How do we choose from the wide variety of sunscreen products available in the hot summer? Let us learn to choose the right sunscreen products through professional advice from the AAD American Academy of Dermatology! 1, how to choose a sunscreen: AAD American Academy of Dermatology recommends that consumers choose sunscreen products three main characteristics: sun protection index of not less than SPF30. Use broad-spectrum sunscreen products – can protect the skin from both UVA and UVB damage, that is, we see the SPF and PA index. Water resistance, that is, to a certain extent to maintain the stability of the efficacy of water, maintain 40 to 80 minutes, but in swimming and sweat, sweat, or should be timely supplemented with sunscreen products. Special Note: The correct choice of sunscreen products can help slow down the skin photoaging caused by UV rays and reduce the risk of skin cancer! 2.Why use sunscreen? What is the difference between UVA, UVB and UVC? UVA, UVB and UVC are the most influential to the skin. UVB can be divided into UVA, UVB and UVC. The wavelength of UVC is shorter and is absorbed and scattered by the ozone layer in the atmosphere, so it cannot reach the ground, while the wavelength of UVB is among the three and only reaches the surface of the skin. UVA, which has a longer wavelength, penetrates deep into the skin and damages the dermis, causing skin aging. 3, what is SPF? What is PA? Sunscreen products are mostly marked with SPF (sun protection factor) is to show the value of sun protection effect to prevent UVB damage. PA (protection UVA) refers to the index of the degree of protection against UVA. The general public is more familiar with SPF, but as dermatologists continue to put forward, emphasizing that although UVA is not easy to sunburn skin, but will cause skin photoaging and lesions, so PA labeling is also increasingly important. The value of SPF applies to everyone and is calculated by assuming that the intensity of UV rays does not change because of time. A person without any sun protection measures will have red skin if he stays in the sun for 20 minutes, and when he uses SPF 15 sunscreen, it means that it can be extended by 15 times, which means that the skin will be red only after 300 minutes. PA is a kind of Japanese sun protection index measurement standard that tests the stability index of lasting dark deposits (PPD) on the skin after 2-4 hours of sun exposure. It is divided into four levels. PA +, PA++, PA+++, PA++++, “+” the more, the better the effect of preventing UVA, the longer the effective protection time. 4, the correct use of sunscreen products: Apply sunscreen 10 minutes before going out, because sunscreen needs some time after application to be absorbed by the skin and play a role. Apply sunscreen every 2-3 hours. When you go out in very sunny weather, it is better to wear a hat, sunglasses or play a sunshade. 5.What are the sunscreen products? How do I clean them? Sunscreen is divided into two categories: physical sunscreen and chemical sunscreen. Chemical sunscreen is also known as organic sunscreen, in which the organic substances and ultraviolet light action to change the wavelength of ultraviolet light, so that the original harmful to the skin of ultraviolet light, turned into harmless. The chemicals themselves do not affect the skin and can be cleaned with ordinary products. Chemical sunscreens need to be absorbed, so they work only after 20 minutes of application, and are generally transparent and refreshing, but allergic people will be allergic to some of the ingredients. Physical sunscreens, which mainly rely on the principle of refraction to block UV rays, have particles that may adhere to the skin and clog pores, and therefore require careful cleaning compared to organic sunscreens. The particles used in physical sunscreens do not need to be absorbed, so they are less burdensome to the skin and are suitable for people who are prone to allergies. More than 80% of the products on the market are a combination of physical and chemical sunscreens. Patients with allergic skin can choose to be purely physical sunscreen products. In addition, girls commonly used isolation cream, as a makeup product, can modify facial imperfections, need to remove makeup oil to remove makeup and then use cleansing products, so as to better clean, so as to avoid residue. Let’s choose the right sunscreen and enjoy the beautiful nature.