THAILAND - Of 46 locations where the Acid Deposition Monitoring Network in East Asia (EANET) set up systems to check the acidity of rainwater, there are six in Thailand, - two in Bangkok, and one each in Kanchanaburi, Chiang Mai, Nakhon Ratchasima and Chon Buri - according to the Pollution Control Department.
The rest are in 12 other Asian countries in the network, which aims to combat acid deposition.
Supat Wangwongwatana, coordinator for EANET Regional Resource Centre for Asia and the Pacific and a deputy head of the Pollution Control Department, said the increasing number of vehicles led to higher consumption of fuel, while farmers still burn their fields.
Coupled with smoke from industrial plants and residue from other human activities, this could worsen the situation.
In Thailand, the department's monitoring showed that from 2001-08 Bangkok was the city with highest chemical deposition, followed by Pathum Thani and Chiang Mai.
"Acid content in the rain has been rising," she said. However, she said the acid content was not yet at a dangerous level - meaning that rainwater is still safe for consumption.
"Overall, the situation is not yet as grave as in the US and Scandinavia and [elsewhere in] Europe, where acid rain destroys the ecosystem. Still, the increasing acidity shows a possibility of destruction on that scale," Supat said.
EANET yesterday kicked off a conference where regional academics exchange findings and experiences.
They warned that acid rain not only polluted rivers and streams and threatened marine life, it also posed a threat to human health and valuable cultural and national heritages (through corrosion of stones, metals and concrete).
The Pollution Control Department will set up more monitoring sites. It will also seek to impose stricter laws and regulations to try to control sulphur-dioxide and nitrogen-oxide emissions.
Other members of the network are Cambodia, China, Indonesia, Japan, Laos, Malaysia, Mongolia, the Philippines, South Korea, Russia and Vietnam.