Did you know that the ozone layer is essential for life to exist?
Its molecules act as a shield protecting us from solar radiation. When the radiation reaches the ozone layer, it passes through the ozone molecules and these are responsible for returning part of radiation back to space, in this way the radiation that reaches us is minimized.
What is the hole in the ozone layer?
It is a hole that allows the entry of large amounts of ultraviolet light and it is located at the poles, on the Antarctic continent and the Arctic Ocean, being especially large during the spring of both hemispheres
and resulting in longer summer seasons.
Why is the hole in the ozone layer harmful?
Although this hole is due to the natural fluctuations of ozone in the atmosphere, it also caused by human activities which emit gases that end up in the stratosphere and degrade the ozone molecules, increasing the size and effect of this hole in the ozone layer. This is an environmental and health problem, since the excess of solar radiation is a threat to any form of life.
(1) What is meant by “ozone hole”?
Since about 1975, scientists have detected a severe drop in ozone concentration in the layer over the Antarctica each spring. The situation then reached an alarming scale in 1987 when an international expedition found that half of the Antarctica’s ozone have disappeared over a region twice the size of the United States, creating an enormous “hole” in the ozone layer. Concentrations of ozone fell by as much as 50% of the norm at altitude of 18 km. At mid-latitudes in the Northern Hemisphere, up to 3% decrease in ozone concentration was also observed.
(2) Why it concerns you?
The ozone molecules form a protective layer which extends from about 16 km to 50 km up above the earth at low latitudes, and from about 8 km to 50 km at high latitudes. The ozone molecules absorb the sun’s ultra violet radiation (UV) which will be harmful to us if it reaches the earth surface. With more UV radiation reaching the earth surface due to ozone depletion, human health and the environment will be adversely affected. The most significant effects will be the increased incidence of skin cancer, eye cataracts, damage to the human immune system and to the ecology of the earth.
(3) What causes this phenomenon?
These ozone-depleting chemicals are extensively used man-made chemicals including the followings: –
1,1,1-trichloroethane (methyl chloroform);
(4) What are these ozone depleting substances (ODS) used for?
The following are the common usage of CFCs and HCFCs :
CFC-11, CFC-12 and HCFC-22 are used as refrigerant in domestic air-conditioners and refrigerators as well as retail store refrigeration systems, chillers and air-conditioners.
CFC-11 and CFC-12 are used as propellants for aerosol sprays such as hair mousses and household cleaning products.
CFC-11 and CFC-12 are also used as blowing agents in the manufacture of foams for home furnishing, insulation and packaging. Some plastics may be shaped using CFCs, e.g. egg cartons, cups and cartons used in fast food operations. Rigid or semi-rigid foams are also used as thermal or sound insulation in refrigeration equipment, buildings and automobiles.
CFC-113 is a solvent for cleaning electronic circuit boards and computer components.
Halons are used as fire extinguishing agents. Bromochlorodifluoromethane (BCF) is commonly used in portable fire extinguishers. Bromotrifluoromethane (BTM) is used in fixed fire-fighting installations. 1,1,1-
trichloroethane is commonly used as a:
solvent for cleaning electronic circuit boards and metal work such as watches and clockworks.
thinner such as that for correction fluid.
cleaning agent in the textile industry (dry cleaning).
Carbon tetrachloride is used as a cleaning agent in textile and electronics industries.
(5) Can we get rid of the ODS?
There has been considerable progress in finding non-ozone-depleting substitutes for ODS in the last few years. Substitutes for air-conditioning and refrigeration applications are now available, such as that HCFC-22 can be replaced by HFC-410A, CFC-12 can be replaced by HFC-134a. There are also
emerging markets for “drop-in” replacement for HCFCs and halons.
Alternative products or processes can be used in some cases including the following:
alternative insulating materials;
substitute food containers such as hydrocarbon blown polystyrene, plastic film wrap and bags.
alternative packaging materials such as plastic film bubble wraps.
air-conditioning and refrigeration plants operating on non-HCFC refrigerants.
HCFCs solvents can be substituted in some applications. For instance, petroleum solvents can be selected as a replacement for CFC-113 or 1,1,1-trichloroethane in cleaning applications. Aqueous cleaning, or even no-clean technology, are also alternative processes that can be used by the electronics
Many household and personal aerosol products, e.g. paint sprays and insecticides, now use hydrocarbons (e.g. propane and butane) as propellants instead of HCFCs or CFCs.
(6) How can I help to protect the ozone layer?
While the vast majority of ODS usage is either industrial or commercial, individuals can help in the following ways:
Buy air-conditioning and refrigeration equipment that do not use HCFCs as refrigerant.
Buy aerosol products that do not use HCFCs or CFCs as propellants.
Conduct regular inspection and maintenance of air-conditioning and refrigeration appliances to prevent and minimize refrigerant leakage.
For existing air-conditioning and refrigeration appliances that operate on HCFCs or CFCs, the refrigerant should be recovered or recycled whenever an overhaul of equipment is to be carried out. Replacing or retrofitting such equipment to operate on non-HCFCs refrigerant should also be considered.
When motor vehicle air-conditioners need servicing, make sure that the refrigerants are properly recovered and recycled instead of being vented to the atmosphere.
Its our duty to protect Mother Nature For us and future generations.