Hanoi is one of the most polluted city in Southeast Asia?
The air quality in Hanoi experienced a significant decline on Friday, with Switzerland-based air quality monitoring facility IQAir AirVisual recording an air quality index (AQI) of over 200 in many locations. However, by noon, the AQI had dropped to an average of 149.
The AQI ranges from 0 to 500, with good air quality falling between 0 and 50. When the index stays between 201 and 300, it is classified as "very unhealthy," indicating that the general public will be noticeably affected and sensitive groups should limit outdoor activities. On the other hand, when it ranges from 101 to 150, it is categorized as "unhealthy for sensitive groups," meaning that the general public and individuals who are sensitive to air pollution may experience irritation and respiratory problems.
In the IQAir city ranking, Hanoi was initially ranked as the fourth most polluted city on Thursday morning, but dropped to the 26th spot in the afternoon.
Another air quality monitoring app called PAM Air, which operates in Vietnam, also measured hazardous levels of air pollution in Hanoi. The AQI ranged between 151-200 in specific locations, including Vietnam National University in Cau Giay District, Nguyen Thi Minh Khai Street in Hai Ba Trung District, and Giang Vo Street in Ba Dinh District.
The PM 2.5 level in Hanoi was recorded at 49 µg/m3, which is 9.8 times higher than the annual air quality guideline value recommended by the World Health Organization. PM2.5 refers to tiny airborne particles that are up to 2.5 microns in size. These particles can penetrate deep into the bloodstream upon inhalation and may lead to health issues such as asthma, lung cancer, and heart disease.
Hoang Duong Tung, chairman of the Vietnam Clean Air Partnership, highlighted that air pollution has been a significant concern in Hanoi for years. Factors contributing to this issue include vehicle emissions, industrial activities, construction, and the burning of fields. The period from October to March is particularly problematic, as it is the winter season characterized by low wind, limited sunshine, and high humidity.
Tung also mentioned that the abnormal air pollution recorded on Friday morning could be attributed to thick fog and high humidity following heavy rainfall in the preceding days.