The Vietnam Environment Administration (VEA), under the Ministry of Natural Resources and Environment, has warned people in Hanoi and other northern cities against outdoor activities and advised protective mask wearing because the air quality in these localities has been at the unhealthy levels.
The VEA’s monitoring systems recorded that many areas have been experiencing worsened air pollution since the second half of October.
More seriously, waves of heavy pollution that last for two to three days each struck the capital city and some northern urban areas at the beginning of November and December.
Particularly, the levels of hazardous small particles known as PM2.5 in the air recorded at automatic air quality monitoring stations in urban areas across the country showed that Hanoi and Ho Chi Minh City were the most polluted places during those periods.
In Hanoi, the PM2.5 index even exceeded the acceptable limit in 11 out of 41 recorded days.
The city’s air quality has been even worse in the past week, with the PM2.5 index measured at monitoring stations in Ba Dinh, Cau Giay, and Bac Tu Liem Districts among the highest.
The PM2.5 index usually reached its highest in the morning and in the evening, experts said, due to a combination of factors such as dry condition, heat inversion, and low atmospheric convection that prevents pollutants from moving higher and further.
Against this context, the VEA advised people to limit outdoor activities in the morning and in the evening, close all doors and windows at times of increased pollution and wear quality protective masks when going outside.