Ultraviolet (UV) radiation from the sun causes sunburn, skin damage, skin cancer and cataracts.
It is important to understand UV radiation, so you can protect yourself from the sun's damaging rays. The UV Index is a simple way to show the intensity of the sun's UV radiation.
The values of the Index range from zero upward; the higher the value, the greater the potential for skin damage. It divides UV radiation levels into:
Ultraviolet (UV) radiation comes from the sun. But, unlike sunlight, it can't be seen or felt. There are three types of UV radiation:
- UVA : transmits freely through the earth's atmosphere.
- UVB : about 15% of UVB transmits through to the earth's atmosphere. The rest is absorbed by ozone.
- UVC : is absorbed by ozone and does not reach the earth's surface.
UVA and UVB both contribute to sunburn, skin ageing, eye damage and skin cancer. Your risk of developing skin cancer is related to the amount of UV radiation you are exposed to over your lifetime, particularly in childhood.
Temperature is not an indicator of UV radiation levels.
You're just as likely to get sunburnt on a mild wet season day as a sweltering day, as the sun is still high in the sky and has a direct pathway through the atmosphere.
UV radiation can penetrate clouds.
Some people don't use sun protection on cloudy days believing that clouds stop UV rays. Thick cloud provides a good filter, but UV radiation can penetrate thin or scattered cloud.
UV radiation can bounce off surfaces
UV rays reach us directly, in a straight line from the sun, as well as indirectly, by reflecting off surfaces such as light-coloured reflective walls, concrete, sand, water and snow. This is why you can get sunburnt in the shade by rays reflecting in from the side.
Many factors affect UV radiation levels, including time of day, time of year, geographical location and altitude.
With so many factors affecting UV radiation levels, it can be difficult to determine if sun protection is needed on any given day.
You can't just step outside and check the weather to see if UV radiation levels are dangerous. The easiest and most accurate way to work it out is to check the UV Alert, which shows the UV Index for your area or an area near you every day. When the index is 3 or above, skin damage can occur, so you need sun protection. The Northern Territory has high to extreme UV radiation levels everyday of the year.
SunSmart Home