HANOI, Oct. 1 (Xinhua) -- The quality of air in Vietnam's capital Hanoi in September was poor, so it was unhealthy to humans, Vietnam News Agency on Tuesday quoted the Vietnam Environment Administration as saying.
On Sept. 12-29, the Air Quality Index (AQI) in Hanoi was poorer than in the past with the concentration of fine dust, known as PM2.5 which is particulate matter with a diameter of less than 2.5 micrometers, sometimes surpassing Vietnam's permissible levels. However, the concentration of other pollutants was within the limits, said the administration.
AirVisual, an international air quality monitoring facility that generates data from public, ground-based and real-time monitoring stations, recorded on Monday that Hanoi continued to be among most polluted cities in the world with the AQI exceeding the red-warning level.
Hoang Duong Tung, chairman of the Vietnam Clean Air Partnership, a social organization under the Vietnam Association for Conservation of Nature and Environment, said the high level of AQI was abnormal and needed careful research to find out why.
Air monitoring in Vietnam remains limited, he said, noting that Hanoi has only two fixed monitoring stations, whereas Ho Chi Minh City has none.
According to him, air pollution in Vietnam's big cities is mainly caused by PM2.5, and direct contact with PM2.5 can lead to serious respiratory, cardiovascular and neurological diseases.
