Jefferson, Oregon Air Quality
Jefferson County, Oregon (OR)
↓ Improvingover 9 years
How Jefferson, Oregon Air Quality Compares
Jefferson, Oregon's median AQI of 31is 24% better than the national average of 41. Air quality has improved by 13 AQI points over the past decade. The area averages 5 unhealthy air days per year. The primary pollutant of concern is Fine Particulate Matter (PM2.5).
Jefferson, Oregon Air Quality: The Full Picture
Jefferson, Oregon (Jefferson County) holds an AirHistory Air Quality Grade of A (excellent, scoring 83 out of 100), built from 9 years of EPA Air Quality System monitoring. Its median AQI fell 13 points between 2014 (44) and 2023 (31), and the five-year median now sits at 28 — inside the "Good" 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 A grade. The single worst reading logged that year hit an AQI of 238 (Very Unhealthy), while the 90th-percentile day — the level the dirtiest 10% of days reach — came in at 63.
In 2023, Jefferson County recorded 266 "Good" air days (73% of the 365 days with valid AQI data), 93 "Moderate" days, and 6 days at "Unhealthy for Sensitive Groups" or above. Over the most recent five years on record, monitors logged 26 days that crossed into "Unhealthy for Sensitive Groups" or worse — about 5 per year.
The decade-long trend is improving: median AQI has been dropping by roughly 2.05 points per year. The cleanest year in the record was 2022 (median AQI 26), and the most polluted was 2018 (median AQI 49). Because the data come straight from federally certified EPA monitors, these figures track the Oregon 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). 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 | 31 | 63 | 238 | 266 | 93 | 6 | PM2.5 |
| 2022 | 26 | 63 | 108 | 272 | 92 | 1 | PM2.5 |
| 2021 | 28 | 61 | 173 | 282 | 77 | 6 | PM2.5 |
| 2020 | 28 | 64 | 1135 | 258 | 92 | 11 | PM2.5 |
| 2019 | 29 | 66 | 122 | 261 | 102 | 2 | PM2.5 |
| 2018 | 49 | 72 | 156 | 96 | 82 | 6 | PM2.5 |
| 2017 | 37 | 99 | 242 | 54 | 29 | 9 | PM2.5 |
| 2015 | 42 | 81 | 160 | 60 | 28 | 4 | PM2.5 |
| 2014 | 44 | 67 | 184 | 52 | 28 | 2 | PM2.5 |
What This Means for Jefferson County Residents
Jefferson, Oregon has received an Air Quality Grade of A (83/100) based on a decade of monitoring data from the EPA's air quality monitoring program. The current median AQI of 31 falls in the "Good" range.
Encouragingly, air quality here has been improving, with the median AQI dropping by 13 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 5 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
Jefferson, Oregon has a current median AQI of 31, which falls in the "Good" range. The area has received an Air Quality Grade of A (83/100) based on 10 years of EPA monitoring data.
Air quality in Jefferson, Oregon is improving over the past decade. The median AQI has changed by -13 points from 2014 to 2023.
Jefferson, Oregon averages 5 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 Jefferson, Oregon is Fine Particulate Matter (PM2.5). This is the dominant contributor to elevated AQI readings in the Jefferson County area.
Jefferson, Oregon averages 5 unhealthy air days per year. This is relatively low, making it a reasonable choice for asthma sufferers. The primary pollutant is Fine Particulate Matter (PM2.5), which is a known asthma trigger.
With a median AQI of 31 (Good), outdoor exercise in Jefferson, Oregon is generally safe year-round. Jefferson, Oregon averages 5 days per year when athletes should move workouts indoors.