West side of Hong Kong and the poor most at risk from city’s dirty roadside air, study finds
Problem will only continue to worsen in the absence of better transport management policies, green group says
Recent Hong Kong government figures may show a general improvement in air quality – but the threat to public health from street level pollution remains dire and will continue to worsen in the absence of better policies in transport management, an environmental group has warned.
The Clean Air Network has found roadside air pollution to be worst in the western parts of Hong Kong, with the hardest hit neighbourhoods also the poorest, most socially deprived, densely populated and clogged with traffic.
“Major air pollutants may be decreasing in concentration but the public’s health is still not sufficiently protected,” said community relations manager Loong Tsz-wai. “The government must target the crux of the problem and that is high traffic density.”
In the first half of the year, average nitrogen dioxide (NO2) concentrations at monitoring stations on the city’s eastern side, including Tseung Kwan O, Tai Po and in Eastern district, averaged about 39 micrograms per cubic metre of air. This was within the city’s own air quality objective and World Health Organisation limit of 40mcg.
In western Hong Kong however, which includes districts such as Sham Shui Po, Central and Western and Tung Chung, the average concentration was a much higher 50mcg.
The group also attempted to measure pollution in West Kowloon districts around the local monitoring stations and found roadside pollution much higher than official readings. At five primary schools located near an expressway, NO2 readings ranged from 76 to 125mcg, far above WHO standards.
Citing previous academic studies, Loong said there was a positive correlation between a district’s population, household income, traffic density and air quality. The more populated and less well-off areas had greater traffic and thus were more exposed to unhealthy air.
“Most districts in western parts of the territory which have lower household incomes and denser populations were found to have worse air quality,” he said, adding that Sham Shui Po, Kwai Tsing and Kwun Tong were the districts in most need of help.
According to the group, a district with high traffic density alone increased the excess risk of mortality from respiratory diseases by 59 per cent. Mortality rates by respiratory and circulatory diseases in such districts were found to be up to 2 per cent higher than in other districts.
Loong admitted that the Environment Bureau had been doing what it could within its policy ambit to curb pollutants, but he urged the new administration to start looking at air pollution from a public health perspective and tackling it with better traffic management policies.
“This is clearly a public health issue ... but the Food and Health Bureau has never devised any action plan on this,” he said. “The Transport and Housing Bureau also never sets any targets for traffic congestion or roadside air quality.”
Acknowledging that congestion worsened roadside air quality, the Transport and Housing Bureau said it was already taking into account recommendations made by the Transport Advisory Committee to tackle traffic congestion, including management of the city’s private car fleet.
A Food and Health Bureau spokeswoman said air quality was an environmental issue and declined to comment.
The Environment Bureau acknowledged that the air was worse in western areas but said partial statistics often did not reflect the full picture of a year’s air quality. Concentrations of major pollutants had fallen by about 30 per cent between 2012 and 2016, it added.