Hanoi air pollution worst in the country in 2020: researchers

By To Hoi   December 1, 2021 | 04:30 pm PT
Hanoi air pollution worst in the country in 2020: researchers
Smog fills up the sky in Hanoi in December 2019. Photo by VnExpress/Gia Chinh
Hanoi had the highest annual average PM2.5 concentration of all Vietnam localities in 2020, researchers said at a conference Wednesday.

The conference focused on fine particulate matter (PM2.5) concentration in Vietnam and the use of satellite data for pollution monitoring and research.

Researchers from the University of Engineering and Technology under the Vietnam National University in Hanoi said the capital city had the highest annual average PM2.5 concentration in 2020.

The researchers were citing Vietnam’s first national scale study using the machine learning statistical model combined with satellite image to evaluate air quality even in areas without air quality stations.

The national standard for yearly average PM2.5 concentration is at 25 μg per m3; and Hanoi exceeded this in both 2019 and 2020. In its 12 downtown districts, the PM2.5 concentration ranged between 31.5-32.9 μg per m3, with the highest concentration detected in Hai Ba Trung District and the lowest in Ha Dong District.

Nationally, 10 out of 25 northern Vietnam localities had yearly average PM2.5 concentration levels exceeding national standards. These were: Bac Ninh, Hung Yen, Hai Duong, Hanoi, Thai Binh, Nam Dinh, Hai Phong, Ha Nam, Ninh Binh and Vinh Phuc.

No localities in the central and southern Vietnam regions exceeded the national standards for yearly average PM2.5 concentration. But certain regions in Thanh Hoa, Ha Tinh, Nghe An, Ho Chi Minh City, Binh Duong and Dong Nai were still impacted by PM2.5 pollution, the study found.

In comparison with PM2.5 concentration standards by the WHO (5 μg per m3 in 2021 and 10 μg per m3 in 2005), all Vietnamese localities surpassed the thresholds during the 2019-2020 period.

The researchers recommended utilizing multi-source approaches and data models based on satellite images in monitoring air quality to create PM2.5 distribution maps for local authorities.

Localities also need to determine PM2.5 sources, among other pollutants, to figure appropriate ways to deal with them, they said.

Hoang Duong Tung, President of the Vietnam Clean Air Partnership, said the fact that 40 percent of northern Vietnam localities have air pollutant levels higher than national standards should prompt policymakers to take serious action.

A previous report by the World Bank based on air samples collected from August 2019 to July 2020 in various air quality stations in Hanoi showed that 26 percent of PM2.5 came from biomass burning, 29 percent from industrial activities and 15 percent from traffic activities.

PM2.5 is defined as ambient airborne particulate that measure up to 2.5 microns in size, just a fraction of the width of a human hair. Their microscopic size allows these particles to be absorbed deep into the bloodstream upon inhalation, potentially causing health effects like asthma, lung cancer, and heart disease.

Exposure to PM2.5 has been linked to negative health effects like cardiovascular disease, respiratory illness, and premature mortality.

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