What is the UV Protection Factor? 4 key points for choosing sunscreen clothing

In addition to sunscreen lotion having SPF, clothes actually have their own set of SPF. Ultraviolet Protection Factor (UPF) is a coefficient used to measure the ability of clothing to protect against UV penetration.

Generally, the UPF of standard sunscreen clothing must be at least greater than 30, and then the sunscreen certification will be granted. If the UPF of clothing is less than 15, it does not have the sunscreen function. How to look at the UPF protection factor? How to choose clothes with sun protection function? Let's take everyone to understand the principle of UPF and provide 4 key points for choosing sunscreen clothing!

What is the UPF UV protection factor?

There are many kinds of light emitted by the sun, which can be divided into infrared, visible light, ultraviolet light, etc. according to the wavelength, and the most harmful to human skin is called ultraviolet (Ultraviolet, UV), and among the ultraviolet rays, it is divided into UVB (Ultraviolet B) And UVA (Ultraviolet A), both are ultraviolet rays that can penetrate the ozone layer and reach the ground.

UVA has strong penetrating power and can penetrate glass windows, clouds and skin, which is the main cause of skin aging, while UVB will stay on the skin surface, causing skin sunburn and skin cancer. In sunlight, UVA is 500 times more abundant than UVB.

The SPF of a sunscreen lotion measures only UVB, but UPF measures both UVB and UVA:

UVB: It is determined by the length of time until the reaction occurs after the skin is exposed to ultraviolet rays.
UVA: Calculates how much UV rays reach the skin.

A piece of clothing with a UPF >50 blocks 98% of sunlight, in other words, only 2% of UV rays reach the skin. The higher the UPF value, the more UV rays can be blocked from reaching the skin. (Recommended Reading: 5 Sunburns Double Your Cancer Risk! Recognize the Link Between UV Light and Skin Cancer)

The following are the sun protection levels and UV penetration rates of UPF:

UPF 15~24: Good protection ability, UV penetration rate of clothing is 4.2~6.7%.
UPF 25~39: Excellent protection ability, UV penetration rate of clothing is 2.6~4.1%.
UPF 40~50+: Excellent protection ability, UV penetration rate <2.5%.

4 key points for choosing sunscreen clothes

Although high UPF clothing can protect the skin from sunburn, the protective effect will vary depending on the fabric and color of the clothing. The following are 4 key points for choosing sunscreen clothing:

Fabric: Fabrics with high fabric density have better sun protection than thin fabrics, such as polyester, nylon, denim, canvas, synthetic fabric, wool and silk, etc., while fabrics with poor sun protection are cotton, linen, and rayon. with hemp fibers. Some fabric manufacturers add special chemicals, such as Optical Brightening Agents (OBAs) and dyes, to the clothing process to absorb UV rays.

Elasticity: Loose clothing has better sun protection than well-fitting clothing. Fitted clothing is easy to stretch and stretch the fabric fibers, making it easier for ultraviolet rays to contact the skin. However, when choosing loose-fitting clothing, don't pick clothes with thin fabrics. If the light is blocked with cloth, the light will pass through at once, which means that the sun protection effect is low.

Color: The darker the color of the clothes, the easier it is to absorb sunlight, so the better the sunscreen performance is, but the real effect of this effect is actually from the UV-blocking dye. The higher the concentration, the more light that can interfere.
Moisture: Generally speaking, wet clothing provides less sun protection, and if you wear wet clothing in the sun, your skin will be exposed to relatively more UV rays.