Colusa, California Air Quality
Colusa County, California (CA)
→ 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 | 55 | 66 | 98 | 115 | 250 | 0 | PM2.5 |
| 2022 | 44 | 59 | 105 | 240 | 122 | 1 | Ozone |
| 2021 | 55 | 76 | 225 | 111 | 238 | 16 | PM2.5 |
| 2020 | 42 | 87 | 221 | 218 | 116 | 32 | PM2.5 |
| 2019 | 41 | 61 | 85 | 260 | 105 | 0 | PM2.5 |
| 2018 | 46 | 84 | 299 | 206 | 131 | 28 | PM2.5 |
| 2017 | 43 | 67 | 213 | 237 | 120 | 8 | PM2.5 |
| 2016 | 45 | 64 | 92 | 222 | 144 | 0 | Ozone |
| 2015 | 53 | 73 | 208 | 141 | 218 | 6 | PM2.5 |
| 2014 | 52 | 67 | 99 | 163 | 202 | 0 | PM2.5 |
What This Means for Colusa County Residents
Colusa, California has received an Air Quality Grade of C (57/100) based on a decade of EPA monitoring data. The current median AQI of 55 falls in the "Moderate" range.
The primary pollutant affecting this area is Fine Particulate Matter (PM2.5). Over the past 5 years, this area has averaged 10 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity.