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.

Live Charleston AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Charleston and Mount Pleasant, North Charleston, Summerville, James Island.

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.

Canairy watches the sensors around your home, your kids' school, and everywhere else you care about, and tells you in plain English when the air changes enough to matter.

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?

This page shows the current AQI for Charleston, calculated from PurpleAir sensors across the city and updated continuously. The map below shows every live sensor, including the ones covering North Charleston's port-adjacent neighborhoods, so you can check the reading closest to your own address.

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 AQI level is unhealthy?

Under the US EPA scale, AQI 0-50 is Good and 51-100 is Moderate. From 101 the air is Unhealthy for Sensitive Groups - kids, older adults, and people with asthma or heart conditions - and above 150 it's Unhealthy for everyone. Canairy translates these numbers into a plain-English verdict, like whether to close the windows or move a workout indoors.

Where does Canairy's Charleston data come from?

Readings come from PurpleAir's network of laser particle sensors across Charleston and surrounding towns, cross-referenced with government monitors and the Google Air Quality API. You can see every sensor behind your numbers on the live map - there's no black box.

Is Canairy free?

Yes. The Canairy app is free to download and includes live air quality for all your saved places, plain-English verdicts, and free push alerts when the air crosses your threshold. A paid plan adds extras like SMS text alerts.

Get Canairy free on Google Play.