Last verified: September 21, 2026 · AirKorea categories, KMA Asian-dust warning criteria and current Korean mask guidance reviewed.
Air quality in Korea can be confusing because two phone apps may show different-looking numbers for the same afternoon.
One may display PM2.5 concentration in micrograms per cubic meter. Another may convert pollution into an AQI index based on a different national standard. Comparing the raw numbers directly can therefore make a normal difference look like a contradiction.
Choose the monitoring station near you → read PM2.5 and PM10 → note Korea’s Good / Moderate / Unhealthy / Very Unhealthy category → adjust long outdoor activity if needed.
Smog and Asian dust over Seoul · Photo: taylorandayumi / Wikimedia Commons · CC BY 2.0
PM2.5 and PM10 are measurements, not AQI scores
PM10 refers to airborne particles 10 micrometers or smaller.
PM2.5 refers to finer particles 2.5 micrometers or smaller, often called ultrafine dust in Korean public information.
AirKorea reports these as concentrations. A separate AQI system turns pollution data into an index.
This distinction explains why one app might show “PM2.5 30 µg/m³” while another presents an AQI number that is much larger.
Read Korea's PM2.5 categories first
| PM2.5 concentration | AirKorea category |
|---|---|
| 0–15 µg/m³ | Good |
| 16–35 µg/m³ | Moderate |
| 36–75 µg/m³ | Unhealthy |
| 76 µg/m³ or higher | Very Unhealthy |
PM10 uses its own concentration bands. AirKorea’s integrated air-quality information displays the local category and pollutant readings together, which is easier than memorizing every threshold before a holiday.
Choose the station near your real location
AirKorea does not treat Seoul as one giant sensor.
It provides readings from monitoring stations across districts such as Jongno, Mapo, Yongsan, Gangnam and many others, as well as cities and provinces around the country.
If your hotel is in Hongdae, a nearby Seoul reading is more useful than a generic national number.
If you are taking a day trip to Incheon, Suwon or Gangwon, check that destination as well.
Do not compare a US AQI number with Korean concentration directly
Some international weather services use the US AQI or another index system.
That can make the number on an overseas app look dramatically different from the concentration displayed by AirKorea.
Look at the unit and system name before deciding that one service must be wrong.
For decisions during a Korea trip, AirKorea’s local station and Korean category provide a consistent baseline.
Use your health and activity to decide what changes
An “Unhealthy” reading does not give every person the same schedule.
AirKorea guidance places greater caution on children, older adults and people with cardiovascular or respiratory conditions. At worse levels, guidance for the general population also becomes more restrictive.
A healthy traveler may decide to replace a two-hour run or strenuous hike with a shorter walk and more indoor time.
Someone with asthma or another relevant condition should follow personal medical advice rather than a travel blog’s generic threshold.
Walking from the subway to a museum and running 10 km beside the Han River are not the same exposure. Consider how long you will be outside and how hard you will be breathing.
Yellow dust is a specific weather event
Korea also uses the term hwangsa (황사), or Asian yellow dust.
This refers to dust transported over long distances and can drive PM10 sharply higher.
KMA’s Asian-dust warning criteria currently include cases where hourly PM10 is expected to reach 800 µg/m³ or more for at least two hours because of Asian dust.
A routine slightly elevated PM10 reading is therefore not the same thing as an official yellow-dust warning.
Check the KF mark when buying a dust mask
Pharmacies and convenience stores in Korea commonly sell masks marked KF80, KF94 or KF99.
KF filtering respirators are regulated products used for protection from particulate matter such as fine dust and yellow dust.
Look for the KF designation and Korean quasi-drug marking on the package rather than assuming every fashion or disposable mask provides the same filtration.
If a medical condition makes mask use difficult, follow your clinician’s advice.
An English-language report on South Korea’s air-quality trends. It provides background context, not today’s pollution reading. Use AirKorea for the live station data before changing an outdoor plan.
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Make the morning check simple
Open AirKorea after breakfast.
Choose your area and note PM2.5, PM10 and the current category.
If you are leaving the city, check the destination.
If readings are poor, reconsider long, strenuous outdoor activities first. Check again later because air quality can change during the day.
If KMA has issued an Asian-dust or other relevant warning, read the official notice rather than relying on yesterday’s app screenshot.
- AirKorea — Current Air Quality
- AirKorea — Air-Quality Index Information
- KMA — Asian-Dust Warning Criteria
- Ministry of Food and Drug Safety — KF Mask Information
Air quality is live data. Check the monitoring station again on the day of outdoor activity.
Two Korea Desserts
Filmed during the 2026 Royal Culture Festival at Gyeongbokgung Palace.
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