sunscreen
TIPS ON SUN PROTECTION
Why do we need protection from sunlight (ultraviolet rays)?
· Sun rays consist of ultraviolet radiations, i.e. UVA, UVB, UVC
· Exposure to both ultraviolet A(UVA) and ultraviolet B (UVB) rays results in cumulated damage that leads to skin ageing, cataracts, corneal burns and the formation of skin cancer.
· Besides sunburn, it can give you headaches; it can cause dehydration and eye damage.
· Exposure to UV radiation triggers increase in darkness of the skin leading to tanning of the skin.
· UV rays penetrate deep into the skin support structure, affecting the skins immune system and increasing cancer risks.
· UVA rays can penetrate glass/windows.
· 80% of the damaging rays can get through clouds.
· 60% of the day’s sun burning radiation occurs between the hours of 10a.m and 4 p.m.
· Reflection from sand, water and white surfaces, results in substantial UVR exposure.
· Heat and brightness are not indicators of UV intensity.
ENVIRONMENTAL FACTORS THAT INFLUENCE THE UV LEVEL
· Sun height- the higher the sun in the sky, the higher the UV radiation level. Thus UV radiation is maximum when the sun is at its maximum elevation, at around midday (solar noon) during the summer months.
· Cloud cover- even with cloud cover, UV radiation levels can be high due to the scattering of UV radiation by water molecules and fine particles in the atmosphere.
· Altitude- with every 1000 meters increase in altitude, UV levels increase by 10% to 20%.
· Ozone- ozone absorbs some of the UV radiation that would otherwise reach the earths surface. Ozone levels vary over the year and even across the day.
· Ground reflection- UV radiation is reflected or scattered to varying extents by different surfaces, e.g. snow can reflect as much as 80% of UV radiation, dry beach sand about 15%, and sea about 25%
· HOW DO SUNSCREENS WORK?
· It has been determined microscopically that sun damage can be reserved by using sunscreens.
· Sunscreens are tropical formulations that stay on or bind to the skin in order to reduce the harmfull effects of sunlight ( particularly the UV spectrum) on the skin.
· They form a protective film over the skin surface and absorb, reflect or scatter sunlight to protect the skin from its harmful effects.
SUN PROTECTIVE FACTOR (SPF) WHAT IS IT?
SPF is an index of protection only from the UVB which causes sunburn. For example, if it took ½ hour for your skin to become sun burned without any sunscreen, then for a sunscreen that has 15 SPF rating, you could stay in the sun for 15 times longer (or 7.5 hours) before you get sun burned. This is provided, of course, that you’ve applied the sunscreen properly so that you’re getting the prescribed protection.
WHY IS IT IMPORTANT TO PROTECT AGAINST UVA RAYS?
Natural light reaching the earths surface is 95% UVA and 5% UVB is almost 20:1.
UVA is of longer wavelength compared to UVB; hence it is less affected by altitude or atmospheric conditions. UVB rays are the suns rays that cause sunburn, whereas UVA rays are the suns rays that cause more long term and permanent damage such as premature ageing and possibly skin cancer. UVA is more important in causing skin tanning. Hence protection against UVA is as important as protection against UVB.
WHAT DOES BROAD SPECTRUM SUNSCREEN MEAN?
Broad spectrum protection means you have protection from both UVA and UVB RAYS. For sunscreen to have broad spectrum action, it should have a combination of specific UVA and UVB protections or agents which protects against both the kinds of UV rays.
WHEN TO APPLY THE SUNSCREEN AND HOW MUCH TO APPLY?
Sunscreen should be applied 15-20 minutes before stepping out in the sun as it takes some time for the action to start. Apply evenly and liberally. It is recommended that to obtain the labeled SPF sunscreen needs to be applied at 2 mg/cm2, if applied half the recommended amount, you get much less than half the SPF protection.
WHEN TO REAPPLY THE SUNSCREEN?
Duration of action: about 2-3 hours after which sunscreens need to be reapplied. It has to be reapplied after swimming, and more frequently in humid conditions where excessive sweating occurs.
WHAT DOES THE STAR RATING ON THE PACK MEAN?
The star rating is the indicator for the performance of sunscreen in the UVA range. It has a maximum of four stars, and a star rating of 3 signifies a good protection of sunscreen in the UVA range.
Why do we need protection from sunlight (ultraviolet rays)?
· Sun rays consist of ultraviolet radiations, i.e. UVA, UVB, UVC
· Exposure to both ultraviolet A(UVA) and ultraviolet B (UVB) rays results in cumulated damage that leads to skin ageing, cataracts, corneal burns and the formation of skin cancer.
· Besides sunburn, it can give you headaches; it can cause dehydration and eye damage.
· Exposure to UV radiation triggers increase in darkness of the skin leading to tanning of the skin.
· UV rays penetrate deep into the skin support structure, affecting the skins immune system and increasing cancer risks.
· UVA rays can penetrate glass/windows.
· 80% of the damaging rays can get through clouds.
· 60% of the day’s sun burning radiation occurs between the hours of 10a.m and 4 p.m.
· Reflection from sand, water and white surfaces, results in substantial UVR exposure.
· Heat and brightness are not indicators of UV intensity.
ENVIRONMENTAL FACTORS THAT INFLUENCE THE UV LEVEL
· Sun height- the higher the sun in the sky, the higher the UV radiation level. Thus UV radiation is maximum when the sun is at its maximum elevation, at around midday (solar noon) during the summer months.
· Cloud cover- even with cloud cover, UV radiation levels can be high due to the scattering of UV radiation by water molecules and fine particles in the atmosphere.
· Altitude- with every 1000 meters increase in altitude, UV levels increase by 10% to 20%.
· Ozone- ozone absorbs some of the UV radiation that would otherwise reach the earths surface. Ozone levels vary over the year and even across the day.
· Ground reflection- UV radiation is reflected or scattered to varying extents by different surfaces, e.g. snow can reflect as much as 80% of UV radiation, dry beach sand about 15%, and sea about 25%
· HOW DO SUNSCREENS WORK?
· It has been determined microscopically that sun damage can be reserved by using sunscreens.
· Sunscreens are tropical formulations that stay on or bind to the skin in order to reduce the harmfull effects of sunlight ( particularly the UV spectrum) on the skin.
· They form a protective film over the skin surface and absorb, reflect or scatter sunlight to protect the skin from its harmful effects.
SUN PROTECTIVE FACTOR (SPF) WHAT IS IT?
SPF is an index of protection only from the UVB which causes sunburn. For example, if it took ½ hour for your skin to become sun burned without any sunscreen, then for a sunscreen that has 15 SPF rating, you could stay in the sun for 15 times longer (or 7.5 hours) before you get sun burned. This is provided, of course, that you’ve applied the sunscreen properly so that you’re getting the prescribed protection.
WHY IS IT IMPORTANT TO PROTECT AGAINST UVA RAYS?
Natural light reaching the earths surface is 95% UVA and 5% UVB is almost 20:1.
UVA is of longer wavelength compared to UVB; hence it is less affected by altitude or atmospheric conditions. UVB rays are the suns rays that cause sunburn, whereas UVA rays are the suns rays that cause more long term and permanent damage such as premature ageing and possibly skin cancer. UVA is more important in causing skin tanning. Hence protection against UVA is as important as protection against UVB.
WHAT DOES BROAD SPECTRUM SUNSCREEN MEAN?
Broad spectrum protection means you have protection from both UVA and UVB RAYS. For sunscreen to have broad spectrum action, it should have a combination of specific UVA and UVB protections or agents which protects against both the kinds of UV rays.
WHEN TO APPLY THE SUNSCREEN AND HOW MUCH TO APPLY?
Sunscreen should be applied 15-20 minutes before stepping out in the sun as it takes some time for the action to start. Apply evenly and liberally. It is recommended that to obtain the labeled SPF sunscreen needs to be applied at 2 mg/cm2, if applied half the recommended amount, you get much less than half the SPF protection.
WHEN TO REAPPLY THE SUNSCREEN?
Duration of action: about 2-3 hours after which sunscreens need to be reapplied. It has to be reapplied after swimming, and more frequently in humid conditions where excessive sweating occurs.
WHAT DOES THE STAR RATING ON THE PACK MEAN?
The star rating is the indicator for the performance of sunscreen in the UVA range. It has a maximum of four stars, and a star rating of 3 signifies a good protection of sunscreen in the UVA range.
