The Seoul Institute of Health and Environment issued an ultrafine dust advisory as of 8 p.m. on the 11th.

In Seoul, the average hourly concentration of ultrafine dust (PM-2.5) is over 75㎍/㎥ for more than two hours.

The research institute said, “From the 8th to the 10th, air congestion occurred due to the influence of high pressure located in China from the 8th to the 10th, and domestic and foreign air pollutants accumulated,” and “On the 11th, additional foreign air pollutants flowed into the metropolitan area, leading to an increase in the concentration of ultrafine dust.” “It is presumed that it is,” he said.

People with respiratory or cardiovascular diseases, the elderly, and children should refrain from going out. Wearing a health mask is recommended when engaging in outdoor activities.