Yellow dust blankets S. Korea; fine dust advisory issued

Almost all of South Korea was shrouded Wednesday by a yellow dust storm originating in the Gobi Desert in northern China and Mongolia, which caused the worst fine dust level of the year, according to the state weather agency and the state-run laboratory.

The yellow storm had spread to almost all of the country as of 1 p.m. and will affect the entire nation until Thursday, according to the Korea Meteorological Administration (KMA).

A fine dust advisory was issued for all parts of South Korea, authorities said.

The average hourly concentration of fine dust particles smaller than 10 micrometers in diameter, known as PM 10, had risen to a yearly-high of 277 micrograms per cubic meter across the country as of 1 p.m., according to the National Institute of Environmental Research (NIER) under the Ministry of Environment.

The average hourly concentration of PM 10 has risen to 346 micrograms per cubic meter on the southern island of Jeju and 255 micrograms per cubic meter in Seoul, according to NIER.

A fine dust advisory is issued when the PM 10 figure stays above 150 micrograms for longer than two hours.

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.”

In a related move, the Ministry of Environment said the second-lowest level of “caution” in the government’s four-stage crisis alert against yellow dust was enforced for almost all parts of the country as of 7 a.m.

The PM 10 density will remain at the “very bad” level in the rest of the country until Thursday, the KMA and NIER said.

The authorities advised people with respiratory illnesses, the elderly and children to stay indoors, and use masks when going outside.

The education authorities in Incheon, located just west of Seoul, have also ordered elementary, middle and high schools to suspend outdoor classes.