Custer, Idaho Air Quality
Custer County, Idaho (ID)
→ 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 | 8 | 25 | 60 | 103 | 1 | 0 | PM2.5 |
| 2022 | 7 | 42 | 98 | 98 | 7 | 0 | PM2.5 |
| 2021 | 8 | 57 | 99 | 93 | 17 | 0 | PM2.5 |
| 2020 | 7 | 38 | 126 | 105 | 7 | 3 | PM2.5 |
| 2019 | 8 | 23 | 51 | 95 | 1 | 0 | PM2.5 |
| 2018 | 7 | 26 | 128 | 85 | 3 | 2 | PM2.5 |
| 2017 | 7 | 48 | 142 | 100 | 8 | 3 | PM2.5 |
| 2016 | 11 | 57 | 170 | 103 | 9 | 4 | PM2.5 |
| 2015 | 8 | 28 | 93 | 113 | 4 | 0 | PM2.5 |
| 2014 | 9 | 29 | 54 | 107 | 3 | 0 | PM2.5 |
What This Means for Custer County Residents
Custer, Idaho has received an Air Quality Grade of A (80/100) based on a decade of EPA monitoring data. The current median AQI of 8 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.