The Sun, at six billion years old, is our most famous star. It provides us with so much, heat and light being just two of its benefits, and yet when it comes to our skin, it can also cause harm
So what are the rays that come from the sun that we should be aware of? ULTRA VIOLET or UV radiation is part of the light spectrum from the sun that reaches us here on earth. UV rays are shorter than the light rays we are aware of, and are invisible to us – this is why we need to be aware of them!
There are three main types of UV rays:
UVA rays – these can pass through glass and penetrate deep into the dermis of our skin. These are the rays that cause damage and can lead to cancer, as well as other health problems. These range from 320 to 400 nanometres (for all you scientists out there, a nanometre is a billionth of a metre!) These types of rays account for 95% of the UV radiation from the sun. They are just as intense on cloudy days as on sunny ones, and can penetrate clouds as well as glass. UVA penetrates the skin more deeply than UVB and causes skin ageing and is a contributing factor in causing skin cancer. When the sun hits the skin over a period of time the skin produces a darker pigment, melanin, to try and counteract the damage. It is this type of damage to the skin that can cause skin cancer. Remember that sun beds focus on emitting UVA rays, and so can be even more dangerous than the sun. It has been argued that first exposure to sun beds during teenage years increases the chances of malignant melanoma by 75%.
UVB rays – are the sun’s burning rays and the primary cause of sunburn. They cannot penetrate glass. These range from 290 to 320 nanometres. UVB reaches the more superficial upper layers of the skin, and as such are also causes of skin cancer, as well as contributing to skin ageing. UVB is at its strongest when the sun is also at its strongest – during midday in summer. Just because you are in the shade, it doesn’t mean you are safe – UVB rays can be reflected by sand and concrete. So always ensure you use sunscreen even if you aren’t in direct sun light. A word of caution in those winter months – UVB rays can also be reflected by snow and ice so can burn your skin if you go sledging or skiing, as well as on sunny summer days.
UVC rays – these are much shorter rays and tend to be absorbed by the earth’s ozone layer. So we tend to be most concerned with UVA and UVB rays.
THE LINK BETWEEN UV RAYS & SKIN CANCER
UV rays damage the skin’s cellular DNA which can lead to skin cancer. The World Health Organisation have confirmed that UV radiation is a proven cause of skin cancer, whether melanoma or non-melanoma cancers.
