Air quality in South Korea: where to check and what to do

Short answer. Check AirKorea, run by the Korea Environment Corporation, for real-time readings and the 3-day forecast ¹². Its Comprehensive Air-quality Index (CAI) runs from 0 to 500 in four levels, from good to very bad ¹. A PM2.5 advisory (주의보) is issued when hourly levels stay at 75 µg/m³ or more for 2 hours ³. On bad days, limit prolonged or strenuous outdoor activity ².

Where can I check air quality right now?

AirKorea (airkorea.or.kr) publishes real-time data from monitoring stations, a forecast for today, tomorrow and the day after, and the history of fine-dust advisories and warnings by region ²³. The CAI was built to make readings easy to understand and to give people guidance on avoiding harm from air pollution ¹.

What do the index levels mean?

The CAI scores six pollutants and uses the highest score; points are added when two or more pollutants reach "bad" at once ¹.

The daily forecast uses the same four grades. For PM2.5 they are 0-15, 16-35, 36-75 and above 75 µg/m³ ². See Air quality index explained.

How polluted is the air on average?

Clearly above WHO guidelines. The population-weighted median of South Korean cities shows about 26 µg/m³ of PM2.5 (annual mean 2021-2023) ⁶, more than five times the WHO guideline of 5 µg/m³ ⁸. Nitrogen dioxide is about 44.9 µg/m³ ⁷, more than four times the WHO guideline of 10 µg/m³ ⁸. That NO2 figure is a regional background over roughly 80 km: a busy street will be higher.

What should I do on a bad air day, or with smoke or dust?

• "Bad" forecast: everyone should limit prolonged or strenuous outdoor activity; people with sore eyes, a cough or a sore throat should avoid going outdoors, and people with asthma may need their inhaler more often ².
• "Very bad" forecast: sensitive people should stay indoors as far as possible and consult a doctor about any outdoor activity ². See Sensitive people and polluted air and Children and polluted air.
• PM2.5 alerts: an advisory follows 2 hours at 75 µg/m³ or more and a warning (경보) 2 hours at 150 µg/m³ or more ³. See Pollution episodes.
• Ozone: taking the weather into account, an ozone advisory is issued when a monitoring station reads 0.12 ppm or more, a warning at 0.3 ppm and a major warning (중대경보) at 0.5 ppm ⁵. During an advisory, AirKorea asks residents to avoid outdoor activity and vigorous exercise, and older people, children and people with respiratory or heart disease to stay out of outdoor activity ⁴. See Ozone days.
• Yellow dust and smoke: see Dust storms, Wildfire smoke, A clean-air room at home and Masks for smoke.

A household plan can list who in your home is sensitive to polluted air and where to shelter.

Frequently asked questions

What is a fine-dust advisory in South Korea?

A PM2.5 주의보 is issued when hourly PM2.5 stays at 75 µg/m³ or more for 2 hours; a 경보 at 150 µg/m³ or more for 2 hours ³.

Who counts as a sensitive group?

AirKorea lists children, older people, and adults with lung disease such as asthma or with heart disease ⁴.

Can I see tomorrow's air quality?

Yes. AirKorea forecasts PM10, PM2.5 and ozone for today, tomorrow and the day after ².

Where do emergency alerts come from?

Disaster texts reach phones directly: see our South Korea alerts page.

Sources

1. 한국환경공단 (Korea Environment Corporation), AirKorea — 에어코리아 : 통합대기환경지수 — https://www.airkorea.or.kr/web/khaiInfo?pMENU_NO=129 (accessed 2026-10-27)
2. 한국환경공단 (Korea Environment Corporation), AirKorea — 에어코리아 : 오늘/내일/모레 대기정보 — https://www.airkorea.or.kr/web/dustForecast?pMENU_NO=113 (accessed 2026-10-27)
3. 한국환경공단 (Korea Environment Corporation), AirKorea — 에어코리아 : 미세먼지, 초미세먼지 (주의보·경보 발령 현황 및 경보기준) — https://www.airkorea.or.kr/web/pmWarning?pMENU_NO=115 (accessed 2026-10-27)
4. 한국환경공단 (Korea Environment Corporation), AirKorea — 에어코리아 : 오존 행동요령 — https://www.airkorea.or.kr/web/o3pollutant?pMENU_NO=198 (accessed 2026-10-27)
5. 한국환경공단 (Korea Environment Corporation), AirKorea — 에어코리아 : 오존 (경보기준) — https://www.airkorea.or.kr/web/o3Warning?pMENU_NO=116 (accessed 2026-10-27)
6. Atmospheric Composition Analysis Group (ACAG), Washington University in St. Louis — Surface PM2.5, V6.GL.02.04 (annual mean 2021-2023) — https://sites.wustl.edu/acag/datasets/surface-pm2-5/ (accessed 2026-10-27)
7. Copernicus Atmosphere Monitoring Service (CAMS) — CAMS global reanalysis (EAC4) — https://ads.atmosphere.copernicus.eu/ (accessed 2026-10-27)
8. World Health Organization (WHO) — WHO global air quality guidelines (2021) — https://www.who.int/publications/i/item/9789240034228 (accessed 2026-10-27)