An environmental protection group has said that roadside air quality across Hong Kong has not improved much in two decades.

The group, Clean Air Network, said in its 2016 Air Quality Review that – for the past 20 years – the average roadside nitrogen dioxide level was consistently twice that of a upper limit suggested by the World Health Organization.

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Hong Kong’s AQI last Thursday was at more severe levels than in Beijing. Photo: HKO.

There has been a downward trend since 2013, but it was still higher than that in 1996. The group linked the high level to the near-doubling of the number of cars on the road over the past 20 years to more than 800,000 in 2016.

Higher nitrogen dioxide pollution level is usually recorded in urban areas – namely Causeway Bay, Mong Kok, Central and Kowloon West districts such as Sham Shui Po, and New Territories West districts such as Tsuen Wan, Kwai Chung and Tuen Mun.

Vehicle speed

It also said the consistently decreasing traffic speed in urban areas also made the traffic congestion more serious, also affecting roadside pollution.

According to the Transport Department, the average traffic speed decreased from 25.6 km/hour in 2003 to 22.7 km/hour in 2013.

The group further found that the west side of Hong Kong generally has a higher traffic flow than the east side – which matched data that suggested nitrogen dioxide levels were higher in the west than the east.

“The out-of-control increase in cars, serious traffic congestion and slow traffic speed are the main reasons that the roadside air quality did not improve over the past 20 years,” it said.

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Clear the Air Network protest. File photo: Clear the Air.

“The mistakes with traffic planning and the out-of control increase in cars have brought huge economic lost to Hong Kong and cost large amount of public funds.”

The group urged the new administration, due to be appointed this year, to form a new comprehensive plan to consider issues such lowering car exhaust levels, improving traffic demand management, and better city planning.

It also asked the government to consider expanding the current “low emission zones” in Central, Causeway Bay and Mong Kok, to charge high polluting cars entering these areas, and set up an electronic road pricing system in core business areas.

Kris Cheng is a Hong Kong journalist with an interest in local politics. His work has been featured in Washington Post, Public Radio International, Hong Kong Economic Times and others. He has a BSSc in Sociology from the Chinese University of Hong Kong. Kris is HKFP's Editorial Director.