What is the difference between UVA and UVB?

The difference between UVA and UVB: the penetration is different

Sunlight penetrates the Earth's atmosphere, and a large part of it is blocked by the atmosphere, but UVA has a stronger penetration ability than UVB, so more than 90% of UV rays are UVA. And UVB is not even easy to pass through the glass!

Similarly, ultraviolet light can also have different penetrating power on the skin: UVB can reach the epidermal layer of the skin, and UVA can reach the dermis layer of the skin.

 

The difference between UVA and UVB: the damage to the skin is different

According to the difference 2, we know that UVA has a strong penetrating ability, but UVB is not easy to ignore because of its high energy, and (UVB) damages the skin. Let's look at the two types of UV damage to the skin:

UVA damage to the skin:

Short-term damage includes melanin deposition, darkening of the skin, and pigmentation. Remember that the vowels of "A" and "Black" are both "ei", and with ei hei, you can remember which is the ultraviolet light that darkens your skin.

Long-term injury: Because UVA can penetrate into the dermis, damage cellular DNA, collagen damage, accelerate skin aging, and even cause skin cancer.

UVB damage to the skin:

Short-term: sunburn, erythema, edema, pain, and even blisters. This is UVB's short-term damage to the skin.

Long-term damage can also damage cellular DNA.

 

The difference between UVA and UVB: the logo of sunscreen products is different

Here, I entered the stage of specific sunscreen product selection. Many years ago, the academic community did not realize that UVA would also harm the skin. Therefore, the sunscreen products at that time only focused on preventing UVB. The internationally accepted identifier in cosmetic products is the spf value. However, after discovering the damage of UVA to the skin, the related anti-UVA UV sunscreen and products were slowly developed. Currently, the PA value is used in our country. The ability to prevent UVA is indicated by PA+, PA++, and PA+++, respectively. However, other countries and regions do not necessarily use the PA value to indicate the ability to prevent UVA. For example, in Europe, the value of PPD is followed by the value of UVA.

 

UVA, the difference between UVB and UVC: Do you want to prevent UVC?

In fact, in addition to UVB and UVA, ultraviolet rays also have UV rays in the UVC section, but this part of the ultraviolet rays is blocked by the atmosphere. Therefore, it is unnecessary to protect the surface.

 

Summary of UVA/UVB:

Skin aging, beginning to relax, appearance of fine lines, loss of skin moisture, collagen loss are directly related to ultraviolet light. UV rays cause sunburn (tanning), which is the primary factor that makes you black. For the difference between UVA and UVB, we have to remember

1. UVA penetrates into the dermis of the skin, making the skin tan

2.UVB causes sunburn on the skin

3. Anti-UVA protection is more difficult, because of its strong penetrating power, try to choose high PA value sunscreen products, at least PA++, PA+++ and above is better.

4. Although UVB is not much in the sun, it has strong energy and great damage to the skin. The domestic sunscreen production uses SPF value identification. The value can be marked to SPF30, exceeding SPF30. For example, SPF50 can only be labeled SPF30+, but not SPF50. Sunscreen products with SPF30 and SPF30+ are available for summer use.