Sun Protective Factor

Ladies, think of the last time you walked through the department store trying just to enter the mall. Most likely you ha to maneuver between one cosmetic counter after another looking down, trying not to make eye contact with any of the associates. Unfortunately your eyes were not glued to the floor that day and the women behind the beauty counters look at then sigh asking how old are you? You inevitably feel bad and were then sold on a product that was supposed to change your world. Oddly enough those products usually have some type of sunscreen in them. Most of us wear some type of sun protective lotion or cream during the summer or even all year around.  What are they really selling you? What does it really mean to have a measurement of 15 or 30 SPF in your products?

SPF abbreviated for Sunburn Protection Factor is an imperfect rating system that the federal government (food and drug administration) came up with to determine the protectiveness of sunscreens which the mass population uses.  The higher the number the more protection it has against the sun’s damaging rays. The SPF only accounts for UVB rays which cause sunburn not UVA which causes the aging of the skin. The amount a person uses for optimal protection is determined by how photosensitive the user of the sunscreen is.  Persons will fair skin and little melanin would need to use higher SPF more often than a person will darker skin with a great amount of melanin. However, every person can benefit from the use some level of a sunscreen.  

The FDA has specific recommendations how sunscreens should be used and applied to the skin. Most people use sunscreens improperly as a result burn. Sunscreens should be applied approximately thirty minutes before your exposure to the sun. This gives the lotion/spray to soak deeper in to the epidermis. For the average adult 1 ounce should be applied and reapplied every two to three hours; more often if profusely sweating of contact with water occurs.

 

The Recommended Sunburn Protection Factors for Specific Skin Types

The calculation of rating of sunscreens are established using derivative calculation. It is not a directly inverse of the transmittance of the UVB region of the spectrum. A person who would burn in the sun within ten minutes using sunburn protection factor 15 would be able to stay out in the sun for about 150 minutes, which is fifteen times longer.

UV Index for Your Area

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Discovery of Sunscreen	Active Ingredients	Skin Cancer
Portrait of the Sun	Home	Want to Learn More?
Ultra-Violet Radiation		Lesson Plans