Air quality in Arapahoe County, Colorado, United States of America today
Mr. Duck’s Air Quality Score
Good air today for Arapahoe County, Colorado, 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 today in Arapahoe County, Colorado is classified as Good. The primary pollutant measured is PM2.5 (fine particles), with a reported concentration of 4.25 µg/m³ based on two valid observations from OpenAQ data.
Overall conditions meet the criteria for a Good rating, and no other pollutants are highlighted in the current 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 current station data listed for this city is focused on particulate matter (PM). In Arapahoe County, Colorado, the dataset contains three rows of observations drawn from two monitoring stations, and the only pollutant reported is PM2.5 measured in micrograms per cubic metre (µg/m³). The most recent reading was recorded at Kelver Library on 2026-02-10 23:03 UTC, which falls within a seven‑day freshness window, indicating that at least one sensor is providing up‑to‑date information.
Across the three entries, PM2.5 values range from a low of 3.81 µg/m³ to a high of 4.25 µg/m³, with a median of 4.0 µg/m³ and the 10th and 90th percentiles at 3.848 and 4.2 respectively, showing relatively tight clustering around the middle of the observed range. Because only PM2.5 is captured and the coverage consists of just two stations, spatial representation is limited; conditions elsewhere in the county may differ from those measured at these sites. The dataset’s freshness is good for the latest record but overall the small number of rows means broader temporal trends cannot be assessed from this snapshot alone.
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 dataset for Arapahoe County includes two valid measurements and is marked as Updated within 3 days, with the latest refresh occurring on 2026‑02‑10 at 23:03 UTC. This snapshot reflects conditions captured at that time; however, air quality can change across different neighborhoods and throughout the day, so values may vary locally and temporally.
OpenAQ station rows
| Station | Parameter | Value | Unit | Last updated |
|---|---|---|---|---|
| May Library | pm25 | 3.81 | µg/m³ | 2026-02-10 22:57 UTC |
| Kelver Library | pm25 | 4.0 | µg/m³ | 2024-08-14 15:18 UTC |
| Kelver Library | pm25 | 4.25 | µg/m³ | 2026-02-10 23:03 UTC |