Bad Air Days in Macomb County, Michigan: 7 a Year
7 bad air days a year
More bad air days than three quarters of monitored counties. Ranked 139 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (19% 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 August. 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.
The worst days on file
In 2000 to 2009 this county averaged 20 bad days a year; in 2016 to 2025, 7. The air has improved. The worst recent year was 2020, with 12 bad days on 299 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2023-06-27 | 195 | PM2.5 |
| 2023-06-28 | 188 | PM2.5 |
| 2023-06-29 | 170 | PM2.5 |
| 2025-07-15 | 166 | Ozone |
| 2023-06-07 | 155 | PM2.5 |
An ordinary day in Macomb
Across 3,242 monitored days from 2016 to 2025, the air in Macomb County rated Good on 68% of them, less often than the 72% typical of monitored counties, and Moderate on 30%. The median day sat at AQI 43; one day in ten went above 68.
The pollutant setting the AQI on an ordinary day here:
- ozone57%1,854 days
- fine particles (PM2.5)43%1,388 days
Every recent year on file
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 365 | 256 | 99 | 10 | 2 | 40 | 166 |
| 2024 | 366 | 259 | 104 | 3 | 0 | 42 | 115 |
| 2023 | 364 | 182 | 170 | 12 | 4 | 51 | 195 |
| 2022 | 365 | 223 | 140 | 2 | 0 | 44 | 126 |
| 2021 | 365 | 180 | 182 | 3 | 0 | 51 | 115 |
| 2020 | 299 | 252 | 35 | 12 | 0 | 36 | 126 |
| 2019 | 292 | 238 | 53 | 1 | 0 | 39 | 101 |
| 2018 | 299 | 229 | 60 | 10 | 0 | 39 | 143 |
| 2017 | 284 | 212 | 69 | 3 | 0 | 42 | 112 |
| 2016 | 243 | 171 | 65 | 7 | 0 | 44 | 147 |
| 2015 | 241 | 158 | 77 | 6 | 1 | 44 | 170 |
| 2014 | 244 | 169 | 70 | 5 | 0 | 43 | 136 |
| 2013 | 244 | 164 | 75 | 5 | 0 | 43 | 129 |
| 2012 | 243 | 142 | 80 | 21 | 2 | 46 | 202 |
| 2011 | 242 | 154 | 74 | 14 | 1 | 43 | 159 |
| 2010 | 244 | 156 | 77 | 11 | 2 | 46 | 159 |
*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
- Cass County6/yr
- Oakland County6/yr
- St. Clair County5/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.