Levels of  PM2.5 dust in the air in the North – particularly in Chiang Mai – on Saturday reached a record high, raising concerns among tourism operators that the situation will affect tourism and travel patterns.

Even though reports of bookings being cancelled have yet to emerge, the presidemt of Chiang Mai's Tourism Industrial Council said operators of outdoor tourism activities in the province are being affected by a drop in demand.

Citing one estimate that the haze situation is expected to last until April, he said the tourism sector and state agencies should step up cooperation to tackle the air pollution problem before it is too late.

The number of tourists arriving and departing Chiang Mai's airport is between 10,000 and 20,000 a day, which is lower than the figures recorded during the past high tourism season when the air was cleaner, the president said.

According to the Pollution Control Department (PCD), almost all areas in the 17 northern provinces recorded a higher level of the PM2.5 dust particles yesterday, ranging from 93 to 203 microgrammes per cubic metre (µg/m3).

The safe level, according the government, should be no more than 50 µg/m3.

Tambon Hang Dong in Hot district of Chiang Mai was found to have the worst PM2.5 resulting from biomass burning.

Bangkok and the surrounding provinces also recorded higher levels of PM2.5 in certain areas, but the situation is expected to begin improving in the coming week when a southern wind is forecast to begin clearing the air, according to the PCD.