1, ultraviolet ray can damage the skin? UVB is the most biologically active band of sunlight that reaches the earth and has an important role in human health, but excessive UVB exposure UVB is a killer of skin health. According to the wavelength of ultraviolet can be divided into three categories: UVA that is, long-wave ultraviolet, penetrating power, it can reach the dermis, destroy elastic fibers and collagen fibers, causing skin aging; UVB that is, ultraviolet medium-wave, easy to cause erythema, sunburn; UVC that is, ultraviolet short-wave, the vast majority of the air is absorbed, generally do not cause harm. Scientists imaginatively compare UVB to “burning light” and UVA to “aging light”. 2.Is it true that the hotter the UVB light, the stronger it is? The heat effect of UVB is not obvious, the intensity is mainly related to the relationship with altitude, for example, climbing mountains, the higher up, the cooler the mountain wind, people even feel cold, but the UVB is very strong at this time. That is to say, every 1000 meters up, the ultraviolet radiation is enhanced by 10%. By the same token, in the sea, the sea breeze makes you feel cool, but at that time the UV rays have reached an extremely strong degree, so do not ignore sun protection because staying in a cool place does not make you hot. 3. Do you need sunscreen only when the sun is out? No, it is not. Ultraviolet light is not visible, there is also ultraviolet light when it is cloudy, clouds for UVA ultraviolet light, hardly play any isolation role, all the UVA ultraviolet light can penetrate the clouds, that is to say, 90% of the ultraviolet light can penetrate the clouds, but only the kind of thick cumulus clouds when it is dim to stop part of the ultraviolet light; In addition, the sun begins to rise when the UVA is stronger than the sun after the sun rises after the sun rises UVA, therefore, the morning out also need to pay attention to sun protection, cloudy weather is also best to use SPF10-15 products. 4, I stay in the office every day during the day, do I also need sun protection? Of course, sun protection is a daily task. UVA rays, which cause skin aging, are very penetrating and can penetrate through glass and clouds and directly into the dermis of the skin, causing direct damage to the skin. So that in the office should also apply sunscreen, but choose those lighter texture of the sunscreen or isolation cream on it, you can also choose to have a maintenance function of the sunscreen day cream, generally SPF15/ PA is enough. 5.What does SPF mean? SPF is the abbreviation of “Sun Protection Factor”, that is, the protection factor of sunlight, we generally call it “sun protection factor”. The SPF value is the smallest base value of 2. It is measured by the time you can endure the sun without sunscreen, until your skin starts to turn red in color, and then multiply this time by the SPF value. For example, if your skin starts to redden after 10 minutes of sun exposure without protection, a sunscreen with SPF 15 can give you 150 minutes (2 1/2 hours) of protection (10 minutes x SPF 15 = 150 minutes). 6.What does PA mean? PA is an indicator used to indicate the ability of Japanese skin care products to prevent UVA protection, with “+” to “++++”, “PA+” refers to the sun protection time of about 4 hours; “PA++” refers to sun protection for about 8 hours. And the United States and Europe sunscreen products are generally used to guard PFA, PPD is how much to identify. 7.How do I know which sunscreen with UV protection level is more suitable for me? Is the higher the SPF value, the better? Generally speaking, the lighter the skin color, the greater the SPF required, but not the higher the SPF value, the better. The higher the SPF, the higher the potential irritation, the more expensive it is, and because of its sticky texture, it is not easily absorbed and tends to clog pores and affect skin oil secretion. Therefore, in general, the use of SPF8-SPF15 sunscreen products will be fine. 8, several different textures of sunscreen products (sunscreen oil, cream, liquid) characteristics are different? Is the sunscreen oil waterproof will be better? Now the texture of sunscreen products is very different from previous years, the general texture is very refreshing and light, even the SPF50 products will not have a heavy feeling. Sunscreen products or “cream” is the most common, spray-type liquid products are more refreshing and convenient to use, and oil or cream products generally have a good waterproof sweat-proof effect, but coated in the face will feel significantly uncomfortable, generally for the body more. 9, sunscreen foundation, sunscreen isolation cream, sunscreen what is the scope of application of each different? If you are a 9 to 5 office worker, and need to wear light makeup to show people, sunscreen foundation is a very convenient choice, make-up is also very easy; if you do not like foundation and want to moderately improve a little skin tone, with a slight moisturizing function of sunscreen isolation cream can meet the needs; if you are in a completely free of any makeup occasions, or will be exposed to strong sunlight during the day, it is best to use the appropriate index of sunscreen. As for the difference between sunscreen and sunscreen barrier cream, the main difference is that barrier creams generally have skin tone correction effects and have the function of helping foundation to go on more easily.