Air quality in Alcalá de Henares, Community of Madrid, Spain today

Mr. Duck’s Air Quality Score

Good air today for Alcalá de Henares, Community of Madrid, Spain

⚠️ This website is currently under active development. Some data may be incomplete or temporarily inaccurate. For health-critical decisions, please verify information through official government or environmental sources.

Categories follow US EPA AQI breakpoints for PM (estimate from latest valid measurements; this project does not compute EPA NowCast/24-hour AQI yet).

This friendly indicator summarizes the latest city readings. For health guidance, please see: EPA AirNow or WHO.

Air quality today

The air quality in Alcalá de Henares today is classified as Good. The main pollutant measured is PM2.5, with a reference value of 4.0 µg/m³, while the reference value for PM10 stands at 2.0 µg/m³. Ten valid measurements were recorded to support this assessment.

Data is shown via OpenAQ and reflects the current conditions in the city. 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 Alcalá de Henares air‑quality dataset contains measurements for seven pollutants – carbon monoxide (CO), nitrogen oxides (NO and NO₂), ozone (O₃), particulate matter of 10 µm and 2.5 µm (PM₁₀, PM₂.₅) and sulphur dioxide (SO₂). All data come from two monitoring stations, giving a total of twenty rows of observations.

The most recent readings are from 2026‑02‑09 15:00 UTC for CO, NO₂, O₃, PM₁₀, PM₂.₅ and SO₂, so the bulk of the dataset is fresh within the last week. The only older entry is NO, whose latest value dates to 2024‑02‑28 23:00 UTC and is flagged as “old data”. Across the seven pollutants, twelve rows are classified as “updated within 7 days”, eight are “old”, and none are unknown or very recent beyond a week.

Typical concentrations show a narrow spread for most species. CO is consistently high at 800 µg/m³ (both median and maximum), while NO₂ hovers around a median of 2 µg/m³ with a maximum of 33 µg/m³, indicating occasional spikes. Ozone’s median value is 61 µg/m³, close to its peak of 63 µg/m³, suggesting limited variability during the recorded period. Particulate matter levels are low, with PM₁₀ medians at 3 µg/m³ (max 25) and PM₂.₅ medians at 8 µg/m³ (max 9). Sulphur dioxide reaches a maximum of 7 µg/m³, while NO ranges from 4 to 17 µg/m³ but only has an old timestamp.

Overall the dataset provides recent coverage for most pollutants, though nitrogen monoxide is less up‑to‑date. Because measurements come from just two stations, conditions can differ across neighborhoods and times not captured by these rows.

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 data shown for Alcalá de Henares is based on ten valid measurements and was updated within three days, with the latest refresh recorded at 2026‑02‑09T15:00:00+00:00. These figures represent a snapshot of current conditions; air quality can differ across neighborhoods and change throughout the day, so values may not reflect every location or moment in the city.

OpenAQ station rows