Smog from China brought a concentration of ultrafine particles in the Yeongdeungpo area of southwestern Seoul on Saturday that was 1.4 times the normal level, prompting health authorities to advise the weak and elderly to stay indoors. The concentration of ultrafine particles also surpassed normal levels in the Gangseo, Yangcheon, Guro and Mapo districts of the capital as well as in Incheon. On Oct. 29, the concentration of ultrafine particles in Dongducheon, Gyeonggi Province north of Seoul was 2.5 times the normal level. The smog blows across the West Sea. It is now common in Beijing for the concentration of...
