Ultraviolet Radiation and Skin Cancer
Skin cancer is caused by exposure to the sun. Skin cancer can develop during long term exposure or during short periods of more intense sun exposure. Ultraviolet light in sunlight damages the DNA in our skin cells. Damage can happen years before cancer can develop so you may not even realize the harmful dangers your body is going through while you are exposed to the sun. In 2016 it is estimated that 13,283 new cases of melanoma skin cancer will be diagnosed in Australia. The estimate is roughly 7,847 males and 5,436 females. In 2012 the rate was forty-nine cases per 100,000 persons which is roughly sixty males and thirty-nine females.
UVA rays and UVB rays both play a role in the development process of skin cancer. UVA rays penetrate into the dermis which is the skin’s thickest layer. Unprotected exposure can lead to things such as premature skin aging (wrinkling and sunspots) and suppression of the immune system. UVB rays will burn the superficial layers of your skin.This is the cause of sunburn. Unlike UVA, UVB rays have different strengths throughout the year. UVB is the most common cause of most skin cancers. UVC rays is the strongest and the deadliest of solar rays but the ozone layer prevents it from reaching earth.
The UV Index is a forecast of the amount of skin damaging UV radiation expected to reach the earth’s surface at the time when the sun is highest in the sky. That is usually around midday. The amount of UV radiation reaching the surface is primarily related to the elevation of the sun in the sky, the amount of ozone in the stratosphere, and the amount of cloud coverage. Thick cloud coverage can reduce the UV radiation levels and certain types of thin cloud can magnify the UV radiation strength. The UV index is calculated based off of four factors: the thickness of the ozone layer which detected using satellites, the cloud cover which blocks the UV radiation up to an extent, the time of year because the seasons such as winter lowers the UV radiation, and the elevation because the higher the elevation the more radiation.
Sunscreen is a combination of organic and inorganic active ingredients. Some inorganic ingredients such as zinc oxide reflect or scatter UV radiation. Organic ingredients such as oxybenzone dissipates as it heats. The Sun Protection Factor (SPF) measures how effective the sunscreen formula limits skin exposure to the UV rays that burn the skin. The higher the SPF is the more protection you will have from UV rays.