Plumas, California Air Quality
Plumas County, California (CA)
↑ Worseningover 10 years
How Plumas, California Air Quality Compares
Plumas, California's median AQI of 50is 22% worse than the national average of 41. Residents experience an average of 36 unhealthy air days per year, above the national threshold for concern. The primary pollutant of concern is Fine Particulate Matter (PM2.5).
Plumas, California Air Quality: The Full Picture
Plumas, California (Plumas County) holds an AirHistory Air Quality Grade of D (poor, scoring 37 out of 100), built from 10 years of EPA Air Quality System monitoring. Its median AQI fell 2 points between 2014 (52) and 2023 (50), and the five-year median now sits at 52 — inside the "Moderate" band on the EPA scale.
The pollutant driving most of the area's AQI readings is Fine Particulate Matter (PM2.5). In 2023, it set the daily AQI on 365 of 365 monitored days (100% of the year), making it the controlling pollutant for the D grade. The single worst reading logged that year hit an AQI of 142 (Unhealthy for Sensitive Groups), while the 90th-percentile day — the level the dirtiest 10% of days reach — came in at 87.
In 2023, Plumas County recorded 186 "Good" air days (51% of the 365 days with valid AQI data), 168 "Moderate" days, and 11 days at "Unhealthy for Sensitive Groups" or above. Over the most recent five years on record, monitors logged 179 days that crossed into "Unhealthy for Sensitive Groups" or worse — about 36 per year.
The decade-long trend is worsening: median AQI has been climbing by roughly 0.66 points per year. The cleanest year in the record was 2019 (median AQI 34), and the most polluted was 2021 (median AQI 67). Because the data come straight from federally certified EPA monitors, these figures track the California county the monitors physically sit in rather than a city boundary.
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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 | 50 | 87 | 142 | 186 | 168 | 11 | PM2.5 |
| 2022 | 55 | 96 | 175 | 148 | 182 | 29 | PM2.5 |
| 2021 | 67 | 170 | 654 | 97 | 184 | 84 | PM2.5 |
| 2020 | 56 | 146 | 755 | 135 | 175 | 50 | PM2.5 |
| 2019 | 34 | 71 | 138 | 220 | 116 | 5 | PM2.5 |
| 2018 | 47 | 85 | 162 | 186 | 154 | 10 | PM2.5 |
| 2017 | 47 | 90 | 189 | 184 | 142 | 25 | PM2.5 |
| 2016 | 43 | 76 | 152 | 203 | 141 | 11 | PM2.5 |
| 2015 | 56 | 102 | 159 | 52 | 66 | 14 | PM2.5 |
| 2014 | 52 | 103 | 158 | 58 | 56 | 13 | PM2.5 |
What This Means for Plumas County Residents
Plumas, California has received an Air Quality Grade of D (37/100) based on a decade of monitoring data from the EPA's air quality monitoring program. The current median AQI of 50 falls in the "Good" range.
Concerning trends show air quality has been declining, with the median AQI rising by 2 points over the monitoring period. This could be driven by increased development, wildfire smoke, or industrial activity.
The primary pollutant affecting this area is Fine Particulate Matter (PM2.5). Over the past 5 years, this area has averaged 36 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
Plumas, California has a current median AQI of 50, which falls in the "Good" range. The area has received an Air Quality Grade of D (37/100) based on 10 years of EPA monitoring data.
Air quality in Plumas, California is worsening over the past decade. The median AQI has changed by -2 points from 2014 to 2023.
Plumas, California averages 36 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 Plumas, California is Fine Particulate Matter (PM2.5). This is the dominant contributor to elevated AQI readings in the Plumas County area.
Plumas, California averages 36 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 Fine Particulate Matter (PM2.5), which is a known asthma trigger.
With a median AQI of 50 (Good), outdoor exercise in Plumas, California is generally safe year-round. Plumas, California averages 36 days per year when athletes should move workouts indoors.