Residents in Hanoi wear masks while driving to protect themselves from air pollution.(Source: VNA)

Hanoi (VNS/VNA) - Air pollution in Hanoi in recent days has been so severe that health experts have warned people to stay indoors.

The Air Quality Index at various air monitoring stations across the capital showed dangerously high levels on Sunday afternoon. For instance, it was at 240 at Pham Van Dong street in Bac Tu Liem district.

The index touched 238 on Hang Dau street, while it was 201 on Tan Mai street.

A number above 150 is unhealthy for anyone, while anything between 201 and 300 is very unhealthy, according to the US Environment Protection Agency.

The heavy concentration of the particulate matter PM2.5 in the air has also raised health alarms.

The PM2.5 concentration in Hanoi last Friday was 400 micrograms per cubic metre on Pham Van Dong street while on My Dinh street was 300. The World Health Organisation safety limit is 25 micrograms per cubic metre.

PM2.5 refers to tiny dust particles that are about 30 times smaller than a human hair. These particles, which can remain longer and spread farther in the air than normal dust, can travel deep into the lungs and the blood.

According to Dr Hoang Duong Tung, head of Vietnam Environment Administration, the sudden deterioration of air quality in Hanoi is due to the increase in traffic as Tet (Lunar New Year) approaching.

He advised people to monitor air quality regularly through the Hanoi City portal (hanoi.gov.vn) or network of the Environment Administration or the US Embassy.

Earlier, at the 2018 year-end review conference of the Ministry of Natural Resources and Environment, Nguyen Duc Chung, Chairman of the Hanoi People’s Committee, said air pollution was a serious environmental problem for the city. According to the city’s assessment, demolition and transportation has caused serious pollution. — VNS/VNA