The sun constantly emits radiation. UV radiation is a part of that electromagnetic spectrum of radiation which reaches Earth from the sun. It is a type of energy located on the spectrum just beyond visible light.
UV radiation brings both beneficial and harmful effects. When anyone exposes their skin to sunlight, it activates vitamin D production, which is needed for healthy bones and muscles.
Nevertheless, UV radiation can also create sunburn and skin ageing. After a specific time, it can become a leading cause of skin cancer.
UV Radiation
UV radiation is a type of electromagnetic energy emitted basically by the sun and particular artificial sources. It falls just above the violet end of the visible light spectrum, making it fully invisible to the human eye.
UV radiation is categorised into three main categories based on the wavelength.
- Ultraviolet A (UVA)
- Ultraviolet B (UVB)
- Ultraviolet C (UVC)
As sunlight passes via Earth’s atmosphere, water vapour, ozone, and carbon dioxide absorb all UVC, most UVB, and some UVA. Henceforth, the types of UV radiation have different energy levels and different impacts on living organisms and materials.
UV radiation plays a vital role in vitamin D synthesis, a vitamin pivotal to health which helps the body intake calcium and phosphorous from food. Thus, experts suggest 5-15 minutes of sun exposure two to three times a week.
Nevertheless, excessive exposure also creates health risks, such as:
- Skin cancer
- Premature ageing
- Sunburn
- Potentially blinding eye conditions
UVA
UVA rays have the longest wavelengths amid the three categories at 315-399 nanometers (nm) and make up the majority of the UV radiation received on Earth.
About 95% of UV rays that reach the ground are UVA rays, UVA is present in sunlight for the whole day, even during overcast conditions. Thus, it is vital for people to wear sun protection all year, even during the fall and winter.
These rays can penetrate the skin more compared to UVB rays, reaching the dermis, the skin’s second layer.
Even though UVA rays are less likely to cause sunburn, they can harm the collagen and elastin in the skin, contributing to premature skin ageing or wrinkles.
UVA exposure leads to free radical production that can damage cells and potentially result in skin cancer. Tanning beds frequently use
UVA rays escalate the risk of skin damage and cancer.
UVB
UVB rays have shorter wavelenghts compared to UVA rays, at 280-314 nm and are responsible for creating sunburn. These rays considerably affect the outer layer of the skin, the epidermis.
Like UVA rays, UVB rays are also crucial for vitamin D synthesis. However, they can also increase the risk of skin damage, including burning, skin cancer and ageing. A small amount of approximately 5% reaches Earth from the sun.
UVC
UVC radiation extends a wavelength of 100-279 nm. Even though it originates from the sun, it never reaches the Earth’s surface because the ozone layer absorbs it efficiently.
Consequently, exposure to UVC radiation happens exclusively through artificial sources, like lasers or specialised lamps. These devices emit UVC rays for particular applications, leveraging their high energy to target and nullify microorganisms efficiently.
Heavy-duty protective gear is mandatory for anyone exposed to UVC rays.
Risks of UV Radiation
Moderate UV radiation is required for life, but undue exposure can damage health. The fundamental risks include:
Skin Ageing
Both UVA and UVB can intensify the ageing process of the skin, creating the following:
- Age spots
- Wrinkles
- Fine lines
This premature ageing, called photoaging, is a result of the skin’s breakdown of collagen and elastin fibres.
Sunburn
Excessive exposure to UVB, and to a fewer extent UVA, can cause sunburn, resulting in the following symptoms:
- Skin peeling
- Redness
- Pain
Sunburn is a visible sign of skin damage linked to a high risk of skin cancer.
Eye Damage
UV radiation can damage the eyes, leading to the development of cataracts and other eye conditions. For instance, if the skiers are not wearing protective goggles at altitude, they risk painful UV burns to the surface of the corneas.
Elongated UV exposure to the eyes can also elevate the risk of macular degeneration, a leading cause of vision loss in older adults.
Skin Cancer
The most alarming risk of over-UV exposure is the elevated likelihood of developing skin cancers, including:
- basal cell carcinoma
- melanoma
- squamous cell carcinoma
UV radiation harms the DNA within skin cells, potentially triggering mutations that result in cancerous growths.
Damages Immune System
Excessive exposure to UV radiation has a suppressing effect on the immune system. Sunburn can alter the distribution & function of disease-fighting WBCs in humans for up to 24 hours after exposure to the sun.
Prevention
Even though it isn’t possible to entirely prevent skin cancer or undo past effects of ultraviolet radiation and sun damage, you can take steps to diminish your risk by:
- Wearing sunglasses with complete UV protection.
- Choosing cosmetic products that provide UV protection.
- Applying sunscreen along with a sun protection factor of 30 or greater 30 minutes prior to sun exposure and then every 2 to 3 hours after. Reapply instantly if you get wet or sweat considerably.
- Avoid direct sun exposure as far as possible at peak UV radiation hours, between 10 a.m. and 4 p.m.
Conclusion
UV radiation is necessay for getting vitamin D to support survival, however it can be harmful when exposed to excessively. Safeguard your skin and lower the risk of skin cancer from UV radiation by applying sunscreen when outdoors and avoiding direct sunlight during peak hours in the middle of the day.
FAQs
1. Why is exposure to UV harmful to humans?
2. What is the highest UV index?
3-7 is moderate to high: ensure you use sunscreen and find shade, particularly during midday
8-11 is very high to the extreme: Apply sunscreen generously and take extra precautions to safeguard your skin.
