Fine dust pollution in Bangkok is expected to rise over the next few days as a result of pollutants being trapped in the atmosphere.
Theerapat Prayoonsithi, the Prime Minister's Office permanent secretary, said on Wednesday he had asked several ministries to amplify efforts to combat health-hazardous PM2.5 micro dust over the city.
The PM2.5 issue has been contained so far, thanks largely to the anti-Covid-19 measures, which include many people working from home.
Air pollution persists, however, due to vehicles' exhaust fumes, work on construction sites and the burning of garbage in open areas.
Mr Theerapat said dust pollution might worsen over the next four days with Bangkok due to be hit by a sudden cool spell. The fluctuation in temperatures is contributing to what meteorologists call "an inversion layer", which prevents the air below it from rising and trapping pollutants.
State agencies had tried to solve the pollution problem but it had been compounded by static winds and worsening air quality throughout the capital, said Mr Theerapat.
The permanent secretary said some busy intersections had seen a rapid surge in levels of dust pollution. Police and other officials have been asked to ensure there is no protracted build-up of traffic at intersections.
In addition, said Mr Theerapat, motorists had been advised to take their cars for regular engine check-ups but some owners had refused, saying their cars were new and not belching black smoke. Public transport vehicles were being inspected for any pollution emission, said Mr Theerapat.