Bad Air Days in Genesee County, Michigan: 3 a Year
3 bad air days a year
About the middle of monitored US counties. Ranked 333 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (18% particle days).
Which months to watch
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in June and May. Averaged over 2016 to 2025.
Is a purifier worth it 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 Genesee
In 2000 to 2009 this county averaged 20 bad days a year; in 2016 to 2025, 3. The air has improved. The worst recent year was 2023, with 11 bad days on 364 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2023-06-27 | 178 | PM2.5 |
| 2023-06-29 | 175 | PM2.5 |
| 2023-06-28 | 165 | PM2.5 |
| 2016-06-10 | 129 | Ozone |
| 2023-06-30 | 129 | Ozone |
Most days, not the worst ones
Across 3,540 monitored days from 2016 to 2025, the air in Genesee County rated Good on 70% of them, close to the 72% typical of monitored counties, and Moderate on 29%. The median day sat at AQI 42; one day in ten went above 62.
The pollutant setting the AQI on an ordinary day here:
- fine particles (PM2.5)53%1,891 days
- ozone47%1,649 days
Genesee County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 303 | 252 | 48 | 3 | 0 | 38 | 126 |
| 2024 | 347 | 252 | 94 | 1 | 0 | 42 | 119 |
| 2023 | 364 | 238 | 115 | 11 | 3 | 44 | 178 |
| 2022 | 364 | 237 | 125 | 2 | 0 | 44 | 112 |
| 2021 | 365 | 247 | 115 | 3 | 0 | 41 | 119 |
| 2020 | 366 | 288 | 77 | 1 | 0 | 39 | 126 |
| 2019 | 340 | 225 | 115 | 0 | 0 | 42 | 75 |
| 2018 | 362 | 255 | 104 | 3 | 0 | 43 | 122 |
| 2017 | 365 | 247 | 118 | 0 | 0 | 42 | 93 |
| 2016 | 364 | 245 | 110 | 9 | 0 | 42 | 129 |
| 2015 | 357 | 203 | 151 | 3 | 0 | 48 | 131 |
| 2014 | 341 | 182 | 156 | 3 | 0 | 48 | 105 |
| 2013 | 238 | 170 | 67 | 1 | 0 | 43 | 105 |
| 2012 | 242 | 155 | 66 | 21 | 3 | 45 | 172 |
| 2011 | 242 | 165 | 69 | 8 | 0 | 43 | 150 |
| 2010 | 242 | 155 | 84 | 3 | 0 | 45 | 115 |
*2025 may be a partial year in EPA's file.
Michigan compared
- Wayne County11/yr
- Marquette County9/yr
- Muskegon County9/yr
- Allegan County9/yr
- Berrien County8/yr
- Macomb County7/yr
- Cass County6/yr
- Oakland County6/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.