Hanoi air pollution reaches unhealthy level

These locations included Thang Long Boulevard, Pham Hung Street, Nguyen Trai Street and Nguyen Chi Thanh Street.

Mai Uyen, an 18-year-old student at the University of Science under Vietnam National University, Hanoi, said the haze was visible to the naked eye on the city's streets.

She usually travels to school by bus and wears a face mask when walking from the bus stop to campus to avoid dust.

Poor air quality also affects older residents. Vu Xuan Dinh, 85, said the city's air had been stuffy and dusty in recent days, affecting older people.

Hoang Duong Tung, an environmental expert and chairman of the Vietnam Clean Air Network, told Tuoi Tre (Youth) online newspaper that the red air quality index (AQI) poses health risks.

Hanoi typically experiences a period of elevated air pollution from around October through March or April of the following year.

During this period, weather conditions are unfavorable for dust to disperse upward, leaving particles concentrated near the ground.

Tung said ongoing construction across Hanoi was another source of dust. Traffic also contributes to pollution, pushing fine particulate matter, particularly PM2.5, to high levels during this period.

Changes in air quality throughout the day depend on several factors, including whether emissions decrease and whether it rains, he said.

“It is difficult to bring air quality down from the red level to a lower level within a single day. Even if conditions improve, the reduction is likely to be slight,” Tung said.

Hanoi has recently stepped up measures to reduce dust, including spraying water mist and requiring vehicles to be cleaned before leaving construction sites. 

However, improving air quality requires efforts from multiple parties, he said.

Some measures include thoroughly cleaning road surfaces to prevent passing vehicles from stirring up dust, as well as reducing the number of private vehicles to cut emissions.