Fine dust and yellow dust in Seoul: how to check air quality
What fine dust (PM10, PM2.5) and yellow dust are, when they are worst, how to read Korea’s air quality grades and what to do on a bad day.
On some days, especially in spring, the air in Seoul turns hazy. Koreans check the fine dust forecast as often as the weather. Here is what it means for your trip.
This page gives general travel information, not medical advice. If you have asthma, a heart or lung condition, or you are pregnant, follow your doctor’s advice.
What is it?
- Fine dust (미세먼지, misemeonji) is tiny particles in the air from traffic, industry and heating. It is measured as PM10 and the even smaller PM2.5 (ultra-fine dust, 초미세먼지).
- Yellow dust (황사, hwangsa) is sand blown from deserts in China and Mongolia, mostly in spring.
When is it worst?
Air quality is usually worst from late winter to spring (roughly February to May), and best in summer and early autumn, when rain and wind clear the air. It changes day by day, so check the forecast.
Korea’s air quality grades
Korean apps and signs use four grades, often with colors:
| Grade | Korean | Color | PM10 (µg/m³) | PM2.5 (µg/m³) |
|---|---|---|---|---|
| Good | 좋음 | Blue | 0–30 | 0–15 |
| Moderate | 보통 | Green | 31–80 | 16–35 |
| Bad | 나쁨 | Yellow / orange | 81–150 | 36–75 |
| Very bad | 매우 나쁨 | Red | 151+ | 76+ |
These are Korea’s national grades. Other countries’ apps may use different scales, so the same air can look “worse” or “better” depending on the app.
How to check
- AirKorea, the official national air quality service, shows live readings by district.
- Naver and most Korean weather apps show the fine dust grade on the main screen.
- Some subway stations and bus stops have air quality displays.
What to do on a bad day
- Wear a KF94 or KF80 mask outdoors. They are sold at convenience stores and pharmacies. Make sure it fits snugly.
- Plan indoor activities: museums, malls, markets with roofs, cafés.
- Limit hard exercise outdoors.
- Drink water, and wash your hands and face when you get back.
- Keep windows closed at your accommodation.
Official sources
- AirKorea: live air quality across Korea
- Korea Meteorological Administration: yellow dust forecasts
Prices, timetables and rules in Korea change often. We check this guide regularly, but please confirm details with the official sources linked above before you travel.