The Seoul city issued a fine dust warning on the 25th.
The Seoul Institute of Health and Environment noted that a fine dust warning was issued based on measurements taken at 5 a.m. on that day.
A fine dust warning is issued when the hourly average concentration of fine dust exceeds 75㎍/㎥ for more than 2 hours. According to the Institute of Health and Environment, the hourly average concentration of fine dust (PM-2.5) in Seoul's 25 districts rose from 77㎍/㎥ at 4 a.m. to 82㎍/㎥ at 5 a.m.
The Institute of Health and Environment explained that the increase in fine dust concentration is presumed to be due to "air pollutants that entered from overseas on the 23rd, and the subsequent stagnation of air led to the accumulation of pollutants in the country, with overseas pollutants entering the metropolitan area on that morning."
The Institute of Health and Environment urged citizens with respiratory or cardiovascular diseases, as well as the elderly and children, to refrain from going outside and to wear protective masks during outdoor activities and outings.