Bad Air Days in Lake County, Ohio: 7 a Year
7 bad air days a year
More bad air days than three quarters of monitored counties. Ranked 163 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (11% 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 June and July and May. Averaged over 2016 to 2025.
What actually helps here
- 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.
The worst days on file
In 2000 to 2009 this county averaged 22 bad days a year; in 2016 to 2025, 7. The air has improved. The worst recent year was 2023, with 10 bad days on 365 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2023-06-28 | 170 | PM2.5 |
| 2023-06-29 | 152 | PM2.5 |
| 2023-06-26 | 151 | PM2.5 |
| 2022-06-22 | 150 | Ozone |
| 2017-07-19 | 147 | Ozone |
An ordinary day in Lake
Across 3,650 monitored days from 2016 to 2025, the air in Lake County rated Good on 72% of them, close to the 72% typical of monitored counties, and Moderate on 26%. The median day sat at AQI 42; one day in ten went above 65.
The pollutant setting the AQI on an ordinary day here:
- fine particles (PM2.5)52%1,887 days
- ozone48%1,755 days
Every recent year on file
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 363 | 244 | 114 | 5 | 0 | 42 | 133 |
| 2024 | 365 | 272 | 89 | 4 | 0 | 41 | 136 |
| 2023 | 365 | 259 | 96 | 10 | 3 | 42 | 170 |
| 2022 | 365 | 281 | 80 | 4 | 0 | 41 | 150 |
| 2021 | 365 | 251 | 107 | 7 | 0 | 41 | 122 |
| 2020 | 366 | 296 | 64 | 6 | 0 | 40 | 140 |
| 2019 | 365 | 292 | 68 | 5 | 0 | 40 | 115 |
| 2018 | 365 | 258 | 98 | 9 | 0 | 42 | 126 |
| 2017 | 365 | 244 | 115 | 6 | 0 | 43 | 147 |
| 2016 | 366 | 225 | 132 | 9 | 0 | 44 | 143 |
| 2015 | 365 | 181 | 176 | 8 | 0 | 51 | 126 |
| 2014 | 365 | 172 | 187 | 6 | 0 | 52 | 129 |
| 2013 | 365 | 167 | 195 | 3 | 0 | 52 | 150 |
| 2012 | 366 | 158 | 174 | 34 | 7 | 53 | 203 |
| 2011 | 365 | 180 | 172 | 13 | 2 | 51 | 161 |
| 2010 | 365 | 169 | 180 | 16 | 1 | 52 | 159 |
*2025 may be a partial year in EPA's file.
Nearby counties on file
- Hamilton County9/yr
- Cuyahoga County7/yr
- Lucas County7/yr
- Butler County6/yr
- Warren County5/yr
- Geauga County5/yr
- Ashtabula County4/yr
- Franklin 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.