The Government Laboratory supports the enforcement of environmental protection legislation and the implementation of various environmental programmes through comprehensive analytical and advisory services. In 2004, the laboratory performed 240 479 tests on environmental samples including air, water, sediment, biota and waste samples, and has provided a large volume of useful data for environmental programmes such as background monitoring, special studies and investigation of illegal discharges. The laboratory's commitment to protect the environment is further exemplified by providing round-the-clock support in the handling of emergencies involving chemical spills or suspected emission of noxious and irritating gas. As part of air quality management, vehicular diesel fuel and unleaded petrol are also routinely tested against legal requirements.

Regarding special studies, the laboratory has continued to offer technical support to the EPD in the implementation of several projects. In particular, the laboratory has analysed stack samples for dioxins to monitor emissions from the Chemical Waste Treatment Centre at Tsing Yi. Furthermore, since 2003, the laboratory has actively participated in a project on the determination of trace organic pollutants in particulates collected in road tunnels. This project was initiated by the EPD in collaboration with the Hong Kong Polytechnic University to provide a better understanding of the air quality in road tunnels. The laboratory has also contributed to the EPD's Toxic Substances Monitoring Program, which keeps toxic substances in the marine environment under close surveillance. The test parameters include dioxins, polychlorinated biphenyls, organochlorine pesticides and polycyclic aromatic hydrocarbons.