XN000022-1995-04-26 — Page 27

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Sulphur dioxide has been recorded at low levels throughout the territory. The yearly averages for all monitoring stations have been well within the air quality objective.

Nitrogen dioxide has been recorded at higher levels, with concentrations within the air quality objective at around 80%, with one exception. Because motor vehicles are a major source of nitrogen dioxide, levels tend to be high in districts with heavy road traffic, e.g. Mong Kok.

TSP and RSP are dust in the air. Levels of TSP have been high and the air quality objective has been exceeded at all stations, except Sha Tin. However, it is RSP which are of more concern in terms of health effects because they are small enough to breathe into the lungs. Levels of RSP have generally been within the air quality objective in Sha Tin, Tai Po and Kwai Chung; but in districts with heavy traffic, e.g. Kwun Tong, Sham Shui Po and Mong Kok, the concentrations of RSP have been higher than the air quality objective.

As for the causes of air pollution, the fuels burnt in factories and used by motor vehicles are the major causes of sulphur dioxide, nitrogen dioxide and particulates; dust emissions from construction works and open burning activities also contribute to the particulates problem.

The Government is determined to improve air quality in Hong Kong. The Air Pollution Control (Fuel Restriction) Regulations introduced in 1990 reduced the sulphur content of liquid industrial fuel to 0.5% by weight and brought ambient sulphur dioxide concentrations well within the air quality objective. A number of other measures have also helped reduce polluting emissions. These include the extension of controls on specified processes under the Air Pollution Control Ordinance; the introduction of unleaded petrol in 1991; the requirement for all vehicles imported since 1992 to comply with stringent vehicle emission standards and newly imported petrol vehicles be equipped with catalytic converters; and the smoky vehicle control programme. In addition, with effect from 1 April 1995, we have introduced cleaner diesel fuel for vehicles and even more stringent vehicle emission standards.

We are also working towards the introduction of additional measures to ensure that the air quality objectives are achieved. The measures being considered include: