The year's worst yellow dust hit much of the nation Sunday, prompting the authorities to issue health warnings against the sandy, chemical-laden wind from China.
  

The Korea Meteorological Administration issued yellow dust advisories in Seoul and 16 cities and counties in its surrounding Gyeonggi Province at 5 p.m. for the first time this year.
  

The advisories were heightened to dust warnings as of 8:10 p.m. as an hourly average dust concentration of more than 700 to 1,100 micrograms per cubic meter is expected to continue for more than two hours in the areas.
  

The office also posted advisories against yellow dust in Incheon and five large islands off the west coast, Sejong, Gwangju, Jeolla, Chungcheong and Gangwon provinces as well as the rest of Gyeonggi Province.
  

A yellow dust advisory is issued when an hourly average dust concentration of more than 400 micrograms per cubic meter is expected to last for more than two hours. More than 800 micrograms leads to a yellow dust warning.
  

People are advised to stay indoors when yellow dust advisories or warnings are in place. When going outside, they are advised to wear protective glasses and yellow-dust masks.
  

As of 8 p.m., Seoul's atmospheric concentration levels of "particulate matter (PM)-10" pollutants recorded 692 micrograms per cubic meter.
  

PM-10 refers to airborne particles 10 micrometers or less in diameter. Epidemiological evidence indicates that exposure to such pollutants causes cardiac and respiratory problems, according to experts.
  

Originating from the deserts in southern Mongolia and northern China, the dusty air flew into the Korean Peninsula on a strong wind over the weekend, according to experts.
  

"With yellow dust advisories or warnings in place in central and South and North Jeolla provinces, yellow dust is being observed in most parts of the nation except South Gyeongsang Province," a meteorologist at the KMA said. "The yellow dust is likely to gradually get stronger to affect North and South Gyeongsang provinces, and the nation will be under thick dust until Monday." (Yonhap)