Worst air pollution Shiojiri, today and tomorrow
Today (16 July): Air quality in Shiojiri is fair. PM1 is fair; AQI and O3 are medium; PM2.5, PM10, NO2, SO2, CO, and HCHO are good. Pollution peaks around 3:00 PM (O3: 53.0/100).
Tomorrow (17 July 2026): Air quality in Shiojiri is medium. PM1 decreases to good; all other pollutants stay as today. Pollution peaks around 12:00 PM (O3: 51.8/100). 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
Use our Strava plugin to check your own exposure.
Shiojiri's air quality reflects the Nagano Prefecture Chikuma River valley position at 758 metres in the central Japanese Alps corridor, with vehicle traffic on surrounding roads and the lacquerware, wine, and manufacturing corridor contributing local sources. The surrounding Honshu Alps create topographic variation, while winter valley inversions create seasonal challenges and Shiojiri generally maintains moderate to good conditions for a Japanese inland Nagano valley city throughout most of the year.
Today - 16 July | Pollution peaks at 15:00
AQI:
Medium
53.0/100
PM2.5 (fine particles):
Good
19.5/100
PM10 (coarse particles):
Good
5.3/100
NO2 (nitrogen dioxide):
Good
9.5/100
O3 (ozone):
Medium
53.0/100
SO2 (sulfur dioxide):
Good
4.2/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
12.0/100
PM1 (ultrafine particles):
Fair
24.4/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 12:00
AQI:
Medium
51.8/100
PM2.5 (fine particles):
Good
12.3/100
PM10 (coarse particles):
Good
3.3/100
NO2 (nitrogen dioxide):
Good
8.4/100
O3 (ozone):
Medium
51.8/100
SO2 (sulfur dioxide):
Good
2.1/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
16.3/100
PM1 (ultrafine particles):
Good
17.1/100
Frequently Asked Questions
Is air quality bad in Shiojiri right now?
On 16 July 2026, overall air quality in Shiojiri is fair. PM1 is the main pollutant at 24.4/100. Pollution peaks around 3:00 PM (O3: 53.0/100).
Will air quality be worse tomorrow in Shiojiri?
On 17 July 2026, air quality conditions in Shiojiri will be better than today, with AQI forecast at medium at 51.8/100. Pollution peaks around 12:00 PM (O3: 51.8/100).
When is air pollution at its worst in Shiojiri?
Air quality in Shiojiri tends to be worse when road traffic and manufacturing activity build up and temperature inversions set in over the valley. The bowl-like terrain here limits how quickly pollutants can escape. This is most pronounced in winter, when inversions are more frequent.
Are air quality levels in Shiojiri 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.
Check air quality in other popular cities:
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