The Ozone Depleting Substances are those substances that damage the ozone layer. Ozone is a special form of oxygen, made up of three oxygen atoms rather than the usual two oxygen atoms. It is found in the stratosphere that encircling the Earth and absorbs most of the Sun's ultraviolet (UV) radiation.
Montreal Protocol on Substances that Deplete the Ozone Layer
The Montreal Protocol is the first worldwide agreement designed to protect human health and the environment against the adverse effects of the depletion of the stratospheric ozone layer.
This protocol divides ozone depleting substances into a variety of lists of chemicals that are subject to different control requirements and on that basis Countries that accepted the treaty commit to:
1. Stop consumption or production of chemicals on Group 1 of Annex A after January 1, 1996 (CFC 11, CFC 12, CFC 113, CFC 114, and CFC 115).
2. Stop consumption or production of chemicals on Group 2 of Annex A after January 1, 1994 (Halon 1211, Halon 1301, and Halon 2402.)
3. Stop consumption or production of chemicals on Groups 1, 2 and 3 of Annex B after January 1, 1996 (CFC 13, CFC 111, CFC 112, CFC 211, CFC 212, CFC 213, CFC 214, CFC 215, CFC 216, CFC 217, carbon tetrachloride, and 1,1,1-trichloroethane)
4. Reduce consumption or production of hydro-chloro-fluoro-carbons listed in Group 1 of Annex C to 1989 levels
5. Reduce consumption or production of methyl bromide to 75% of 1991 levels beginning in 1999.
List of Ozone depleting substances controlled by Montreal Protocol
1. Chlorofluorocarbons (CFCs)
3. Carbon tetrachloride (CCl4), Methyl chloroform (CH3CCl3)
4. Hydrobromofluorocarbons (HBFCs)
5. Hydrochlorofluorocarbons (HCFCs)
6. Methyl bromide (CH3Br)
7. Bromochloromethane (CH2BrCl)