Dangers of the Sun

How safe is sun exposure?

Sunshine is essential for our health and well-being. Being outside in the sunshine is a big part of life here in Australia. We have all, at some time, enjoyed the warming sensation of the sun's rays on our skin. It is not considered safe, however, for us to be exposed to the sun's rays without appropriate protection.

What damage can be caused by the sun?

Apart from producing heat and light, the sun also emits many different types of radiation. One type of radiation is ultra violet radiation (or 'UV' radiation). Ultra violet radiation is very damaging to all forms of life here on Earth.

UV radiation can be divided into three categories, UVA, UVB and UVC. UVA is radiation that will cause damage to human skin in the form of wrinkles and discolouration. It is the least damaging of the UV radiations. UVB radiation damages proteins in the skin and can cause severe sunburn and skin cancers. UVC radiation is extremely dangerous as it can cause mutations in DNA.

As well as damaging our skin, increasing our risk of cancer and causing damage to DNA, radiation from the Sun has other potentially damaging effects. It can be a cause of cataracts, an eye condition that can lead to blindness. It can also affect our immune systems, causing immune diseases, and metabolic conditions such as herpes simplex, tuberculosis and lupus.

High doses of UV radiation can also affect the growth of many plants. This is turn, can affect the survival of various animal species as the natural ecosystem becomes unbalanced.

As you can see, the sun's radiation has the potential to cause disaster here on Earth if exposure is strong and constant.

What is the ozone layer?

Much of the radiation produced by the sun is prevented from reaching us on Earth. This is due to a natural sun block called the ozone layer.

Ozone is a poisonous gas made by the action of sunlight on oxygen. It is constantly produced in small amounts in a layer of the atmosphere called the stratosphere. At the same time that it is being made, ozone is also being broken down by another natural process.

In theory this should mean that there is always a similar amount of ozone present in the stratosphere. If this process was to remain untouched by external sources, the amount of ozone produced would be enough to prevent Earth from damage from UV rays. This protection in the stratosphere is what is known as the ozone layer.

What damages the ozone layer?

Over many years, damage has been slowly occurring to the ozone layer. Several years ago scientists discovered that many man made chemicals (and some natural products) used here on Earth are capable of reducing the amount of ozone in the ozone layer. When there is less ozone in the stratosphere, more ultra violet radiation reaches us here on Earth. You may have heard this damage referred to as 'holes' in the ozone layer.

Chemicals known to cause damage to the ozone layer are called ozone depleters. These chemicals take several years to reach the stratosphere. This means that the damage resulting from many years of chemical usage has only recently begun causing considerable concern.

Chemicals called chlorofluorocarbons (CFCs) are probably the most well known ozone depleting chemicals .CFCs are now banned in Australia and some other countries because of the damage they cause to the ozone layer. 

CFCs were typically used in air-conditioning and refrigeration systems and as a propellant in aerosol products like fly sprays, deodorants, hairsprays and air fresheners. Since CFCs were banned, products such as these have been made using far less damaging chemicals that do a similar job. 

How can we protect ourselves against the sun's harmful rays?

Even though precautions are now being taken to reduce the use of some ozone-depleting substances, the problem continues due to the number of chemicals currently in use. The usage of depletion chemicals will hopefully begin to slow in the near future. For the moment, however, UV radiation remains a very serious problem for us on Earth.

In order to avoid or limit damage to our health from these UV rays emitted by the sun, there are a number of precautions we can take. First, where possible, stay out of the sun. If it is necessary for you to be outside for a period of time, try to remain in the shade where possible. If you are at the beach, it is a good idea to sit under a large umbrella or a specially designed sun shelter when you are out of the water.

If you know that you will be outside for a long period of time, you should wear protective clothing that covers your entire body, including your arms and legs. If you plan on spending time in the water, special swim suits made of UV resistant materials are now available. Many of these are designed to cover your arms and legs to protect you more fully. 

When out in the sun, it is very important to always wear a wide-brimmed hat. Not only will this protect the top of your head and the sensitive skin on your face but also the very sunburn-prone section on the back of your neck. It is easy to forget to protect the back of our necks because we cannot see this area.

As well as covering up your skin from harmful rays, it is equally important to cover your eyes. Eyes are also prone to damage from UV radiation. Wear wrap-around sunglasses for the best protection and make sure they carry the maximum UV protection rating.

Finally, before you go outside, be sure to always apply SPF 30+ water resistant sunscreen to all the exposed areas of your skin. When in the sun for long periods of time, sunscreen needs to be reapplied every two hours. One application will not last a whole day. It will gradually wear off and you will again be in danger of sun damage. If you are swimming during that time, be sure to apply it even more regularly as it washes off in water. 

Does cloud prevent sun damage?

We are still at risk of UV damage on a cloudy or cold day. UV risks are not necessarily associated with just the heat and light of the sun. Even though some clouds may block a little UV radiation this does not necessarily reduce the risks. Some clouds can actually increase the intensity of UV rays by reflecting them and changing their direction.

Even if you take all the necessary precautions, there is still no guarantee that you will not be affected by the sun's harmful UV rays at some time. It is important to always be aware of the dangers and also have regular medical checks to monitor your health and reduce any damage caused by sun exposure.