According to the Korea Meteorological Administration (KMA), almost all parts of the nation came under the influence of high levels of yellow dust that originated in the Inner Mongolian region in northern China and the vicinity of the Gobi Desert over the weekend and was moving south by riding the northerly wind.
The latest yellow dust storm is forecast to begin to weaken Wednesday but may continue to affect the nation depending on the flow of atmospheric pressure on the Korean Peninsula, the KMA said.
On Monday, Beijing and other Chinese cities were shrouded by what the local weather agencies call the biggest sandstorm in a decade due to the same heavy winds blowing in from the Gobi Desert and nearby regions.
The average hourly concentration of fine dust particles smaller than 10 micrometers in diameter, known as PM 10, rose to 139 micrograms per cubic meter in Seoul, 168 micrograms on Jeju Island, 123 micrograms in Incheon and 153 micrograms in Gyeonggi Province as of 3 p.m.
Authorities issued a fine dust advisory for 10 cities and counties in the southwestern province of South Jeolla at 1 p.m., as the hourly average of PM 10 surged to 224 micrograms in those regions.
The corresponding figures for Busan, Daegu, Gwangju and Daejeon were lower at 88, 26, 59 and 76, respectively, the KMA noted.
The weather authorities here categorize concentrations of PM 10 between zero and 30 micrograms as "good," between 31 and 80 as "normal," between 81 and 150 as "bad" and more than 151 as "very bad." A fine dust advisory is issued when the PM 10 figure stays above 150 micrograms for longer than two hours.
The Ministry of Environment has already issued a preliminary yellow dust advisory for Seoul and almost all regions, except the southeastern provinces of Gyeongsang and Gangwon Province, east of the capital, warning that the PM 10 reading is expected to soar above 150 micrograms in the affected regions.
As fine dust particles can cause various ailments and undermine the body's immune system, government officials ask that citizens with respiratory or cardiovascular problems, children and other vulnerable people, refrain from going outdoors.
Citizens across country refrained from going outside throughout the day, though they are accustomed to always wearing masks in public due to the coronavirus pandemic.