Air quality in Kusatsu, Japan today

Mr. Duck’s Air Quality Score

Moderate air today for Kusatsu, Japan

⚠️ 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 Kusatsu is currently classified as Moderate. The primary pollutant identified is PM2.5 (fine particles), with a measured concentration of 21.0 µg/m³ based on eleven valid observations reported through OpenAQ.

These measurements reflect the present conditions without implying any trend or cause. 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 air‑quality record for Kusatsu currently draws on eleven data rows collected from two monitoring sites, all of which were last updated on 2026‑02‑10 22:00 UTC, so the information is fresh within the past three days. Six pollutants are reported: carbon monoxide (CO), nitrogen oxide (NO), nitrogen dioxide (NO₂), total nitrogen oxides (NOX), fine particulate matter (PM2.5) and sulfur dioxide (SO₂). Each pollutant has at least one recent measurement, but the number of rows varies by type because some stations only record a subset of the suite.

CO is the most uniform, with a single reported value of 0.4 ppm across all rows. SO₂ also shows no variation, recorded consistently at 0.001 ppm. In contrast, the nitrogen‑oxide family displays a modest spread: NO ranges from 0.0 to 0.017 ppm (median 0.0085 ppm), NO₂ sits between 0.02 and 0.022 ppm (median about 0.021 ppm), and NOX varies from 0.02 to 0.039 ppm (median roughly 0.030 ppm). PM2.5 measurements are clustered between 17.0 and 21.0 µg/m³, with a median of 19 µg/m³, indicating relatively stable fine‑particle concentrations during the latest sampling period.

Because only two stations contribute data, spatial coverage across Kusatsu is limited; conditions can differ in neighborhoods that lie beyond the reach of these sensors. Nevertheless, the dataset provides a recent snapshot of six key pollutants, with most values showing narrow ranges and all timestamps reflecting updates from the same day, ensuring that the presented figures represent the city’s air quality at a single point in time rather than long‑term trends.

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 reflects 11 valid measurements and is Updated within 3 days, with the most recent reading recorded on 2026‑02‑10 at 22:00 UTC. These figures represent a snapshot of ambient conditions across Kusatsu; air quality can differ by specific location and time of day within the city, so individual experiences may vary from the values presented here.

OpenAQ station rows