By Lee Hyo-sikIt has become an annual ritual around this time of the year to buy a mask to cover your mouth and stock up on bottled water at home and the office due to the unwelcomed guest of spring _ the yellow dust storm blowing in from China.Koreans tend to eat more pork during the yellow dust season, believing some elements in the pork will absorb the dust caught in the respiratory organs and help the body emit the accumulation.This year, they may have to remain on alert for the yellow dust at all times from April to May as more storms are forecast to develop in Manchuria, the northeastern part of China, which could reach the Korean Peninsula within 24 hours.In the past, the majority of the dust storms blew from the Gobi Desert and Inner Mongolia, north of China, which usually took least 2 days to blanket the Korean Peninsula. This gave people here more time to prepare.But this year Koreans will be caught off guard more often as the yellow sand storms could hit Korea in a matter of hours after they form.According to the National Institute of Meteorological Research (NIMR), Friday, a total of 93 yellow sand storms blowing from China affected the Korean Peninsula from 2002 to 2011. Of them, 49 storms developed in either the Gobi Desert or Inner Mongolia. About 18 storms originated in Manchuria.Between 2002 and 2006, only 6 sand storms reached Korea from Manchuria. But from 2007 to 2011 there were 12, indicating more yellow dust generated in northeast China in recent years.For instance, on May 14, 2011, the sand storm created in Manchuria covered the peninsula only within 12 hours by shifting southeast on a fast-moving wind. It caught meteorologists off guard, leaving many vulnerable to a severe sand dust storm.“Manchuria and other northeastern part of China have been grappling with severe droughts for years due to low precipitation. At the same time, people there have cleared wooded areas to grow crops and raise livestock,” an NIMR researcher said.“Chronic drought as a result of global warming and increasing agricultural activities by humans has contributed to making the land more barren, creating perfect conditions for sand storms to develop.”The researcher warned that yellow dust blowing from Manchuria may contain more salt and other harmful particles of disease-causing metals, advising residents to take precautionary measures.