Sheridan, Montana Air Quality
Sheridan County, Montana (MT)
→ Stableover 10 years
10-Year AQI Trend
The solid line shows the median AQI each year. The dashed line shows the 90th percentile (worst 10% of days).
Air Quality Day Breakdown
Number of days per year in each EPA AQI category. Green = Good (AQI 0-50), Yellow = Moderate (51-100), Orange = Unhealthy for Sensitive Groups (101-150), Red = Unhealthy or worse (151+).
Year-by-Year Data
| Year | Median AQI | 90th Pct | Max AQI | Good Days | Moderate | Unhealthy+ | Pollutant |
|---|---|---|---|---|---|---|---|
| 2023 | 18 | 56 | 160 | 96 | 12 | 4 | PM2.5 |
| 2022 | 16 | 36 | 66 | 85 | 4 | 0 | PM2.5 |
| 2021 | 17 | 52 | 98 | 108 | 12 | 0 | PM2.5 |
| 2020 | 13 | 27 | 58 | 103 | 4 | 0 | PM2.5 |
| 2019 | 16 | 36 | 57 | 101 | 3 | 0 | PM2.5 |
| 2018 | 20 | 52 | 118 | 99 | 12 | 1 | PM2.5 |
| 2017 | 17 | 37 | 75 | 109 | 5 | 0 | PM2.5 |
| 2016 | 15 | 31 | 81 | 113 | 4 | 0 | PM2.5 |
| 2015 | 16 | 38 | 155 | 109 | 3 | 3 | PM2.5 |
| 2014 | 17 | 42 | 74 | 109 | 5 | 0 | PM2.5 |
What This Means for Sheridan County Residents
Sheridan, Montana has received an Air Quality Grade of B (75/100) based on a decade of EPA monitoring data. The current median AQI of 18 falls in the "Good" range.
The primary pollutant affecting this area is Fine Particulate Matter (PM2.5). Over the past 5 years, this area has averaged 1 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity.