Charleston, SC Air Quality in April
Across 2019–2025, Charleston's April air quality had a median AQI of 49 (Good) over 210 monitored days in the Charleston-North Charleston, SC area. 0.5% of April days (1 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 55.2% of days. The cleanest April on record here was 2019 (median AQI 43, 0 days above 100) and the worst was 2023 (median 49, 1 day above 100, peak AQI 101).
- Good: 60.5%
- Moderate: 39.0%
- Unhealthy for Sensitive Groups: 0.5%
- 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.
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How is the air in Charleston in April?
Good on a typical day: median AQI 49 across 2019–2025, with 0.5% of April days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓60.5% of April days were Good (AQI 0–50), 39.0% Moderate (51–100).
- ✓1 day of 210 reached AQI 101+; the April peak was 101.
- ✓Best April: 2019; worst April: 2023.
Frequently asked questions
What is the air quality like in Charleston in April?▾
Across 2019–2025, the median daily AQI in Charleston in April was 49 (Good). 60.5% of days were Good, 39.0% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is April a good time for outdoor exercise in Charleston?▾
A typical April day in Charleston sits in the Good range (median AQI 49), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
Which pollutant causes Charleston's April air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 55.2% of April days in Charleston. The highest April AQI recorded in 2019–2025 was 101 (Unhealthy for Sensitive Groups), in 2023.
Charleston April air quality, year by year
Charleston April 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 | 30 | 43 | 0 | 62 | PM2.5 |
| 2020 | 30 | 44 | 0 | 61 | O3 |
| 2021 | 30 | 52 | 0 | 93 | PM2.5 |
| 2022 | 30 | 48 | 0 | 74 | O3 |
| 2023worst | 30 | 49 | 1 | 101 | PM2.5 |
| 2024 | 30 | 49 | 0 | 67 | O3 |
| 2025 | 30 | 51 | 0 | 77 | PM2.5 |
What April air means in Charleston
A typical April day in Charleston sits in the Good range (median AQI 49), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
April's median AQI of 49 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 April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Charleston runs above the national April norm; 0.5% of its April days topped AQI 100 versus 0.7% nationally (about the same).
April is part of Charleston's spring season (March, April, May); the spring 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.