The worst winter seasonal yellow dust in five years blanketed the Korean Peninsula on Monday, prompting the authorities to issue health warnings against the sandy, chemical-laden wind from China.
  

According to the Korea Meteorological Administration, yellow dust warnings were issued at 10 a.m. in Incheon, Seoul, Gyeonggi Province and part of Gangwon Province with dust advisories in place for most other parts of the peninsula except some southeastern cities, including Busan and Ulsan.
  

The dust warnings in the capital area were to be lowered to advisories at 4 p.m. as the number of fine dust particles gradually decreased.
  

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 4 a.m., Seoul's atmospheric concentration levels of "particulate matter (PM)-10" pollutants soared to 1,044 micrograms per cubic meter. This marks the worst yellow dust that has hit the peninsula during a winter season since Dec. 25, 2009, when the level recorded 963 micrograms.
  

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.
  

This also is the fourth highest level since the authorities began filing records for fine dust concentration.
  

Yellow dust warnings had previously been in place in Seoul five times -- in March 2002, April 2002, April 2006, December 2009 and November 2010.
  

Monday's yellow dust was the result of the combination of low precipitation and low pressure in the deserts in southern Mongolia and northern China where the dust mainly originates from as well as a strong northwesterly wind, the KMA said.
  

The weather office forecast that the yellow dust will gradually weaken starting in the afternoon. Light yellow dust is expected to continue in some areas until Tuesday, it added. (Yonhap)