NASA satellite images of the Antarctica hole in the ozone layer indicate that for the second straight year now the ozone hole has been below the average of the past decades. While one year is not enough data to conclude the improvement trend will continue, 2012 saw the second smallest hole in two decades. More importantly perhaps is that “minimum value of total ozone in the ozone hole was the second highest level in two decades.” In ordinary language that means there is probably more ozone now than there has been in twenty years.
The ozone layer became a household word in the 1980’s when scientists who had been monitoring the annual appearance of the Antarctica hole for several years reported that ozone was being destroyed by the products containing chemicals called CFC’s. These products were very commonly used as propellants in spray cans for everything from paint to hair spray.
In 1987 most developing countries in the world agreed to reduce the widespread use many chemicals connected with the measurable reduction being observed in the ozone layer and most importantly, the increase in the size of the annual hole which develops over Antarctica.
Ozone is formed when there is a combining of three oxygen atoms (O3). We benefit from this rather unstable arrangement of oxygen in much of our daily lives. We use ozone as bleach, or in deodorants. Many public utility services use them to sterilize water for drinking. Many buildings and a growing number of homes even have air purification systems which use ozone. What is does for Earth is act as a filter of harmful ultraviolet sunlight. The sun’s rays categorized as UV-B are reported to be the most harmful form of sunlight; being credited as the primary cause of melanoma cancer.
As far as anyone can actually determine, the ozone layer contained within the lower sections of the stratosphere has been blanketing the earth for as long as Earth has had a multi-layered atmosphere. The layer starts at just about 50,000 feet above the surface and varies in thickness with the seasons. While many commercial planes routinely fly in the lower regions of the layer, few people other than the military ever exceed the roughly 110,000 feet of altitude which marks the typical maximum height. While the function of being a UV-B filter is widely accepted, the ideal thickness of the layer is undetermined as other factors such as acting as an insulating barrier might well contribute to climate changes. There is plenty of room for the ozone layer to expand since the stratosphere continues to approximately 170,000 feet of altitude
Because of the many unknowns about the effects of a either an increase or reduction in the thickness of the ozone layer, and the popularity of ozone in sterilization systems, the question is often asked; can ozone be good and bad at the same time? This is one reason that NASA has joined with other agencies to monitor the ozone over Antarctica. And when the record reductions in ozone layer loss was observed these past two years, the climate change debate took new directions for many who would expand government control based on global warming or man-made atmospheric destruction.
While the EPA continues to call for its control to be increased over consumer and industrial products based reports that the risk of melanoma has “more than doubled” since 1990, the latest measurements by NASA seem to contradict their claim. There has developed a general concensus among ozone monitoring stations on the surface and in orbit is that the good ozone layer has improved since the 1990’s.
If it is true, as NASA reports, that the famous Antarctica hole in the ozone is exceptionally smaller this year, and even set a record for its reduced size last year, how can the EPA report also be true that melanoma risks due to ozone layer depletion are greater than ever?
by Marcus Murray