The smoke haze over Chiang Mai has reportedly thickened on Monday although the level of dust particles remained below the safety level.
But, Chiang Mai's deputy head of public health, Dr. Surasing Visaruthrat, warned that even though the dust particles might appear non-harmful yet, the current condition still presents risks to people with respiratory problems.
Dr. Surasing has warned at-risk residents to avoid spending too much time outdoor and to keep their medicines handy.
The latest report showed that the air quality, illustrated by the Particle Pollution (PM10) Concentration, measured at 87 micrograms per cubic meter at the Chiang Mai City Hall and at 105 micrograms per cubic meter in another part of the city center.
However, Dr. Surasing stated that the situation can worsen if no rain comes down soon. Therefore, locals are asked to refrain from all outdoor burning activities in order to prevent the problem from escalating.