UVA? UVB? What's the difference?

During the summer months we hear a lot about protecting our skin from the sun's harmful rays. What I, personally, didn't understand in it's entirety, was the difference between UVA and UVB rays and also the difference in all the ranges of SPF. With a little research of my own, I'll help clear up any questions you may have in the world of "sun protection!"

UVA rays are what we are exposed to the most. They penetrate the skin farther than UVB rays and make up 95% of the UV radiation that reaches the earth. These rays can penetrate glass and clouds and are longer than UVB rays. When we tan, our skin darkens as a defense mechanism. What we see when we have that nice brown tan, that we spend money getting from tanning beds or lying in the sun for hours, is actually damage to the skin's DNA, which could lead to skin cancer.
Tanning beds emit doses UVA rays that are 12 times stronger than that of the sun! People who use tanning salons on a regular basis are 1.5 - 2.5 times more likely to develop some type of skin cancer. Those statistics may seem small, but put into that perspective, why take the chance of being the 1.5%?

UVB rays are what cause sunburns on the surface of the skin and increase the signs of aging. These are the rays that get have different strengths throughout the day. For example, during the spring and summer months, the strongest UVB rays reach the earth between the hours of 10 a.m. and 2 p.m. These rays can damage your skin year round, even during the winter. UVB radiation doesn't penetrate glass like UVA radiation does.

A suntan lotion with an SPF of 15 simply means that it'll take a person 15 times longer to get a sunburn with the lotion than without. An SPF of 15 blocks 93% of the sun's UVB rays and anything over 30 will block 97 - 98%.
When purchasing suntan lotion, don't just look at the SPF. Make sure you see the phrase UVA/UVB protection on the sunscreen label.

There's no harm in getting that summer tan. Just be careful and take the proper steps to protect your skin.