Sunlight is a major factor affecting skin aging and formation of spots on skin. Melanin deposition results in blackening of skin.
So, you need a good sunscreen to protect your skin from sunlight to prevent the stimulation of melanin production. A sunscreen actions principally by blocking the ultraviolet radiations and prevent these radiations reaching your skin and initiating skin pigmentation process and the processes leading to development of skin cancer and other conditions such as post inflammatory hyperpigmentation.
UV radiation spectrum ranges over a wavelength of 100-400nm. It is divided into three bands
- Wavelength 100-290nm of ultraviolet spectrum (UVC)
- Wavelength 290-320nm of ultraviolet spectrum (UVB )
- Wavelength 320-400nm of ultraviolet spectrum (UVA)
Ultraviolet light of different wavelengths have different depths of penetration to the skin.
UVC due to absorption through the large gas reservoir, the mostly by the ozone layer, do not reach the Earth’s surface with high strength. So, this does not pose a hazard to human skin.
UVB is dangerous for skin. It is mostly absorbed by the epidermis and superficial dermis. It has carcinogenic effects, which means it can cause skin cancer. But this spectrum can be blocked by thick clouds, clothing and glass.
UVA is absorbed in skin in small portion; most can penetrate deep into the skin. UVA arrives mostly at noon and in the summer. Its strength is about 100 times than that of UVB. Therefore this is the most culprit portion of the ultraviolet spectrum.
What harm ultraviolet radiation can cause to your skin?
- Increased melanin synthesis. So, can cause skin pigmentation such as dark spots, freckles, melasma and other dark spots.
- Keratinocyte proliferation and skin collagen fibers and elastic fibers destruction. So, this can cause skin hypertrophy, loose and rough skin, and the formation of wrinkles.
- Telangiectasia formation. This is the proliferation and formation of new blood vessels in skin. It can result in erythema or redness.
- Decline in immunity of your skin. This can result into formation of skin cancer or other precancerous lesions (stages which precede development of a cancer) such as light keratosis, squamous cell carcinoma , melanoma, and so on.
So, a good sunscreen not only improves and maintains your skin health but also prevents development of cancer and other skin conditions. This is mediated mainly by blocking the ultraviolet rays which are coming in sunlight.
To maintain healthy and great looking skin, use your broad spectrum sunscreen daily.