BANGKOK — The air pollution battle in Thailand’s capital has taken to the skies in an unprecedented operation, as aircraft release -70°C dry ice to punch through Bangkok’s pollution-trapping atmospheric layer.
Bangkok Governor Chadchart Sittipunt received a significant donation of dry ice from Bangkok Industrial Gas Company on January 6, 2025, marking a new phase in the city’s battle against PM2.5 air pollution. The donation will support the Royal Rainmaking Department’s atmospheric ventilation operations across Bangkok.
According to Governor Chadchart, recent test flights have shown promising results in creating atmospheric ventilation channels to disperse pollutants. The Bangkok Metropolitan Administration (BMA) has partnered with Aeronautical Radio of Thailand to coordinate flight paths and operations in inner Bangkok areas.
“While initial results are encouraging, we may need additional investment for larger aircraft and dry ice production facilities in the future,” Chadchart noted. “Given that air pollution causes damages worth tens of billions of baht, long-term investment in this solution could be justified if it proves consistently effective.”
Rachen Silaparaya, Deputy Director-General of the Royal Rainmaking Department, explained the science behind the operation. “Our scientific instruments can detect dust concentrations, and we’ve now received permission to conduct flights over Bangkok. When high pollution levels are detected, we deploy aircraft to create ventilation channels in the atmosphere,” he said.
Test results have shown noticeable reductions in pollution levels following these operations, particularly during the 11:00-12:00 and 14:00-15:00 time slots.
The operation uses dry ice, which has a temperature of -70°C, to penetrate the heat film in the atmosphere that typically traps pollution. This technique, based on King Rama IX’s rainmaking formula, creates pathways for PM2.5 particles to disperse. The department uses approximately 10 tons of dry ice daily for these operations.
Thalerngsal Pathong, Regional Director of Aeronautical Radio of Thailand, detailed the flight protocols. Operations are conducted within a 20×20 kilometer radius, carefully coordinated to avoid interference with Don Mueang and Suvarnabhumi airports’ flight paths. Flights typically occur at 10:00 a.m. and 2:30 p.m., lasting 20-30 minutes each, at altitudes between 3,000-4,000 feet.
Bangkok Industrial Gas Company, which has been experimenting with atmospheric ventilation techniques for 4-5 years, has donated 300 tons of dry ice to support the initiative, sufficient for 30 days of operations.
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