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Hong Kong Observatory Adopts

New UV Index Classification Scheme

(7 August 2002)

The Hong Kong Observatory (HKO), in co-operation with the Department of Health (DH), will implement a new Ultraviolet (UV) Index classification scheme tomorrow (August 8).

The new scheme (Table 1) was introduced by the World Health Organization (WHO) recently based on a joint recommendation with the World Meteorological Organization (WMO), the United Nations Environment Programme (UNEP), and the International Commission for Non-Ionizing Radiation Protection (ICNIRP). The purpose is to provide a harmonised UV Index classification scheme for adoption by authorities and other organisations in reporting the UV Index and in skin cancer prevention work.

HKO has been providing UV Index advisory service to the public since October 1999, using a UV Index classification scheme made available by WHO at that time.

The UV index is a measure of the potential harm of UV radiation on human health. The higher the UV Index, the more intense and dangerous the UV radiation. When working or playing in the sun, one should always pay attention to the latest UV Index broadcast by the media and take appropriate precautions against over-exposure. Children are especially vulnerable. Therefore, they should not be left in the sun for extended periods of time.

Precautions against over exposure to the sun are given in the new pamphlet 'Be Safe in the Sun - Beware of UV Radiation' produced jointly by HKO and DH to raise the public awareness on the issue. The pamphlet also contains background information on UV radiation, its effect on human health as well as the UV Index classification scheme. This pamphlet is available at HKO's Resource Centre on the 23rd Floor of Miramar Towers, Tsimshatsui, and at DH's clinics/ health centres. It can also be downloaded from the Observatory's homepages at and where additional information on UV radiation can be found.

Last revision date: <20 Dec 2012>