Rowan Jacobsen

But you're still going to get a bunch of UVA

Which they figured out, like in the 90s, does cause skin cancer.

It blocks the UVB, but...

The UVA comes through, but you'll never have a burn reaction because of it.

And so like in the U.S., people get slightly higher rates of skin cancer on the left side of their body.

In the U.K., they get slightly higher rates of skin cancer on the right side.

Yeah.

So window glass is— Slightly?

Slightly.

It's like 52, 48.

It's not huge.

Statistically significant, yeah.

There must be something weird about that guy.

It could be different lighting.

But so the thing is, so those sunscreens...

that were acting kind of like window glass in the 70s and 80s and even into the 90s before we got the broad spectrum sunscreens.

They're blocking the UVB, so you weren't going to ever burn.

And that's what SPF actually measures is how many more times you can be out in the sun without burning.

But it's based totally on UVB.

So if you've got SPF 30, in theory, you can spend 30 times as long outside before you start to burn.