The smog choking Bangkok is expected to ease this week as the weather forecast predicts rainfall for 30% of the capital over the next four days, said permanent secretary of the Natural Resources and Environment Ministry Wijaran Simachaya on Saturday.
An air quality check conducted by the Pollution Control Department (PCD) at noon on Saturday showed that the airborne particulate matter (PM 2.5) was measured at 45-54 microgrammes per cubic metre (µcg) -- slightly above the safety standard of 50 µcg -- along Intharaphithak Road in Thon Buri district, one of the city's six pollution hotspots.
The level of dust particles in the city will likely decrease, while the levels are expected to stay at the safety standard in all areas of the city today, Mr Wijarn said.
The Meteorological Department has also predicted rainfall covering 20-30% of Bangkok from Sunday until Wednesday, which will decrease dust particle levels.
On Thursday morning, PM 2.5 levels hit 84 µcg along Intharaphithak Road.
The PCD reported the airborne particulate matter on Wednesday surged above the safety limit of 50 µcg in many areas of Bangkok since last week, a level that can endanger people's health.
Its size of less than 2.5 micrometres in diameter means it can enter the lungs easily if people do not wear masks.
Mr Wijarn said cloud-seeding to make artificial rain to bring down dust levels in Bangkok's five surrounding provinces cannot yet start due to unsuitable weather conditions. Plans are in motion to make rain and let the winds carry rain clouds over the capital.
The five provinces -- Nonthaburi, Pathum Thani, Samut Sakhon, Samut Prakan and Nakhon Pathom -- have been told not to conduct any agricultural burning.
Meanwhile, Suwanna Jungrungrueng, deputy clerk of the Bangkok Metropolitan Administration (BMA), on Friday said that the BMA agencies have been instructed to clean roads in the areas with high levels of dust particles.
The cleaning started at Victory Monument on Friday, and continued yesterday along Rama IV Road from the Henri Dunant intersection to Sala Daeng intersection, and along Ratchadamri Road from Sala Daeng to Ratchadamri intersection. The cleaning operation will resume tonight in Bang Na.