Thurston, Washington Air Quality
Thurston County, Washington (WA)
↓ Improvingover 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). 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 |
|---|---|---|---|---|---|---|---|
| 2023 | 28 | 48 | 82 | 327 | 31 | 0 | PM2.5 |
| 2022 | 28 | 51 | 157 | 309 | 36 | 3 | PM2.5 |
| 2021 | 19 | 41 | 63 | 309 | 20 | 0 | PM2.5 |
| 2020 | 28 | 53 | 242 | 316 | 43 | 7 | PM2.5 |
| 2019 | 33 | 58 | 74 | 290 | 75 | 0 | PM2.5 |
| 2018 | 29 | 55 | 181 | 291 | 46 | 6 | PM2.5 |
| 2017 | 32 | 62 | 156 | 287 | 72 | 4 | PM2.5 |
| 2016 | 31 | 52 | 91 | 308 | 41 | 0 | PM2.5 |
| 2015 | 34 | 58 | 99 | 295 | 62 | 0 | PM2.5 |
| 2014 | 32 | 60 | 95 | 294 | 69 | 0 | PM2.5 |
What This Means for Thurston County Residents
Thurston, Washington has received an Air Quality Grade of B (76/100) based on a decade of EPA monitoring data. The current median AQI of 28 falls in the "Good" range.
Encouragingly, air quality here has been improving, with the median AQI dropping by 4 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 2 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity.