In order to better understand why it is so important to ensure one's sunscreen offers broad spectrum protection from both UVA and UVB rays, it is first necessary to understand exactly what is meant be the term UV radiation.
What is UV Radiation?
The sun's energy is recognised as travelling in wave-like pattens which may differ in terms of both their frequency and length. UV and Gamma rays are thus the form in which the highest frequency and shortest wave-length energy from the sun reaches the earth. These UV rays come in three spectrums including UVA, UVB and UVC, each of which have different wave lengths and frequency levels. UV rays are more harmful in certain locations and at certain times of the year. For example, those living close to the equator or at high altitudes are more at risk with UV rays also being more harmful during the summer months.
It is important to be aware that even when the weather appears cloudy, UV radiation is still present, making it possible to suffer skin damage despite not seeing the sun. Information on UV predictions can be seen on weather forecasts and in daily newspapers.
Understanding UVA Radiation
UVA radiation has both the longest wavelength and the lowest frequency with levels remaining fairly stable all year round. Tanning salons will usually use UVA radiation to create a tanning effect through the use of UVA bulbs. Unfortunately for those who regularly use tanning facilities, it is UVA rays which are believed to penetrate the skin very deeply and thus result in signs of premature aging, including wrinkles on the face. There is also research indicating that UVA may serve to initiate the most dangerous form of skin cancer known as malignant melanoma as a result of damaging DNA.
Recently, studies have identified that this form of radiation affects the body's immune system and acts as a immunosuppressive agent. Research has also shown that exposure to UVA actually causes a large fall in the body's immune cells which in turn make it easier for malignant cells to grow.
Understanding UVB and UVC Radiation
Research has clearly identified a direct link between UVB radiation and the development of tumours resulting in every different type of skin cancer. UVB is significantly more harmful than UVA during the summer months. This form of radiation is recognised to damage DNA and this then results in tumours developing. When UVA tanning salon bulbs age they also start to produce UVB damage making them a potentially very serious health risk.
In direct contrast to UVA, UVC has the highest frequency and the shortest wavelength and is recognised to be the most harmful of all. The ozone layer is currently absorbing the majority of UVC rays which prevent them reaching the earth. However, due to the environmental state of the planet, this layer is being depleted and will eventually greatly increase the risk of suffering from skin cancer.
As highlighted above, UV rays are part of how the energy from the sun reaches the earth and include UVA, UVB and UVC forms of radiation. Risk factors associated with the development of malignant melanoma and other forms of skin cancer significantly increase the closer a person lives to the equator and the higher the altitude.
Source:
McClay et al. (2004) 100 Questions and Answers About Melanoma and Other Skin Cancers Massachusetts: Jones and Bartlett
Kate Le Page - Kate Henning-Le Page writes about eating disorders, body image and recovery issues. She specializes in anorexia recovery.
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