UVA (Ultraviolet A) rays are rays with a wavelength of 320-420 nm. In the scorching sunlight, UVA rays can reach up to 95% of our skin and up to 80% on days with weak sunlight. UVA is therefore a ray. that we should be careful Because in addition to being able to affect the skin a lot It can also penetrate into the skin, harming the collagen and elastin in the skin, causing wrinkles in the skin. wrinkled skin It causes the skin to age prematurely and is also a cause of all types of skin cancer. If you don't protect your skin at all
As for UVB rays (Ultraviolet B), they are rays with a shorter wavelength range of 290-320 nm. They are more abundant in sunlight. 5% Although UVB rays do not penetrate the skin as deeply as UVA, they are very powerful rays because UVB rays can cause our skin to get sunburned, stinging, red, and dark circles as well. Even though it doesn't seem as serious as UVA, I would like to say that the rays UVB can also be a cause of skin cancer.
So if you don't want your skin to be damaged, lose its beauty, or risk skin cancer. We should apply sunscreen to protect our skin every day. If you want to prevent UVA rays that cause wrinkled skin and wrinkles. Choose a sunscreen with a PA rating. The higher the PA+ rating, the more protection from UVA rays.
As for protection against UVB rays that cause skin irritation and sunburn, you must choose sunscreen with an SPF value of at least SPF30, and people with sensitive skin should not use sunscreen with an SPF value of more than 50 because it can cause the skin to become allergic. Or if you want to choose to have complete protection from both UVA and UVB, choose sunscreen that has both SPF and PA+ to suit your skin. It will help reduce skin problems caused by these two types of radiation.

Source: Ramkhamhaeng Hospital