夏日防晒必不可挡！
The dog days of summer are here. While soaking up the sunshine is a must, exposing our skin to ultraviolet (UV) radiation poses some serious health hazards. This is where sunscreen comes in handy to protect our skin.
随着大热天的来临，晒日光浴是必不可少的环节。但我们的皮肤赤裸裸地暴露在紫外线下，很容易危害健康。想要保护我们的皮肤，防晒霜就派上了大用场。
There are many misconceptions with sunscreen.You have those people who think that getting the highest SPF will protect them better than a lower SPF.
对于防晒，有不少误区。很多人认为高SPF比低SPF防晒的效果更好。还有一些人认为自己不会晒黑，所以根本不需要高防晒指数的防晒霜。
SPF stands for Sun Protection Factor.
SPF是防晒系数的意思。
To figure out how long you are safe from the sun (at least the UVB rays) you need to do a little math.Take the number of SPF and multiply it by 10.
需要计算一下才能知道你在太阳下可以待多久而不会被晒伤(至少不被UVB射线晒伤)。将SPF系数乘以10得出来的时间就是防晒产品的保护时间。
That is the time that if you were under perfect conditions, you’d be safe from the sun’s rays.For example: SPF 20 x 10 = 200 minutes of sun protection.
例如：SPF20的防晒产品可以保护200分钟之久。理想的条件意味着你不是在水里或是在出汗。
Then, there are those who won’t use sunscreen with a high SPF because they think they won’t get a tan.Here are the facts.Higher SPF’s aren’t always necessary.
然而事实并非如此。高的防晒指数并非总是必需的。
下面几种情形告诉大家选择什么样的防晒霜。。
1. Day of commuting and indoor fun
通勤与室内活动
Scenario: You’re headed to the office or school, or are engaging in indoor activities that require little time in the sun.
适用情境：去公司上班、去上学，或是参与几乎晒不到太阳的室内活动。
SPF (Sun Protection Factor) requirement: 15 or less
防晒系数: ≤15
Solution: Even a two-hour shopping spree in a brightly lit indoor mall is equivalent to spending about an hour in the sun, because fluorescent light bulbs also emit UV rays.
防晒建议：在灯火通明的购物中心里扫货两小时，几乎等于在大太阳底下曝晒一小时，因为商场里的各种荧光灯也会产生紫外线辐射。
2. Season for traveling and outings
外出旅游与户外活动
Scenario: Exploring a city on foot is the best way to absorb the local culture. But strolling around also takes time and exposes your skin to UV rays.
适用情境：想要体验当地文化，在一个城市中徒步探索是最好的选择，然而，到处溜达不仅占了时间，也使我们的皮肤长时间暴露在阳光下。
SPF requirement: 30 or less
防晒系数: ≤30
Solution: Wearing a hat and long-sleeved clothes is sensible, but putting on a sunscreen with a broad-spectrum SPF of 30 is the ultimate protection, especially during the peak hours for sunrays between 10 am and 4 pm. However, sunscreen often degrades fast when exposed to the sun for more than an hour, so make sure you reapply it at least every 90 minutes.
防晒建议：带帽子、穿长袖都是明智选择，然而，终极保护还是需要防晒系数30的广谱防晒霜，特别是在日照最强烈的早10点至下午4点之间。需要注意的是，暴露在太阳下一小时以后，防晒霜的保护效果会迅速下降，所以，保险起见，建议至少每一个半小时重新涂抹一次防晒霜。
3. Sunbathing on the beach
沙滩日光浴
Scenario: Sunbathing gives us a healthy tan, but overexposure to the sun’s rays can do more harm than good to our skin.
适用情境：日光浴能为我们带来健康的小麦色肌肤，然而，过度暴晒则弊大于利。
SPF requirement: 50 or more
防晒系数: ≥50
Solution: Keep in mind that you need the strongest sun protection you can get. Look for a thick sunscreen with an SPF of at least 50 that offers broad-spectrum protection. Or better still, a waterproof one that will give you longer-lasting protection. Don’t forget to reapply it every 60 minutes, or whenever you sweat or get wet.
防晒建议：这时候，你需要最强效的防晒保护：一层厚厚的防晒霜，其防晒指数不得低于50，并且要能抵挡所有波长的紫外线。当然，要想取得更好更持久的防护，你需要选择具有防水功能的防晒霜。最后，别忘了每1个小时，或是每次你出了汗的时候都重涂一次防晒。
Perfect conditions mean that you aren’t in water or sweating.Because you want to be safe from the sun, I’d recommend applying every 1-2 hours, no matter the SPF.
要做到防晒，我的建议是，不管防晒系数是多少，每隔一两个小时涂一次防晒霜
