THE ENVIRONMENT
were conducted in environmental monitoring programmes on air, water, sediment, aquatic species, effluent and sewage discharge, and 2 415 tests for litigation purposes. On-site investigations and advisory services were also provided for emergency handling of chemical spillage and emission of noxious gases.
Apart from acting as analytical experts in assisting clients to oversee environmental impact assessment projects, the laboratory also provided support for Hong Kong's participation in various environmental programmes such as the National Marine Environmental Monitoring Network organised by the Mainland. The participation would facilitate resolving the cross-boundary environmental problems concerned.
To enhance the scope and speed of analytical services, efforts were made for continuing development of test methodology. Testing techniques developed in 1999 included selective accelerated solvent extraction for trace organic analysis, determination of dioxins in various types of environmental samples and measurement of volatile organic carbons in ambient air.
Besides maintaining strict quality control in analytical work, the laboratory has also adopted measures to reduce the impact of its operations on the environment. In 1999, the three environmental Sections of the laboratory were certified under the ISO14001 for environmental management.
Climate
Hong Kong's climate is sub-tropical, tending towards the temperate for nearly half the year. During November and December, there are pleasant breezes, plenty of sunshine and comfortable temperatures. Many people regard these as the best months of the year.
January and February are cloudier, with occasional cold fronts bringing in cold northerly winds. Temperatures can drop below 10 degrees Celsius in urban areas. Sub-zero temperatures and frost occur on high ground and in the New Territories infrequently.
March and April can be mild and pleasant but occasional spells of high humidity occur. Fog and drizzle sometimes disrupt air traffic and ferry services because of reduced visibility.
May to August are hot and humid with occasional showers and thunderstorms, particularly in the morning. Afternoon temperatures often exceed 31 degrees, but at night temperatures generally remain around 26 degrees.
Hong Kong is most likely to be affected by tropical cyclones in September, although tropical cyclones of varying strength are not unusual at any time between May and November. On average, about 31 tropical cyclones form over the western North Pacific and the China Seas every year, and about half of them reach typhoon strength with maximum winds of 118 kilometres per hour or more.
When a tropical cyclone is about 700 to 1 000 kilometres southeast of Hong Kong, the weather is usually fine and exceptionally hot, but isolated thunderstorms sometimes occur in the evening. If the cyclone's centre comes closer to Hong Kong, winds will increase and rain may become heavy and widespread. The heavy rain may last a few days, and landslips and flooding sometimes cause considerably more damage than the winds.
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