1.All sunscreens protect your skin from wrinkles, age spots, and sunburn.



Some sunscreens protect against only UVB rays, which are the primary cause of sunburn, but UVA rays penetrate deeper into your skin. Both UVB and UVA exposure can lead to premature skin aging, skin cancer, and sunburn. 

Only sunscreens labeled as both "Broad Spectrum" and "SPF 15" (or higher) can reduce the risk of skin cancer, and reduce the risk of early skin aging -- if they’re used regularly, as directed, and in combination with other sun protection measures that will help prevent sunburn. (The SPF – sun protection factor -- rating refers only to the level of protection from UVB rays, not UVA rays.)



2.In 2012, the FDA will require warning labels on sunscreens that have not been shown to protect against skin cancer or early skin aging?
Beginning in 2012, sunscreens that aren’t both broad spectrum andSPF 15 (or higher) must carry a warning label that states: “These products have not been shown to protect against skin cancer and early skin aging. They have been shown only to help prevent sunburn.”
3.A base tan can help protect your skin from the sun.
There's no such thing as a safe tan; any sun exposure subjects your skin to damaging ultraviolet rays. Any time you tan, you damage your skin, increasing your risk for skin cancer and accelerating your skin's aging process.
4.Makeup can help protect your skin from the sun.化妝可以讓你的肌膚避免晒傷?
Compressed powder contains tiny pigmented talc particles that provide a certain amount of protection, and some moisturizers, eye creams, foundations, and lipsticks have SPF ratings of 15 and higher. Avoid shiny, high-gloss lipsticks, which can act like baby oil, attracting UV rays to your lips. If you want the wet look, apply a colored lipstick first, then top with the gloss.
5.What percentage of the sun's UV rays can pass through clouds?大約多少比例的紫外線可以穿過雲層呢?
Clouds don't protect you from sun damage. According to the American Academy of Dermatology, up to 80% of the sun's UV rays can pass through clouds and damage your skin. You should wear sunscreen or protective clothing even on cloudy days.
6.Window glass protects your skin from all harmful UV rays.車窗玻璃可以替你阻擋傷害你的紫外線?
UVB rays, which cause sunburns, can’t penetrate glass, but UVA rays can. The American Academy of Dermatology recommends that you use a broad-spectrum, water-resistant sunscreen with an SPF of at least 30 year-round, even if you’re going to be inside.



7.A sunscreen with an SPF of 30 provides double the protection of one with an SPF of 15?
SPF 30的防曬產品提供的防曬能力是SPF的兩倍?

SPF stands for "sun protection factor," and that refers to how much longer it takes you to sunburn while wearing that sunscreen, not to how much protection you're getting. For example, it should take 15 times longer for you to sunburn with an SPF 15 sunscreen than it would if you weren't wearing any; with an SPF 30, it should take 30 times longer. 

An SPF 30 screens out only a small percentage more UVB rays (96.6%) than an SPF 15 (93%), so higher SPF numbers do not indicate a proportionately higher amount of sunscreen strength. No sunscreen provides 100% protection.

如SPF30 29/30x100%=96.6%
所以SPF 15遮蔽率為93.3%
8.Most people use the recommended amount of sunscreen.大多數人使用到建議的防曬劑量
You need about an ounce of sunscreen to properly cover the exposed areas of your body, and most people don't use enough. According to the American Academy of Dermatology, most people apply only 25% to 50% of the recommended amount of sunscreen.


9.How long can you stay in the water without having to reapply a water-resistant sunscreen?
A “water-resistant” label means the sunscreen works in the water for about 40 minutes. Very water-resistant sunscreens give you about 80 minutes in the water. (No sunscreen is completely waterproof.) Like all sunscreens, water-resistant products should be reapplied after two hours, regardless of water exposure, and after toweling off.
10.Some sunscreens contain a chemical that can be harmful to your health.


Some sunscreens contain a naturally occurring chemical called Benzophenone-3 (BP-3), which passes through the skin into the body. According to the CDC, scientists have discovered widespread exposure to BP-3 in Americans and “the human health effects from skin exposure to low levels of BP-3 are unknown.” However, the CDC also states, “finding a measurable amount of BP-3 in urine does not mean that levels of BP-3 cause an adverse health effect.”

The American Cancer Society “continues to support the use of sunscreen products as one of the measures to limit skin exposure to ultraviolet radiation, while encouraging continued research on the safety and efficacy of these products.”

11.Unprotected exposure to the sun is the best way to get Vitamin D.不要擦防曬會得到比較多的維生素D
According to the American Cancer Society, "Whenever possible, it is better to get vitamin D from your diet or vitamin supplements rather than from sun exposure because dietary sources and vitamin supplements do not increase risk for skin cancer, and are typically more reliable ways to get the amount you need." Dietary sources of vitamin D include eggs, fish, and foods fortified with vitamin D, such as milk, yogurt, and some cereals and bread. Sunscreen limits the amount of sun rays hitting your skin, so wearing sunscreen will decrease your skin's production of vitamin D.
12.How many blistering sunburns does it take to double a child's lifetime risk of skin cancer?
One blistering sunburn doubles a child's lifetime risk of developing skin cancer. Children are at particular risk in the sun, because it's easier for them to get sunburned; it can take less than 10 minutes for an infant’s skin to burn. Children are also at higher risk because they tend to spend a lot of time outdoors and because they're unlikely to be mindful of the sun's dangers. Babies younger than six months old should be kept out of the sun or shielded by hats and protective clothing.
13.Which of the following provides better protection from the sun?A large beach umbrella?An SPF 15 sunscreen?
Large beach umbrellas provide good shade, but most provide little protection from UV rays, partly because UV rays can reflect off the sand and under the umbrella. In fact, the amount of UV radiation under an umbrella can be up to 84% of what you'd get out in the open sun. The SPF of a typical beach umbrella ranges from 3 to 10.
14.Darker-skinned people don't need sunscreen.皮膚比較黑的不用防曬?
Although darker skin offers more natural protection from the sun than fair skin, groups including African-Americans, Hispanics, Asians, and Native Americans can still burn and still need to protect themselves from sun damage and skin cancer.
15.Dark clothes protect you from the sun better than light-colored clothes.深色衣服比淺色衣服防曬效果好?

In general, ultraviolet rays pass through lighter-colored fabrics easier than dark-colored fabrics. Experts say you get the best protection from deep blue and black colors or bright colors, such as orange and red. Also, tightly woven fabrics offer more protection than loose weaves.  

If you can see light through the fabric when you hold it up to the light, the sun's damaging rays are passing through to your skin. Look for a UPF (UV protection factor) rating on clothing made especially for sun protection. UPF ratings work in a similar way as SPF ratings: the higher the UPF, the more protection from ultraviolet rays.




16.Dark sunglasses block more of the sun's UV rays than lighter-colored sunglasses.

Light-colored glasses can be just as effective as dark glasses at blocking UV light. Look for labels that say "Meets ANSI UV Requirements" or "UV absorption up to 400 nm,” which means the glasses will block 99% of UV rays, compared with about 70% for most cosmetic glasses.  

Sunglasses are an important aspect of sun safety, because the eyelid area is a frequent site of skin cancer (5% to 10% of all skin cancers) and sun exposure can contribute to cataracts, macular degeneration, sunburn of the cornea (keratitis), and several cancers of the eye.





17.Which of the medications can increase your sensitivity to the sun?哪種藥物會增加你的光敏感性?
Birth control pills, naproxyn and other NSAIDs, and thiazide diuretics can increase your risk of burning. You also need to be careful if you take tricyclic antidepressants, sulfonylureas for diabetes, or tetracycline, sulfa drugs, or many other antibiotics. Ask your doctor or pharmacist if any medicines you're taking might make you more sensitive to the sun.


18.Melanoma -- the most deadly form of skin cancer -- most commonly occurs on ??黑色素細胞瘤最常發生在哪邊?
Although most skin cancers occur on frequently exposed parts of the body, such as the face, ears, neck, forearms, and hands, melanoma most commonly occurs on the upper back for men and the lower legs and upper back for women. So it's important to consider all areas of your body when planning for a day in the sun.


    WebMD 防曬 SPF UVA UVB


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