Bad Air Days in Granville County, North Carolina: under 1 a Year
under 1 bad air days a year
Rare: among the cleanest-air counties EPA monitors. Ranked 829 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 April and June and July. 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 Granville
In 2000 to 2009 this county averaged 46 bad days a year; in 2016 to 2025, under 1. The air has improved. The worst recent year was 2023, with 1 bad day on 242 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2022-06-22 | 112 | Ozone |
| 2023-04-20 | 105 | Ozone |
| 2024-07-03 | 101 | Ozone |
| 2016-04-19 | 97 | Ozone |
| 2017-05-16 | 93 | Ozone |
The air on a normal day
Across 2,377 monitored days from 2016 to 2025, the air in Granville County rated Good on 89% of them, more often than the 72% typical of monitored counties, and Moderate on 11%. The median day sat at AQI 41; one day in ten went above 55.
The pollutant setting the AQI on an ordinary day here:
- ozone100%2,377 days
Granville County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 238 | 222 | 16 | 0 | 0 | 39 | 87 |
| 2024 | 244 | 206 | 37 | 1 | 0 | 42 | 101 |
| 2023 | 242 | 202 | 39 | 1 | 0 | 43 | 105 |
| 2022 | 244 | 223 | 20 | 1 | 0 | 42 | 112 |
| 2021 | 242 | 237 | 5 | 0 | 0 | 38 | 67 |
| 2020 | 238 | 237 | 1 | 0 | 0 | 36 | 51 |
| 2019 | 240 | 195 | 45 | 0 | 0 | 44 | 87 |
| 2018 | 233 | 193 | 40 | 0 | 0 | 42 | 93 |
| 2017 | 243 | 210 | 33 | 0 | 0 | 43 | 93 |
| 2016 | 213 | 179 | 34 | 0 | 0 | 41 | 97 |
| 2015 | 215 | 168 | 47 | 0 | 0 | 44 | 87 |
| 2014 | 214 | 169 | 45 | 0 | 0 | 43 | 100 |
| 2013 | 214 | 191 | 23 | 0 | 0 | 38 | 93 |
| 2012 | 214 | 166 | 43 | 5 | 1 | 42 | 154 |
| 2011 | 212 | 130 | 78 | 4 | 1 | 49 | 156 |
| 2010 | 214 | 122 | 86 | 6 | 0 | 48 | 136 |
*2025 may be a partial year in EPA's file.
North Carolina compared
- Mecklenburg County4/yr
- Jackson Countythin data
- Forsyth County2/yr
- Union County2/yr
- Swain County2/yr
- Haywood County2/yr
- Graham County1/yr
- Guilford County1/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.