Does sunscreen really protect against the sun? Why sunscreen protects against the sun

This is not true. Wearing sunscreen can only reduce the severity of sunburn, not completely avoid it. In addition, sunscreen can only prevent ** from being tanned in one aspect.

Its role is more to reduce the damage of ultraviolet rays, prevent aging due to sun exposure, and prevent cancer. If you want to avoid sunburn, you should apply sunscreen with other methods.

Sunscreen can also tan you, but the degree of sunburn is reduced. Sunscreen has a certain protective effect on the sunscreen, mainly to prevent photoaging. Because people's exposure to sunlight, especially after absorbing ultraviolet rays, they are prone to pigment changes, wrinkles, roughness, laxity, telangiectasia and other adverse symptoms, which will make them worse.

Sunscreen can prevent these symptoms, where pigment changes are the cause of darkening, so sunscreen can reduce sunburn.

If you want to avoid sunburn, you can take other precautions, such as preventing your face from getting tanned, wearing a parasol, a hat or a mask when you go out, and minimizing the degree of exposure. If you want to prevent being tanned, you need to wear long-sleeved sun-protective clothing, which can reduce the contact between sunlight and sunshine, inhibit the absorption of ultraviolet rays, and prevent you from being tanned. With a high-quality sunscreen, you will have better sun protection.

What does sunscreen do?

In summer, the sun is very strong, when people are doing outdoor activities, many people often apply some sunscreen on the sun in order to avoid sunburn, these sunscreens can protect them from the sun, so the question is, why can sunscreen protect from the sun? What is the principle of sunscreen sun protection?

We know that sunlight includes not only visible light, but also ultraviolet light, which has a lower wavelength than visible light. Ultraviolet rays have the effect of sterilization and disinfection, which is beneficial to health. However, excessive UV exposure can cause burns to turn black, wrinkle, and potentially lead to cancer.

The main function of sunscreen is to block the ultraviolet rays in the sun's rays.

According to the degree of damage to **, ultraviolet (ultraviolet, abbreviated as UV) can be divided into three bands. The wavelength of which is 320 400 nanometers, called UV-A. This part of the ultraviolet rays is highly penetrating and can reach the dermis, and dark clouds and glass cannot block it.

Its damage to ** is mainly manifested as chronic damage, such as tanning, wrinkles, sagging and other symptoms over time. This is the reason why people who work in the field or live at high altitudes** age earlier. Ultraviolet rays with a wavelength of 290 320 nanometers are called UV-B.

This part of the UV light is less penetrating and cannot reach below the epidermis, but it can cause acute damage, such as erythema and burns. UV-A and UV-B together account for only 1 10 of the sun's ultraviolet rays, and the rest are the parts with wavelengths less than 290 nanometers, also known as UV-C. It is the culprit of causing **cancer, but because it can be absorbed by the ozone layer in the atmosphere, it will not harm us under normal circumstances**.

However, due to the destruction of the ozone layer, some sunscreens also include UV-C protection.

The sunscreen ingredients in sunscreens include inorganic compounds such as titanium dioxide and zinc oxide, as well as certain aromatic organic compounds. These two types of substances are usually used together: the function of inorganic substances is to form a barrier layer on the surface of ** to reflect sunlight; The function of organic matter is to absorb sunlight, and their specific molecular structure determines them.

The light energy absorbed by the molecule from ultraviolet light is equal to the energy required to cause the "photochemical excitation" of the molecule, so as to convert the light energy into heat energy or harmless visible light and radiate it, which effectively prevents ultraviolet tanning and sunburn**.

Some UV absorbers can absorb both UV-A and UV-B; Some ultraviolet absorbers only absorb UV-B, and less absorb UV-A, the use of this sunscreen, can meet the needs of sunbathers, so that the ** tanned into a toned bronzer, but will not cause acute burns. Sunscreens that are now commercially available have clear markings for either UV-A or UV-B. Some natural products, such as extracts of seaweed, chitin, sea buckthorn, aloe vera, rutin, skullcap, ginkgo biloba, and olive tree leaves, also have UV protection because these plants contain specific UV-absorbing chemicals.

It must be reminded that even with the use of sunscreen, excessive sun exposure can still cause various damages.