Sun Protection Factor in Sunscreen
Sunscreen refers to the sun block lotion or cream that is used to protect the skin from ultraviolet B radiation which can cause sunburn. Sun block lotion, cream or other topical products used for sun protection can also contain compounds that may shield the skin from ultraviolet-A radiation if applied. The UVA is a kind of radiation that can advance the aging process of the skin. It can also bring long-term adverse effects to the human skin.
The ability of a sunscreen to block ultraviolet-B radiation is measured in terms of SPF or sun protection factor. SPF is an indication of the time an individual protected by a sunscreen may be exposed to sunlight before experiencing sunburn relative to the time an individual may get sun burn with no protection.
Determining the amount of time that you can be protected by a sunscreen can be made by checking the time you would usually get sun burn without the sun protection. There may be variations in the time. Some may get sunburn after 10 minutes of sun exposure. If the 10 minutes is the usual time that you will get a sun burn, you can multiply that number to the number of SPF of a sunscreen. For instance if a sunscreen has Sun Protection Factor of 10, then, you multiply 10 minutes to the SPF10 which would result to 100 minutes of protection if the sunscreen is applied. It is also equivalent to 1 hour and 40 minutes of protection. The higher the SPF of a sunscreen, the more period of protection it could bring against ultraviolet-B rays.
However, there may be variations to the time a sunscreen can effectively protect the skin of a person. They may depend on some factors such as the activities of an individual, the amount of sunscreen applied and the frequency of re-application and the skin type of a person. The amount of sunscreen that can be absorbed by the skin is another factor.
The number of sun protection factor that can be found in a sunscreen may range from 2 to 60. In choosing for a sun block lotion or cream, it is important to have an SPF of 15 or more. It could provide longer protection and might limit the frequency of re-application.
While Sun Protection Factor or SP
F is used to measure the UVB protection, some sunscreens can also be rated according to the amount of protection it can bring against UVA. The method is called Persistent Pigment Darkening or PPD. This method is applied in EU sunscreens as a provision for consumer awareness of the sunscreen's UVA protection. As a guideline, a sunscreen should have a PPD of not less than one-third of the SPF to secure a UVA seal.
