Thailand uses dry ice to tackle air pollution

Flying through Bangkok's cloudless blue skies, a small aircraft sprays a white mist over a thick haze of pea soup smog below.

Thailand's government on Friday deployed small aircrafts to spray white mist over the dense smog blanketing Bangkok in an effort to alleviate the city’s stifling air pollution, which reached eight times the World Health Organisation's recommended daily maximum average.

The scourge has made more than one million people ill since late 2023 and cost Thailand more than $88 million in medical expenses, the Ministry of Public Health said earlier this month.

According to Bangkok Governor Chadchart Sittipunt, the main culprits are vehicle emissions, crop burning in the wider region and closed weather conditions, a warm atmospheric lid covering the dust, preventing it from dispersing.

Twice a day, the Royal Rainmaking Department sends aircraft up to spray cold water or dry ice into the layer of warm air to cool it down.

The new technique was first used last year and is still in its testing stages. The dry ice (solidified carbon dioxide) is provided by Thailand's oil and gas giant PTT and other energy companies.

Another fossil fuel company, Bangkok Industrial Gas, also donated dry ice to the programme this month, with managing director Piyabut Charuphen saying in a statement the gift was part of their commitment to creating a sustainable future.

Carbon dioxide is itself a greenhouse gas and the environmental and health effects of spraying dry ice in the atmosphere are not fully understood.

One flight can cost up to $1,500, and with aircraft taking off from three bases around the country, it can reach $9,000 per day.