Most Fine Dust Pollution Last Month Came from China

Up to 82 percent of the fine dust pollution that blanketed Korea's skies last month came from China, a study shows.

In mid-January, fine dust in Korea's atmosphere reached the worst levels since authorities began collecting such data in 2015, including 129㎍/㎥ in Seoul. Anything above 35㎍/㎥ is considered "bad" and above 75㎍/㎥ "very bad."

The National Institute of Environmental Research on Wednesday said it analyzed the sources of PM 2.5 fine dust from Jan. 11-15 and found that 69 to 82 percent came from outside Korea. On Jan. 11, 71 percent came from outside Korea rising to 81.8 percent on Jan. 15.

The figures were calculated using atmospheric models according to pollutants emanating from different regions of Northeast Asia. Calculations based on highly concentrated fine dust as seen during Nov. 3-6 of last year showed only 18 to 45 percent of pollutants emanating from outside Korea.

"It appears that the effects of fine dust pollution from overseas are highly affected by weather conditions," the institute said.

The study counters claims by China that most of the fine dust pollution in Korea must be created within the country. Korean and Chinese environmental officials met from Jan. 22 to 24 to discuss the issue, but no in-depth talks did not take place for fear that the subject would escalate into a diplomatic row.

The study showed two instances of massive amounts of fine dust from China flowing into Korea. A strong high-pressure front that formed in China's Shandong Province in the north from Jan. 10 to 11 caused winds to carry fine dust into Korea. On Jan. 13, a high-pressure front in China's northern region also caused fine dust to flow into Korea.

That was clearly reflected in data collected. The average daily fine dust concentration in Seoul on Jan. 10 stood at 34㎍/㎥, but rose to 57㎍/㎥ the following day and to 129㎍/㎥ on Jan. 14. In the western port city of Incheon, fine dust levels reached 107㎍/㎥ on Jan. 14, in North Chungcheong Province 123㎍/㎥, and in Daejeon in the central part of the country 94㎍/㎥.

Pollution tended to reach dangerous levels in China a day earlier than in Korea. In coastal regions in the northeast including Beijing, Tianjin and Hebei Province, fine dust rose to dangerous levels until Jan. 14. In Beijing they increased from 76㎍/㎥ on Jan. 10 to 191㎍/㎥ on Jan. 12, and 112㎍/㎥ on Jan. 14, affecting Korea around a day later.