Bad Air Days in Anoka County, Minnesota: 4 a Year
4 bad air days a year
About the middle of monitored US counties. Ranked 301 of 996 monitored counties, where 1 is worst.
What makes them bad: a mix of particles and ozone (51% particle days).
When the bad days come in Anoka
- 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 to buy, and what not to
- 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.
Better or worse than it was
In 2000 to 2009 this county averaged 6 bad days a year; in 2016 to 2025, 4. The air has improved. The worst recent year was 2023, with 17 bad days on 365 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2025-06-03 | 177 | PM2.5 |
| 2023-06-14 | 175 | PM2.5 |
| 2025-07-12 | 168 | PM2.5 |
| 2025-08-01 | 168 | PM2.5 |
| 2023-06-21 | 164 | Ozone |
The air on a normal day
Across 3,650 monitored days from 2016 to 2025, the air in Anoka County rated Good on 72% of them, close to the 72% typical of monitored counties, and Moderate on 27%. The median day sat at AQI 41; one day in ten went above 63.
The pollutant setting the AQI on an ordinary day here:
- ozone54%1,962 days
- fine particles (PM2.5)45%1,629 days
- nitrogen dioxide1%46 days
Year by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 363 | 269 | 85 | 9 | 4 | 38 | 177 |
| 2024 | 366 | 286 | 79 | 1 | 0 | 41 | 125 |
| 2023 | 365 | 217 | 131 | 17 | 2 | 46 | 175 |
| 2022 | 365 | 289 | 76 | 0 | 0 | 40 | 93 |
| 2021 | 365 | 258 | 100 | 7 | 2 | 41 | 162 |
| 2020 | 366 | 289 | 77 | 0 | 0 | 38 | 87 |
| 2019 | 364 | 274 | 89 | 1 | 0 | 39 | 122 |
| 2018 | 365 | 223 | 141 | 1 | 0 | 44 | 115 |
| 2017 | 365 | 239 | 126 | 0 | 0 | 43 | 90 |
| 2016 | 366 | 291 | 74 | 1 | 0 | 38 | 145 |
| 2015 | 365 | 278 | 85 | 2 | 0 | 41 | 105 |
| 2014 | 364 | 265 | 99 | 0 | 0 | 41 | 93 |
| 2013 | 365 | 232 | 131 | 2 | 0 | 44 | 126 |
| 2012 | 366 | 210 | 151 | 5 | 1 | 47 | 185 |
| 2011 | 365 | 200 | 162 | 3 | 0 | 48 | 133 |
| 2010 | 365 | 161 | 201 | 3 | 0 | 53 | 117 |
*2025 may be a partial year in EPA's file.
Elsewhere in Minnesota
- Blue Earth County10/yr
- Saint Louis County5/yr
- Wright County5/yr
- Cass County4/yr
- Beltrami County4/yr
- Hennepin County4/yr
- Becker County4/yr
- Stearns County3/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.