CHIANG RAI - The popping sounds become louder as we traipse up the mountain. Every few steps, I slide backwards on the ash underfoot, flailing at the charred remains of tall vegetation around. Suddenly, the forest blaze comes into view as a flaming tree on the ridgeline emits a thundering crack.
Firefighters within our party surge forward. It has been 24 hours since the fire started in the Chiang Rai forest and flames have already scorched 16 ha of land. It was probably started by a hunter to displace wildlife, they say.
Such fires are one of the causes of choking smog that blankets Thailand’s northern provinces like Chiang Rai during the dry season from February to April every year. Another is the burning of agricultural waste, which is considered quicker and cheaper than trucking trash to faraway disposal facilities on this mountainous terrain.
Most of the smog is caused by highland corn farms near the borders that Thailand shares with Myanmar and Laos.
Officially there is a 60-day no-burning rule until April 15, but enforcement is difficult because burning is considered a “way of life” here.
“Even if a fire starts in the forest, the locals usually know who did it,” says Dr Nion Sirimongkonlertkun, a lecturer at Rajamangala University of Technology Lanna. But they would be ostracised by the community if they told on their neighbours.
According to the firefighters, this same forest in Mae Khao Tom sub-district was set alight last year.
“If you don’t love nature, you can’t do this work,” says Mr Kasemchai Saenchang, as he takes a break from scraping the undergrowth with a large broom to create a firebreak. “Once, when I was fighting a bushfire, the wind suddenly changed direction. I could barely breathe in the smoke.”
The 25-year-old man belongs to a forest fire unit called Sua Fai, or “Fire Tigers”. Their equipment appears modest compared to the giant blazes they battle: Rubber fire-beaters, 14-litre strap-on tanks of water, as well as a leaf blower.
Experts say the situation will not improve until the farmers are introduced to more sustainable crops as well as farming methods.
Until then, residents in the lowlands would have to grapple with the choking smog, which doctors warn could have longer-term effects.
This is especially since Thailand sets lower air quality standards than global benchmarks. The Kingdom’s Pollution Control Department classifies air quality unacceptable if the amount of PM10 pollutants in the air exceeds 120 micrograms per cubic metre. The World Health Organisation sets 50mg per cu m as a guideline.
PM10 particles are those that are 10 micrometres or less in diameter.
This disparity makes a big difference in what sets off alarms. On March 15, for example, while PM10 levels exceeded 120 mg per cu m in Chiang Mai, Chiang Rai, Mae Hong Son and Phayao provinces, they also exceeded 50 mg per cu m in Lampang, Nakon Sawan, Nan and Phrae.
Meanwhile, measurements of PM2.5 – finer particles that can be absorbed into the bloodstream and considered more dangerous to health – are not revealed on its website.
Current health statistics are a cause for worry: The incidence of tracheal, bronchial and lung cancer in the north is higher than in other regions.
Between 2010 and 2012, the incidence of these types of cancer among men in the north was 36.6 for every 100,000 persons, compared to the national mean of 22.7, according to data from the National Cancer Institute. Among women, the incidence was 21.5, compared to 10.1. Lamphun province topped the national charts among men with 44.6.
According to Dr Rungsrit Kanjanavanit, a cardiologist at Chiang Mai University’s Faculty of Medicine, the rate of admission for heart attacks at his institute’s hospital also spikes by 50 per cent during the annual smog season in the north.
The doctors add, however, that more detailed research would need to be done before the ailments can be directly linked to the smog.