UVA, UVB and UVC Rays: What They Are and How Sunscreen Protects You

At the most basic UVA, UVB and UVC are the ultraviolet rays that reach the earth from the sun and, as the Skin Cancer Foundation says, UVA and UVB rays cause skin cancer, premature aging, wrinkles, sunburn and even eye damage (sunglasses are a good idea!). Luckily the right sunblock - including Block Island Organics sunscreen - can protect you. Let's explore a little more with an infographic and additional details.

UVA Rays

These are the most prevalent rays and make up as much as 95% of the UV radiation that reaches the Earth. The thing to know is that studies show UVA rays cause both skin aging (wrinkles, sun spots, lines) and skin cancer so they're definitely something you want to protect yourself from.

A few other important things from the Skin Cancer Foundation article referenced above:

"They are present with relatively equal intensity during all daylight hours throughout the year, and can penetrate clouds and glass."

Thus you need protection from them no matter what time of year (even the Winter!) and time of day. These are also the type of rays used in tanning booths - something we highly advise against - and penetrate untreated glass (think driving in your car for hours on end). Interestingly, UVA rays are not the primary cause of sunburn. That's left up to the pernicious UVB rays.

UVB Rays

So we know UVB rays cause sunburn but what else do they do? Well, they are also a major factor in skin cancer and a prominent, although possible less than UVA rays, role in premature skin aging. Whereas UVA rays are prevalent year round and all day, UVB rays are more prevalent from the spring to the fall and from late morning to late afternoon.

That said, they still hit you in the winter and if you are around snow or ice you'll get a double dose when they reflect off that shiny surface. Also, SPF is a measure of protection from UVB rays (find out more in our article What a Sunscreen's SPF Really Means). One last point is that glass is a pretty good barrier to UVB rays but not UVA rays.

UVC Rays

Very quickly, UVC rays you don't need to worry about. These rays are absorbed by the ozone layer and generally don't reach the earth's surface.

What Does This All Mean

It's best to protect yourself against UVA and UVB rays year-round and luckily it's easy to protect against both.

How to Protect Yourself from UVA and UVB Rays

Sunscreen of course! But not all sunscreens. Make sure it's a broad spectrum sunblock. Fortunately new US Food & Drug Administration (FDA) regulations make sunscreens disclose this. Only sunblocks with an SPF 15 or higher that contain active ingredients that filter both UVA and UVB, like Block Island Organics' sunscreens, can legally be labeled broad spectrum. So if you see "Broad Spectrum" on a sunblock label it should do the work you need. Here's even more on this topic in our post "Broad Spectrum Sunscreen - What It Is and Why It's a Must".

Also note that while SPF measures protection from UVB rays, it is not a direct measure of protection from UVA rays. Rather, the FDA says a broad spectrum sunscreen's SPF rating measures UVA protection in proportion to UVB protection. Thus the higher the SPF rating on a broad spectrum sunblock, the better the UVA protection should be but it won't necessarily have the same level of UVA and UVB protection.

Now mineral sunscreens like ours protect against UVA and UVB because they use zinc and/or titanium (see our article "Mineral Sunscreen: What It Is"). Chemical sunscreens however, need the right mix of chemicals or a blend of chemical and mineral. Here's a good chart from the Skin Cancer Foundation on what ingredients protect against which UV rays:

Other Sun Protection Methods

Additional ways to protect yourself include wearing appropriate clothing, hats, staying in the shade and applying a UV-protective film to glass.

I'm all for these methods but I also forget from time to time, I want to be active outside enjoying the sun and sometimes it all seems like a pain to stay so vigilant.

Do Your Best to Stay Protected

So I say do your best to observe all these measures but make sure you're having fun too and, while not quite a "set-it-and-forget-it" method, applying sunblock as part of your daily routine is certainly one of the easiest things to observe.

Heck...it even protects you from skin cancer and if you want even more details check out our About UV Rays page, our UV rays posts, or our Suncare Smarts series.