Worst air pollution Chiyoda-ku, today and tomorrow
Today (21 September): Air quality in Chiyoda-ku is poor. AQI and NO2 are poor; PM2.5 is moderate; PM10, SO2, and PM1 are fair; O3, CO, and HCHO are good. Pollution peaks around 1:00 PM (NO2: 71.5/100).
Tomorrow (22 September 2026): Air quality in Chiyoda-ku is very poor. AQI worsens to very poor; PM10 increases to moderate; NO2 increases to very poor; PM1 increases to moderate; all other pollutants stay as today. Pollution peaks around 5:00 PM (NO2: 95.3/100). Airmine updates local air quality forecasts four times daily.
Get the full experience in the Airmine app.
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
Follow your pollen exposure and performance with the free Airmine–Strava integration. See your pollen and air quality exposure for every Strava activity.
Chiyoda-ku's air quality reflects Tokyo's central government and imperial palace district, with vehicle traffic on surrounding expressways and the extraordinary concentration of national government ministries, Diet Building, and corporate headquarters generating sustained NO₂. The Imperial Palace park provides limited green space ventilation, while the broader Tokyo metropolitan regional background elevates all readings and summer photochemical ozone is the primary warm-season concern throughout the year.
Today - 21 September | Pollution peaks at 13:00
AQI:
Poor
71.5/100
PM2.5 (fine particles):
Moderate
40.4/100
PM10 (coarse particles):
Fair
28.5/100
NO2 (nitrogen dioxide):
Poor
71.5/100
O3 (ozone):
Good
11.7/100
SO2 (sulfur dioxide):
Fair
24.2/100
CO (carbon monoxide):
Good
0.9/100
HCHO (formaldehyde):
Good
5.1/100
PM1 (ultrafine particles):
Fair
34.3/100
Levels show the poorest local air quality during the day
Tomorrow - 22 September | Pollution peaks at 17:00
AQI:
Very poor
95.3/100
PM2.5 (fine particles):
Moderate
48.3/100
PM10 (coarse particles):
Moderate
42.5/100
NO2 (nitrogen dioxide):
Very poor
95.3/100
O3 (ozone):
Good
14.8/100
SO2 (sulfur dioxide):
Fair
37.8/100
CO (carbon monoxide):
Good
1.6/100
HCHO (formaldehyde):
Good
7.7/100
PM1 (ultrafine particles):
Moderate
46.9/100
Frequently Asked Questions
Is air quality bad in Chiyoda-ku right now?
On 21 September 2026, overall air quality in Chiyoda-ku is poor. AQI is the main air quality indicator at 71.5/100. Pollution peaks around 1:00 PM (NO2: 71.5/100).
Will air quality be worse tomorrow in Chiyoda-ku?
On 22 September 2026, air quality conditions in Chiyoda-ku will be worse than today, with AQI forecast at very poor at 95.3/100. Pollution peaks around 5:00 PM (NO2: 95.3/100).
When is air pollution at its worst in Chiyoda-ku?
The biggest local contributors to pollution in Chiyoda-ku are traffic emissions along with heavy industry such as steel, cement, or petrochemical processing, particularly once warm, sunny weather takes hold. Strong sunlight reacting with local emissions drives up ground-level ozone. Cooler temperatures for the rest of the year keep this in check.
Are air quality levels in Chiyoda-ku 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.
Check air quality in other popular cities:
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.
Get the full experience in the Airmine app.