Air quality
Air quality in Kotō today
Updated
Good (US AQI 25) Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. Model estimate for Mon, Oct 26, 10:00 am (01:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Kotō, Kumamoto, Japan, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 25 Good
- PM2.5
- 3.7 µg/m³ 0.2× WHO 24-h guideline
- PM10
- 3.7 µg/m³
- Ozone
- 45 µg/m³
- Dominant pollutant
- PM2.5 sub-index 25
- Best hour today
- 6:00 pm AQI 21
- European AQI
- 15
Air quality in Kotō right now
Right now the modelled US Air Quality Index for Kotō, Kumamoto, Japan is 25, which falls in the "Good" band (up to 50). Air quality is satisfactory and poses little or no risk; a good time for outdoor activity.
The index is driven mainly by PM2.5, whose own sub-index is 25. Fine and coarse particles come from traffic, heating, industry, dust and smoke; they build up on calm nights and clear when wind or rain arrives.
PM2.5 is 3.7 µg/m³, within the WHO 24-hour guideline of 15 µg/m³; PM10 is 3.7 µg/m³ against a guideline of 45; ozone is 45 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 7.1 µg/m³ (below the 24-hour guideline of 25).
Also this hour: UV index 0.7, carbon monoxide 193 µg/m³.
NASA FIRMS shows 1 fire hotspot within 300 km in the last day (nearest about 110 km), but particle levels are not elevated enough to point to smoke right now.
Kotō AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 21 around Mon 6:00 pm to 36 around Tue 10:00 am, staying "Good" throughout.
The following day is expected to be worse, averaging about 44 against 26 for the next 24 hours.
| Local time (Asia/Tokyo) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Mon 10:00 am | 25 | Good | 3.7 | 4 | 45 |
| Mon 1:00 pm | 23 | Good | 5.6 | 6 | 42 |
| Mon 4:00 pm | 23 | Good | 4.7 | 5 | 49 |
| Mon 7:00 pm | 21 | Good | 2.5 | 3 | 51 |
| Mon 10:00 pm | 23 | Good | 2.8 | 3 | 56 |
| Tue 1:00 am | 25 | Good | 4.5 | 6 | 67 |
| Tue 4:00 am | 29 | Good | 5.9 | 8 | 75 |
| Tue 7:00 am | 33 | Good | 8 | 12 | 79 |
| Tue 10:00 am | 36 | Good | 10.8 | 16 | 86 |
| Tue 1:00 pm | 38 | Good | 12.5 | 17 | 87 |
| Tue 4:00 pm | 40 | Good | 7.3 | 9 | 87 |
| Tue 7:00 pm | 40 | Good | 8.5 | 12 | 80 |
| Tue 10:00 pm | 44 | Good | 10.3 | 14 | 53 |
| Wed 1:00 am | 49 | Good | 10.4 | 14 | 47 |
| Wed 4:00 am | 51 | Moderate | 10 | 13 | 42 |
| Wed 7:00 am | 52 | Moderate | 11.8 | 15 | 46 |
| Wed 10:00 am | 52 | Moderate | 10.4 | 14 | 77 |
Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.
Best time to be outside in Kotō today
Between 6 am and 9 pm local time, the cleanest air today is forecast around 6:00 pm (AQI 21, Good) and the worst around 10:00 am (AQI 25). The difference across the day is small, so timing matters little.
Kotō vs the rest of Japan
Across 176 Japan cities we track, the average US AQI right now is 47 (Good). Kotō at 25 is 22 points cleaner than average.
It ranks 20 of 176 from cleanest to most polluted; the cleanest is Gifu (15) and the most polluted Sakado (70).
For context, the median across 3,556 cities worldwide is 58.
Air quality in cities near Kotō
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Kumamoto | 6 km | 28 | Good | 2.2 |
| Kurume | 64 km | 23 | Good | 3.8 |
| Isahaya | 66 km | 31 | Good | 3.7 |
| Nagasaki | 81 km | 31 | Good | 3.7 |
| Chikushino-shi | 83 km | 28 | Good | 2.3 |
| Kasuga | 87 km | 28 | Good | 2.3 |
| Ōnojō | 88 km | 28 | Good | 2.3 |
| Beppu | 90 km | 25 | Good | 5.1 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Kotō, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.
Advice for sensitive groups
With the AQI at 25, there is no need for sensitive groups to change plans. People with asthma should still carry their reliever inhaler as usual.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for Kotō
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.