Larimer, Colorado Air Quality
Larimer 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 | 51 | 77 | 156 | 175 | 185 | 5 | Ozone |
| 2022 | 51 | 84 | 126 | 176 | 179 | 10 | Ozone |
| 2021 | 54 | 112 | 159 | 164 | 151 | 50 | Ozone |
| 2020 | 49 | 89 | 159 | 197 | 147 | 22 | Ozone |
| 2019 | 50 | 77 | 129 | 183 | 176 | 6 | Ozone |
| 2018 | 53 | 97 | 169 | 160 | 177 | 28 | Ozone |
| 2017 | 52 | 87 | 154 | 165 | 187 | 13 | Ozone |
| 2016 | 51 | 87 | 151 | 162 | 196 | 8 | Ozone |
| 2015 | 51 | 80 | 165 | 177 | 171 | 17 | Ozone |
| 2014 | 50 | 80 | 140 | 196 | 152 | 17 | Ozone |
What This Means for Larimer County Residents
Larimer, Colorado has received an Air Quality Grade of C (51/100) based on a decade of EPA monitoring data. The current median AQI of 51 falls in the "Moderate" range.
The primary pollutant affecting this area is Ground-Level Ozone. Over the past 5 years, this area has averaged 19 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity.