Air Quality in Charleston, South Carolina — Live
Live readings from PurpleAir sensors across Charleston — with plain-English verdicts for ozone season and the port-area neighborhoods that watch their air closest.
AQI 62 from 4 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Charleston, South Carolina is AQI 62 — Moderate and holding steady — with PM2.5 at 14.8 µg/m³, the median of 4 live PurpleAir sensors reading 53 to 64. Canairy's verdict: Mostly clear.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
Pollen today in Charleston: grass pollen is the strongest of the three at a low level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
Live PurpleAir sensor map for Charleston and Mount Pleasant, North Charleston, Summerville, James Island. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Charleston
The sensors Canairy reads in Charleston agree right now — all 4 sit in the Moderate band, a 11-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.8 mi WSW | 64 | Moderate |
| 1.9 mi NW | 62 | Moderate |
| 6.5 mi NW | 60 | Moderate |
| 6.7 mi NW | 53 | Moderate |
Charleston's air is genuinely clean by national standards most of the year — the American Lung Association's 2025 State of the Air report gave the Charleston-North Charleston metro an A for short-term particle pollution, ranking it among the cleanest in the country. The exception is ozone: the same report handed the region a B, down from an A the year before, driven by Lowcountry summer heat and humidity rather than any single event. There's no wildfire-smoke season here the way there is out West — the real story is a slow summer ozone problem, plus a well-documented, still-open question in the port-adjacent neighborhoods of North Charleston's south end.
What Canairy does for Charleston
A clear verdict
Not just a number — a plain-English call for Charleston: open the windows, or keep them shut.
Smoke alerts
A push or text the moment the air crosses your threshold — and again when it clears.
A heads-up before it's bad
Trend alerts catch the air turning, so you can close up the house before the smoke settles in.
Every place you care about
Home, work, the kids' school — across Charleston or across the country, on one screen.
Ozone, not smoke, is Charleston's air-quality problem
The American Lung Association's 2025 State of the Air report graded the Charleston-North Charleston metro A for short-term particle pollution — ranked 204th-worst out of 223 U.S. metro areas, essentially as clean as particle monitoring gets. Ozone told a different story: the metro's grade slipped from an A in 2024 to a B in 2025, averaging 0.7 unhealthy ozone days a year and ranking 149th-worst out of 228 metros nationally. South Carolina advocacy director Danna Thompson said plainly that too many people in the Charleston metro are still living with unhealthy ozone pollution, even in a metro that otherwise ranks among the country's cleanest.
Ozone forms when vehicle exhaust and industrial vapors react with sunlight and heat, and South Carolina's environmental agency runs its official ozone forecast season from April through September — squarely Charleston's hottest, muggiest stretch. Charleston County's own guidance leans on the same summer playbook other Southern cities use: combine errands, avoid driving in peak afternoon heat, and hold off on refueling the car or running gas-powered lawn equipment until after 6 p.m., since those vapors react fastest in full sun.
The real test case is North Charleston's port-adjacent south end
The city's most closely watched air isn't downtown — it's eight neighborhoods on North Charleston's south end: Union Heights, Chicora-Cherokee, Five Mile, Howard Heights, Accabee, Liberty Hill, Rosemont, and Windsor Place. The nonprofit CCRAB (Charleston Community Research to Action Board) started tracking fine-particle pollution there not long after SC Ports opened the Hugh K. Leatherman Terminal in 2021, concerned that more container traffic would mean more diesel trucks moving through neighborhoods that already sit near industrial operations like the KapStone paper mill on the Cooper River.
Three years in, the data hasn't confirmed the worst fears — but it hasn't ruled them out either. The monitoring network combines four CCRAB PurpleAir sensors with instruments run by MUSC's Air Quality Lab at the Gethsemani and Perry-Webb community centers and two EPA regulatory stations, and it has logged mostly 'good' PM2.5 readings; the Post and Courier reported in 2024 that the south end's air was measuring at normal levels. The same reporting noted that every single monitoring site had recorded at least one unhealthy spike along the way — exactly why a single citywide average would miss what these eight neighborhoods actually breathe, and why a hyperlocal sensor reading is worth more than a metro-wide number here.
Flat, low, and wrapped in water — Charleston's geography cuts both ways
Charleston sits barely three feet above sea level on a peninsula where the Ashley, Cooper, and Wando Rivers converge to form Charleston Harbor. That flat, low-lying, water-bound geography generally works in the city's favor: there's no ridge or valley bowl to trap pollution the way inversions do in mountain-ringed Western cities, and the sea breeze that rolls in off the Atlantic on most afternoons helps clear out what does build up.
But the same coastal setup that keeps particle pollution low does little to stop ozone on a hot, still, humid July afternoon, when there's barely enough wind to move air off the peninsula at all. That combination — strong sun, thick summer humidity, and long stretches of light wind — is the real reason ozone, not wildfire smoke or valley haze, is the number worth watching in Charleston each summer.
Charleston air quality FAQ
What is the air quality in Charleston right now?
As of September 14, 2026 at 10:24 AM EDT, the air quality in Charleston, South Carolina is AQI 62 — Moderate — with PM2.5 at 14.8 µg/m³, the median of 4 live PurpleAir sensors. Sensitive groups may want to take it slower outside.
Why is ozone Charleston's biggest air-quality problem?
Ground-level ozone forms when vehicle and industrial emissions react with sunlight and heat, and South Carolina's environmental agency runs its ozone forecast season from April through September to cover exactly that stretch. The American Lung Association's 2025 State of the Air report gave the Charleston-North Charleston metro a B for ozone, down from an A the year before, even as the region held onto its A grade for particle pollution — ozone, not smoke or soot, is the metric actually moving the wrong way here.
Is air quality worse near the Port of Charleston?
It's the question North Charleston's south-end neighborhoods have spent three years trying to answer. A community-academic monitoring network, including sensors run by CCRAB and MUSC's Air Quality Lab, has found PM2.5 levels mostly 'good' since the Hugh K. Leatherman Terminal opened in 2021, though every site has recorded at least one unhealthy reading along the way. Canairy's map lets you check the sensor nearest Union Heights, Chicora-Cherokee, or any of the other port-adjacent neighborhoods directly, rather than relying on one citywide number.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 4 curated PurpleAir sensors Canairy tracks in and around Charleston, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
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Air quality near Charleston
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