April 16th, 2009 Ozone Depletion: A Growing Concern
You may have heard about the formation of holes in the ozone layer and the potential risk of exposure to ultraviolet light. What you have heard is no myth. The FACT remains that ozone depletion is occurring and with that comes many negative consequences. But what exactly is ozone depletion and what consequences can we expect to experience?
What is Ozone Depletion?
As early as 1912, explorers in Antarctica observed veil-type clouds in the atmosphere (1). These clouds were an early indicator of ozone depletion, which was later measured by the Dobson Spectrophotometer (1957). Increased observation led to the discovery of the current issue of ozone damage. Ozone depletion is the destruction of the stratospheric ozone layer which protects the earth from ultraviolet radiation. The stratosphere extends 30 miles above the earth and contains a gas formed by three atoms of oxygen, commonly known as ozone. 90 percent of ozone is contained within the stratosphere. The ozone is present in order to absorb harmful sun rays before they reach the earth.
What is Ozone?
Ozone is a gas comprised of three atoms of oxygen and is formed when O2 (the gas we breathe) is split into single oxygen molecules by sunlight. Ozone in the stratosphere is beneficial to life on earth because it absorbs harmful radiation before it can reach the earth. Ozone concentrated in the troposphere, the lowest level of the atmosphere is damaging to humans and vegetation. Near the earth’s surface ozone can be created by chemical reactions caused by air pollutants.
How is the Ozone Layer Damaged?
Human activity accounts for 75-85 percent of the damage that has been done to the ozone layer (2). Human activity such as the release of compounds containing bromine and chlorine is an example of a contributor to ozone depletion. Perhaps the strongest cause of damage to the ozone layer is CFCs, or chlorofluorocarbons which are used in aerosols and coolants. When UV radiation comes into contact with a CFC, a chlorine is released which then reacts with ozone to form Chlorine monoxide (ClO) and a single oxygen molecule (O2). A single oxygen molecule reacts with a Chlorine monoxide to produce a single oxygen molecule and a chlorine molecule. This chlorine molecule promotes ozone depletion. Ozone holes form where ozone concentrations are lower than normal. Holes in the ozone cannot be fixed. The only solution is to prevent their formation.
What are the Effects of Ozone Depletion?
Exposure to ultraviolet rays will prove detrimental in many ways. Continual exposure to radiation can increase the number of skin cancer cases and other health problems such as cataracts and damage to the immune system. Plant growth can be stunted, unbalancing the ecosystem.
What can be done to Prevent Ozone Depletion?
CFCs are being replaced with more environmentally friendly alternatives, such as HCFCs, or hydrochlorofluorocarbons which contain carbon, hydrogen, chlorine and fluorine. HCFCs are not a solution, merely a lesser evil and research must be continued in order to find a truly “ozone friendly” alternative. Other efforts to prevent ozone damage include minimizing rocket and aircraft fights (oxygen reduction and water vapor deposition), encouraging plant growth and preventing deforestation, and establishing guidelines to ensure that chemicals released in high quantities are safe for the ozone layer. As a consumer, close observation of aerosol labels and the energy efficiency levels of appliances such as a refrigerator do much to aid in prevention of ozone depletion.
The consequences we can expect to face are up to our own choosing. We are the greatest contributors to ozone depletion; our fate rests in our own hands.
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