Bad Air Days in Olmsted County, Minnesota: 3 a Year
3 bad air days a year
About the middle of monitored US counties. Ranked 384 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly particles: smoke and dust (69% particle days).
When the bad days come in Olmsted
- 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
- 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 Olmsted
In 2000 to 2009 this county averaged 7 bad days a year; in 2016 to 2025, 3. The air has improved. The worst recent year was 2023, with 15 bad days on 365 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2023-06-28 | 167 | PM2.5 |
| 2025-07-31 | 166 | PM2.5 |
| 2025-08-01 | 161 | PM2.5 |
| 2025-06-03 | 158 | PM2.5 |
| 2024-05-13 | 155 | PM2.5 |
The air on a normal day
Across 3,616 monitored days from 2016 to 2025, the air in Olmsted County rated Good on 71% of them, close to the 72% typical of monitored counties, and Moderate on 29%. The median day sat at AQI 41; one day in ten went above 61.
The pollutant setting the AQI on an ordinary day here:
- fine particles (PM2.5)60%2,181 days
- ozone40%1,435 days
Olmsted County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 344 | 239 | 97 | 8 | 3 | 39 | 166 |
| 2024 | 366 | 234 | 131 | 1 | 1 | 44 | 155 |
| 2023 | 365 | 189 | 161 | 15 | 1 | 49 | 167 |
| 2022 | 359 | 280 | 78 | 1 | 0 | 41 | 110 |
| 2021 | 361 | 275 | 84 | 2 | 0 | 39 | 125 |
| 2020 | 366 | 292 | 73 | 1 | 0 | 38 | 111 |
| 2019 | 364 | 271 | 93 | 0 | 0 | 40 | 86 |
| 2018 | 361 | 222 | 139 | 0 | 0 | 44 | 98 |
| 2017 | 365 | 254 | 111 | 0 | 0 | 42 | 87 |
| 2016 | 365 | 294 | 70 | 1 | 0 | 37 | 104 |
| 2015 | 365 | 274 | 90 | 1 | 0 | 41 | 116 |
| 2014 | 361 | 267 | 93 | 1 | 0 | 41 | 103 |
| 2013 | 365 | 232 | 133 | 0 | 0 | 44 | 100 |
| 2012 | 359 | 215 | 141 | 3 | 0 | 44 | 112 |
| 2011 | 360 | 203 | 157 | 0 | 0 | 46 | 99 |
| 2010 | 360 | 184 | 172 | 4 | 0 | 50 | 123 |
*2025 may be a partial year in EPA's file.
Nearby counties on file
- 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.