Air quality in Ulsan, South Korea today

Mr. Duck’s Air Quality Score

Moderate air today for Ulsan, South Korea

⚠️ 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 Ulsan is currently classified as Moderate. The primary pollutant identified is PM2.5. The latest snapshot reports a PM2.5 concentration of 19.72 µg/m³ and a PM10 concentration of 25.0 µg/m³. These figures are based on 127 valid measurements collected for the city. Both fine particles and coarse particles are included in the reporting, providing a view of particulate matter levels at this time.

The dataset is compiled and displayed through the OpenAQ platform, which aggregates observations from participating monitoring stations. The reported values reflect the most recent data available for Ulsan and are presented without interpretation. 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

Ulsan’s open‑air quality feed includes six measured pollutants – carbon monoxide (CO), nitrogen dioxide (NO₂), ozone (O₃), particulate matter 10 µm (PM10), particulate matter 2.5 µm (PM2.5) and sulfur dioxide (SO₂). The dataset draws from 25 monitoring stations and contains 146 individual rows of observations. Freshness is high: 133 rows were recorded within the last 30 days, while only 13 rows are older than that, and none are flagged as unknown or from the very recent three‑day window. Each pollutant is represented by roughly the same number of rows (24 – 26) and stations (23 – 25), indicating fairly even spatial coverage across the city.

The most recent values, all logged on 2026‑02‑10, show a median PM2.5 concentration of 15.5 µg/m³ with a minimum of 7.0 µg/m³ and an extreme maximum reported as 9 999 µg/m³, suggesting occasional outliers or sensor errors. CO’s median is 0.375 ppm, ranging from 0.23 ppm up to the same placeholder maximum, while NO₂ and O₃ have medians of 0.00985 ppm and 0.04065 ppm respectively, each with very low minima and similarly high placeholder maxima. PM10’s median sits at 21 µg/m³ (12 µg/m³ minimum), and SO₂’s median is 0.00215 ppm (minimum 0.0014 ppm). The latest single‑point readings—PM2.5 at 19.72 µg/m³ (NASA GSFC 2), CO at 0.37 ppm, NO₂ at 0.0119 ppm, O₃ at 0.0353 ppm, PM10 at 25.0 µg/m³ and SO₂ at 0.0019 ppm—all come from the 효문동 site and were updated at 18:00 UTC (or 18:02 UTC for PM2.5).

Because the dataset contains a small proportion of older rows, the overall picture reflects recent conditions but may miss short‑term spikes that occurred before the 30‑day window. The uniform station count across pollutants means that spatial differences are less likely to be driven by sensor placement, though the presence of placeholder maximum values indicates that occasional data quality checks are advisable when interpreting extreme readings.

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

These data are based on 127 valid measurements and are Updated within 30 days. The most recent set was recorded on 2026-02-10T18:02:13+00:00. While this provides a current overview of Ulsan’s air quality, conditions can differ across neighborhoods and change throughout the day, so the values shown represent a snapshot rather than a comprehensive, city‑wide constant.

OpenAQ station rows