What is the difference between UVA rays and UVB rays

Unknown Friday, July 25, 2008

what is the difference betweenuva rays and uvb rays


When you buy sunblocker, have you ever asked yourself "What is the difference between UVA rays and UVB rays'? If not, then read on how you can protect your skin and yourself beter from the sun.



SPF



Everybody knows about SPF: "the higher the better". But what does SPF actually mean?


SPF stands for sun protection factor. It tells you how many times longer you will be protected against skin reddening from UVB rays.



How many times longer to get red
compared with the time it takes to get sunburned without any product.



Don't try this at home: it may take up to 24 hours after sun exposure for redness to become visible!!!



SPF sunscreen example



Let's give an example: if your skin is fair and it's your first day of the year tanning, then 10 minutes will be enough to get sunburned.



Using a sunblocker with SPF 30 tells you that you can sit 30 times multiplied 10 minutes : equals to 300 minutes sun bathing without getting red.



Of course the sun-lotion itself wont last that long, so reapply every time after swimming or every other hours.



UVA and UVB



Oops, you must have noticed that SPF only relates to UVB rays... So what about UVA rays?




  • UVB rays or Ultra Violet B rays cause primarily sunburn and used to be considered the main cause of skin cancer. "Used to be" is the most important keyword here!

  • UVA rays or Ultra Violet A rays are sunrays that have an equal effect on your skin, no matter where you are on this planet, sitting in the sun but also behind glas! UVA rays cause aging, wrinkling and leathering of the skin.
    If you ever wondered why some women in the tropics have "very old looking hands", it's because they have been constantly exposed to UVA rays. Especially when driving in a car under the hot sun.
    Further on: UVA not only increases UVB 's cancer-causing effects, but may directly cause skin cancer.



So next time you buy sun-lotion or UV protective clothing, make sure they block or screen both UVA and UVB rays!



If you want to know more about what is the difference between UVA rays and UVB rays, please ask in a comment.



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