ENG-1992 — Page 439

THE ENVIRONMENT

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The results of measurement at the Kwai Chung, Central and Western, and Mong Kok monitoring stations are reported each month and published in the leading newspapers. These stations broadly represent air quality respectively in districts close to industrial areas, in combined commercial and industrial districts, and near road traffic in built-up urban areas.

The department also operates a mobile air quality monitoring laboratory. In 1992, it was used to conduct an air quality study in Chai Wan, where no fixed station has yet been established.

In view of concerns about high nitrogen dioxide levels adjacent to roads, a territory-wide survey of nitrogen oxides concentration was carried out starting from the end of 1991, to supplement measurements made at the fixed air quality monitoring stations. About 100 passive diffusion tube samplers were used to record nitrogen oxide levels. The results so far confirm that nitrogen oxides levels are generally high throughout Hong Kong's busy road network.

The department measures municipal solid waste arisings twice a year to collect up-to-date information for planning future waste disposal facilities. Compared with the 1991 arisings, total waste quantities deposited at landfills and incinerators dropped by 15 per cent to 20 300 tonnes per day in 1992. The decrease was due to a 24 per cent reduction in the amount of construction waste received at the landfills whereas the quantities of domestic waste, industrial waste and commercial waste increased by seven per cent, one per cent and 11 per cent respectively. The decrease in construction waste disposed of at landfills was due to the increased use of such wastes to create land in reclamations.

Local waste recovery activities continued to play an important role in waste manage- ment, resulting in the export of substantial quantities of recovered waste materials for recycling overseas. A total of 1.4 million tonnes of waste materials including waste paper, metals and plastic were exported in 1992, generating export earnings of $2.4 billion. About 550 000 tonnes of waste paper, used lubricating oil, metals, plastic scrap and glass were reprocessed locally in 1992.

The government continued to encourage waste separation at source, which will help recycling activities and reduce the demand for scarce landfill space. A pilot scheme for construction waste recycling, involving sorting and reprocessing different types of construction waste, was carried out in May 1992. The main finding of the trial was that a large proportion of construction waste could be used to create land after limited sorting and removal of undesirable material such as wood. It was concluded that much of this separation of different materials in construction wastes could practically take place at

source.

The Environmental Protection Department also carries out noise monitoring and surveys. It is concerned about roads in densely populated and congested metropolitan areas. Resurfacing noisy roads with quiet surfacing material will continue to provide relief for people adversely affected by traffic noise.

The need to protect residents from the impact of future operational noise from major development projects is a continuing preoccupation for the noise specialists in the Environmental Protection Department. For example, in the cases of the Western Harbour Crossing and the development of Container Terminal 9, not only quiet surfacing material, barriers and road covers have been thoroughly considered and acoustic insulation will be offered to some 3 000 homes to reduce the noise.