Bad Air Days in Johnston County, Oklahoma: 3 a Year
3 bad air days a year
About the middle of monitored US counties. Ranked 394 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (0% particle days).
Which months to watch
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in October and July and August and September. Averaged over 2016 to 2025.
What actually helps here
- 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 Johnston
In 2000 to 2009 this county averaged 5 bad days a year; in 2016 to 2025, 3. The air has improved. The worst recent year was 2023, with 5 bad days on 246 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2023-08-17 | 161 | Ozone |
| 2023-07-25 | 122 | Ozone |
| 2024-10-11 | 119 | Ozone |
| 2016-10-11 | 108 | Ozone |
| 2023-09-18 | 108 | Ozone |
Most days, not the worst ones
Across 1,151 monitored days from 2016 to 2024, the air in Johnston County rated Good on 83% of them, more often than the 72% typical of monitored counties, and Moderate on 17%. The median day sat at AQI 41; one day in ten went above 62.
The pollutant setting the AQI on an ordinary day here:
- ozone100%1,151 days
Johnston County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2024 | 257 | 192 | 62 | 3 | 0 | 44 | 119 |
| 2023 | 246 | 166 | 75 | 5 | 1 | 46 | 161 |
| 2020 | 289 | 267 | 22 | 0 | 0 | 38 | 97 |
| 2019 | 141 | 128 | 13 | 0 | 0 | 40 | 67 |
| 2016 | 218 | 199 | 18 | 1 | 0 | 39 | 108 |
| 2015 | 84 | 75 | 8 | 1 | 0 | 41 | 108 |
Elsewhere in Oklahoma
- Love County10/yr
- Tulsa County6/yr
- Oklahoma County6/yr
- Jefferson County5/yr
- McClain County5/yr
- Ottawa County4/yr
- Carter County4/yr
- Washington County4/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.