The Challenges of Modelling Air Quality in Hong Kong

Only a numerical air pollution modelling system can link together all the processes involved in determining air quality coherently to provide a science-based picture. The PATH (Pollutants in the Atmosphere and their Transport over Hongkong) modelling system was set up in the year 2000 and has since provided useful information on the various aspects of air pollution in and around Hong Kong. The system has also been enhanced to make short-term forecast of air quality. Further upgrade of the system to meet new challenges is continuing. 1. The Basics of Air Pollution – Processes to Simulate Air pollution can be described as a “source to receptor ” relationship. Between the emission sources and what is experienced at the receptors are the transport, transformation and removal of the pollutants. The emissions contributing to Hong Kong’s air pollution come from many sources: power plants, cars, ships, cooking, solvent and chemical usage in industrial and domestic activities as well as nature – vegetation … etc. Ad hoc emissions like fireworks, hill fires and lightnings also impact air quality. All these sources are distributed widely in different area