Bad Air Days in Carlton County, Minnesota: 2 a Year
2 bad air days a year
About the middle of monitored US counties. Ranked 456 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly particles: smoke and dust (100% particle days).
Which months to watch
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in July and June and August. Averaged over 2016 to 2025.
What actually helps 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.
Better or worse than it was
In 2000 to 2009 this county averaged under 1 bad days a year; in 2016 to 2025, 2. It has got worse. The worst recent year was 2025, with 12 bad days on 355 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2025-07-12 | 184 | PM2.5 |
| 2025-07-30 | 163 | PM2.5 |
| 2025-07-31 | 163 | PM2.5 |
| 2025-08-01 | 162 | PM2.5 |
| 2025-06-03 | 160 | PM2.5 |
Most days, not the worst ones
Across 3,596 monitored days from 2016 to 2025, the air in Carlton County rated Good on 90% of them, more often than the 72% typical of monitored counties, and Moderate on 9%. The median day sat at AQI 31; one day in ten went above 50.
The pollutant setting the AQI on an ordinary day here:
- fine particles (PM2.5)52%1,855 days
- ozone48%1,741 days
Carlton County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 355 | 294 | 49 | 12 | 7 | 33 | 184 |
| 2024 | 366 | 326 | 39 | 1 | 0 | 34 | 114 |
| 2023 | 362 | 266 | 91 | 5 | 1 | 38 | 156 |
| 2022 | 355 | 351 | 4 | 0 | 0 | 25 | 57 |
| 2021 | 365 | 318 | 43 | 4 | 0 | 31 | 143 |
| 2020 | 354 | 347 | 7 | 0 | 0 | 25 | 84 |
| 2019 | 356 | 341 | 15 | 0 | 0 | 28 | 80 |
| 2018 | 354 | 319 | 35 | 0 | 0 | 30 | 94 |
| 2017 | 365 | 334 | 31 | 0 | 0 | 31 | 84 |
| 2016 | 364 | 337 | 26 | 1 | 0 | 31 | 101 |
| 2015 | 275 | 238 | 36 | 1 | 0 | 37 | 101 |
| 2014 | 230 | 226 | 4 | 0 | 0 | 31 | 87 |
| 2013 | 204 | 195 | 9 | 0 | 0 | 33 | 93 |
| 2012 | 222 | 212 | 9 | 1 | 0 | 32 | 122 |
| 2011 | 207 | 207 | 0 | 0 | 0 | 32 | 49 |
| 2010 | 365 | 356 | 8 | 1 | 0 | 18 | 101 |
*2025 may be a partial year in EPA's file.
Minnesota compared
- Blue Earth County10/yr
- Saint Louis County5/yr
- Wright County5/yr
- Cass County4/yr
- Beltrami County4/yr
- Hennepin County4/yr
- Anoka County4/yr
- Becker 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.