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By Meteorologist Randy Mann
Article published on April 12, 2021

With each passing day, the sun gets higher in the sky before it peaks on the first day of summer on June 20.

With the higher sun angles, our bodies will be exposed to more ultraviolet radiation (solar UVR) from the sun. When our skin is overexposed to the sun’s energy, some of our skin cells are damaged, which we’ll see as a tan or a sunburn.

The UV Index describes the strength the solar UVR, and since we’re heading into the high sun seasons, the UV Index will be higher. Each day, the front page of the Coeur d’Alene Press provides the day’s expected UV Index reading. If the number is a 1 or 2, then the reading is low. A moderate reading will be listed as a 3 to 5. A 6 or 7 UV Index is high and our unprotected skin will burn much faster. Very high readings are higher than an 8 with an extreme reading at 11.

According to numerous studies, when your skin is unprotected from the sun, the ultraviolet radiation can not only damage the skin, but your DNA as well. If the body is unable to repair the damage caused by the sun, then the cells can grow and divide in an uncontrolled manger that could lead to permanent damage to skin and eyes leading to forms of skin cancer. It is strongly advised that if the UV Index is expected to be at a moderate 3 or higher, then use clothing to cover your shoulders, arms and legs. Sunscreen with a SPF30 or higher is recommended. Hats and sunglasses are also important to help protect your skin.

It’s also possible to get a sunburn on a cloudy day. Although, clouds do reduce some of the ultraviolet rays from the sun, they don’t block all of them. The UV rays can also be intensified by light-colored reflective surfaces like snow and ice.

Skin cancer is one of the most common cancers in the U.S. In the Southern Hemisphere, Australia and New Zealand rank one and two respectively in terms of skin cancer cases across the globe. There are more instances in these two countries because this part of the world has more UV exposure. One reason is that it sees a seasonal depletion of the ozone layer at the South Pole. This layer is a high concentration of ozone that is located about 10 to 18 miles above the Earth’s surface that absorbs much of the sun’s UV radiation.

The Southern Hemisphere also has a much lower population when compared to the Northern Hemisphere, and fewer particles of air pollution to help block the UV radiation. And, Australia and New Zealand are about 3 million miles closer to the sun during their summer season, which is our winter. On average, the summer sun in the Southern Hemisphere is more intense by approximately 7 percent when compared to the summers in the Northern Hemisphere.

From the middle of August of 2020 through last November, the naturally occurring ozone hole over the Antarctic regions grew to one of the deepest and largest gaps in the last 4 decades. It was 14.9 square miles wide and was caused by a very strong polar vortex and very cold temperatures in the upper atmosphere. There was a record Arctic ozone hole in 2020. Both ozone holes did close, but will open up again this year.

In 1987, the Montreal Protocol banned the use of harmful chemicals to the ozone layer called chlorofluorocarbons (CFCs). These chemicals tore a hole in the ozone layer, but the layer has been repairing itself over the last several decades as our emissions of those chemicals have substantially decreased. However, according to an article in LiveScience.com, the oceans absorbed many of these aerosol chemicals that were used prior to 1987. New studies from computer models predict that the oceans are likely to release more of the CFCs than they absorb by 2075 as the atmospheric CFC levels will continue to drop. Since colder oceans absorb more CFCs, they could start emitting, rather than absorbing the CFCs sooner if global temperatures continue to rise.

UV Radiation Chart