Air quality in Hakodate, Japan today

Mr. Duck’s Air Quality Score

Moderate air today for Hakodate, 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 Hakodate is currently assessed as Moderate. The primary pollutant identified is PM2.5 (fine particles). Measurements show a PM2.5 concentration of 15.0 µg/m³, based on ten valid observations collected through OpenAQ.

These data reflect the present conditions without speculation about causes or future changes. 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 Hakodate includes five measured pollutants – nitrogen monoxide (NO), nitrogen dioxide (NO₂), total nitrogen oxides (NOX), fine particulate matter (PM2.5) and sulfur dioxide (SO₂). Data come from three monitoring stations, providing a total of ten recent observations across the city. All recorded values were last updated on 2026-02-10 at 22:00 UTC, which falls within the “updated within three days” freshness window, so the information reflects current conditions rather than historic or stale readings.

PM2.5 concentrations range from 9.0 to 15.0 µg/m³, with a median of 12.0 µg/m³ and the inter‑decile spread (10th–90th percentile) between 9.6 and 14.4 µg/m³. NO values are very low, spanning 0.000 to 0.002 ppm; the median sits at 0.001 ppm and most readings cluster between 0.0002 and 0.0018 ppm. NO₂ shows a slightly broader band from 0.015 to 0.020 ppm, median 0.0175 ppm, with the central 80 % of observations falling between 0.0155 and 0.0195 ppm. NOX mirrors NO₂ closely, ranging 0.015–0.022 ppm, median 0.0185 ppm, and a 10th‑90th percentile window of 0.0157 to 0.0213 ppm. SO₂ is reported at a single consistent level of 0.001 ppm across its lone measurement.

The coverage is uneven: while PM2.5 has three separate sensor rows, each of the gas pollutants is represented by only two rows (except SO₂ with one). This means spatial detail is richer for particulate matter than for the gases. Nevertheless, because every row’s timestamp is recent, users can rely on these figures to understand the present air quality snapshot in Hakodate, keeping in mind that conditions may differ across neighborhoods and over time.

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 are based on ten valid measurements and were refreshed recently, with the latest update recorded on 2026‑02‑10 at 22:00 UTC; the dataset is marked as Updated within 3 days. While this snapshot provides a reliable overview of Hakodate’s current air quality, conditions can differ across neighborhoods and change throughout the day, so local variations may not be fully captured.

OpenAQ station rows