After a week of severe air pollution, the PM2.5 dust in Bangkok and nearby areas gradually receded to safe levels, thanks to an abrupt change in weather patterns, with wind blowing away the particles. Heavy rain also helped.
Finally, the blanket of fine dust particles that shrouded Bangkok's skyline -- and on Monday sent the air quality index in 49 out of 50 districts above the "safe" threshold of 50 microgrammes per cubic metre -- dissipated quickly.
Numerous netizens thanked Mother Nature, not the performance of state authorities, for combating the dust. That means people cannot pin much hope on authorities solving the root causes of PM2.5.
The public cannot expect the Bangkok Metropolitan Administration (BMA) to do anything beyond spraying water to wash dust from roads and trees; or traffic police to do anything beyond arresting motorists who drive polluting cars; or the Department of Land Transport to do anything much other than setting emission checkpoints during the seasonal PM2.5 period.
Looking at the big picture, the public cannot hope that the government and Prime Minister Prayut Chan-o-cha will come up with any creative and inspiring solutions other than following recommended policies by bureaucrats, which are spraying water, ordering schools and offices to be closed, and working from home when air pollution reaches critical levels.
Indeed, it has been almost three years since the capital city acknowledged there was a big problem with PM2.5 levels. However, the authorities' response towards the PM2.5 has been disappointing. They tend to stick to knee-jerk reactions, dealing with the hazardous PM2.5 particles during or after the problems occur.
In November, Bangkok governor Aswin Kwanmuang made a bold announcement that the city would ban lorries with more than six wheels from inner-city areas during the day.
The governor made the decision based on the fact that lorries are deemed to be one of major sources of PM2.5 in the transport sector. However, the policy was thwarted when lorry operators threatened to go to the Administrative Court to sue the BMA, Royal Thai Police, and Department of Land Transport. The operators claimed the ban was unfair and biased as there are other sectors that generate the hazardous dust.
Faced with that threat, the BMA, RTP and the Minis-try of Land Transport caved in right away, without raising any objections.
Indeed, the authorities could do much better. In particular, a cabinet resolution issued in October last year empowered the governor to order polluting activities to stop when the PM2.5 level exceeded 75 microgrammes per cubic metre.
Governor Aswin should have exercised this power.
On Wednesday -- after PM2.5 in some areas peaked at 100 microgrammes per cubic metre for two days, he only asked contractors of high-rise buildings and the skytrain to halt some polluting activities. City districts with high levels of dust frantically engaged in "big cleaning" as if it were a photo op.
That order might have given the image that the Bangkok governor was being tough in trying to reduce PM2.5 levels, despite the fact that construction activities are not the source of PM2.5, but rather the larger and less hazardous PM10 dust particles.
PM2.5 haze will likely continue for another two months. Authorities still have the opportunity to prove that they can protect public health and do much better than just carrying out "big cleaning".