Bad Air Days in El Dorado County, California: 19 a Year
19 bad air days a year
Among the worst tenth of monitored US counties. Ranked 34 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (7% 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 July and September and June. Averaged over 2016 to 2025.
What to buy, and what not to
- Ozone drives many bad days here. Purifiers and filters do not remove ozone, so do not buy one for that. Ozone peaks on hot afternoons: exercise outside in the morning.
- Sign up for EnviroFlash ozone alerts for this area during the worst months.
The worst days on file
In 2000 to 2009 this county averaged 69 bad days a year; in 2016 to 2025, 19. The air has improved. The worst recent year was 2016, with 43 bad days on 366 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2021-08-23 | 375 | PM10 |
| 2021-08-22 | 274 | PM10 |
| 2018-08-02 | 203 | Ozone |
| 2020-08-20 | 190 | Ozone |
| 2021-08-24 | 188 | PM10 |
An ordinary day in El Dorado
Across 3,650 monitored days from 2016 to 2025, the air in El Dorado County rated Good on 70% of them, close to the 72% typical of monitored counties, and Moderate on 25%. The median day sat at AQI 43; one day in ten went above 85.
The pollutant setting the AQI on an ordinary day here:
- ozone96%3,507 days
- coarse dust (PM10)2%75 days
- fine particles (PM2.5)2%68 days
Year by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 365 | 320 | 44 | 1 | 0 | 40 | 115 |
| 2024 | 366 | 261 | 97 | 8 | 0 | 44 | 115 |
| 2023 | 365 | 259 | 101 | 5 | 0 | 44 | 119 |
| 2022 | 365 | 258 | 93 | 14 | 2 | 43 | 186 |
| 2021 | 365 | 247 | 96 | 22 | 6 | 43 | 375 |
| 2020 | 366 | 256 | 87 | 23 | 6 | 43 | 190 |
| 2019 | 365 | 273 | 86 | 6 | 0 | 43 | 122 |
| 2018 | 365 | 221 | 107 | 37 | 10 | 45 | 203 |
| 2017 | 362 | 235 | 96 | 31 | 0 | 45 | 147 |
| 2016 | 366 | 221 | 102 | 43 | 12 | 45 | 172 |
| 2015 | 365 | 238 | 103 | 24 | 2 | 44 | 166 |
| 2014 | 365 | 223 | 96 | 46 | 3 | 45 | 163 |
| 2013 | 365 | 221 | 121 | 23 | 0 | 45 | 147 |
| 2012 | 366 | 212 | 102 | 52 | 6 | 45 | 177 |
| 2011 | 355 | 234 | 80 | 41 | 6 | 42 | 172 |
| 2010 | 365 | 250 | 90 | 25 | 2 | 42 | 192 |
*2025 may be a partial year in EPA's file.
Nearby counties on file
- San Bernardino County138/yr
- Riverside County132/yr
- Kern County109/yr
- Tulare County107/yr
- Los Angeles County106/yr
- Fresno County81/yr
- Kings County49/yr
- Imperial County40/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.