Air Quality in Mount Pleasant, South Carolina — Live
Live readings from PurpleAir sensors across Mount Pleasant — with free alerts the moment the air changes.
AQI 61 from 5 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Mount Pleasant, South Carolina is AQI 61 — Moderate and holding steady — with PM2.5 at 14.7 µg/m³, the median of 5 live PurpleAir sensors reading 53 to 66. 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 Mount Pleasant: grass pollen is the strongest of the three at a very 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 Mount Pleasant and Sullivan's Island, Isle of Palms, Awendaw, Daniel Island. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Mount Pleasant
The sensors Canairy reads in Mount Pleasant agree right now — all 5 sit in the Moderate band, a 13-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 9.6 mi W | 61 | Moderate |
| 9.7 mi W | 63 | Moderate |
| 12.4 mi SW | 57 | Moderate |
| 13.5 mi WNW | 53 | Moderate |
| 15.2 mi NW | 66 | Moderate |
Mount Pleasant sits on a peninsula east of Charleston Harbor, and the sea breeze that comes with that location does real work: most days here run Good or Moderate, and the town avoids the worst of the ozone problems that build up in landlocked parts of the Southeast. The exceptions are specific and local — still, hot summer afternoons when ozone can climb, cooler-season days when smoke drifts in from prescribed burns in the Francis Marion National Forest just up Highway 17, and the rare summer when wildfire smoke from as far away as Canada reaches the South Carolina coast, as it did more than once in 2023.
What Canairy does for Mount Pleasant
A clear verdict
Not just a number — a plain-English call for Mount Pleasant: 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.
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The sea breeze keeps most days clean
Mount Pleasant occupies a peninsula pinched between the Wando and Cooper rivers, and that geography rarely goes long without an onshore breeze off the Atlantic. That steady marine air is the single biggest reason the town's ozone and particle readings tend to run better than inland parts of the Lowcountry — there's usually enough wind moving through to keep pollution from settling.
But the same flat, low-relief coastline that lets the breeze in has nothing to interrupt airflow when that breeze fails. When summer high pressure stalls and winds go slack for a few days in July and August, heat and humidity cook up ground-level ozone the same way they do across the rest of the Southeast, and that's when Mount Pleasant is most likely to see a Moderate or Unhealthy for Sensitive Groups reading.
Prescribed burns from the Francis Marion National Forest send smoke into town
Mount Pleasant's Highway 17 corridor runs roughly 24 miles from the Old Village north to Awendaw, and just off that road sits the Francis Marion National Forest — hundreds of thousands of acres of pine and pocosin that the US Forest Service treats with prescribed fire most years. Recent burn seasons have covered roughly 50,000 planned acres across the forest in Charleston and Berkeley counties, including tracts near Highway 41 and the Wando area, a few miles from Mount Pleasant's northern neighborhoods.
These are managed fires, set mostly in the cooler, more humid months when smoke behaves predictably — not wildfires. But planned doesn't mean invisible: the Forest Service's own burn notices routinely warn that smoke will drift toward Highway 17 or Highway 41 depending on the day's wind, and the plumes are hardest to spot from satellite in the morning and easiest to see by afternoon. A backyard in Park West or Carolina Park can smell like a campfire on a burn day even though nothing nearby is actually on fire.
Port traffic on Long Point Road is an everyday, local source
The Wando Welch Terminal, the SC Ports Authority's container port, sits inside Mount Pleasant town limits at the end of Long Point Road. A Phase II expansion has pushed the terminal's capacity past 5 million containers a year, and because the terminal was built without an on-site rail yard, containers bound for rail have to be trucked roughly 12 miles to North Charleston — funneling a steady stream of diesel trucks through the Long Point Road and I-526 corridor.
The federal government has put roughly $195 million toward rebuilding the I-526/Long Point Road interchange specifically to ease that truck bottleneck, which is a fair measure of how much local traffic the port now generates. It doesn't put Mount Pleasant in the same category as North Charleston's industrial peninsula, but it's a real, everyday layer of diesel exhaust layered on top of the ozone and smoke story, concentrated along Long Point Road rather than spread evenly across town.
Mount Pleasant air quality FAQ
What is the air quality in Mount Pleasant right now?
As of September 14, 2026 at 10:14 AM EDT, the air quality in Mount Pleasant, South Carolina is AQI 61 — Moderate — with PM2.5 at 14.7 µg/m³, the median of 5 live PurpleAir sensors. Sensitive groups may want to take it slower outside.
Why does Mount Pleasant sometimes smell like smoke with no fire nearby?
Most likely a prescribed burn. The US Forest Service manages the Francis Marion National Forest just north of town with planned fire on tens of thousands of acres most years, mostly in the cooler months, and smoke can drift down Highway 17 or Highway 41 into Mount Pleasant depending on the day's wind. Canairy's live sensors will show it even before you smell it.
Does port traffic affect Mount Pleasant's air quality?
It adds a real, local layer of diesel exhaust. The Wando Welch container terminal sits at the end of Long Point Road inside town limits, and because it has no on-site rail yard, trucks haul containers roughly 12 miles to North Charleston, concentrating truck traffic — and the exhaust that comes with it — along Long Point Road and the I-526 corridor.
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 5 curated PurpleAir sensors Canairy tracks in and around Mount Pleasant, 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 Mount Pleasant
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