Hanoi air quality improves, still among Southeast Asia’s worst

The city’s average PM2.5 level last year was 40.8 micrograms per cubic meter of air as opposed to 45.8 in 2017, according to Switzerland-based air quality monitor IQAir AirVisual's 2018 World Air Quality Report.

IQAir AirVisual, which generated data from public, ground-based and real-time monitoring stations, surveyed air quality in over 3,000 cities globally by measuring PM2.5 levels, referring to particulate matter of up to 2.5 microns in size, regarded as the pollutant with the most health impact.

But the Vietnamese capital remained among the most polluted capital cities in the world, ranked the 12th worst in the list of 62.

In Southeast Asia, Hanoi was the second most polluted city behind Jakarta, Indonesia, which had a PM2.5 level of 45.3.

PM2.5, also described as super fine particles, is a fraction of the width of a human hair, which is released from vehicles, industry and natural sources like dust. The World Health Organization (WHO) Air Quality Guideline recommends an annual mean exposure threshold of 10 μg/m3 to minimize health risks.

But 64 percent of the cities surveyed exceeded this guideline. In Southeast Asia, the rate was 95 percent.

Saigon’s air quality worsened during last year to 26.9 from 23.6 in 2017. The southern Vietnamese metro was the 15th most polluted city in Southeast Asia.

The 15 most polluted cities in Southeast Asia in 2018, with Hanoi in second place and Ho Chi Minh City in 15th. Photo screenshot from IQAir AirVisual's 2018 World Air Quality Report

Vietnam ranked 17th globally and second in Southeast Asia with an average PM2.5 level of 32.9.

The report blamed pollution in Southeast Asia on the burning of biomass and vehicular emissions.

In urban areas, there is a strong correlation between transportation and industry and air pollution, it said.

Hanoi in particular, which has 7.7 million people, has more than five million motorbikes and 550,000 cars.

Nguyen Duc Chung, the city chairman, warned in July 2017 that air pollution had reached the level of "red alert", and blamed it mainly on vehicles.

The report said governments should increase the number of air quality monitoring stations to generate more public data, while the average citizen should make lifestyle changes such as choosing environment-friendly modes of transport like cycling and walking and reduce household energy usage to combat pollution.