I have noticed that a large number of people that I talk to seem to believe that UVA and UVB are the same. There is no real debate that both are harmful, but they are different.

UVB are the burning rays and are generally easy to filter out. Many car and building window tints do a fairly good job of fitering UVB.

The nasty guy is UVA, because it shows little reaction on the skin and is the cause of skin cancers. UVA radiation is also what ages the skin. It is much harder to block.

Most sunscreens do a fairly good job of handling UVA, but only physical blocks like Titanium Dioxide and Zinc oxide work on UVB

The way I remember the difference is that I refer to UVA as UVAging and UVB as UVBurning

So as far as skin cancer and aging go, that office with a window might not be such a good thing.

From what I read on the EWG skin deep report most sunscreens block UVB more than UVA (according to their little chart). I have also read somewhere that both rays contribute to cancer and aging. I also read that avobenzone isn't very stable so how much UVA is it really blocking? There are some uv films that people can put on that office window that protect from the suns rays.

Here are some sites I found:

http://www.windowfilmdepot.com/

http://www.concordwindowfilms.com/

I will assume that since glass blocks uvb these filters are for UVA.

You know what's funny? Products that claim to block UVC rays when they are filtered by the ozone layer-or is the ozone layer thinning enough to let them through?