Sun's ultraviolet of wavelength 200~400 nm radiation, is the shortest wavelength of sunlight. Contains UVA, UVB and UVC three types of UV-ray, and their effect on the skin are also different.
Wavelength of UVA-rays 320~400 Nano, also known as Tan, admittance up to human dermal layer, strong penetrability, slow effects lasting characteristics. UVA although does not caused skin acute inflammatory, but it on glass, and clothing, and water and the human epidermal has is strong of penetrating force, can first penetrating epidermal arrived skin of underlying and lurking up, cumulative on will serious disrupt skin of immune system, caused body oxidation free base increased, damage elastic organization, thus and produced of consequences is: skin ahead of aging, horny had thick, epidermal rough, has wrinkles and spots, muscle relaxation, and droop, while increased UVB on human of injury.
Wavelength of UVB-rays to 280~320 nanometers, also known as the Red Sun, admittance up to human epidermal layer, causing Erythema, is the main band sunburned skin, light can cause skin irritation, pain, severe cases can produce blisters, peeling.
UVA and UVB radiation exposure is excessive, may give rise to cells DNA mutations, skin cancer.
UVC rays wavelength 200~280 nm also known as the sterilization period, admittance only to the stratum corneum of the skin, and most of the detention by atmosphere, no harm on the human skin.
Sunscreen cosmetics is the formula contains a certain amount of sunscreen, Sun block thus has a certain function of cosmetics. Sunscreen is the ability to protect the skin from UV damage of the material, according to their mechanism of different chemical physical scattering agent and absorbent can be divided into two types. Chemical absorbents absorb UV energy and then to harmless forms such as heat release, for Sun protection purposes; the physical scattering agent mostly inorganic powder, mainly through its own scattering effect of blocking ultraviolet rays and skin contact, thereby preventing UV damage.
Sun protection cosmetics, Sunscreen SPF value to represent the size of the effect of. Sun Block SPF multiples, also known as SPF, is shorthand for SUN PROTECTION FACTOR refers to cosmetics extended skin from the Sun caused skin and reddish multiples of the time required. General low Sunscreen SPF value of 2~6, 6~10, high 10~15, high intensity for more than 15. Women generally do not want to be tanned, therefore, preferably full-band UVB-UVA-proof sunscreen products. The General type of sunscreen the skin using SPF8~15, for Sun-sensitive people, to choose a higher SPF value products, to 15~20. If the field work, tourism and waterfront, to use SPF products of higher value; in the spring and summer to use SPF value greater than 12 products, in order to guarantee better resistance to drying effect, should use waterproof sunscreen cosmetics.
Facial sunburn occurs, gently massages the milk may be insufficient in the face, skin contraction after 2-3 minutes; and lemon dressing, sunburn will gradually lighten; and sliced cucumber fruit, along with arrowroot, honey dressing in face, 5-8 minutes, 3~5 after sunburn can be eliminated.