Worst air pollution Ōmihachiman, today and tomorrow
Today (21 September): Air quality in Ōmihachiman is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 11:00 PM (O3: 25.4/100).
Tomorrow (22 September 2026): Air quality in Ōmihachiman is fair. PM2.5 increases to fair; all other pollutants stay as today. Pollution peaks around 2:00 PM (O3: 27.1/100). 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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Ōmihachiman's air quality benefits from its exceptional Shiga Prefecture Lake Biwa eastern shoreline position adjacent to the historic merchant town canals, with consistent Lake Biwa breezes providing reliable natural ventilation. Vehicle traffic on surrounding roads and the traditional crafts, medical equipment manufacturing, and tourism corridor contribute local sources, while the outstanding lake ventilation and the Nishino-ko reed bed wetland create distinctive natural filtration and Omihachiman generally maintains good to moderate conditions throughout most of the year.
Today - 21 September | Pollution peaks at 23:00
AQI:
Fair
25.4/100
PM2.5 (fine particles):
Good
13.9/100
PM10 (coarse particles):
Good
9.6/100
NO2 (nitrogen dioxide):
Good
6.9/100
O3 (ozone):
Fair
25.4/100
SO2 (sulfur dioxide):
Good
1.0/100
CO (carbon monoxide):
Good
0.5/100
HCHO (formaldehyde):
Good
4.4/100
PM1 (ultrafine particles):
Good
3.0/100
Levels show the poorest local air quality during the day
Tomorrow - 22 September | Pollution peaks at 14:00
AQI:
Fair
27.1/100
PM2.5 (fine particles):
Fair
25.7/100
PM10 (coarse particles):
Good
19.7/100
NO2 (nitrogen dioxide):
Good
8.1/100
O3 (ozone):
Fair
27.1/100
SO2 (sulfur dioxide):
Good
0.8/100
CO (carbon monoxide):
Good
0.6/100
HCHO (formaldehyde):
Good
3.0/100
PM1 (ultrafine particles):
Good
4.2/100
Frequently Asked Questions
Is air quality bad in Ōmihachiman right now?
On 21 September 2026, overall air quality in Ōmihachiman is fair. AQI is the main air quality indicator at 25.4/100. Pollution peaks around 11:00 PM (O3: 25.4/100).
Will air quality be worse tomorrow in Ōmihachiman?
On 22 September 2026, air quality conditions in Ōmihachiman will be similar to today, with AQI forecast at fair at 27.1/100. Pollution peaks around 2:00 PM (O3: 27.1/100).
When is air pollution at its worst in Ōmihachiman?
Air quality in Ōmihachiman tends to be worse when vehicle traffic, light manufacturing, along with seasonal tourism traffic build up and winds are light and dispersion is poor. 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 Ōmihachiman 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.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
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Data provided by Airmine — Last update: 22 September 2026 at 02:59 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.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.
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