Despite nationwide social distancing being in effect, the streets in Hà Nội could still be seen crowded with traffic on April 21. — VNA/VNS Photo

HÀ NỘI — The concentration of fine dust PM2.5 in Hà Nội exceeded Việt Nam’s standard of 50 micrograms per one cu.m of air on some days last week, as the country is placed under a social distancing period, the Việt Nam Environment Administration (VEA) has reported.

From April 13-19, in Hà Nội, three of seven days had concentrations of PM2.5 exceeding the permissible limit of the National Technical Regulation on Ambient Air Quality set by the Ministry of Natural Resources and Environment (MoNRE).

Hà Nội was still the city with the highest level of PM2.5 fine dust pollution, said a VEA representative. In some other urban areas such as Việt Trì (Phú Thọ Province) and Hạ Long (Quảng Ninh Province) in the northern region or Huế and Khánh Hòa in the central region, the air quality was maintained at a good and moderate level.

VEA also reported air quality in most provinces and cities remained at good and moderate levels during the social distancing period following the drastic reduction of traffic and suspension of construction due to the COVID-19 pandemic.

Meanwhile, in HCM City, although there was no day that the concentration of fine dust PM2.5 exceeded the permissible limit, the city also recorded three days (April 13-15) of high PM2.5 levels.

VEA reports looked at the impact factors that in the days of sharply increasing PM2.5 in the two cities, the traffic flow in the inner areas increased. The air in Hà Nội was also influenced by weather changes.

The results of high PM2.5 fine dust and air pollution index (AQI) at most air monitoring stations in Hà Nội showed that on two days of April 15 and 16, air quality remained at a poor level (AQI from 101-150).

“On these days, April 15-16, there was less wind and the temperature difference between day and night is quite high. Additionally, the density of traffic also increased,” a VEA representative said.

From April 17 to 19, the PM2.5 dust pollution in the city reduced with the air quality at a moderate level. — VNS