Air quality in Chiayi, Taiwan today

Mr. Duck’s Air Quality Score

Unhealthy for sensitive groups for Chiayi, Taiwan

⚠️ 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 today in Chiayi is classified as USG. The main pollutant identified is PM2.5 (fine particles). Measurements show a PM2.5 concentration of 39.0 µg/m³ and a PM10 concentration of 58.0 µg/m³, based on six valid readings.

Data is shown via OpenAQ. 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 Chiayi pulls information from two monitoring sites and contains twelve recent observations across six key pollutants – carbon monoxide (CO), nitrogen dioxide (NO₂), ozone (O₃), particulate matter 10 µm or less (PM₁₀), particulate matter 2.5 µm or less (PM₂.₅) and sulfur dioxide (SO₂). All of the latest readings were recorded at 2026‑02‑10 23:00 UTC, which places every value within the “updated within seven days” freshness category.

For CO the highest reported concentration is 0.4 ppm while the lowest is 0.14 ppm; the median sits near 0.27 ppm and most values fall between roughly 0.17 ppm (10th percentile) and 0.37 ppm (90th percentile). NO₂ ranges from a minimum of 0.0039 ppm to a maximum of 0.018 ppm, with a median of about 0.011 ppm and the central 80 % spanning 0.005 ppm to 0.017 ppm. O₃ shows a spread from 0.009 ppm up to 0.0325 ppm, median 0.021 ppm, and typical values between 0.011 ppm and 0.030 ppm.

Particulate matter exhibits broader absolute variation. PM₁₀ measurements range from 25 µg/m³ to 58 µg/m³; the middle value is 41.5 µg/m³, with most observations clustered between 28 µg/m³ and 55 µg/m³. PM₂.₅ values run from 13 µg/m³ to 39 µg/m³, median 26 µg/m³, and the inter‑decile range is roughly 16 µg/m³ to 36 µg/m³. SO₂ is the least variable, staying between 0.0011 ppm and 0.0017 ppm, median 0.0014 ppm, with a tight central band of 0.0012‑0.0016 ppm.

Overall the data set offers complete coverage for all six pollutants across two stations, with every reading fresh as of early February 2026. The pollutant values show modest spreads for gases, while particulate matter displays wider variability, reflecting differing local conditions within the city at the time of measurement.

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 reflect six valid measurements and were updated within three days, with the most recent reading recorded at 2026‑02‑10T23:00:00+00:00. This snapshot provides a brief view of current conditions in Chiayi; however, air quality can differ across neighborhoods and change throughout the day, so values may not represent every location or moment within the city.

OpenAQ station rows