What’s the difference between UVA and UVB rays?

We all know that the sun rays are dangerous and can cause a lot of damage, including wrinkles and cancer. But not everyone knows how this happens or what’s the difference between UVA and UVB rays. And did you know that there are also UVC rays? Yes, that’s right, there are three types of ultraviolet, radioactive rays the sun emits but the good news is that UVC are short wave and are filtered out by the atmosphere and never reach the earth. But what about UVA and UVB rays?

What are UVA rays?

UVA rays emit long wave ultraviolet radiation and represent about 95% of the radiation that reaches the earth. They are present every day, all year long, from the time the sun comes up to when it goes down, in any climate and weather condition. That is why, even though they are weaker than UVB rays they actually cause more damage. In addition, UVA rays can penetrate through clouds and windows (and deeper into the skin!) and are the reason why you should wear a broad-spectrum sunscreen even when driving or indoors.

Because UVA rays are so numerous and constantly around us even if we don’t see them, they create very severe and continuous skin damage. UVA rays are those that make our skin tan but they also generate free radical damage, which is the main cause of aging. They also decrease elastin, the substance that gives skin its structure and elasticity, and for these reasons, those than tan tend to get deep wrinkles pretty early. But photo-aging isn’t the only problem with UVA rays. In addition, they can cause abnormal cell production and, combined with UVB rays, increase the risk of developing skin cancer.

What are UVB rays?

UVB rays emit medium wave ultraviolet radiation and only about 5% of it reaches our planet. That’s because part of them are absorbed by the clouds and the other part by the ozone layer. So, as you probably guess, the hole in ozone layer has really bad effects not only for the earth and environment but for our skin too. They are stronger between 10 a.m and 4 p.m. (that’s why you should avoid the sun during those hours!) but can’t pass through clouds or windows.

Although less numerous than UVA rays, the are more powerful and can still cause a lot of damage. Unlike UVA rays, this damage is instantly visible as it is the UVB rays that cause sunburn. In addition, they also cause abnormal cell mutations and growth pattern and can cause skin cancer.

The Bottom Line

So now you know why it is very important to use a broad-spectrum sunscreen to protect your skin from both UVA and UVB rays instead than one that only protects from UVB rays (and sadly that are lots of sunscreen around that only protect from UVB radiation). Go check out your sunscreen and if it doesn’t include UVA filters (Titanium Dioxide, Zinc Oxide, Mexoryl, Tinosorb or Avebenzone) switch to one that does and apply frequently. Your skin will thank you for it. :)

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  1. says

    Thanks for sharing this information, I remember going on a seminar about UVB and UVA and its really informative to know! thanks for the reminder!

  2. says

    Very informative! I use a zinc oxide and titanium oxide based sunscreen because they are the most stable and long lasting (on me, at least). It feels heavier, but it works better for me. What do you use?

    • beautifulwithbrains says

      Tammy, I prefer to use sunscreens that contain Zinc Oxide and Titanium Dioxide as these ingredient offer protection from both UVA and UVB rays and are less likely to cause negative reactions than chemical filters. I may sometimes switch and try something with Mexoryl if it’s a product that particularly interests me but usually I stick with Zinc Oxide and Titanium Dioxide. Sure, they may feel a bit heavier and sometimes leave a white cast, but I think that’s a very small price to pay for the good protection they offer. :)

    • beautifulwithbrains says

      Dee, you’re welcome. I only recently found out about UVC rays too but I’m glad we don’t have to worry about them as they never reach the earth. :)

    • beautifulwithbrains says

      Dao, that’s a great and simple way to remember the difference between UVA and UVB rays. :) That sounds like a good powder. The weather is very hot here too so it’s nice to retouch makeup with a finishing powder with SPF for some added protection. :)

  3. louise says

    Hi there – my website will be live in a weeks time..
    I am setting up a skincare business and will be raising skin cancer awareness too. The UVA UVA diagram you have is brilliant. Could I please ask your permission to use this?
    I look forward to hearing from you.
    Best Regards,

    • beautifulwithbrains says

      Louise, hi. I think it’s great that you wanna raise skin cancer awereness and I wish you all the best with your skincare business.

      The diagram isn’t mine, but it’s from the Make Me Heal website, so you should ask them. You can find the link to the site at the end of the post.

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