South China Morning Post — 18th Feb. 2011
Poor visibility in Hong Kong is mainly caused by photochemical smog.
Under sunlight, volatile organic compounds react with nitrogen oxides to form ozone, which in turn helps in the formation of fine particulates.
The accumulation of ozone, fine particulates and other gaseous pollutants results in photochemical smog.
Smog is harmful to our health, especially for senior citizens and children.
Nitrogen oxides are released when nitrogen and oxygen in the air react together under high temperature, such as in the exhaust of fossil-fuel vehicles and power stations.
Volatile organic compounds are released from sources such as petrol, paints and solvents.
The most effective way to have better visibility in Hong Kong is to curb emissions of both.
What Hong Kong can do locally is: (1) rationalise bus routes; (2) phase out all commercial diesel vehicles and buses of early Euro standards; (3) widen use of electric vehicles; (4) introduce vehicle congestion charges in commercial business districts; (5) make use of low-sulphur diesel mandatory for all vessels entering Hong Kong waters; (6) replace town gas with natural gas for cooking and heating; (7)restrict use of coal to less than 20 per cent of the fuel mix for power generation; and (8) extend the coverage of building energy efficiency regulations to all commercial buildings.
Given that air quality in Hong Kong is significantly subject to cross-border influence, it is imperative that the Guangdong provincial government also align itself with the best practices in the world to curb emissions from its power, transport and industrial sectors.