When our skin is exposed to sunlight for a longer period, it gets red, and we call it a sunburn. Sunburn is the most palpable short-term effect of overexposure to Ultraviolet Radiation. Most of us are aware that excessive exposure to the sun and frequently getting sunburnt causes many skin problems, as serious as skin cancer. Sunburn should be avoided at all costs. Children are most vulnerable to it. Therefore, we should wear enough sunscreen before going out. Also, try to wear clothes that cover your maximum body. The sunlight is strongest between 10 am and 4 pm so we should try to limit exposure to the sun during this period. In this blog, Ishine365 discusses the scales to measure sun protection and in the next article, we shall discuss the ways of sun protection.
What is UVR?
It stands for Ultraviolet Radiation, an important component of sunlight. UVR can be classified as UVA, UVB, and UVC. It is a major jeopardy to our skin. Over-exposure to sunlight can damage the skin, increasing the vulnerability to skin cancer and other skin diseases. Excessive exposure to UVR especially during childhood increases the vulnerability to cancer during adulthood. How to measure UV intensity in sunlight? Through Ultraviolet Index or UVI! It measures the highest UV level stretched each day at a specific location. We know that the ozone layer shields the Earth from harmful UVR. So, ozone depletion and seasonal and weather disparities cause the different quantities of UVR to reach Earth at a given time. UVI measured by the weather services predicts the UVR levels for the next day, helping people to take appropriate measures for sun protection.
There are two scales to measure the UVR protection given by clothes and sunscreen, named UPF and SPF scales respectively. These are described as follows:
UPF Scale
It’s the maximum Ultraviolet Protection Factor for sun protection provided by clothing. This scale was set by Australian, US, and New Zealand Government rating agencies. UPF scale indicates the extent of UV radiations absorbed by the fabric. By absorbing the sunrays, the fabric prevents them from reaching your skin! For instance, a fabric with a UPF level of 50 only allows 1/50th of the harmful UVR falling on the surface of the fabric to penetrate it. In other words, such fabric blocks 98% of the harmful UV rays. The new UPF fabric scale requires the fabric, especially designer swimwear, claiming to be sun protective should be prepared in special ways before testing.
SPF Scale
It stands for Sun Protection Factor, the scale determined experimentally indoors by exposing the persons’ skin to a light spectrum simulating to the midday sun. in the experiment, some subjects wear sunscreen and others do not. Hence, SPF is calculated by the amount of light, inducing redness in sunscreen-protects skin divided by the amount of light, inducing redness in unprotected skin. It is a measure of UVB protection, ranging from 1 to 45 or above. For instance, a sunscreen with 15 SPF filters 92% of UVB. In other words, a sunscreen with 15 SPF will delay the initiation of sunburn to burn in 150 minutes in a person who’d otherwise burn in 10 minutes! Hence, 15 SPF sunscreen enables the wearer to stay in sunlight 15 minutes longer.
