Hanoi's air quality dropping over large scales

By Vo Hai   March 6, 2024 | 05:00 am PT
Hanoi's air quality dropping over large scales
Aerial view over the Thang Long Avenue in Hanoi reveals layers of haze at around 11 a.m., March 6, 2024. Photo by VnExpress/Ngoc Thanh
Air quality in Hanoi has been dropping as the levels of fine dust particles in the air were twice as much as the normal standard on several days.

The Hanoi People's Committee is seeking opinions on the management of air quality until 2030, with vision until 2035, to combat the worsening trend of air quality on a large scale at the capital.

Citing national environmental reports, Hanoi authorities said the average level of PM2.5 in the air for the 2018-2020 period was twice as much as the national standard (at 25 μg/m3). 30.5% of the days in 2019 recorded low air quality levels, they added.

Over the past few months, Hanoi has seen frequent haze in the morning and the evening, with air quality levels at unhealthy and hazardous levels.

Data from Swiss air quality technology company IQAir showed Hanoi's pollution was at "very unhealthy" level on Monday and Tuesday morning, meaning a PM2.5 level of 150.5-250.4 μg/m3. The quality improved in the afternoon but was still deemed unhealthy and possible to cause health effects to the large public.

Treatment, economic cost

Reports showed large discrepancies between yearly average PM2.5 levels between Hanoi’s districts and towns, with higher dust levels in downtown areas and lower levels in suburban areas, except for Gia Lam, Dong Anh and Thanh Tri districts.

The level of PM2.5 during the winter is especially high due to unstable weather patterns, which limit the propagation of pollutants. In the summer, air quality tends to be better thanks to the presence of rains washing away air pollutants, and winds coming from the sea that help propagating pollutants elsewhere.

So far, Hanoi has not listed out all sources of air pollutants in their entirety. However, research from the Ministry of Natural Resources and the Environment, as well as the World Bank, revealed that the main sources of PM2.5 and PM10 dusts are road traffic vehicles and road dusts. Traffic-related sources in particular account for 66.3% of the PM2.5 pollutants, and 54% of the PM10 pollutants.

The burning of straws and industrial activities are also considered as the second-largest source of PM2.5 and PM10 pollutants.

"The city is facing an air pollution issue, mainly caused by PM2.5 dusts, that impacts community health and incurs economic losses," the report said, citing how Hanoi records over 1,000 cases of hospitalization due to cardiovascular diseases and 3,000 cases due to respiratory diseases a year on average, accounting for 1.2% and 2.4% of all hospitalized cases, respectively.

In the 2011-2015 period, the cost of medical diagnoses and treatment, as well as economic losses incurred due to people taking days off work, in downtown areas amount to around VND1,500 (6.1 U.S. cents) per person per day, totaling to around VND2 trillion ($80.95 million) a year for a downtown population of 3.5 million people.

Another 2020 study by the National Economics University in Hanoi also revealed that air pollution costs Vietnam $10.82-13.63 billion a year.

Future goals

Hanoi currently aims for at least 75% of the days within a year to see at least average air quality levels based on the VN-AQI criteria by 2030. The index is calculated using statistics on the level of air pollutants in Vietnam, with good air quality having an index between 0-50, average air quality at 51-100, poor air quality at 101-150, unhealthy air quality at 151-200, very unhealthy air quality at 201-300 and hazardous air quality at 301-500.

Hanoi also aims for the level of PM2.5 in downtown areas to be below 40 μg/Nm3 on yearly average, and below 35 μg/Nm3 on yearly average for suburban areas. Such values are still higher than the national standard at below 25 μg/Nm3.

The capital also aims to reduce PM2.5 emissions from main sources, specifically a citywide 20% reduction from 2019, amounting to a reduction of 6,200 tons of PM2.5. For other pollutants like sulfur dioxide, nitrogen dioxide and carbon monoxide, the city will ensure to keep the levels of these pollutants within national standards.

In April last year, a report by the Hanoi People's Council determined that air quality levels in the capital in 2020 and 2021 were either good or average. There was a disruption in data collection in 2022 due to several stations stopping operation over the lack of components.

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