How to prevent UV damage
How to Prevent UV Damage
Understanding Ultraviolet Light
The ultraviolet region of sunlight can be divided into three segments. It can be divided into three sections. The wavelength area of 400-320nm is called UV-A; the wavelength area of 320-280nm is called UV-B; the wavelength area of 280-200nm is called UV-C. UV-C has a shorter wavelength, has been absorbed in the air, and cannot reach the earth’s surface. Ultraviolet rays account for about 6% of sunlight, with UV-A accounting for a larger proportion and UV-B accounting for a smaller proportion. UV-A will penetrate beneath the epidermal tissue, causing muscles to lose elasticity, roughening the skin, and causing wrinkles. UV-B can cause skin cancer. Therefore, it is required to effectively shield the short wavelength parts of UV-B and UV-A.
UVA
320-400nm
Occupies 98.9% of surface UV
Weak damage
Can penetrate the ozone layer
UVB
280-320nm
1.1% of surface UV
Strong damage
Most of it is absorbed by stratospheric ozone and increases due to the destruction of ozone
Effects of UV rays on skin
UVA
It reaches the dermal layer of the skin and damages elastic fibers and skin capillaries, causing skin aging, darkening, and loss of elasticity.
UVB
It can cause skin darkening and sunburn in the short term, and can cause skin cancer in the long term.
Currently, due to the destruction of the earth’s ozone layer by chlorofluorocarbons (ClFCs), the ozone concentration in the ozone layer hole discovered in 1997 is 40% less than in the 1980s. According to analysis, if the level of the ozone layer is reduced by 1%, the transmission amount of UV-B can be increased by 2%, and the incidence of skin cancer will increase by 0.5-5%. According to statistics, between 1980 and 1996, the number of skin cancer patients doubled. In the United States alone, the number of people increased from 200,000 in 1990 to 1 million in 1996. Therefore, it is very important to carry out UV protective finishing of fabrics, especially UV protective finishing of summer clothing fabrics.
Ultraviolet Index (UVI)
During an hour of strong sunlight at noon (approximately 11:30~12:30), the amount of accumulated radiation per unit area of the ground reached by ultraviolet rays that cause skin redness, measured in hundreds of joules per square meter.
Comprehensive sun protection measures
Total body sun protection
Physical protection
Sunscreen lotions and creams
Antioxidants
Total body sun protection
2-3 grams of L-vitamin C and 1-2 grams of vitamin E per day will increase the low redness-causing dose of the skin.
Polypodiumleucotomos
b carotenoids
Physical sunscreen
Clothing is an excellent way to protect yourself from the sun
Determining the sun protection ability of clothing depends on the density of weaving of clothing
Pure cotton and polyester cotton clothing have the same sun protection capabilities
Dark clothing has better sun protection effect
Sun protection is less effective when clothing is wet
Physical sunscreen
Hat brim less than 2.5 cm can only provide about SPF1.5 protection for the nose
Hat with brim 2.5-7.5 cm (SPF3 for nose, SPF2 for cheeks and neck)
Hat with brim 284m67.5cm (nose SPF7, cheeks SPF3 and neck SPF5)
The ability of the earth’s surface to reflect sunlight
Snow 85%
Sand 17%
Water 5%
Grassland 3%
Why choose products with SPF greater than 15?
The SPF measurement is calculated based on the minimal redness-causing dose of Minimal Erythema Dose (MED)
MED refers to a low dose that can produce reddish skin after exposure to light
If it takes 15 times for the skin to become red after applying sunscreen, its SPF is 15, which theoretically blocks 93.3% (14/15) of the ultraviolet effect.
Is SPF15 sunscreen product really enough?
SPF30vsSPF15
96.7%vs93.3%
Dosage: About 1-2g each time on face
Frequency: 2 hours
Location: Indoor, outdoor swimming pool, skiing
Skin type: gel, lotion, cream, ointment
How to choose sunscreen products that protect against UVA?
PA+,++,+++
IPD
PPD
Ingredients of sunscreen cosmetics
Sunscreen main agent
Anti-free radical substance agent
Dosage Form Excipients
Additives
Sunscreen main agent
Physical sunscreen
Principle: reflection, scattering
Common ingredients; Titaniumdioxide, Zincoxide, Silicate, ferricoxide
Chemical sunscreen
UVA:benzophenone,Parso1789,Mexory;
UVB: PABA Cinnmate and derivatives (Octyl-methoxycinnamate)
Antioxidants
Vitamin C
Divalent zinc ion
Flavonoid、polyphenoliccmpound
Fruits: blue plums, grapes, tomatoes, oranges and other citrus plants
Vegetables: cucumber, broccoli
Oil: Olive oil
Beverages: green tea, red wine
Test standards
UPF (Uitiraviolet Protection Factor), also known as UV shielding factor, represents the ability of fabrics to protect against UV rays. It is the ratio of the average amount of UV radiation to unprotected skin to the UV radiation after blocking by the fabric to be tested.
Ultraviolet transmittance: refers to the percentage of the ultraviolet radiation intensity transmitted through when there is a sample to the ultraviolet radiation intensity when there is no sample.
According to the Chinese-German definition of the national standard, UPF refers to “the ratio of the average effect of ultraviolet radiation calculated when the skin is unprotected to the average effect of ultraviolet radiation calculated when the skin is protected by fabric.”
The higher the UPF value, the better the UV protection effect. However, the national standard for textiles with a high UPF value is 50+, which means that the UPF is greater than 50. After it should be greater than 50, the impact on the human body is completely negligible.
The “Evaluation of UV Protection Performance of Textiles” standard promulgated by the General Administration of Quality Supervision, Inspection and Quarantine stipulates:
A Only when the UPF value of the sample is greater than 30 and the transmittance of UVA is less than 5%, can it be called an “UV-resistant product”. These two conditions are insufficient.Not even one. This is a constant indicator of whether a product is a “UV protection product”.
B UV protection products should have three aspects on the label:
1. National standard number: GB/T188302
2.UPF value
3.30+, or 50+
Remarks:
If the measured UPF value is greater than 30 and the UVA transmittance is less than 5%, the mark is: 30+
If the measured UPF value is greater than 50 and the UVA transmittance is less than 5%, the mark is: 50+
The protective properties provided by this product may be reduced with long-term use and when it is stretched or wet. cMNuU9zjDh
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