How to Check Fine Dust and Yellow Dust Before a Korea Trip

Use AirKorea for local PM2.5 and PM10 readings and forecasts, and the Korea Meteorological Administration (KMA) for Asian-dust warnings. Before comparing two apps, check whether each screen shows a concentration in µg/m³, Korea’s CAI, or U.S. AQI—the same air can receive different colors and labels on different scales.

This guide was fact-checked on August 10, 2026. It is for travelers who want a practical check before departure and a simple decision routine in Korea, especially when asthma, heart or lung disease, allergies, pregnancy, age, or a young child makes exposure more consequential.

Use a three-stage check, not a seasonal guess

An exact dust episode cannot be judged from the month alone. Keep the broad seasonal reputation in the background, then make decisions from current official readings.

• Before you book: leave some indoor flexibility if air quality matters medically. A spring date can carry yellow-dust risk, but it does not tell you which hours or days will be affected.
• About three days before an outdoor-heavy plan: check AirKorea’s today, tomorrow, and day-after PM2.5 forecast, then check the KMA severe-weather page for an Asian-dust warning.
• Each morning and before a long walk or run: open AirKorea’s current air-quality page, choose the area or nearby monitoring station, and read PM2.5 and PM10 separately. Note which pollutant is responsible for the overall category.

The first slide shows AirKorea’s regional web map and local panel; the second shows its mobile view with PM2.5, PM10, ozone, and forecast shortcuts. The values in these official screenshots are examples from February 2024, not today’s readings.

A nearby station is usually more useful than a national headline. If your day crosses Seoul or another large city, recheck near the area where you will actually spend several hours. Station values, update times, and forecast categories can differ, so record the pollutant, unit, location, and time rather than saving only a color.

Decode the Korean labels first

On Korean services, 미세먼지 normally refers to PM10 and 초미세먼지 to PM2.5. English speakers can stumble here because “fine particulate matter” often means PM2.5. The AirKorea health guide defines the Korean terms by particle diameter: PM10 is up to 10 micrometers and PM2.5 is up to 2.5 micrometers.

황사, usually translated as yellow dust or Asian dust, describes a meteorological dust event and source, not a separate AQI scale. It often pushes PM10 sharply upward. AirKorea tells you the measured particulate concentration; KMA tells you whether an Asian-dust warning is in force or expected.

KMA’s formal Asian-dust warning threshold is severe: an hourly mean PM10 concentration of at least 800 µg/m³ expected for two hours or more. Do not interpret the absence of that warning as “clean air.” AirKorea can already show an unhealthy PM10 or PM2.5 category at much lower concentrations.

Why one app says “good” and another says “moderate”

Three different things can look like the same number:

• Concentration is a measured amount such as PM2.5 12 µg/m³.
• Korea’s CAI is a 0–500 health index. AirKorea’s CAI explanation says it calculates an index for six pollutants, uses the highest one, and can add points when several pollutants are elevated.
• U.S. AQI also runs from 0–500, but it uses different category boundaries and includes an “Unhealthy for Sensitive Groups” band.

For Korean PM2.5 categories, AirKorea lists 0–15 µg/m³ as good, 16–35 as moderate, 36–75 as unhealthy, and 76 or more as very unhealthy. Korea’s overall CAI bands are good 0–50, moderate 51–100, unhealthy 101–250, and very unhealthy 251–500.

The current U.S. EPA breakpoint table puts PM2.5 at 0.0–9.0 µg/m³ for U.S. AQI “Good” and 9.1–35.4 for “Moderate.” With the same raw PM2.5 input of 12 µg/m³, a Korean concentration category can therefore read “good” while a U.S.-AQI app reads “moderate.” Different update times, stations, averaging methods, and modeled data can widen the gap.

A number such as “110” is meaningless until the screen names its unit or index. It could be 110 µg/m³, Korea CAI 110, or U.S. AQI 110—three very different readings. Compare the raw PM2.5 or PM10 concentration when possible, then follow the health guidance attached to the scale you are actually viewing.

Travelers do notice this mismatch. In a recent r/koreatravel discussion, one resident described a Korean app showing a lighter category while a U.S. weather app labeled the air unhealthy. Other replies ranged from “manageable with monitoring” to reports of noticeable symptoms, especially among people with asthma or smoke sensitivity. Those are personal experiences, but the disagreement itself is a useful prompt to check the scale instead of trusting color alone.

Prepare for a bad-air day if you are sensitive

AirKorea identifies pregnant people, infants and children, older adults, and people with cardiovascular, respiratory, or allergic disease as groups at greater risk from fine-dust exposure. Bring the medication and written plan your clinician recommends; if you have asthma, COPD, heart disease, or another condition affected by air quality, discuss travel-specific thresholds and mask tolerance before departure.

When readings are poor, shorten outdoor exposure and reduce strenuous or prolonged activity. Move a run, hike, or long viewpoint visit indoors or to a cleaner window of the day. The CDC Yellow Book’s travel guidance likewise advises travelers with asthma, COPD, or heart disease to limit strenuous or prolonged outdoor activity when air quality is poor.

For a Korean health mask, check the package for the Ministry of Food and Drug Safety’s KF mark. The MFDS explains that KF80, KF94, and KF99 are performance classes; higher filtration also comes with lower breathability. Choose a model that fits properly and that you can tolerate. A properly fitted mask can reduce particle exposure, but it does not make an unhealthy outdoor day risk-free—a point also raised in a 2026 Korea travel discussion about KF94 use.

The shortest reliable routine is: AirKorea for local PM2.5 and PM10, KMA for Asian dust, then verify the unit and scale before reacting to a color. Sensitive travelers should make the decision from the pollutant reading, their own medical plan, and the amount of outdoor exertion—not from whether other people nearby are wearing masks.

Photo credits

• Seoul fine-dust photo: Hyeonyoung Lee 21 via Wikimedia Commons, licensed under CC BY-SA 4.0.
• PM10 and PM2.5 size graphic: AirKorea, Korea Environment Corporation; used with written operator permission.
• AirKorea web and app screens: Korea Environment Corporation Pu-Ru-Mi official Naver Blog; used with written operator permission.