Who is the ozone layer KILLER??

Ozone (O₃ layer) presents at stratosphere which is 10-50 kilometers above the ground that we are standing on. Practically, ozone is located at 15-30 kilometers above the Earth. It is a highly reactive molecule that made up of 3 oxygen atoms which is covering the Earth, protecting all the organisms from the harm of ultraviolet B radiation emitted by the sun like a shield. Generally, the radiation mentioned will cause skin cancer and cataracts in human and affecting other organisms as well. So, we should appreciate the present of ozone layer.

However, the ozone layer is depleting rapidly in previous 50 years! People might be asking,” What has happened to the ozone? What causes this to be happened?” The fact is it is because of releasing of pollution gases which contains chlorine and bromine when human’s activities. In addition, the main KILLER is Chlorofluorocarbon (known as CFC) which was invented in the late 1920s and early 1930s, by an American scientist called Thomas Midgley. Generally, it acts as coolants in refrigeration system and air-conditional. Moreover, it acts as solvent in order to clean electric components too and plastic foam, and other use in factories. The chart below shows usage of CFC in USA, which is one of the countries that uses CFC pretty much in the world, within 1978.

Usage of CFC in daily life:

So, how does CFC deplete the ozone layer? After some observations and experiments have been done, scientists discover that when CFC flows to higher position, it will eventually undergo dissociation because of sunlight (which means higher temperature), after that, the chlorine molecules will be separated from CFC and reacts with ozone to form oxygen (O₂). Things are getting worse when they found that one molecule of chlorine is able to react with OVER HUNDRED molecules of O₃!! It is because O atom in the ozone will attack the O atom in ClO when present of sunlight too, which means ClO will be reduced to Cl^- ion, then the process starts all over again!

Those reactions can be simplified to:

a) CFCl₃(CFC) + uv → CFCl₂ + Cl^-

b) Cl^- + O₃ → ClO + O₂

c) ClO + O₃ → 2O₂ + Cl^-

**The reactions (b) and (c) will carry on till over hundred times.

As a result, it is starting to have “ozone holes”. Ozone holes, which first found at Antarctica, allow more ultraviolet B radiation reaches the surface of Earth. Study shows that every 1% of ozone depletion will allow 2% of ultraviolet B radiation enters to Earth. As we know, the ultraviolet B radiation will cause harm to all organisms on Earth. For example, human will get skin cancer easily if the percentage of exposure to ultraviolet radiation increases. Moreover, rates of malaria and other infectious diseases will increase as well too. For environment, the life cycle of plant, as well as food chain of animals, will be affected due to the increase amount of radiation.

Although the disaster of CFC has been discovered and some countries have banned usage of CFC, some industries and factories in some countries are still using it because of the advantageous chemical characteristics of CFC such as low in toxicity, nonflammable, noncorrosive, and nonreactive with other chemical species. In addition, the disaster will still go on at least 50 years if the usage of CFC is totally banned in order to let the environment to re-fix the “ozone holes”.

So, what do you think about when you are reading the content above? Are you in air-conditional room now? Or perhaps you were just taking foods from refrigerator? When you know about the consequences of using CFC, what do you do? Undeniable, most of us ignore it, or don’t care about the consequences. The owners of industries or even government encourage the usage of CFC because of their greediness. They want to get more benefits!! Lastly, who is killing the ozone layer? CFC or human?

Resources:
1. http://www.fraqmd.org/OzoneChemistry.htm
2. http//www.ausetute.com.au/cfcozone.html