Ozone-depleting substances

Developing countries will receive $540 million to continue their work in phasing out ozone-depleting chemicals, according to UN Environment Programme. The funds will be provided by developed countries for three years starting from 2018 through the Multilateral Fund for the Implementation of the Montreal Protocol, which has disbursed over $3.7 billion since 1991 to support developing countries to phase out chemicals that destroy the ozone layer.

Montreal Protocol parties made the funding commitment during the joint 11th meeting of the Conference of the Parties to the Vienna Convention and the 29th Meeting of the Parties to the Montreal Protocol that concluded on 24 November in Canada, the UN Environment Programme said in a statement on Monday. The climate-warming chemicals are hydrochlorofluorocarbons and hydrofluorocarbons (HFCs) used widely used in refrigerators, air-conditioners and aerosol sprays.

Ozone is the gas present naturally in the environment. Its chemical formula is O3, while chemical formula of oxygen is O2. In presence of halogens O3 gets converted to O2. Ozone is present is two layers of the atmosphere. About 10% of ozone is present in lower layer of atmosphere called troposphere, which is located at a distance of about 6-10 miles from the surface of the earth.

The major part of ozone is present in the upper layer of atmosphere called stratosphere located at the distance of about 30 miles from the surface of the earth. It is this layer which is called as the ozone layer. The sun radiates large variety of radiations including ultraviolet radiations which are very harmful to the human body. The ozone layer absorbs ultraviolet radiation rays and prevents them from coming to the surface of the earth thus saving the human beings from harmful rays, writes http://www.brighthubengineering.com.

Ozone depleting substances (ODSs) are those substances which deplete the ozone layer and are widely used in refrigerators, airconditioners, fire extinguishers, in dry cleaning, as solvents for cleaning, electronic equipment and as agricultural fumigants.

Ozone depleting substances controlled by Montreal Protocol include: Chlorofluorocarbons (CFCs), Halon; Carbon tetrachloride (CCl4), Methyl chloroform (CH3CCl3), Hydrobromofluorocarbons (HBFCs), Hydrochlorofluorocarbons (HCFCs), Methyl bromide (CH3Br) and Bromochloromethane (CH2BrCl).

There are other ozone depleting substances, but their ozone depleting effects are very small in comparison to these controlled substances, according to http://www.environment.gov.au.