Starting in October, Seoul Metropolitan Government began issuing warnings about ultra-fine dust via texting, bus and street bulletin boards, and Twitter. Ultra-fine dust is not visually discernible, but it can be fatal to humans if exposed to it for even a short period.
People suffering from respiratory or cardiovascular diseases in particular should refrain from going out or at least wear a yellow-dust mask upon receiving an ultra-fine dust warning by text.
Ultra-fine dust can be as thin as 1/30 the diameter of a hair, so it cannot be filtered by the nose hair or airway, but infiltrates the pulmonary alveoli, thus having a more harmful effect on the body than fine dust. As ultra-fine dust can scarcely be perceived even in high concentrations, Seoul Metropolitan Government has installed automatic gauges in twenty-five locations across the city’s districts in order to measure the concentration of ultra-fine dust and issue warnings accordingly.
Seoul Metropolitan Government’s ultra-fine dust warning system will be implemented one year earlier than the projected 2015.
Seoul Metropolitan Government issues a “Watch” message if ultra-fine dust persists for two hours at an average hourly concentration of over 85㎍/㎥, and a “Warning” message if it persists for two hours at a concentration of over 120㎍/㎥.
Whenever the concentration of ultra-fine dust in the atmosphere increases dramatically, elderly people, children, and patients with respiratory and cardiovascular diseases should refrain from going out or should avoid traveling in areas with heavy traffic. When going out, citizens are advised to wear yellow-dust masks and clothes with long sleeves.
|※ Ultra-fine dust (PM-2.5) : refers to tiny dust particles sized under 2.5㎛; sized 1/30 to 1/200 of a hair’s diameter ( 50~70㎛) (PM-10) : under 10㎛ in diameter . *1㎛= one-millionth of 1m|