On the 22nd, as fine dust levels surged to "very bad" due to yellow dust, a fine dust advisory was issued for the greater Seoul area, including Seoul.
According to the Seoul Metropolitan Government and the National Institute of Environmental Research, as of 1 p.m. that day, a fine dust advisory was issued for all 31 cities and counties in Seoul and Gyeonggi. A fine dust advisory is issued when the hourly average concentration of fine dust is 150㎍ (micrograms, one-millionth of a gram)/㎥ or higher for two hours or more.
As of 1 p.m. that day, the fine dust concentration in Seoul was 339㎍/㎥, more than double the "very bad" threshold (151㎍/㎥ or higher). The one-hour average concentration in Gyeonggi was tallied at 363㎍/㎥ in the central area, 306㎍/㎥ in the eastern area, 305㎍/㎥ in the southern area, and 272㎍/㎥ in the northern area.
The National Institute of Environmental Research projected that concentrations at "very bad" levels would persist from late morning to early afternoon in the greater Seoul area, western Gangwon, and South Chungcheong; during the afternoon in eastern Gangwon, Daejeon, Sejong, North Chungcheong, and Honam; and from late afternoon into the night in Yeongnam and Jeju.
Rain was forecast through midday that day in inland and mountainous Gangwon, North Chungcheong, and central and northern North Gyeongsang (excluding the east coast), with sprinkles expected in South Chungcheong, Honam, Daegu, southern North Gyeongsang, and northwestern inland South Gyeongsang. Caution is advised as the rain may be mixed with yellow dust.
Yellow dust is expected to affect Korea through the 23rd. On the morning of the 23rd, fine dust concentrations are expected to rise at times to "very bad" levels in the greater Seoul area and Gangwon, and during the day in the Chungcheong region.