Worst air pollution Sejong, today and tomorrow
Today (16 July): Air quality in Sejong is poor. AQI and O3 are poor; PM2.5 and PM1 are fair; NO2 is medium; PM10, SO2, CO, and HCHO are good. Pollution peaks around 2:00 PM (O3: 64.2/100).
Tomorrow (17 July 2026): Air quality in Sejong is poor. All pollutants stay as today. Pollution peaks around 3:00 PM (O3: 65.4/100). 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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Sejong's air quality reflects the flat Chungcheong Geum River corridor's new administrative capital position at 30 metres, with vehicle traffic on surrounding expressways and the government, construction, and expanding urban character contributing local sources. Seasonal Chinese dust transport elevates PM10 during spring yellow dust episodes, while the regional industrial background influences readings and Sejong generally maintains moderate South Korean central corridor administrative capital readings throughout most of the year.
Today - 16 July | Pollution peaks at 14:00
AQI:
Poor
64.2/100
PM2.5 (fine particles):
Fair
21.9/100
PM10 (coarse particles):
Good
9.8/100
NO2 (nitrogen dioxide):
Medium
41.2/100
O3 (ozone):
Poor
64.2/100
SO2 (sulfur dioxide):
Good
7.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
9.7/100
PM1 (ultrafine particles):
Fair
26.3/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 15:00
AQI:
Poor
65.4/100
PM2.5 (fine particles):
Fair
21.4/100
PM10 (coarse particles):
Good
7.0/100
NO2 (nitrogen dioxide):
Medium
45.0/100
O3 (ozone):
Poor
65.4/100
SO2 (sulfur dioxide):
Good
6.8/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
12.3/100
PM1 (ultrafine particles):
Fair
26.0/100
Frequently Asked Questions
Is air quality bad in Sejong right now?
On 16 July 2026, overall air quality in Sejong is poor. AQI is the main air quality indicator at 64.2/100. Pollution peaks around 2:00 PM (O3: 64.2/100).
Will air quality be worse tomorrow in Sejong?
On 17 July 2026, air quality conditions in Sejong will be similar to today, with AQI forecast at poor at 65.4/100. Pollution peaks around 3:00 PM (O3: 65.4/100).
When is air pollution at its worst in Sejong?
In Sejong, traffic on the surrounding roads, construction dust, and shipbuilding and port operations are the main local sources, with conditions worsening when dry spells bring strong winds. Dust carried on these winds adds substantially to particulate levels. These episodes tend to cluster in spring and autumn.
Are air quality levels in Sejong 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