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 monitoring data from the EPA's air quality monitoring program. 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. The American Lung Association's State of the Air report provides additional context on long-term health risks from air pollution exposure.
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Frequently Asked Questions
Larimer, Colorado has a current median AQI of 51, which falls in the "Moderate" range. The area has received an Air Quality Grade of C (51/100) based on 10 years of EPA monitoring data.
Air quality in Larimer, Colorado is stable over the past decade. The median AQI has changed by +1 points from 2014 to 2023.
Larimer, Colorado averages 19 unhealthy air quality days per year over the past 5 years. On these days, sensitive groups including children, the elderly, and those with respiratory conditions should limit outdoor activity.
The primary pollutant affecting Larimer, Colorado is Ground-Level Ozone. This is the dominant contributor to elevated AQI readings in the Larimer County area.
Larimer, Colorado averages 19 unhealthy air days per year. With frequent unhealthy air days, asthma patients should use a HEPA air purifier indoors and check AQI before any outdoor activity. The primary pollutant is Ground-Level Ozone, which is a known asthma trigger.
With a median AQI of 51 (Moderate), outdoor exercise in Larimer, Colorado is safe most days, though sensitive individuals should check daily AQI before intense workouts. Larimer, Colorado averages 19 days per year when athletes should move workouts indoors.