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  • David Price

Rays of Light

Without the Druids and Gandalf lookalikes dancing around Stonehenge on Monday, you'd never know that the summer solstice had arrived and passed. This celebration of the longest day usually confirms that summer has well and truly arrived and we should expect endless hours of uninterrupted sunshine.

Sadly, the start of summer has been slow, but that doesn’t mean that we haven’t had a few introductory days as a sign of things to come. Whether the sun is out or not, the chances of coming into contact with the Ultraviolet radiation (UV) are still very high so we thought we'd highlight what we are dealing with.

What is UV radiation?

UV radiation is a form of electromagnetic energy that can come from a natural course like the sun, but artificially it can come from such sources like lasers, tanning beds and black lights. The suns production come by way of a nuclear reaction at the suns core which then travels to the earth via its rays. The UV rays are classified according to wavelength: UVA (longest wavelength), UVB (medium wavelength), and UVC (shortest wavelength).

UVA rays;

Have a higher wavelength, but lower energy levels than the other UV rays and are more penetrating than the UVB rays. This can affect the inner cells in the top most layer of the skin, including the dermis. It will also cause the skin to age prematurely, leading to visible effects such as sun spots and wrinkles .

Unfortunately, the UVA rays are not absorbed by the ozone layer with about 95% of the UV rays that reach the ground being UVA rays. The immediate effect of such, without protection will be sunburn with the effects of UVA rays tending to appear right away.

The rays can penetrate windows and clouds.

UVB rays:

Unlike the UVA rays, the UVB rays have shorter wavelengths but higher energy levels, damaging and burn the top layers of the skin, leading to blistering. Long term effects from UVB rays can be premature ageing of the skin as well as skin cancer. The majority of the damaging UVB rays are absorbed by the earth's ozone layer but around 5% of the total UV rays that reach the ground are UVB rays and are unable to penetrate the windows.

UVC rays;

The least well known of the 3,UVC rays have the shortest wave lengths but the highest energy levels of the three types of UV rays. As a result, they can cause serious damage to the top layer of skin like ulcers, lesions and severe burns. Fortunately, the majority of the UVC rays are completely filtered out by the ozone layer and never reach the ground. Although UVC isn’t considered a risk for skin cancer, man-made sources from welding torches, special bacteria-killing light bulbs, and mercury lamps can be very harmful ,causing severe damage to the eyes and skin, including burns, lesions, and ulcers on the skin.

Factors affecting the strength of the rays.

  • Time of the day: UV strength is at its highest between 10 a.m. and 4 p.m. This is a result of the sun’s rays have less distance to cover making it very harmful.

  • Season: As expected the UV strength is at its highest during the spring and summer months where the sun is at a higher angle, which increases UV ray intensity. However, the sun can still affect you during autumn and winter season.

  • Latitude: The strength of the UV rays is highest the closer you get to the equator, where UV rays have less distance to travel before reaching the ground.

  • Altitude: With having less distant to travel, the rays are stronger the higher the elevation.

  • Clouds: Clouds filter out some of the UV rays from reaching the ground. However, it depends on the type of cloud. Dark, water-filled clouds may block out more UV rays than high, thin clouds. They also play their part with regards to reflection as the rays are often reflected from the snow(80%), water(25%) sand and roads(15%) back into the clouds which are reflected back to earth once again.

  • The Ozone layer: also called the stratosphere, is vital for the continued existence on Earth, without it, the planet would look very similar to many of the other planets in the solar system. The ozone layer is composed of the ozone gas (90% of the total ozone in the atmosphere). This gas has three oxygen atoms, and it is the result of the action of Ultra Violet (UV) radiation on oxygen molecules, composed of two oxygen atoms.

  • As the sunlight passes through the atmosphere, all of the UVC and the majority of the UVB (95%) are absorbed by the ozone layer. As the ozone layer gets thinner, the protective filter activity of the atmosphere is progressively reduced increasing UV intensity.


As mentioned, long term exposure to the UV rays has been known to cause both damage and contribute to some skin cancers. UV radiation is a proven cause of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), which often appear on sun-exposed areas of skin. Fortunately, when discovered early enough, these common forms of skin cancer are almost always curable.


The sun's rays can be dangerous, but with adequate protection you can prevent and limit any possible damage. Using a sun screen with a minimum 30 SPF and reapplying it every 2 hours, (more regularly if you perspire a lot) is essential when spending long amounts of time outside. Along with the sunscreen, adequate clothing , hat and glasses should also be handy. Avoid or limit your exposure between 10am-2pm when the sun is at its strongest over summer.

Vitamin D:

Seeing the sun after a dull period can raise the spirits of many, especially if you suffer from SAD (Seasonal Affect Disorder). The sun is also a natural way to increase the bodies source of vitamin D. Although caution should still be practised when outside. Other sources of vitamin D are, fatty fish like salmon, tuna, sardines, and mackerel. Vitamin D can also be found in egg yolks and foods and drinks that are fortified with vitamin D, like milks, cereals, and orange juice. You may also want to consider taking vitamin D supplements.


It's great to spend as much time outside as you can over the drier months but you should always bear in mind the damage the sun can do whilst outside. Natural protection from our skin cells called melanocytes make melanin which provide some cover, but to be totally sun safe, practice caution...enjoy the summer.

Brett's view:

It's tough not to go out and make the most of the good weather when it appears, long gone are the lazy days of trying to fry yourself without any sunscreen. Let's hope that the long hot summer that we are all looking forward too, does eventuate and slapping on the sunscreen is the least of our problems.

David's view:

I really enjoy the outdoors and especially being in warm sunny places, but every time I have a check up there is a long pause when the doctor examines all the freckles from sun burn on my back ! I now make sure that I put plenty of cream on shoulders and back as a result. Make sure lotions contain UVA, UVB and Min SPF30.

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