THE ENVIRONMENT
Monitoring and Investigation
259
It is important that public and private sector resources for controlling pollution are used effectively and efficiently; to achieve this it is essential to identify the nature and extent of the problems. This requirement, together with the need to check on the effectiveness of newly introduced control measures and to recognise new adverse trends, has led to various monitoring schemes and investigational projects.
The government's network of six multi-pollutant air quality monitoring stations con- tinues in operation and over 20 million measurements were taken, analysed and reported during the year. Results from the network demonstrate that the urban levels of sulphur and nitrogen oxides, which are emitted as a result of fuel combustion from stationary sources and motor vehicles, are generally low. As would be expected, the highest con- centrations were observed in industrial areas such as Kwun Tong or Kwai Chung. Levels of these pollutants in 1985 declined 'somewhat when compared with 1984 values. Monitoring of acid rain commenced at selected urban and rural locations during the year. Particulate levels remained relatively high throughout the territory, notably during dry winter months. The high particulate levels observed in Junk Bay during the year show that the problem is not confined to urban areas. Preliminary measurements of respirable particulate matter indicate that these fine size fractions represent a major proportion of atmospheric particulates in the urban areas.
As in previous years, there was little indication of photochemical smog occurring at monitoring stations on Hong Kong Island or in Kowloon. A number of aerial ozone sampling exercises were carried out, using aircraft of the Royal Hong Kong Auxiliary Air Force. Concentrations measured were not in general excessive; however, the presence of photochemically generated pollutants was detected on some flights.
Investigations of photochemical pollution in rural areas are to be followed up by the EPA, using a new mobile air quality monitoring laboratory. This facility has been provided in order to expand monitoring to areas not covered by the present network of fixed stations and to provide added flexibility in air monitoring capabilities. In addition to rural ozone monitoring, the laboratory will be used for monitoring vehicle pollution and for special short-term investigations at specific locations.
Major surveys have been undertaken on the impact of industrial noise on residential premises, the economic impact of proposed industrial noise controls and the back- ground noise of various land configurations. These surveys have produced a large amount of information for the development and implementation of industrial noise control legislation.
Extensive monitoring of solid and semi-solid wastes have been carried out to assist the planning of future collection and disposal facilities. It is estimated that general waste will increase from the present level of over 6 000 tonnes a day to as much as 9 000 tonnes a day by the end of the decade. The most recent survey shows that in 1984 the main components of municipal wastes were paper (22 per cent by weight), putrescibles (33 per cent), plastics (18 per cent) and rags and cotton (5 per cent), whereas industrial waste comprised mainly paper (20 per cent), plastics (18 per cent), rags and cotton (23 per cent), glass (10 per cent) and wood (8 per cent). The quantities of waste recycled increased in 1985; the recycled quantities of paper, board and aluminium alone were 25 per cent of the wastes delivered to the incinerators and controlled tips, and this helped significantly to reduce the amount of wastes requiring disposal.
A growing awareness among industrialists concerning the proper disposal of toxic, hazardous and difficult wastes was reflected in the number of occasions on which advice