72% of Seoul's high concentration fine dust affected by China

A recent research finding has suggested that over 70 percent of high concentration ultrafine particles (PM2.5) in Seoul comes from outside the territories, including China.

The Seoul Metropolitan Office announced Thursday that its final report titled “Establishment of PM2.5 Source Inventory and Research on Close Monitoring,” and concluded that 72 percent of PM2.5 alerts announced in Seoul in 2015 were due to foreign influences. When alerted as PM2.5, the particles are referred to as “high concentration fine dust,” which shows an increase of 17 percent from the average 55 percent in non-alerted situations.

The recent findings were based on data analysis conducted for the period from Oct. 19 to Oct. 22, 2015 when PM2.5 alert was issued for four consecutive days. During the same period in different years, 16 percent of PM2.5 came from Seoul, while 12 percent came from other domestic regions. In normal circumstances, Seoul emitted 22 percent, while other local areas emitted 23 percent.

Seng-Hyun Kang byhuman@donga.com