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Air Quality


◆ What are coarse particles?

Coarse particles (PM10) refers to a complex mixture of extremely small particles and liquid droplets in the atmosphere with an aerodynamic diameter of less than 10㎛. They can be manufactured and naturally occurring. Type 1 fine particles are emitted due to processes of small-scale combustion related to industrial, transportation, or residential activities, while Type 2 fine particles, such as nitrates and sulphates, are created through atmospheric reactions. Sources of manufactured fine particles include factories, power generators, and automobiles, while fogs, fires, yellow sand, and volcanic eruptions are natural sources of such particles. Coarse particles cause asthma and other respiratory and cardiovascular problems, leading to an increase in disease and hospitalization rates. They are also known to cause an increase in the death rate and are related to urogenital abnormalities, such as low birth weight and premature births. In addition, fine particles impair visibility; deposits of fine particles on plant leaves interfere with metabolic processes; and deposits on buildings and structures cause corrosion.

◆ Forecast Levels and Instructions for Citizens

Forecast Level Good Moderate Unhealthy Very Unhealthy
(Coarse Particle Concentration:㎍/㎥/Day) 0~30 31~80 81~150 Over 151
Instructions for Citizens (Sensitive Groups) No need to change usual outdoor activities, but only engage in such activities after considering the status of your health Avoid spending long periods of time outdoors or engaging in strenuous outdoor activities. People with asthma may need to use their inhaler more often. Stay indoors as much as possible. Consult your doctor before engaging in outdoor activities.
Instructions for Citizens (General) Avoid spending long periods of time outdoors or engaging in strenuous outdoor activities. In particular, anyone experiencing discomfort such as sore eyes, cough, or sore throat should avoid outdoor activities. Avoid spending long periods of time outdoors or engaging in strenuous outdoor activities. Anyone experiencing symptoms such as coughing or throat irritation must avoid outdoor activities.
(※ Sensitive Groups: Children, the elderly, the infirm, and adults suffering from asthma, other lung conditions, or heart conditions)

◆ Alert Levels and Instructions for Citizens

Level Criteria Instructions for Citizens
Advisory Concentrations remain at a moving average of 120㎍/㎥ or higher for over 24 hours or an hourly average of 200㎍/㎥ or higher for more than 2 hours ▪ Sensitive groups (children, the elderly, the infirm, and people with lung or heart conditions) are advised to limit outdoor activities and stay indoors.
▪ The general public should avoid spending long periods of time outdoors or engaging in strenuous outdoor activities. When experiencing eye irritation, coughing, or sore throat, refrain from outdoor activities completely.
▪ If you must go out, wear a protective mask. People with lung conditions are advised to wear masks after consulting with their doctors.
▪ Refrain from going to areas with heavy traffic.
▪ Kindergartens and elementary schools should forbid students from engaging in outdoor activities.
▪ operation of outdoor sports facilities operated by public organizations should be limited.
▪ Citizens at parks, sports facilities, subway and train stations, and bus terminals must be informed that they should refrain from strenuous outdoor activities.
Warning Concentrations remain at a moving average of 250㎍/㎥ or higher for over 24 hours or an hourly average of 400㎍/㎥ or higher for more than 2 hours ▪ Sensitive groups (children, the elderly, the infirm, and people with lung or heart conditions) are prohibited from engaging in outdoor activities. If you must engage in an outdoor activity, consult your doctor first.
▪ The general public must avoid spending long periods of time outdoors or engaging in strenuous outdoor activities. Stay indoors if you experience coughing or a sore throat.
▪ If you must go out, wear a protective mask.
▪ If possible, do not go to areas with heavy traffic.
▪ Kindergartens and elementary schools should forbid students from engaging in outdoor activities.
▪ Middle and high schools should not hold outdoor activities
▪ The operation of outdoor sports facilities operated by public organizations must be suspended.
▪ Citizens at parks, sports facilities, subway and train stations, and bus terminals must be informed that they should not engage in strenuous outdoor activities.