Ultraviolet radiation
Every day, just about every Australian is exposed to ultraviolet radiation
(UVR) from the sun.
How the sun affects our skin depends on the type of UVR, the amount we’re exposed to, as well as our behaviour and personal traits.
Types of UVR
There are three types of wavelengths that form solar UVR: UVA, UVB and UVC.
- UVA – causes premature ageing and wrinkling of the skin and is a cause of skin cancer
- UVB – is more dangerous than UVA and causes sunburn, cataracts and skin cancer
- UVC – is extremely dangerous but does not reach the earth’s surface
All of the UVC is absorbed by the earth’s upper atmosphere and less than 10% of UVB reaches the earth’s surface. UVA on the other hand, reaches the earth’s surface with little change. Therefore, most of the UVR that reaches the earth’s surface is UVA and some UVB.
Overexposure to UVR can cause serious damage to your skin and eyes. The effects
of tanning build up over your lifetime, even if you haven’t been burnt often. Most
Australians' lifetime exposure to UVR happens during childhood to young adulthood.
It’s important to protect your skin throughout your life but particularly during
these life stages.
Amount of UVR
While we can't control the type of UVR that reaches the earth's surface, we can
control the amount of UVR our skin receives. We can do this by protecting our skin
and by being aware of the changing intensity of UVR.
Because Australia is relatively close to the equator, we receive higher overall
levels of UVR than countries such as Canada, Germany or the United Kingdom.
The amount of UVR our skin receives is also influenced by the sun's position in
the sky. The higher the sun, the higher the levels of UVR. This is why the biggest
danger-zone for our skin is the four hour period around noon. During daylight savings,
it's best to seek shade between the hours of 11am and 3pm.
While heavy cloud cover can reduce UVR levels, in certain situations clouds can
actually increase the amount of ambient UVR. Due to the changing nature of clouds,
it's best to be prepared with sun protection.
UV Index meter exposure advice
The UV Index is a measure of the strength of ultraviolet radiation (UVR) at a
particular place on a given day, date and time. The website changes colour according
to the current UV level. The UV Index is grouped into colour-coded categories.
|
Low
|
< 2
|
|
Moderate
|
3 - 5
|
|
High
|
6 - 7
|
|
Very High
|
8 - 10
|
|
Extreme
|
11+
|
Check the UV Index page
Being aware of the UV Index can help you plan your sun protection needs before heading outdoors.
Download the Desktop UV Index Weather Tool. This tool sits on your desktop to provide you with UV Index and temperature information.
Interesting links:
Bureau of Meteorology: www.bom.gov.au/info/about_uv.shtml