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Ultraviolet light (UV) is a type of radiation found naturally in sunlight. Exposure to UV can cause our skin to tan or burn - so although you cannot see or f...
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- Met Office - Learn About Weather
- Overview
- What is UV radiation?
- UVA
- UVB
- UVC
- Risks of UV radiation
- Frequently asked questions
- Summary
UV radiation comes primarily from the sun. It comprises UVA, UVB, and UVC rays, each with unique properties. While some types of UV radiation provide health benefits, they can also pose risks.
The sun continuously emits radiation. Ultraviolet (UV) radiation is one part of the electromagnetic spectrum of radiation that reaches Earth from the sun. It is a form of light energy situated on the spectrum just beyond visible light.
UV radiation has both beneficial and harmful effects. When someone exposes their skin to sunlight, it stimulates vitamin D production, which is necessary for healthy bones and muscles. However, UV radiation can also cause sunburn and skin aging. In the long term, it is one of the leading causes of skin cancer.
This article explains what UV radiation is and explores its effects, risks, and benefits.
UV radiation is a form of electromagnetic energy emitted primarily by the sun and specific artificial sources. It falls just beyond the violet end of the visible light spectrum, making it invisible to the human eye.
UV radiation is divided into three main categories based on wavelength:
•ultraviolet A (UVA)
•ultraviolet B (UVB)
•ultraviolet C (UVC)
As sunlight passes through Earth’s atmosphere, ozone, water vapor, oxygen, and carbon dioxide absorb all UVC, most UVB, and some UVA. Therefore, the types of UV radiation have varying energy levels and different effects on living organisms and materials.
UVA rays have the longest wavelengths among the three categories at 315–399 nanometers (nm) and make up most of the UV radiation received on Earth. About 95% of UV rays that reach the ground are UVA rays.
UVA is present in sunlight throughout the day, even in overcast conditions. Therefore, it is important for people to wear sun protection all year, even in fall and winter.
These rays can penetrate the skin more deeply than UVB rays, reaching the dermis, the skin’s second layer.
While UVA rays are less likely to cause sunburn, they can damage the collagen and elastin in the skin, contributing to premature skin aging or wrinkles.
It’s easy to remember that UVA rays “age” the skin. UVA exposure also contributes to free radical production that can damage cells and potentially lead to skin cancer.
Tanning beds often use UVA rays, increasing the risk of skin damage and cancer.
UVB rays have shorter wavelengths than UVA rays, at 280–314 nm, and are responsible for causing sunburn. These rays significantly affect the outer layer of the skin, the epidermis. UVB rays “burn” the skin.
Like UVA rays, UVB rays are also essential for vitamin D synthesis. But they can also increase the risk of skin damage, including burning, aging, and skin cancer.
UVC radiation spans a wavelength of 100–279 nm. While it originates from the sun, it never reaches the Earth’s surface because the ozone layer absorbs it efficiently.
As a result, exposure to UVC radiation occurs exclusively through artificial sources, such as specialized lamps or lasers. These devices emit UVC rays for specific applications, leveraging their high energy to target and neutralize microorganisms effectively.
Sunburn
Overexposure to UVB, and to a lesser extent UVA, can cause sunburn, leading to the following symptoms: •redness •pain •skin peeling Sunburn is a visible sign of skin damage linked to an increased risk of skin cancer.
Skin aging
Both UVA and UVB rays can accelerate the aging process of the skin, causing the following: •wrinkles •fine lines •age spots This premature aging — known as photoaging — results from the skin’s breakdown of collagen and elastin fibers.
Eye damage
UV radiation can harm the eyes, contributing to the development of cataracts and other eye conditions. For example, skiers not wearing protective goggles at altitude risk painful UV burns to the surface of the corneas. Prolonged UV exposure to the eyes can also increase the risk of macular degeneration, a leading cause of vision loss in older adults.
Which type of UV radiation is most harmful?
UVC is the most damaging type of UV radiation, but as none reaches Earth, it poses no real risk. Medium-wavelength UVB significantly promotes skin cancer development. Therefore, it could be considered the most harmful. However, more recently, experts have found that UVA also contributes to skin cancers, so people must protect themselves from UVB and UVA radiation.
Are there any health benefits of UV radiation exposure?
Despite the risks of excessive UV exposure, there are also some health benefits of moderate UV exposure, including: •Vitamin D synthesis: UV rays help the skin synthesize vitamin D, which is crucial for maintaining healthy bones, supporting the immune system, and regulating cell growth. •Mood enhancement: Sunlight, including UV radiation, can have a positive impact on mood by stimulating the release of serotonin, a neurotransmitter associated with feelings of well-being. •Skin conditions: Controlled exposure to UV radiation is sometimes used in medical settings to treat certain skin conditions, such as psoriasis.
UV radiation comes primarily from the sun and is made up of UVA, UVB, and UVC rays. UVC rays do not reach Earth, but both UVA and UVB rays pose health risks.
While UVB rays are the primary culprits behind immediate skin damage and sunburn, the deeper-reaching UVA rays also contribute to long-term skin aging. Both types of radiation can contribute to skin cancer development.
Apr 1, 2023 · Ultraviolet light or UV is electromagnetic radiation in the wavelength range of 10 to 400 nanometers (nm), which is between x-rays and visible light. Because it is largely invisible to humans, another name for UV is black light.
Jun 21, 2022 · Skin cancers are caused primarily by exposure to ultraviolet radiation (UVR), either from the sun or from artificial sources such as sunbeds. Globally in 2020, over 1.5 million cases of skin cancers were diagnosed and over 120 000 skin cancer-associated deaths were reported.
Jun 7, 2021 · What does UV mean? What is the electromagnetic spectrum? How does the visible light spectrum work? Why is ultraviolet light hazardous? What are the most common varieties of ultraviolet light? How does ultraviolet light damage eyesight? How do sunglasses keep UV light from damaging the eyes?
- Tom Mangan
There are a variety of ways we put ultraviolet (UV) radiation to good use – vitamin D production, sterilisation and disinfection, astronomy, fluorescence and lighting, and curing. For more resources related to UV, this article introduces the range of content we have.
People also ask
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Jul 29, 2024 · Ultraviolet (UV) radiation covers the wavelength range of 100–400 nm, which is a higher frequency and lower wavelength than visible light. UV radiation comes naturally from the sun, but it can also be created by artificial sources used in industry, commerce and recreation.
