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Sunlight is an indispensable element in life, it brings us light, warmth and energy. However, there are also secrets and risks in the sun, the most familiar of which isultraviolet rays. What is that ultraviolet light? Is it beneficial or harmful to human health? Let's go down and see~~
What is UV?
Ultraviolet radiation (UV)It is a kind of electromagnetic radiation, its wavelength is shorter than that of visible light, it is located outside the violet part of the visible light spectrum, and its energy is higher, which is invisible to the naked eye. UV rays can be divided into three main types based on wavelength:
| Ultraviolet A (UVA) | Ultraviolet B (UVB) | Ultraviolet C (UVC) | |
| Wavelength (nm, nanometer, ie 10-9 rice) | 320 ~ 400nm (long wave ultraviolet) | 280～320nm (UVB) | 100～280nm (short-wave ultraviolet light) |
| degree of absorption by the ozone layer | Able to penetrate the ozone layer and clouds | Mostly absorbed by the ozone layer | Almost absorbed by the ozone layer and atmosphere |
| Amount reaching the surface | high | Low | almost none |
| harm to humans | Skin tanning, skin aging, etc. | The culprit of skin redness, swelling, heat pain, sunburn, peeling, skin lesions, etc. | Cannot reach the surface, so has no direct effect on humans. |
What are the symptoms of a sunburn??
Symptoms of sunburn vary depending on the degree of sun exposure and individual sensitivities, but common symptoms include:
- redness and burning sensation: The initial symptoms of a sunburn are usually red, swollen skin that may be accompanied by pain and a burning sensation.
- peeling and drying: After sunburn, the skin may start to peel, which is a response of the body to repair itself, and the damaged skin may become dry and rough.
- Blisters appear: Severe sunburn may cause blisters, which are signs of badly damaged and inflamed skin.
- fatigue, fever and headache: In case of severe sunburn, symptoms such as fever, headache and malaise may be accompanied.
How to avoid sunburn?
Here are some ways to avoid UV sunburn:
- Avoid periods of strong sunlight: Try to avoid the most intense sunlight10:00 am to 4:00 pmbetween prolonged exposure to sunlight.
- wear appropriate clothing: Wear long sleeves, a wide-brimmed hat, and sunglasses to minimize skin and eye damage from UV rays.
- use sunscreen: selection has enoughSun protection products with SPF (Sun Protection Factor) value, and make sure they block UVA and UVB rays.
- find shade: When the ultraviolet rays are the strongest, try to stay indoors or in a cool place to reduce the time your skin is exposed to the sun.
Besides being bad, are UV rays good for humans?
In addition to the disadvantages, ultraviolet rays also have some benefits to humans, including the following:
- Synthesis of Vitamin D: Ultraviolet rays are one of the sources of vitamin D synthesis by the human body. Vitamin D is essential for bone health by aiding in the absorption of calcium to help maintain healthy bones and teeth. In addition, vitamin D plays an important role in the regulation of the immune system, cardiovascular health and insulin secretion.
- improve mood: Sunlight and ultraviolet rays can regulate the secretion of melatonin in the brain. Known as the sleep hormone, melatonin not only regulates sleep, but also affects mood and emotions.
- regulate biological clock: Sunlight can help regulate the body's biological clock and help maintain a normal sleep and wake cycle.
- Dermatology Treatment: Ultraviolet light therapy (phototherapy) is often used to treat some skin diseases such as psoriasis, jaundice, eczema and chronic dermatitis.
What are the industrial uses of UV rays?
The following are several major applications of ultraviolet light in industry:
- UV curing: UV curing technology is widely used in industrial fields such as printing, paint, glue and coating. When a material containing a special photosensitizer is irradiated with ultraviolet rays, a photochemical reaction will be triggered, causing the material to harden or cure quickly, thereby speeding up production and saving energy.
- Disinfection and Sterilization: Ultraviolet rays have a strong bactericidal effect, can effectively eliminate bacteria, viruses and other microorganisms in the air and water, and are widely used in drinking water treatment, sewage treatment, medical and sanitation and other fields.
- Food Processing and Preservation: Ultraviolet rays can be used for sterilization and preservation in food processing, which can prolong the shelf life of products and ensure food safety at the same time.
- semiconductor manufacturing: During semiconductor manufacturing, ultraviolet light is used to create tiny circuits and components. Specific wavelengths of UV light can be used to etch, expose and fabricate fine structures, which are crucial in the semiconductor industry.
- Detection and Analysis: Ultraviolet light can be used to analyze and detect many chemical substances, which is very useful in chemistry, environmental monitoring and pharmaceutical research.
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References
1. ultraviolet rays - Wikipedia
2. The pictures in the article are all from the CC0 free gallery.
