What Is a UV Rating?

Ultraviolet index refers to the possibility that when the sun's position in the sky is the highest (usually around noon, that is, from 10 am to 3 pm), the ultraviolet radiation in the sun's rays reaching the surface of the earth can affect human skin. degree of damage. The range of UV index change is expressed by a number of 0-15. Generally, the UV index at night is 0, and the UV index in tropical, plateau, and sunny days is 15. When the UV index is higher, it means that the degree of erythema damage to human skin is worsened by UV radiation. Similarly, the higher the UV index, the greater the damage to the skin in a shorter period of time.

UV index rating

The ultraviolet index is composed of two parts, one is the measured ultraviolet intensity of the sun at different wavelengths, and the other is the ultraviolet dose required to reflect the erythema after different types of skin are irradiated by ultraviolet rays. These two parts are combined mathematically. After processing, it is converted into numbers according to prescribed standards to form the UV index released to the public. Therefore, the UV index can be understood as the intensity of the sun's UV rays reaching the ground and the degree of influence of human bare skin. The larger the UV index number, the greater the damage to the skin. Medical tests have shown that taking skin redness as a standard, the damage of ultraviolet rays to the skin is not only related to the intensity of ultraviolet rays, but also to the type of skin and the time of sun exposure. Therefore, in the practical application of ultraviolet index, we need to know not only the The specific meaning also needs to know more about sun protection. ^[1]

Schedule

Grade of UV Index

Divided into grades 1 ~ 5, see the attached table for the grading method

Level 1: 0, 1, 2 Weakest <5100 ~ 180 No protective measures are required; if you are outdoors for a long time, it is recommended to apply sunscreen skin care products with SPF between 8-12.

Level 2: 3, 4 Weak 5 ~ 1060 ~ 100 You can take some protective measures appropriately, and apply sunscreen skin care products with SPF between 12-15 and PA +.

Level 3: 5, 6 Medium 10 ~ 1530 ~ 60 Wear sun hat, sunglasses and sun umbrella when going out; apply sunscreen skin care products with SPF higher than 15, PA +.

Level 4: 7, 8, 9 Strong 15 ~ 3020 ~ 40 Avoid exposure to sunlight from 10 to 14 o'clock. Wear sun hats, sunglasses and umbrellas when going out, and apply sunscreen skin care products around SPF20 and PA ++.

Level 5: 10 and greater than 10 Very strong> = 30 and less than 20 Not to be outdoors as much as possible. When you must go out, you must take various effective protective measures. ^[1]