Sunlight and Its Effect on Our Health

The sun is an essential source of energy for all living organisms on Earth. However, if not taken into account, it also harbors harmful effects that can lead to significant problems. Since we live in a country with more sunny days than the global average, it is essential for us to be more aware of the positive and negative effects of sunlight on human health.

A Foreign Concept for Many of Us: Ultraviolet Radiation!

As we know, the sun emits energy across a very wide spectrum of wavelengths. Ultraviolet (UV) rays have shorter wavelengths than visible blue or violet light, and they are largely absorbed by the ozone layer in the stratosphere. However, some of this radiation reaches the Earth’s surface, causing sunburns (and other negative effects on human health). Scientists divide ultraviolet radiation into three types: UV-A, UV-B and UV-C. UV-C radiation has the shortest wavelength (100 – 280 nanometers) and is completely absorbed by the ozone layer, so it does not reach the Earth’s surface. Therefore, we do not discuss harmful effects of UV-C radiation on our bodies. UV-B radiation, with wavelengths between 280 to 320 nanometers, is partially absorbed by the ozone layer. While it does not penetrate as deeply into the layers of the skin as UV-A, scientific studies have proven its role in causing sunburn, skin darkening, DNA mutations, and skin cancer. UV-A radiation is the type of ultraviolet radiation that poses the greatest risk to human health among ultraviolet rays. (wavelength 320 – 400 nanometers) UV-A radiation penetrates the skin’s deepest layer and plays a role in sunburns and tanning. Additionally, UV-A radiation is known to damage the structure of the skin, leading to wrinkles and sagging. Perhaps the most serious effect of UV-A radiation is its association with skin cancer. Additionally, another harmful effect of UV-A radiation is its ability to suppress the immune system and cause permanent damage to the eyes.

Ultraviolet Radiation Levels Vary!

We know that the ozone layer absorbs ultraviolet radiation to a large extent, preventing it from reaching the Earth’s surface. However, ozone levels vary throughout the day and throughout the year. It is widely recognized today that ozone depletion occurs in certain regions of the world due to gases that break down ozone molecules. The higher the sun is in the sky, the higher the level of ultraviolet radiation. Yes, ultraviolet radiation varies throughout the day and throughout the year. In regions outside the tropical zone, the highest levels of ultraviolet radiation are typically reached during the summer months, around midday when the sun is directly overhead. As we approach the equator, the level of ultraviolet radiation increases.

Ultraviolet radiation can be reflected and scattered by different surfaces to varying degrees. For example, fresh snow can reflect up to 80% of ultraviolet radiation, dry sands on beaches can reflect about 15%, and sea water can reflect up to 25% of ultraviolet radiation. Ultraviolet radiation can penetrate up to 40% of the surface level even half a meter below the sea. Ultraviolet radiation levels can still be high on cloudy days. For instance, more than 90% of this radiation can penetrate through light cloud cover. On a cloudy summer day, even if the weather is not very hot, we can still get sunburned from the sun. Scattering of rays also affects the total level of ultraviolet radiation by contributing to reflection from various surfaces.

The Sun and Our Health

The link between the Sun and health issues such as skin cancer and premature skin aging has been scientifically proven beyond any doubt today. According to World Health Organization (WHO) data, globally each year, there are approximately three million cases of non-melanoma skin cancer and around 132,000 cases of malignant melanoma skin cancer. One out of every three diagnosed cancer cases worldwide is skin cancer, according to findings. In addition, it has been determined that sun exposure is a significant factor in the onset of cataracts in approximately 20% of patients diagnosed with the condition.

The most common known effect of excessive exposure to ultraviolet radiation is a rash called sunburn. Depending on skin type, the skin’s redness threshold and ability to adapt to ultraviolet radiation vary from person to person. Long-term exposure to ultraviolet radiation causes deterioration of skin cells, fibrous tissues and blood vessels. Ultraviolet radiation accelerates skin aging; As the skin loses its elasticity, wrinkles form and the skin thickens.

Common Misconceptions About Solar Radiation

FalseTanning provides protection from the harmful effects of the sun.rlı etkisinden korunmayı sağlar.
Correct Tanning for a light-skinned person provides as much protection as a sunscreen with a protection factor of 4.
False: It is not possible to get sunburned on a cloudy day.
True 90% of ultraviolet radiation from the Sun can pass through a thin layer of clouds. Fog in the atmosphere can lead to increased levels of ultraviolet radiation.
False Ultraviolet radiation in winter is not dangerous.
Correct Ultraviolet radiation levels are generally lower in winter than in summer. However, reflection from snow causes the amount of ultraviolet radiation to double, especially at high altitudes. It is especially necessary to be careful in the spring months when air temperatures are low but the rays from the sun are strong.
False “Since sunscreen protects me, I can stay in the sun for a long time.”
Correct Sun protection creams should be used not to stay in the sun for longer, but to protect against inevitable sun exposure.
False If you take regular breaks while sunbathing, sunburn will not occur.
Correct: It is important how long you are exposed to ultraviolet radiation in total during the day; The total harm of ultraviolet radiation does not change even if it is exposed at intervals.
False If we do not feel the heat of the sun’s rays, we will not get sunburned.
True Sunburn is caused by ultraviolet radiation, and ultraviolet radiation does not cause a warming sensation. The feeling of warmth depends on infrared radiation from the sun; not ultraviolet radiation.