San Juan, Colorado Air Quality
San Juan County, Colorado (CO)
→ 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 | 9 | 20 | 50 | 120 | 0 | 0 | PM2.5 |
| 2022 | 10 | 26 | 75 | 115 | 4 | 0 | PM2.5 |
| 2021 | 9 | 33 | 79 | 114 | 5 | 0 | PM2.5 |
| 2020 | 9 | 31 | 73 | 115 | 4 | 0 | PM2.5 |
| 2019 | 9 | 19 | 32 | 116 | 0 | 0 | PM2.5 |
| 2018 | 10 | 33 | 100 | 109 | 9 | 0 | PM2.5 |
| 2017 | 9 | 21 | 49 | 119 | 0 | 0 | PM2.5 |
| 2016 | 8 | 18 | 31 | 121 | 0 | 0 | PM2.5 |
| 2015 | 8 | 20 | 55 | 120 | 1 | 0 | PM2.5 |
| 2014 | 10 | 22 | 37 | 118 | 0 | 0 | PM2.5 |
What This Means for San Juan County Residents
San Juan, Colorado has received an Air Quality Grade of B (78/100) based on a decade of EPA monitoring data. The current median AQI of 9 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 0 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity.