Worst air pollution Ōtsu, today and tomorrow
Today (16 July): Air quality in Ōtsu is medium. AQI and O3 are medium; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 12:00 PM (O3: 56.1/100).
Tomorrow (17 July 2026): Air quality in Ōtsu is medium. All pollutants stay as today. Pollution peaks around 4:00 PM (O3: 45.5/100). Airmine updates local air quality forecasts four times daily.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Ōtsu's air quality benefits from its exceptional Lake Biwa shoreline position in Shiga Prefecture, with consistent Lake Biwa breezes providing reliable natural ventilation along Japan's largest lake. Vehicle traffic on surrounding roads and the manufacturing, Enryaku-ji temple tourism, and university corridor contribute local sources, while the outstanding lake ventilation and the Hiei Mountain backdrop create distinctive topographic variation and Otsu generally maintains moderate to good conditions for a major Japanese lakeside city throughout most of the year.
Today - 16 July | Pollution peaks at 12:00
AQI:
Medium
56.1/100
PM2.5 (fine particles):
Good
13.9/100
PM10 (coarse particles):
Good
4.2/100
NO2 (nitrogen dioxide):
Good
12.1/100
O3 (ozone):
Medium
56.1/100
SO2 (sulfur dioxide):
Good
8.4/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
9.9/100
PM1 (ultrafine particles):
Good
16.8/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 16:00
AQI:
Medium
45.5/100
PM2.5 (fine particles):
Good
13.9/100
PM10 (coarse particles):
Good
4.6/100
NO2 (nitrogen dioxide):
Good
8.1/100
O3 (ozone):
Medium
45.5/100
SO2 (sulfur dioxide):
Good
1.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
9.1/100
PM1 (ultrafine particles):
Good
16.7/100
Frequently Asked Questions
Is air quality bad in Ōtsu right now?
On 16 July 2026, overall air quality in Ōtsu is medium. AQI is the main air quality indicator at 56.1/100. Pollution peaks around 12:00 PM (O3: 56.1/100).
Will air quality be worse tomorrow in Ōtsu?
On 17 July 2026, air quality conditions in Ōtsu will be similar to today, with AQI forecast at medium at 45.5/100. Pollution peaks around 4:00 PM (O3: 45.5/100).
When is air pollution at its worst in Ōtsu?
Air quality in Ōtsu tends to be worse when traffic on the surrounding roads, light manufacturing, together with seasonal tourism traffic build up and still air allows pollutants to build up. Local weather patterns add further variation on top of these sources. Local weather patterns add further day-to-day variation.
Are air quality levels in Ōtsu 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