Much of northern Thailand as far south as Saraburi lay under a heavy blanket of haze and smoke Friday from hundreds of fires, mostly set on purpose by farmers in Thailand and Myanmar.

The crisis areas were spotted in the far North, the lower North and upper Central provinces. Saraburi, where the air quality index (AQI) touched a dangerous 104 at noon Friday, had an air pollution index of 128 which, roughly translated, means “sensitive groups such as children, older people and asthmatics should stay indoors”.

Any AQI over 100 is dangerous to health, according to the Pollution Control Department, which maintains a website with information from around the country.

The most dangerous place in Thailand Friday afternoon was Mae Hong Son, where the AQI in the “pristine province” was 219. The index says an AQI this high is “an emergency condition. The entire population is more likely to be affected.”

At mid-afternoon Friday, “dangerous” readers were recorded at Chiang Mai City Hall (106), the Lampang Meteorological Station (159), and the Phrae station, which had a reading of 134.

Viewed from the steps to Doi Suthep, the city of Chiang Mai was barely visible through the haze Friday morning.

Dramatic satellite photos and charts from Nasa showed the cause and extent of the wildfires, which are set on purpose every year at this time, supposedly to prepare fields for a new crop when the rainy season begins, in April or May.

The Nasa Worldview website, which shows satellite photos of Earth in near real-time, was a dramatic mass of red dots in northern Thailand and, even more, in next door Myanmar. Each dot represented an individual fire, seen from space.

The ThaiForestFire site, a Google Map mashup showing hot spots in Thailand, was a virtual sea of yellow and red Friday.

Residents of the North described a “hell in the air” throughout the region.

“It is the worst I have seen in years,” said a Lampang resident, who added the haze this week came suddenly on Thursday after a brief rain shower had cleared the air on Wednesday.

“I woke up with the taste of smoke in my throat,” said a Chiang Mai resident.

via Polluting haze blankets the North | Bangkok Post: news.