Climate change, thinning ozone layer have detrimental effects on skin

Key Points

Buenos Aires, Argentina - As the frequency of pre-cancerous lesions, such as actinic keratosis, and cancerous lesions, such as basal cell carcinoma, squamous cell carcinoma and melanoma, are on a steady rise worldwide, scientists and physicians are determined more than ever to find the cause or causes of this alarming trend.

According to one expert in the field, the sun is being blamed for the increase in pre-cancerous and cancerous skin lesions seen by dermatologists. In reality, the problem is a thinning ozone layer, he says.

"Knowledge is power, and this is one piece of information that I believe physicians should know about. Our ongoing studies and analyses have proven that the increased UV (ultraviolet) radiation that arrives to the surface of our skin is not due to a 'stronger' sun, but rather is due to a thinner ozone layer," says Rubén Piacentini, Ph.D., director of the Institute of Physics, National University of Rosario, Argentina. "This is a very common misconception, and dermatologists should know this."

He says the sun has not changed in intensity, but what is changing is the thickness of our ozone layer, which is allowing an increase in harmful UV rays to reach our skin.

"We have collected data from many different sources, such as satellite data and ground data obtained in different countries by different instruments, that confirm that at least in the last decades, there was only a very small variation in the UV radiation emitted by the sun. These data show that the sun has changed less than 1 percent in the 280 to 400 nm UV range.

"Therefore, the sun as a source of solar radiation is not directly responsible for the increase in skin cancers detected worldwide," said Dr. Piacentini, speaking at the 21st World Congress of Dermatology.

"Dermatologists can inform their patients that the thinning ozone layer is one of the problems causing increased UV radiation, and not the sun."

The thickness of the ozone layer was decreasing as a mean all over the world 3 percent to 4 percent per year from the beginning of the 1980s to about the middle of the last decade.

In 1987, the Montreal Protocol was introduced to restrict the production of ozone-damaging contaminants (mainly Freon and halon gases). The international agreement took force in 1989, and has since been credited with beginning the process to reverse the damage to the ozone layer.

According to Dr. Piacentini, the decrease in the ozone layer was not uniform all over the world, with a small value in the intertropical region, a larger value at mid-latitudes and an even larger value at high latitudes, especially in the Southern Hemisphere, due to the Antarctic ozone hole.

He says people now are exposed to more UV radiation at the Earth's surface, mainly at middle and high latitudes, and naturally their skin is suffering from the increased impact of detrimental UV effects.

"This is important for dermatologists, because they should be aware that they should be able to expect an increase in skin cancers in the future due to the time delay in their development," Dr. Piacentini tells Dermatology Times.

However, Dr. Piacentini says that the depletion of the ozone layer is not the only factor that affects the skin and the environment. Other co-factors, such as airborne particulates known as "aerosols" and the cloud variation over a particular region in the world, also play an important role.

A thicker cloud cover or an increase in the microscopic particles in the air as a result of pollution can also block solar UV from reaching the skin to some degree.

In cities around the world where there is a high level of air contamination with particles, less UV radiation is detected.