Whenever the sun exposed skin should be protected from radiation exposure, either through the use of clothing (preferably light-colored, natural fiber) and the use of hats or caps and, in areas of exposed skin through the use of sunscreen. The sunscreens contain substances that act as sunscreens, reducing the amount of rays that penetrate the skin, avoiding burns and degenerative changes of the skin if used properly.
Depending on how acting filters can be physical or chemical.
- Physical filters: are substances impervious to sunlight, creating a screen in areas where it has been applied and reflects light. Prevent the passage of the three types of radiation: ultraviolet, visible and infrared. The most commonly used are zinc oxide, titanium dioxide and mica.
- Chemical filters: they absorb solar ultraviolet radiation. Some of those used are the PABA (para-amino benzoic acid), cinnamic acid, sulfonic acid, camphor, benzophenone and dibenzoylmethanes.
To quantify the filtering capacity of sunscreen is used the so-called Sun Protection Factor: a number that measures how many times it can be exposed to the sun to produce the same redness or erythema that if he had not used the cream sunscreen. That is, if not for the skin starts to turn red (erythema), the first day that we must take the sun 10 minutes, using an SPF cream 5, it will take 50 minutes.
The SPF indicates the time that we expose to the sun without risk of burns. The higher the SPF, the higher the protection from sunlight.
