Ultraviolet Radiation (UVR)

Everyone is exposed to UV radiation from the sun on a daily basis. Other sources include solariums, sun lamps and arc welders. Although UV is invisible and cannot be felt, it penetrates our cells, causing sunburn, ageing, eye damage and skin cancer. There are three types of UV, but only UVA and UVB reach the earth's surface. UVC is filtered out by the ozone layer.

  • UVA
can cause premature ageing, skin darkening and wrinkles, DNA skin cell damage and contributes to skin cancer risk

  • UVB
causes sunburn and is the major cause of skin cancer
  • UVC
is the most dangerous type of UV. Ozone in the atmosphere absorbs it so that none reaches the earth's surface

What Affects the Amount of UV?

UV is most dangerous when the sun's rays are most direct and intense. This is affected by a number of things.

  • Time of year
UV remains high in Hong Kong all year round. However the highest-risk months are usually July to October
  • Time of day
UV rays are strongest between 11am and 4pm and are most intense when the sun is high in the sky, around midday
  • Reflection
UV can be reflected off surfaces such as snow, sand, light paint, tiles, cement and water, and can reach your face even under a hat
  • Clouds
UV radiation is absorbed and scattered by clouds and haze, but you can still burn on a cloudy day

What is the UV Index?

UV Index indicates the strength of UV radiation ˇV the higher the number, the stronger the UV radiation. On average, Hong Kongˇ¦s UV index remains at a high level throughout the year, and can often reach extreme levels during the summer. The Hong Kong Observatory publishes daily reports of the UV index. Remember, UV rays can pass through cloud and pollution, so protect your skin year-round.





The Hong Kong Observatory
updates UV readings daily.
Click here for Hong Kong’s local UV index: http://www.hko.gov.hk/wxinfo/uvindex

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