THE ENVIRONMENT
noise from its operation. Construction activities still generate smoke and dust as well as producing vast quantities of solid waste that need safe disposal.
The Noise Control Ordinance, its regulations and two technical memoranda, are the major instruments for the control of construction noise. The Environmental Protection Department controls the operation of powered mechanical equipment in general con- struction work during weekday night-time (7 pm to 7 am) and on Sundays and public holidays by means of a construction permit system. The department assesses permit applications in accordance with noise criteria and procedures contained in a technical memorandum. The permits generally specify the number and type of equipment that may be used.
The department has recognised the need to provide controls on specific types of particularly noisy construction equipment during daytime. Hand held percussive breakers and air compressors, which affect tens of thousands of people when being used for demolition and in road works, are the first equipment to come under control. The regulations came into effect on March 1, 1992 and were implemented in stages through the year. All hand held breakers and air compressors must now satisfy stringent noise requirements and need a 'green' noise emission label before they may be used in Hong Kong. There were 2 915 label applications and 2 763 labels issued.
Whenever practical, the department will require the use of silenced equipment and adoption of noise reduction measures to minimise the noise impact. The EPD and the police respond to complaints relating to night-time construction work, and carry out inspections. In 1992, there were 1 670 permit applications; 1412 permits issued; and 36 prosecutions.
For the construction of the airport core projects, the department issued a total of 80 permits. The Executive Council granted exemptions for the construction of the new airport and the Lantau fixed crossing subject to the provision of noise mitigation measures and stringent monitoring requirements.
The Noise Control Ordinance bans percussive piling from 7 pm to 7 am on weekdays and any time on Sundays and public holidays. Percussive piling at other times is controlled by a permit system, which confines operations to specific hours in a day. It employs a time restriction mechanism so that those piling operations that most affect noise sensitive receivers will be allowed to work fewer hours. This system encourages contractors to use some of the quieter piling methods currently available and to enable noise sensitive receivers to plan their activities to minimise interruption. During 1992 there were 496 permit applications; 495 permits issued; and six prosecutions.
One of the important air pollution concerns in construction and demolition is the control of asbestos. The Air Pollution Control (Amendment) Bill submitted to the Legislative Council in June 1992, proposed to introduce a full range of measures for the control of materials containing asbestos in buildings and ships, registration of asbestos consultants, contractors, supervisors and laboratories, and banning the import and sale of asbestos (amosite and crocidolite). To pave the way for the effective enforcement of the new regulations, the Environmental Protection Department installed a transmission electron microscope in September 1991. This provides analytical support for the definitive identification of asbestos fibres.
During 1992, the department made 360 inspections, mainly on building demolition and renovation sites, including Kowloon Walled City, temporary housing areas, housing estates
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