Prime Minister Han Duck-soo on Friday instructed relevant authorities to take emergency measures to cope with ultrafine dust plaguing the nation.

"With the environment minister taking the lead, ministries and local governments should thoroughly implement emergency reduction measures in accordance with the current high-concentration ultrafine dust measures," Han said in a statement.

Han also ordered relevant ministries to reduce emissions by coal-fired power plants and other facilities, the statement said.

The instruction came as the ultrafine dust advisory was issued in South Gyeongsang, North Chungcheong, North Jolla and Gyeonggi Provinces earlier in the day. The alerts were expanded later in the day to many other parts of the country, including Seoul, Incheon, Gyeonggi and South Chungcheong Provinces.

The advisory is issued when the hourly average concentration of PM 2.5 -- particles smaller than 2.5 micrometers in diameter -- stay above 75 micrograms per cubic meter for over two hours.

Later in the day, the environment ministry said emergency measures to reduce fine dust emissions will be implemented across the country, except for northeastern coastal areas in Gangwon Province, from 6 a.m. to 9 p.m. on Saturday.

Under the measures, waste incinerators and other high-emission public facilities are to adjust their hours and operational rates, while construction sites are to change or adjust their work hours and use dust-proof covers.

The environment ministry plans to use unmanned aerial vehicles and other tools to strengthen its crackdown on fine dust polluters, with the provincial authorities set to increase the frequency of street cleaning activities.

As the measures come on the weekend, the authorities do not plan to restrict the operation of diesel cars. (Yonhap)