What is Ultraviolet Radiation?
Ultraviolet radiation (UVR) in sunlight is made up of UVA, UVB and UVC rays. Only some UVB and most UVA rays reach the earth’s surface. UVC and shorter UVB rays are either absorbed in space or in the ozone layer. There is less UVR in the morning and evening, when the sun is closer to the horizon and less in winter than in summer. During the middle hours of the day UVR is greater because there is less atmosphere for it to pass through. There is also more UVR closer to the equator, at high altitudes and when pollution levels are low. Solar UVR levels are generally not related to temperature. There can be high UVR levels even on cool days. UVR and temperature usually reach their maximums at different times of the day. UVR is usually highest around midday but the temperature is often highest later in the afternoon. Due to scattering of solar UVR by molecules and particles in the atmosphere there is about as much UVB received from the open sky as there is from the direct sun. If you are in the shade but can see a lot of blue sky you are still exposed to UVR scattered from the sky. At times the amount of scattered solar UVR that reaches your skin may exceed that from the direct sun.
Why Do We Need Shade?
The sun’s rays are harmful to the skin. Melanin, the natural pigment in the skin, gives some protection from these damaging rays, but for most people it is not enough. UVB rays cause sunburn and also affect the DNA in the skin, which may cause skin cancer. UVA rays damage the skin causing wrinkling, sagging and premature aging and may also have a role in causing skin cancer. If you spend a lot of time in the sun without protection, you risk sunburn, wrinkles, sunspots, eye disorders, coarse leathery skin and skin cancer.
Sun Sense Tips
UVA and UVB rays are the strongest and most dangerous between the hours of 10am and 3pm.
Choose shaded areas where you cannot directly see the open sky. Even if you are out of the direct sun, UVR can still reach you from the open sky.
- Clouds don’t block out Harmful UVA and UVB rays.
- Light surfaces (e.g. cement, snow, sand, water) reflect sunlight and increase your exposure to UVA and UVB rays.
- Sunlight goes through water and can burn your skin while you swim.
- Wind may be cooling, but the sun still burns the skin.
- Wear sunglasses that meet the Australian Standard and will block out harmful UVA and UVB rays, not just look fashionable.
- If you spend a lot of time walking in the sun a UV protective hand held umbrella would help provide further protection.
- Ensure any shade product you use or buy is going to provide the maximum protection your body needs from the suns harmful UV rays.
- Wear clothing designed to cover the arms and legs as well as the body.
- Wear a broad-brimmed or legionnaire style hat to shade the eyes, face, ears and back of the neck.
- Apply at least SPF-15 sunscreen to all areas of your body not covered by clothing. Reapply sunscreen after swimming or perspiring as it can wear off.
- Remember that if the temperature drops it does not mean that the UVR level has also decreased.
- Protect young children from excessive sun exposure with shade, suitable clothing, hats, sunglasses and sunscreens. They are unaware of the dangers. Apply sunscreen liberally and often to children following the directions on the container. Use pram covers and shades for babies.
- Set an example for your children