring
Across 2019–2025, Charleston's spring (March–May) air quality had a median AQI of 48 (Good) over 644 monitored days in the Charleston-North Charleston, SC area. 0.2% of spring days (1 of 644) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 63.7% of days. The cleanest spring on record here was 2019 (median AQI 44, 0 days above 100) and the worst was 2023 (median 51, 1 day above 100, peak AQI 101).
- Good: 57.3%
- Moderate: 42.5%
- Unhealthy for Sensitive Groups: 0.2%
- 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 spring?
Good on a typical day: median AQI 48 across 2019–2025, with 0.2% of spring days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓57.3% of spring days were Good (AQI 0–50), 42.5% Moderate (51–100).
- ✓1 day of 644 reached AQI 101+; the spring peak was 101.
- ✓Cleanest month: May; worst month: April.
Frequently asked questions
What is the air quality like in Charleston in spring?▾
Across 2019–2025, the median daily AQI in Charleston in spring was 48 (Good). 57.3% of days were Good, 42.5% Moderate, and 0.2% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is spring a good time for outdoor exercise in Charleston?▾
A typical spring day in Charleston sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of spring days reached AQI 101+ in 2019–2025.
Which pollutant causes Charleston's spring air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 63.7% of spring days in Charleston. The highest spring AQI recorded in 2019–2025 was 101 (Unhealthy for Sensitive Groups), in 2023.
Charleston spring air quality, year by year
Charleston spring 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 | 92 | 44 | 0 | 66 | PM2.5 |
| 2020 | 92 | 45 | 0 | 61 | PM2.5 |
| 2021 | 92 | 51 | 0 | 93 | PM2.5 |
| 2022 | 92 | 49 | 0 | 84 | PM2.5 |
| 2023worst | 92 | 51 | 1 | 101 | PM2.5 |
| 2024 | 92 | 47 | 0 | 90 | O3 |
| 2025 | 92 | 51 | 0 | 77 | O3 |
What spring air means in Charleston
A typical spring day in Charleston sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of spring days reached AQI 101+ in 2019–2025.
Spring's median AQI of 48 is in line with Charleston's whole-year median of 47, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Spring AQI across every EPA metro area (307,196 metro-days, 2019–2025) is 43, so Charleston runs above the national Spring norm; 0.2% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).
Within the season, May is the cleanest month (median AQI 48, 0.0% of days above 100) and April the worst (median 49, 0.5% above 100).
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 season 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.