Cleaner air with new link

January 1, 2019

The world’s largest air purification system will clear most of the pollutants generated from vehicles using Hong Kong’s new Central-Wan Chai Bypass & Island Eastern Corridor Link.


The system will handle more than five million cubic metres of tunnel exhaust per hour, the largest of its kind globally in terms of volume of air handled, from the 4.5 km-long link, which includes a 3.7 km tunnel section.


“Every hour it can handle 5.4 million cubic metres of vehicle exhaust and reduce 80% of the respirable suspended particulates and nitrogen dioxide from the tunnel exhaust,” Highways Department Project Manager/Major Works Kelvin Lo said.


Large fans will suck tunnel exhaust into the air purification plants in three ventilation buildings along the tunnel section of the link.


In the system, the exhaust will pass through two major components that remove the pollutants.


It will first go through the electrostatic precipitator that separates respirable suspended particulates, which are charged and attracted to collector plates.


Nitrogen dioxide will then be removed from the exhaust in the system’s denitrification filter which is filled with activated carbon.


Purified air will then exit the system, improving the nearby air quality.


The project will also cut down the journey time from Central to the Island Eastern Corridor from about half-an-hour to five minutes and divert traffic from other parts of the city.


Mr Lo said: “The faster journey time will mean lesser emissions of carbon dioxide.


“Every year, we estimate that it can reduce the carbon dioxide by 11,000 tonnes. This is equivalent to the absorption power of 480,000 trees, which is equivalent to 67 Victoria Parks.”


Green inspiration

The Highways Department also saw the project as an opportunity for greening the urban environment.


The West Ventilation Building, with its streamlined green roof which stretches over the Central Tunnel Portal, is shaped like a suspended green leaf, while scrubs and lianas are planted around the East Ventilation Building.


“It’s the department’s drive to always provide aesthetically pleasing and appealing designs, so in this project we try to enhance the greening so that it looks beautiful for the adjacent community,” Mr Lo added.


The East Vent Shaft is designed to look like a sail of a boat and will also light up Victoria Harbour at night.


The major project will alleviate traffic congestion at the city’s major thoroughfares and will open on January 20.

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