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AirNow →Air quality in Charleston County, SC
Includes Charleston, Mount Pleasant and North Charleston · EPA monitor readings, 2021 to 2025 · 408,000 people
For today's air and tomorrow's forecast, check AirNow by ZIP code.
Bad-air days a year
<1
day with an AQI over 100
1 bad-air day in 5 years of readings, 2021 to 2025. That's down from about 7 a year in the early 2000s. Charleston County is tied with 1 other South Carolina county for the 4th fewest bad-air days of the 13 with monitors.
0days unhealthy for everyoneAQI over 150, a year
46AQI on a typical dayGood: fine for everyone
8bad-air days since 2016Too few to show a season
160worst day since 2016Nov 16, 2016, fine particles
How to read the AQIThe EPA's air score runs from 0 to 500. Higher is worse. Over 100 counts as a bad-air day.
Typical day 46 (Good)Worst day 160 (Unhealthy)
Good0 to 50Moderate51 to 100Sensitive groups101 to 150Unhealthy151 to 200Very unhealthy201 to 300Hazardous301 to 500
Bad-air days by month in Charleston County
Bad air is rare here: 8 bad-air days in 10 years of daily readings since 2016, too few to show a season. Each tile is the average for that month.
Jan0
Feb0.2
Mar0
Apr0
May0.1
Jun0.1
Jul0
Aug0
Sep0
Oct0
Nov0.4
Dec0
The worst day since 2016 was November 16, 2016: AQI 160, from fine particles.
What causes it
The 8 bad-air days since 2016 were 7 fine-particle days (in February 2016, November 2016, June 2020 and February 2025) and 1 ozone day (on May 10, 2017).
CDC estimates by month, 2001 to 2022
The CDC's model counts bad-air days at the county's worst spot, from monitors and satellites. Particles (brown) fill the inside of the ring and ozone (blue) the outside.
See the numbers by month
| Month | Fine particles | Ozone |
|---|---|---|
| January | 0 | 0 |
| February | 0 | 0 |
| March | 0 | 0.1 |
| April | 0 | 0.6 |
| May | 0 | 0.6 |
| June | 0.1 | 0.9 |
| July | 0.1 | 0.5 |
| August | 0.1 | 0.3 |
| September | 0 | 0.3 |
| October | 0 | 0 |
| November | 0.1 | 0 |
| December | 0 | 0 |
What helps in Charleston County
The air here is clean most days: 8 bad-air days in 10 years of daily readings. Wildfire smoke can still drift in from far away, so it's worth being ready.
Keep a cheap backup
A box fan with a MERV 13 filter clamped to it cleans a room in a pinch.
Build one →Keep one room clean on smoky days
Shut the windows and run an air purifier sized for the room.
Choosing a purifier →For today's reading and tomorrow's forecast, check AirNow by ZIP code. Its fire and smoke map adds smoke plumes.
Smoky days are rare here, so a purifier is optional. If you want one for wildfire season anyway, see the 3 models we'd buy, each with a verified smoke rating.
Every year since 2000
Bad-air days each year. The striped part is days unhealthy for everyone, over AQI 150. The worst recent year was 2025, with 1 bad-air day.
Unhealthy for sensitive groups (101 to 150)Unhealthy or worse (over 150)
See the numbers by year
| Year | Bad-air days | Over 150 |
|---|---|---|
| 2000 | 13 | 2 |
| 2001 | 3 | 0 |
| 2002 | 9 | 1 |
| 2003 | 5 | 0 |
| 2004 | 7 | 1 |
| 2005 | 16 | 0 |
| 2006 | 17 | 1 |
| 2007 | 5 | 1 |
| 2008 | 6 | 0 |
| 2009 | 0 | 0 |
| 2010 | 2 | 0 |
| 2011 | 4 | 1 |
| 2012 | 1 | 0 |
| 2013 | 0 | 0 |
| 2014 | 0 | 0 |
| 2015 | 1 | 0 |
| 2016 | 5 | 2 |
| 2017 | 1 | 0 |
| 2018 | 0 | 0 |
| 2019 | 0 | 0 |
| 2020 | 1 | 0 |
| 2021 | 0 | 0 |
| 2022 | 0 | 0 |
| 2023 | 0 | 0 |
| 2024 | 0 | 0 |
| 2025 | 1 | 0 |
Charleston County and its neighbors
Bad-air days a year, 2021 to 2025. South Carolina counties with monitors averaged about 1 bad-air day a year, weighted by population.
Charleston County<1
Nearest counties with a full report: Horry County, SC (under 1 bad-air day a year), Aiken County, SC (under 1 bad-air days a year).
Questions people ask about air in Charleston County
How often is the air bad in Charleston County?
From 2021 to 2025, monitors in Charleston County recorded almost no bad-air days a year with an AQI above 100, which is unhealthy for sensitive groups or worse. The worst year in that stretch was 2025, with 1 bad-air day.
What causes bad air in Charleston County?
The 8 bad-air days since 2016 were 7 fine-particle days (in February 2016, November 2016, June 2020 and February 2025) and 1 ozone day (on May 10, 2017).
Where can I see today's air quality in Charleston County?
AirNow, run by the EPA and its partners, shows the current AQI and tomorrow's forecast for your ZIP code. Its fire and smoke map adds smoke plumes. On a typical day the AQI in Charleston County is about 46, which is good, fine for everyone. Bad days are rare here, so check it when wildfire smoke is in the news.
About these numbers
Day counts come from the EPA's county air quality summaries, which take the worst reading across a county's monitors each day. Monitors here reported on about 365 days a year from 2021 to 2025. A county is large, and your street can be cleaner or worse. CDC's model, which estimates every county from monitors and satellites, gives the worst spot in Charleston County almost no high-particle days and almost no high-ozone days a year from 2018 to 2022.
Sources: EPA AirData county AQI summaries (2000 to 2025) and daily county AQI (2016 to 2025); CDC Environmental Public Health Tracking Network modeled PM2.5 and ozone (2001 to 2022). Updated November 8, 2026.