The higher the SPF, definitely the better.

防晒系数越高肯定越好。

At a minimum, you'll want SPF 30.

至少，你需要 SPF 30 的防晒霜。

And the amount of time spent outside is somewhat correlated to SPF.

在户外度过的时间多少与防晒系数有关。

These days, skincare and cosmetics companies are packing SPF into a variety of their products.

如今，护肤品和化妆品公司在各种产品中加入防晒剂。

Opt for a sunscreen with an SPF of at least 15, although 30 is better.

选择至少有SPF15的防晒产品，当然SPF30的会更好。

Ideally, you're using an SPF level that's between a 30 and a 50.

理想情况下，你使用的防晒指数在30到50之间。

So they're no better than about SPF 5.

它们的作用不到SPF5。

I forgot I have this lip balm with SPF 30.

我忘了我有一支 SPF 30 的润脣膏。

SPF 15 does a pretty good job by blocking 93% of UVB rays.

SPF15的防晒可以阻挡93%的b波紫外线。

How much should I pay attention to SPF?

我需要多在意防晒指数？

You get a slight increase as SPF goes up, with SPF 30 blocking 97%, and 50 blocking 98%.

SPF值的升高，它的阻挡力也会稍许增加，SPF30可以阻挡97%，而SPF50则可以阻挡98%。

When we choose a sunscreen, we can compare application method, the SPF, and the active ingredients.

当我们选择防晒霜时，我们可以比较它们的使用方法，比较SPF，和其他的成分。

SPF is clearly labeled on the front.

SPF值在防晒产品上都会清楚地标明。

Now I'm going to try some powder makeup that claims to have an SPF of 30.

现在我要试试声称有 SPF 30 的粉状化妆品。

SPF is based on the quantity of solar exposure.

SPF值根据的是太阳曝光的量。

The photosensitivity and subsequent malar butterfly rash can be prevented by using sunscreen, preferably SPF 50 or greater.

使用防晒霜（最好是 SPF 50 或更高）可以预防光过敏和随后的颧骨蝴蝶疹。

I'm a little skeptical of this because dermatologists say you can't really rely on the SPF in makeup.

我对此有点怀疑，因为皮肤科医生说，化妆品中的 SPF 值并不可靠。

SPF is a nonlinear scale of how much UVB radiation is needed to give protected skin a sunburn.

SPF是一种非线性的比例，关于的是造成晒伤的b波紫外线的量。

Like give me my SPFs, make sure they're on my face.

就像给我防晒霜一样，确保它们涂在我的脸上。

It has 30 SPF in it.

它有 30 SPF。