ENG-1982 — Page 311

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THE ENVIRONMENT

and co-ordinate investigations involving mainly the Labour Department, the Fire Services Department, the Education Department, the Government Laboratory and the EPA. Out of the total number of cases reported, possible causes for nine were found. However, there was no uniformity in the type of incidents giving rise to the reports. Some were due to the release of a stink bomb inside a class-room, or odour emission from sludge cleaning or petrol filling outside a school, or from improperly disposed zoological specimens. In the other cases, sources could not be found even after thorough investigation.

The 12-month mean averages of sulphur dioxide recorded at the four daily monitoring stations at Hung Hom, Queen Elizabeth Hospital, Sham Shui Po and Central Market were respectively 50 μg/m3, 76 μg/m3, 23 μg/m3 and 52 μg/m3 and the corresponding smoke density readings were 19 μg/m3, 36 μg/m3, 42 μg/m3 and 58 μg/m3. The highest daily reading of sulphur dioxide registered was 420 μg/m3, which was below the maximum guideline of 1 310 μg/m3 recommended by the former Advisory Committee on Air Pollution.

An environmental survey, Project Simla, was conducted under the supervision of the Air Pollution Control Division and carried out by students from the Chemistry Department of the University of Hong Kong during the summer vacation. This year's programme included an investigation of nuisance dustfall levels in the vicinity of construction sites, quarries, and landfill areas, and a survey to study sulphur dioxide concentration in the plumes of existing industrial discharges.

Envisaged under the Air Pollution Control Bill is a scheme for air quality management and planning that represents a new concept for Hong Kong. In terms of this scheme, it is proposed that Hong Kong should be divided into air control zones to be declared by the Governor-in-Council, with the air quality objectives for each zone being set by the Secretary for Home Affairs, following consultation in both cases with EPCOM. It is further proposed that major new polluting processes, i.e. those scheduled in the bill as 'specified processes', should be subject to licensing and required to use the best practicable means to prevent the discharge of noxious or offensive emissions. Existing specified processes, it is intended, should be required to be registered but will otherwise generally be exempt from the licensing requirement.

During the year, the EPA took measurements of sulphur dioxide and coefficient of haze at six sites throughout Hong Kong to provide data on air quality in urban areas and Junk Bay. Measurements are supplemented by on-site acquisition of meteorological data at a number of locations, together with air chemistry measurements of oxides of nitrogen and ozone at an urban site.

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In addition to these measurements, the EPA continued its survey of kerbside levels of traffic-related air pollutants, including carbon monoxide, coefficient of haze, total suspended particulate matter, lead and benzo(a)pyrene.

Water Pollution

The effects of strong coastal currents in Hong Kong waters have helped to a large extent to dilute the severity of its pollution problems. With the main centres of population and industry being concentrated around Victoria Harbour, a new treatment works is being built to serve northwest Kowloon, and existing outfalls are being extended to deeper water for better dispersion and dilution.

The establishment of new towns and the expansion of the industrial base in areas of restricted water circulation (such as Tolo Harbour) has led the Engineering Development Department to develop a new approach to maintain and improve conditions. The new