What Is a UV Block?

The UVA band is part of the division of ultraviolet wavelengths, with a wavelength of 320 to 420 nm, also known as the long-wave black spot effect ultraviolet. It has a strong penetrating power, UVA can reach the skin's dermis, destroy elastic fibers and collagen fibers, and tan the skin.

UVA

(UV classification)

UVA band is

According to different biological effects, the ultraviolet is divided into four bands according to the wavelength:

The classification of UV is UVA, UVB, UVC and UVD. Among them, UVC can't reach the ground because of its short wavelength, which has been absorbed and scattered by the ozone layer in the atmosphere. The wavelength of UVB is among the three, and the wavelength can only reach the epidermis of the skin, while the longer wavelength UVA will penetrate deep into the skin, hurt the dermis of the skin, and cause skin aging.

UVA band, wavelength 320-420nm, also known as long-wave black spot effect ultraviolet rays. It has a strong

When buying sunscreen, pay attention to the SPF value, which prevents UVB rays. The higher the SPF value, the better. The higher the skin, the more difficult it is to "breathe." When choosing sunscreen, you must also pay attention to preventing UVA rays. The index of preventing such rays is expressed by PA. The more plus signs, the better the sunscreen effect. At the same time, the sunscreen is scheduled to be applied 15 minutes before going out, because the sunscreen will not work until 15 minutes. All parts of the body should be rubbed, especially where the ultraviolet rays are strong. Apply sunscreen on the back of your hand. After spraying with water, it is best to pick one that can form drops of water. ^[3]