The department estimates that about 58.65 per cent of primary PM2.5 originates within Hanoi, with the remainder coming from neighbouring localities and transboundary sources. A comprehensive emissions inventory is under way and is expected to be completed in the first quarter of 2026.

At the meeting, Professor Hoang Xuan Co of the Vietnam Association of Environmental Economics said Hanoi needed to better understand how secondary fine particles form and why pollution worsens in winter, citing temperature inversion, and called for vertical meteorological monitoring.

Hoang Duong Tung, chairman of the Vietnam Clean Air Network, said air quality management should be devolved to commune and ward level, backed by digitised emissions data, GIS-based mapping of polluters and tougher, progressive penalties.

Nguyen Xuan Dai, director of the Hanoi Department of Agriculture and Environment, said the city had made notable progress, including phasing out coal briquettes and manual brick kilns and cutting the burning of straw and agricultural by-products by about 80 per cent.

Waste treatment had also improved significantly with the operation of large waste-to-energy facilities such as the Soc Son and Seraphin plants. Two more plants will be built in Soc Son and Son Tay, which should allow Hanoi to handle most of its household waste by 2028, Dai said.

The department will consolidate expert recommendations and advise the city’s leadership on short- and long-term measures to curb air pollution and strengthen coordination across the capital, he added.