Prime minister Han Duck-soo has ordered ministries and local authorities to devise scrupulous measures as a spike in ultrafine dust levels triggered a slew of advisories and warnings on Friday.

His office relayed his instructions for the environment ministry, other relevant agencies and municipal governments to strictly implement emergency fine dust reduction measures.

Han asked the energy, transport and oceans ministers to enforce steps for large facilities to reduce emissions and restrict operations of thermal power plants.

The health, education and labor ministries were instructed to monitor vulnerable citizens including seniors, children and outdoor workers.

Ultrafine dust advisories are in effect in many parts of the country while a warning was issued for the southeastern port city Busan.