The Korea Environment Corporation announced that a fine dust advisory has been issued for Seoul as of 3 p.m. on Wednesday.
 
The average hourly fine dust concentration in the capital area stood at 248 micrograms per square meter.
 
A fine dust advisory is issued when the hourly average of fine dust concentration is 150 micrograms per square meter or more for two hours.
 
During high concentrations of ultrafine or fine dust, the elderly, children, patients with respiratory illnesses, and cardiovascular diseases are asked to refrain from outdoor activities.
 
Even healthy adults are advised to reduce their outdoor activity and wear a mask when going out.