The air quality index (AQI) in Bangkok, its adjacent provinces and some northern provinces has reportedly improved following the first day of rainmaking flights by the Department of Royal Rainmaking and Agricultural Aviation (DRRAA).
Deputy Minister of Agriculture and Cooperatives Itthi Sirilathayakorn said on Tuesday that the operations aimed to mitigate the level of PM2.5 fine particulate matter in Bangkok and nearby provinces as well as those in the North.
Mr Itthi said the Royal Rainmaking Operation Units in Prachuap Khiri Khan's Hua Hin district and Kanchanaburi province began their mission in the afternoon on Monday.
They used the technique of reducing the inverse temperature of the atmosphere by sprinkling water, using two Casa aircraft. Each sprayed 1,600 litres of cooled water into the air in a spiralling circle with a radius of 5-7 miles (8-11 kilometres) above areas in Phetchaburi and Samut Sakhon provinces.
After the operation, the overall AQI in Bangkok had improved from early morning, when it stood at 154 micrograms per cubic meter (µg/m³), an unhealthy level, down to 66 µg/m³, a moderate level, he said.
In the northern region, the Royal Rainmaking Operations Unit in Chiang Mai also conducted flights about 5pm on Monday. Afterward, it was found the AQI had slightly improved from 84 µg/m³ to 83 µg/m³.
Rachen Silaraya, deputy director-general of operations at DRRAA, said this was a proactive measure to reduce air pollution. The department would develop new technology and techniques to manage it more efficiently, he added.
The Geo-Informatics and Space Technology Development Agency (Gistda), on Tuesday monitored the level of PM2.5 using satellite data via the "Check Dust" app. It found the air quality in Bangkok still exceeded safety standards, reaching levels that pose a risk to respiratory health, with PM2.5 levels surpassing 100 µg/m³ in all areas.
The highest level was recorded in Laksi district at 156.4 µg/m³. Nationwide, 11 provinces were reported to have PM2.5 levels in the red zone, which poses a significant health risk.
The worst five were Nonthaburi (129.4 µg/m³), Bangkok (127.7 µg/m³), Pathum Thani (118.9 µg/m³), Samut Prakan (108.7 µg/m³) and Nakhon Pathom (100.2 µg/m³).