:: ENVIRONMENTAL SCIENCE ::

1. What is ozone and its layer?
Ozone (O3) is a molecule made up of three oxygen atoms. The oxygen we breathe (O2) is similar but has only two oxygen atoms. High up in the upper atmosphere region called as stratosphere, light rays break down oxygen into two individual oxygen atoms. Single oxygen atoms are quite reactive and ozone is formed when one of these lone oxygen bump into and combine with O2.
But ozone isn't very stable either. If a high-energy ray like ultraviolet-B (UV-B), strikes an ozone molecule, it too break down, back to the single oxygen and O2.
Over a period of time, as the atmosphere formed, the reactions that create and break down ozone came into a dynamic equilibrium resulting into formation of ozone band in the stratosphere. This band is popularly called as the ozone layer. But the equilibrium is delicate, and ozone is rare even in the ozone layer.
Ozone absorbs harmful ultraviolet radiation, which would otherwise find it's way down to earth and cause a variety of problems for humans, animals, and plants. Let it be cleared that stratospheric ozone is different from ground-level ozone, which promotes smog in cities.

2. What have human beings done to the ozone layer?
Formation and destruction of ozone is natural in atmosphere. Human beings on earth, have damaged the ozone layer by adding molecules containing chlorine or bromine that lead to ozone depletion. The largest group among these are chlorofluorocarbons (CFCs). At earth level, these molecules are stable and have many uses in industrial and domestic applications. However, when they are released into the atmosphere, they drift up to the stratosphere, pushed by winds and atmospheric mixing.
At that high altitude, energetic rays like UV rays break down such molecules in a reaction that releases an atom of chlorine (Cl). This chlorine atom reacts with ozone and break it down to chlorine oxide and O2. Further, this Chlorine oxide breaks down, releasing the Cl to enable it to destroy ozone. It may be noted that one Cl can destroy upto 1,00,000 ozone molecules!
As a result, ozone in the stratosphere has reduced an extent that a hole opened-up above Antarctica. This problem is not limited to Antarctica, but all over. Stratospheric ozone has reduced over most of the earth and research shows that this permits the dangerous UV-B rays to reach the surface of the earth. This damage to ozone is more because of undesired releases of CFCs, HCFCs etc. from refrigerated appliances.

3. How could CFCs & HCFCs affect the ozone layer?
Ozone is constantly being created in our atmosphere, normally by colliding oxygen molecules (O2) and oxygen atoms (O). In the nature's cycle, Ozone is also constantly being destroyed by similar collisions between O3 molecules and O atoms, resulting in pairs of O2 molecules. In this hypothesis, there is a balance between generation and destruction that results in a constant layer of ozone.
CFCs and HCFCs are Chlorofluorocarbons and Hydrochlorofluorocarbons. CFC molecules are made of chlorine, fluorine, and carbon. HCFC molecules also carry hydrogen atoms attached to them. The world over accepted hypothesis of ozone depletion states that these molecules, when emitted to the atmosphere, they ultimately are broken down over number of years into their individual atoms. The chlorine atoms then reacts with the ozone causing ozone destruction and this occurs faster than ozone creation. Thus both these fluids/ refrigerants affect Ozone layer.

4. What has been done to protect the ozone layer?
Through extensive research, scientists confirmed that the man-made chemicals are responsible for the destruction of stratospheric ozone. Based on evidence emerged on the extent of the threat to the ozone layer, all nations on the earth jointly agreed to control use of ozone-depleting substances and scheduled a timetable for complete phase out. This agreement is popularly known as the 'Montreal Protocol' and is an achievement in international cooperation and environmental protection. Further, the protocol provides an on-going process so that, as the scientific understanding of ozone depletion improves and the process of phase out is accelerated. The protocol also provides a powerful precedent for similar international efforts to deal with subjects like global warming.
In India, the Ozone cell under Ministry of Environment & Forests is charged with enforcing the requirements of the Montreal Protocol. A set of suitable rules are issued by them in the year 2000. In its accord chlorofluorocarbon, carbon tetrachloride, methyl chloroform, methyl bromide are being phased out at different dates. It may be noted that the use of CFCs in manufacturing has ended in Dec 2002 and their use in service too will be phased out by 1st Jan 2010. Similarly all hydrochlorofluorocarbons (HCFC) will be phased out by 1st Jan 040.
 

4. Is ozone depletion related to global warming?
No. Ozone depletion and global warming are separate issues, though some chemicals contribute to both. Chlorofluorocarbons (CFCs) are one of the main causes of ozone deletion and also also potent heat-trapping gases. Yet, CFCs are responsible for about 10 percent of total atmospheric warming, much less than the contribution of carbon dioxide (CO2). Thus, more attention is paid to CFCs has on their ozone depletion role. This will change as CFCs are phased out and replaced by hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs such as R-134a). These chemicals have little or no effect on the ozone layer but are strong heat-trapping gases. As their concentration in the atmosphere is already rising, the likely net effect in the future is that reductions in the CFC-related contribution to global warming will be offset by the presence of HCFCs and HFCs.
Only hydrocarbons (HCs like propane, iso-butane and a blend of propane-isobutene) have almost negligible effect on global warming.

5. Why is ozone depletion considered harmful?
Because stratospheric ozone protects us on earth from harm created by ultraviolet rays, ozone depletion means people, animals and plants are all affected by these rays when the ozone layer becomes thin and unable in stopping them. This may include:

	Increases in skin cancers.
	Increases in cataracts of the eyes that could result in loss of sight.
	Reduction in the yields of important food crops, according to some scientists etc.

The Govt. of India signed the Montreal Protocol on Substances, which deplete the Ozone layer. It is an international agreement to reduce and eventually ban the production and use of most ozone depleting chemicals. In order to implement the Montreal Protocol in India, Ministry of Forests, Govt. of India issued ODS (regulation) rules-2000 under Environment protection act 1986. This directed all consumers of CFCs, HCFCs etc. to implement regulations to phase out CFCs, HCFCs etc.
The production of CFCs based refrigeration and air-conditioning appliances in our country is banned with effect from 1st Jan 2003. CFCs are much more harmful to the environment than HCFCs, but HCFCs are next in line for elimination. The HCFCs like R-22 will be banned w.e.f 1st Jan 2040.

6. What action is planned at Godrej?
In order to protect environment and follow the ODS (regulation) rules -2000 that are framed to fulfill the requirements of Montreal Protocol, Godrej decided to adopt the Hydrocarbons as alternate refrigerant and blowing agent for the PUF insulation. Thus Godrej stopped using the CFCs in manufacturing of refrigeration appliances. However in service the use of CFCs could be continued till 1st Jan 2010, the date finalized and published in above rules.
 

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