Worst air pollution Saku, today and tomorrow
Today (16 July): Air quality in Saku is fair. PM2.5, HCHO, and PM1 are fair; AQI, NO2, and O3 are medium; PM10, SO2, and CO are good. Pollution peaks around 1:00 PM (O3: 55.0/100).
Tomorrow (17 July 2026): Air quality in Saku is fair. PM2.5 decreases to good; NO2 decreases to good; PM1 decreases to good; all other pollutants stay as today. Pollution peaks around 12:00 PM (O3: 55.5/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Saku's air quality benefits from its exceptional Nagano Prefecture Saku basin position at 700 metres in the Honshu Alps, with consistent mountain valley breezes from the surrounding Yatsugatake and Asama volcanic highlands providing clean natural ventilation. Vehicle traffic on surrounding roads and the electronics manufacturing, cabbage farming, and services corridor contribute local sources, while the outstanding alpine highland setting generally maintains Saku among Japan's more pleasantly ventilated inland mountain basin city environments throughout most of the year.
Today - 16 July | Pollution peaks at 13:00
AQI:
Medium
55.0/100
PM2.5 (fine particles):
Fair
21.2/100
PM10 (coarse particles):
Good
6.3/100
NO2 (nitrogen dioxide):
Medium
41.1/100
O3 (ozone):
Medium
55.0/100
SO2 (sulfur dioxide):
Good
6.8/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Fair
21.3/100
PM1 (ultrafine particles):
Fair
24.8/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 12:00
AQI:
Medium
55.5/100
PM2.5 (fine particles):
Good
8.6/100
PM10 (coarse particles):
Good
2.3/100
NO2 (nitrogen dioxide):
Good
15.8/100
O3 (ozone):
Medium
55.5/100
SO2 (sulfur dioxide):
Good
7.0/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Fair
20.2/100
PM1 (ultrafine particles):
Good
12.0/100
Frequently Asked Questions
Is air quality bad in Saku right now?
On 16 July 2026, overall air quality in Saku is fair. PM1 is the main pollutant at 24.8/100. Pollution peaks around 1:00 PM (O3: 55.0/100).
Will air quality be worse tomorrow in Saku?
On 17 July 2026, air quality conditions in Saku will be similar to today, with HCHO forecast at fair at 20.2/100. Pollution peaks around 12:00 PM (O3: 55.5/100).
When is air pollution at its worst in Saku?
Air quality in Saku tends to be worse when road traffic, manufacturing activity, along with agricultural activity build up and still air allows pollutants to build up. Local weather patterns add further variation on top of these sources. Background emissions and local weather both play a role in day-to-day changes.
Are air quality levels in Saku based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
For long term forecasts and maps, see the Airmine app