Weld, Colorado Air Quality
Weld County, Colorado (CO)
↑ Worseningover 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 in this area has been declining over the past decade.
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 | 55 | 80 | 162 | 146 | 214 | 5 | Ozone |
| 2022 | 51 | 87 | 133 | 170 | 185 | 10 | Ozone |
| 2021 | 54 | 101 | 154 | 156 | 169 | 40 | Ozone |
| 2020 | 52 | 84 | 140 | 166 | 187 | 13 | Ozone |
| 2019 | 53 | 77 | 129 | 152 | 205 | 8 | Ozone |
| 2018 | 54 | 87 | 133 | 138 | 217 | 10 | Ozone |
| 2017 | 51 | 79 | 155 | 173 | 184 | 8 | Ozone |
| 2016 | 49 | 71 | 129 | 201 | 162 | 3 | Ozone |
| 2015 | 47 | 80 | 133 | 224 | 132 | 9 | Ozone |
| 2014 | 46 | 74 | 126 | 239 | 122 | 4 | Ozone |
What This Means for Weld County Residents
Weld, Colorado has received an Air Quality Grade of D (47/100) based on a decade of EPA monitoring data. The current median AQI of 55 falls in the "Moderate" range.
Concerning trends show air quality has been declining, with the median AQI rising by 9 points over the monitoring period. This could be driven by increased development, wildfire smoke, or industrial activity.
The primary pollutant affecting this area is Ground-Level Ozone. Over the past 5 years, this area has averaged 15 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity.