Air quality in Colfax, California, United States of America today
Mr. Duck’s Air Quality Score
Moderate air today for Colfax, California, United States of America
This friendly indicator summarizes the latest city readings. For health guidance, please see: EPA AirNow or WHO.
Air quality today
The air quality in Colfax, California is classified as Moderate today. The primary pollutant identified is PM2.5 (fine particles).
Measurements from OpenAQ show a PM2.5 concentration of 10.0 µg/m³ based on two valid readings. No PM10 data are available for this assessment. This page is informational; for health guidance, use official sources such as EPA AirNow or WHO.
Latest sensor values
PM categories follow US EPA AQI breakpoints, shown here as an estimate derived from the latest valid measurements (this project does not compute EPA NowCast/24-hour AQI yet).
What the data includes
The dataset for Colfax, California contains measurements for two key air‑quality constituents: ozone (O3) and fine particulate matter (PM2.5). Both pollutants are represented by a single monitoring station, giving a total of two data rows—one for each pollutant. The most recent values were recorded on 2026-02-10 at 23:00 UTC, and both entries fall within the “updated within 7 days” freshness category, meaning the latest observations are less than a week old.
For ozone, the sensor reports a constant concentration of 0.029 ppm across its minimum, median, and maximum values, indicating no observed variation in the limited sample period. The PM2.5 reading is similarly uniform, with a single value of 10.0 µg/m³ reported as the minimum, median, and maximum. Because each pollutant has only one recorded measurement, statistical spread (such as inter‑percentile ranges) cannot be assessed beyond the identical values shown.
Overall, the coverage is very narrow: just one monitoring location provides data for both pollutants, and there are no older or unknown‑age records in the set. This means that while the current snapshot is recent, it does not capture spatial differences across Colfax or temporal changes beyond the single timestamp. Users should keep in mind that air quality can fluctuate throughout the day and between neighborhoods, so a broader network of stations would be needed to describe citywide conditions more comprehensively.
Learn more about sources and filtering: About the data.
Trusted references: WHO (Air pollution) · US EPA AirNow · European Environment Agency (Air)
Latest sensor values (bars)
PM categories follow US EPA AQI breakpoints, shown here as an estimate derived from the latest valid measurements (this project does not compute EPA NowCast/24-hour AQI yet).
Data notes
The current data for Colfax reflects two valid measurements and is marked as Updated within 3 days, with the most recent reading recorded at 2026‑02‑10T23:00:00+00:00. This snapshot provides a brief view of air quality conditions; however, concentrations can differ across neighborhoods and change throughout the day, so local variations may not be captured in these figures.
OpenAQ station rows
| Station | Parameter | Value | Unit | Last updated |
|---|---|---|---|---|
| Colfax | o3 | 0.029 | ppm | 2026-02-10 23:00 UTC |
| Colfax | pm25 | 10.0 | µg/m³ | 2026-02-10 23:00 UTC |