At around 11.30 pm on October 15, a specialised dust-control truck pulled into a water-filling point near La Thanh metro station.
Refilling is a mandatory step before the vehicle begins its overnight shift on central roads under a trial programme run by Hanoi Urban Environment Company (URENCO).
The truck, manufactured in 2025, has a 5,300-litre water tank that can be filled in about seven minutes.
Its system is designed to release ultra-fine water droplets directly into the air.
Once refilled, the truck sets off on its route. On the night of October 15, three mist-spraying vehicles were deployed across the city’s streets.
The operation is scheduled mainly between 11 pm and dawn. Amber warning lights flash at the rear of each truck to alert road users and discourage them from entering the spray.
Inside the cab, the driver activates the misting system through a control panel. The vehicle travels at 6-8km/h to maintain consistent coverage, while a monitor displays footage from a camera observing the spray equipment at the rear.
As the truck moves along central streets, its nozzles release a fine mist into the lower atmosphere. When water droplets come into contact with airborne dust, they can help particles clump together and settle more quickly, reducing the amount of dust dispersed along the vehicle’s route.
Operating at night, when roads are quieter, allows the trucks to maintain a steady speed and distribute the mist more evenly while minimising disruption to traffic.
Under URENCO’s plan, the trial ran from October 8 to 15 across six routes, covering a combined equivalent spraying distance of about 71.38km.
The misting operation is intended to complement routine street sweeping, dust extraction, water spraying and road washing to improve urban cleanliness.
The results from the central streets will help authorities assess the system’s effectiveness before deciding whether to expand the programme across the capital.
Hanoi and northern Vietnam are approaching winter, when dry weather and light winds can prevent pollutants from dispersing and cause them to accumulate close to the ground.
According to IQAir, Hanoi ranked third among the world’s most polluted cities at 9 am on October 15, with an air quality index (AQI) of 175.
