Understand the measurement
PM10 and PM2.5 describe airborne particles in different size ranges. Korean information commonly labels them 미세먼지 and 초미세먼지. Concentration is often reported in micrograms per cubic metre, written µg/m³.
Use AirKorea, Korea's official air-quality service, to check local observations, forecasts and alerts. Check the location and update time, because a regional forecast and a nearby monitoring station can describe different conditions.
Do not compare colours without checking the scale
Apps may use Korean or overseas air-quality indices. They may also display an hourly observation, a daily average or a forecast. A raw concentration is comparable only when the pollutant and measurement period are also comparable.
A category such as “unhealthy for sensitive groups” does not guarantee that everyone else is unaffected. Read the health advice attached to the index and consider your own health and planned activity.
Distinguish a forecast grade from an active alert
Korea's daily forecasts commonly use the labels Good, Moderate, Bad and Very Bad. Separately, AirKorea publishes particle-pollution advisories and warnings based on sustained hourly measurements and other conditions.
Follow active local instructions. Pollution-control measures may affect transport, facilities or outdoor programmes as well as the advice for individuals.
Adjust outdoor activity to the conditions
When pollution is high, reduce prolonged or strenuous outdoor activity and consider moving an exposed hike or run to another day. An indoor alternative is useful when the building has cleaner indoor air; a roof alone does not remove pollution.
If you have a heart or lung condition or are otherwise more vulnerable, follow your clinician's advice and the guidance for sensitive groups. Seek medical help for significant breathing difficulty or other serious symptoms rather than relying on a mask.
Choose and fit a mask properly
KF is a Korean mask-performance classification. KF80, KF94 and KF99 products meet different laboratory filtration requirements. The classification is not a guarantee of the same protection on every face: fit and correct use matter.
Buy an appropriately labelled product, follow its instructions and replace it as directed. A particulate mask does not remove every gas or pollutant. If wearing one makes breathing difficult, move to a cleaner environment and seek appropriate advice.
Check conditions throughout the year
Spring can bring yellow dust, called 황사, but poor air quality is not confined to one month. Check the actual conditions during your visit instead of assuming a season is always good or bad.
