Bad Air Days in Anderson County, South Carolina: under 1 a Year
under 1 bad air days a year
Rare: among the cleanest-air counties EPA monitors. Ranked 882 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (0% particle days).
The bad-air season here
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in August and September. Averaged over 2016 to 2025.
What to buy, and what not to
- Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
- On the odd bad day, check AirNow and keep windows shut.
The record for Anderson
In 2000 to 2009 this county averaged 32 bad days a year; in 2016 to 2025, under 1. The air has improved. The worst recent year was 2019, with 1 bad day on 85 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2024-08-26 | 115 | Ozone |
| 2019-09-12 | 108 | Ozone |
| 2023-08-23 | 97 | Ozone |
| 2023-06-03 | 93 | Ozone |
| 2023-06-10 | 93 | Ozone |
The air on a normal day
Across 2,316 monitored days from 2016 to 2025, the air in Anderson County rated Good on 92% of them, more often than the 72% typical of monitored counties, and Moderate on 8%. The median day sat at AQI 39; one day in ten went above 51.
The pollutant setting the AQI on an ordinary day here:
- ozone100%2,316 days
Anderson County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 264 | 241 | 23 | 0 | 0 | 40 | 84 |
| 2024 | 255 | 213 | 41 | 1 | 0 | 43 | 115 |
| 2023 | 270 | 233 | 37 | 0 | 0 | 42 | 97 |
| 2022 | 246 | 230 | 16 | 0 | 0 | 39 | 74 |
| 2021 | 263 | 240 | 23 | 0 | 0 | 38 | 87 |
| 2020 | 265 | 257 | 8 | 0 | 0 | 35 | 71 |
| 2019 | 85 | 66 | 18 | 1 | 0 | 42 | 108 |
| 2018 | 148 | 147 | 1 | 0 | 0 | 35 | 51 |
| 2017 | 264 | 254 | 10 | 0 | 0 | 37 | 80 |
| 2016 | 256 | 240 | 16 | 0 | 0 | 41 | 90 |
| 2015 | 200 | 185 | 15 | 0 | 0 | 38 | 80 |
| 2014 | 218 | 199 | 19 | 0 | 0 | 38 | 74 |
| 2013 | 221 | 211 | 10 | 0 | 0 | 34 | 80 |
| 2012 | 186 | 154 | 27 | 5 | 1 | 41 | 161 |
| 2011 | 263 | 175 | 82 | 6 | 0 | 45 | 150 |
| 2010 | 337 | 253 | 79 | 5 | 0 | 41 | 126 |
*2025 may be a partial year in EPA's file.
South Carolina compared
- Cherokee Countythin data
- York County2/yr
- Spartanburg County2/yr
- Richland County1/yr
- Colleton County1/yr
- Greenville County1/yr
- Charleston Countyunder 1/yr
- Chesterfield Countyunder 1/yr
How this is counted
A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day, and on why a purifier does not touch ozone in smoke vs ozone.