How many types of UV rays are there? Which type is bad for the skin?

The article was professionally consulted by Specialist Doctor I Le Thi Thu Hang - Dermatologist - Department of Medical Examination & Internal Medicine, Vinmec Hai Phong International General Hospital

UV rays are the biggest "enemies" of anyone's skin, especially women, when summer comes. However, how many types of UV rays are there? Are all UV rays harmful to the skin?

UV rays (from English Ultraviolet), also known as ultraviolet rays or ultraviolet rays, are electromagnetic waves with wavelengths shorter than visible light but longer than X-rays. The ultraviolet spectrum includes the near ultraviolet wall. (with wavelengths from 380 to 200 nm) and ultraviolet or vacuum ultraviolet (with wavelengths from 200 to 10 nm).
When considering the harmful effects of ultraviolet rays on human health and the environment, the spectrum of ultraviolet rays is divided into parts:
UVA group (ultraviolet wavelength A) 95% of the sun's rays are UVA. The harmful effects of A-wave ultraviolet rays are causing our skin to wrinkle. Zinc oxide and titanium oxide are very effective in blocking UVA rays. The UVB group (ultraviolet B wavelength) causes sunburn, reducing the skin's ability to produce collagen and elastin. UVC group: UVC rays and part of UVB rays do not reach the earth because they are filtered through the atmosphere. This light can destroy nucleic acids in cells, destroy DNA existing in living organisms... UVC is the ghostly light that haunts the existence and life of humans on earth. This is the most damaging type of ray. However, there are two basic types of ultraviolet rays that reach the earth's surface: UVB and UVA.

UVA rays are considered "silent killers" because unlike UVB rays, you don't feel its effects, but actually it is penetrating deep into the skin, wreaking havoc on every layer of the skin. silently. The harmful effects of UV rays are caused mainly by UVA rays. This is the leading cause of wrinkles and increases the risk of skin cancer for the most part.
UVA rays are considered "silent killers", you will not feel anything, but the harmful effects of UVA ultraviolet rays are still silently destroying your skin.
Another difference is that UVA rays have the ability to penetrate glass to cause harmful effects of ultraviolet rays to the skin, while UVB rays do not. Unless your car window or car windows are specifically designed to filter out UVA rays, using sunscreen is extremely important to protect your skin from these harmful UV rays.

We must have a way to protect our skin against the harmful effects of UV rays with these safe sun protection measures:
3.1. Sunscreen Helps us to minimize the harmful effects of ultraviolet rays. We must know how to choose the right sunscreen according to the following criteria: broad-spectrum (against both UVA and UVB rays), SPF ≥ 30, water-resistance or very water- resistance) and how to use it (cream, oil, lotion, gel or spray).
However, when using sunscreen, we need to note:
Apply 30 minutes before going out in the sun, repeat every 2 hours; Apply sunscreen to sun-exposed areas at a dose of 2mg (or ml)/cm2 of skin; Avoid swallowing sunscreen. After using sunscreen, you need to wash your hands thoroughly; avoid contact with the area just applied sunscreen before the cream dries; Absolutely do not use sunscreen for children under 6 months old because at this time their skin is still very thin and sensitive.
3.2. Clothing When out in the sun, expose it to direct sunlight. Your body will be exposed to UV rays. Therefore, it is necessary to use hats, wide-brimmed hats, clothes, eyeglasses to protect your delicate skin. When going out in the sun, you should use dark and heavily woven fabrics or fabrics with a glossy finish. Dark clothes make you feel hotter than light colors because they absorb more ultraviolet rays. But it is because of these characteristics that they are better able to protect the skin from UV damage. The glossy fabric helps to reflect the sun, so it's also very useful.
3.3. Eating and drinking Using a lot of water and fruit is a measure to help beautiful skin from the inside. Do not eat foods that are too sweet or too sour. Some vegetables rich in potassium such as: centella asiatica, spinach, jute vegetables, botan... or vitamin-rich fruits such as strawberries, watermelons, oranges, grapefruits, apples, bananas... are good for you in the summer days. sunshine, especially when going to the beach.
In addition, to be safe, it is necessary to reduce the time of sun exposure, avoid the harmful effects of UV rays: avoid working and exposure to sunlight for too long. In the summer, avoid sun exposure, sunbathe a lot at beaches and swimming pools...
3.4. Using a mechanical sun protection tool Mechanical sun protection is a method of taking advantage of sun protection tools such as hats, sunscreen cloths, umbrellas, gloves, masks and sun glasses to protect the skin every time you go out. outside.
Sun protection by shielding is not harmful to health, but the effectiveness is not high. UVA rays have a long wavelength, so they still silently penetrate car glass, sunscreen fabric, and shade to affect the dermis layer of the skin. As a result, the harmful effects of UV rays cause melasma, freckles, aging and skin cancer.