Sunscreen protects your skin from ultraviolet rays in 2 ways. Some work by reflecting light away from your body, others absorb ultra violet light rays before they reach your skin.
Up until a few years ago, choosing a good sun screen meant you looked for a high sun protection factor (SPF). The SPF rates how well the sunscreen protects against one type of cancer causing ultraviolet ray, UVB.
Ultra violet ray A is the ageing ray which doesn’t burn skin but penetrates deeply into skin to cause wrinkles. According to the EPA, 98% of skin changes associated with ageing are caused by lifetime exposure to UVA.
The best sunscreen for sunny Arizona are those with broad spectrum protection for UVA and UVB. An SPF of 15 or higher is good for UVB protection. There is no rating to tell you how good a sunscreen is for blocking UVA rays.
To determine UVA protection, you will need to look at the ingredients. Look for a sunscreen which contains at least one of the following:
If you normally burn within 15 minutes of being in the sun a sunscreen with an SPF of 15 multiplies that by a factor of 10, meaning that you can stay in the sun for up to 150 minutes before burning.
For most people an SPF of 15 is fine. Individuals with very fair skin or a family history of skin cancer need to consider an SPF of 30 or higher.
The higher the SPF the smaller the increased protection benefit. SPF 30 is not twice as strong as SPF 15. SPF 30 filters out 97% of ultra violet rays. SPF 15 filters out 93%.
No matter how good you are at applying sunscreen, it does not protect you completely. The other things you need to do for complete sun protection include:
Stay in the shade
Avoid sun exposure when ultra violet rays are the strongest (between 10 Am and 4 PM)
Wear a broad brimmed hat
Wear clothing with an ultra violet protection rating.