Napa, California Air Quality
Napa County, California (CA)
↓ Improvingover 8 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). This area has seen measurable air quality improvement over the 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 |
|---|---|---|---|---|---|---|---|
| 2021 | 41 | 56 | 77 | 108 | 32 | 0 | Ozone |
| 2020 | 39 | 66 | 224 | 259 | 91 | 15 | PM2.5 |
| 2019 | 37 | 54 | 119 | 295 | 66 | 2 | Ozone |
| 2018 | 46 | 65 | 195 | 210 | 142 | 12 | PM2.5 |
| 2017 | 53 | 71 | 274 | 137 | 214 | 14 | PM2.5 |
| 2016 | 44 | 61 | 90 | 219 | 147 | 0 | PM2.5 |
| 2015 | 53 | 72 | 108 | 158 | 206 | 1 | PM2.5 |
| 2014 | 55 | 69 | 90 | 111 | 254 | 0 | PM2.5 |
What This Means for Napa County Residents
Napa, California has received an Air Quality Grade of B (78/100) based on a decade of EPA monitoring data. The current median AQI of 41 falls in the "Good" range.
Encouragingly, air quality here has been improving, with the median AQI dropping by 14 points over the monitoring period. This trend suggests continued investment in emission controls and cleaner energy.
The primary pollutant affecting this area is Fine Particulate Matter (PM2.5). Over the past 5 years, this area has averaged 6 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity.