Ozone Layer

Acetylene is a hydrocarbon with the chemical formula C₂H₂. While it is a greenhouse gas, it is not considered a significant contributor to ozone depletion.

Methane (CH₄) is a potent greenhouse gas, contributing significantly to global warming. However, it does not directly destroy ozone molecules in the same way that CFCs do. While methane can indirectly contribute to ozone depletion by enhancing other greenhouse gases' effects, its primary role is in climate change.

Halons

• They are compounds formed by Br, F and C.
• Because of their ability to put out fires, they are used in fire extinguishers, although their manufacture and uses are prohibited in many countries because of their ozone-depleting action.
• Their ability to harm the ozone layer depletion is very high because they contain Bromine, which is much more effective than atom destroying ozone than Chlorine.
• It has been used historically as a fire suppression agent and for fighting fires, but it is now only allowed in minimal situations.

Carbon Tetrachloride (CCI₄)

• It is a compound widely used as a raw material in many industries, such as manufacturing CFCs and as a solvent.
• It was no longer used as a solvent when it was found to be carcinogenic.
• It is also used as a catalyst in certain processes where chlorine ions need to be released.
• It is used in fire extinguishers and as a fumigant to kill insects in grain.

Chlorofluorocarbons (CFCs)

• Chlorofluorocarbons (CFCs) are non-reactive, non-flammable, non-toxic organic molecules. They are therefore used in refrigerators and air conditioners, in the production of plastic foam, and by the electronic industry for cleaning computer parts.
• The most common Chlorofluorocarbons (CFCs) are CFC-11, CFC-12, CFC-113, CFC-114, and CFC-115.
• CFCs transport agents that continuously generate chlorine radicals into the stratosphere and damage the ozone layer.
• One free Chlorine atom from a CFC molecule can do much damage, destroying ozone molecules for a long time.
• CFCs have a lifetime in the atmosphere of about 20 to 100 years.

The ring of ozone around the Tibetan Plateau is thought to be a result of air currents and the plateau's influence on atmospheric circulation. When air from lower altitudes enters the upper atmosphere, it can lead to a decrease in ozone density over the center of the plateau, while higher ozone concentrations are observed in a surrounding ring.

The Montreal Protocol sits under the Vienna Convention for the Protection of the Ozone Layer (the Vienna Convention). Adopted on 16 September, 1987, the Protocol is, to date, one of the rare treaties to achieve universal ratification. The Montreal Protocol phases down the consumption and production of the different ODS in a step-wise manner, with different timetables for developed and developing countries (referred to as "Article 5 countries"). Under this treaty, all parties have specific responsibilities related to the phase out of the different groups of ODS, control of ODS trade, annual reporting of data, national licensing systems to control ODS imports and exports, and other matters.

Developing and developed countries have equal but differentiated responsibilities, but most importantly, both groups of countries have binding, time-targeted, and measurable commitments. The Meeting of the Parties is the governance body for the treaty, with technical support provided by an Open-ended Working Group, both of which meet on an annual basis. The Parties are assisted by the Ozone Secretariat, which is based at UN Environment Programme headquarters in Nairobi, Kenya.

The Montreal Protocol sits under the Vienna Convention for the Protection of the Ozone Layer (the Vienna Convention). Adopted on 16 September, 1987, the Protocol is, to date, one of the rare treaties to achieve universal ratification. The Montreal Protocol phases down the consumption and production of the different ODS in a step-wise manner, with different timetables for developed and developing countries (referred to as "Article 5 countries"). Under this treaty, all parties have specific responsibilities related to the phase out of the different groups of ODS, control of ODS trade, annual reporting of data, national licensing systems to control ODS imports and exports, and other matters.

Developing and developed countries have equal but differentiated responsibilities, but most importantly, both groups of countries have binding, time-targeted, and measurable commitments. The Meeting of the Parties is the governance body for the treaty, with technical support provided by an Open-ended Working Group, both of which meet on an annual basis. The Parties are assisted by the Ozone Secretariat, which is based at UN Environment Programme headquarters in Nairobi, Kenya.

The Montreal Protocol sits under the Vienna Convention for the Protection of the Ozone Layer (the Vienna Convention). Adopted on 16 September, 1987, the Protocol is, to date, one of the rare treaties to achieve universal ratification. The Montreal Protocol phases down the consumption and production of the different ODS in a step-wise manner, with different timetables for developed and developing countries (referred to as "Article 5 countries"). Under this treaty, all parties have specific responsibilities related to the phase out of the different groups of ODS, control of ODS trade, annual reporting of data, national licensing systems to control ODS imports and exports, and other matters.

Developing and developed countries have equal but differentiated responsibilities, but most importantly, both groups of countries have binding, time-targeted, and measurable commitments. The Meeting of the Parties is the governance body for the treaty, with technical support provided by an Open-ended Working Group, both of which meet on an annual basis. The Parties are assisted by the Ozone Secretariat, which is based at UN Environment Programme headquarters in Nairobi, Kenya.

Montreal Protocol was signed in 1987 and entered into force in 1989. The parties to the Protocol meet once a year to make decisions aimed at ensuring the successful implementation of the agreement.

• According to the UN, the Montreal Protocol has led to the phase-out of 99% of ozone-depleting chemicals in refrigerators, air-conditioners and many other products.
• Ozone layer protection efforts have also contributed to the fight against climate change by averting an estimated 135 billion tonnes of carbon dioxide equivalent emissions, from 1990 to 2010.
• Part of the ozone layer has recovered at a rate of 1-3% per decade since 2000, and it is expected to return to pre-1980 levels by 2050.

• According to the UN, the Montreal Protocol has led to the phase-out of 99% of ozone-depleting chemicals in refrigerators, air-conditioners and many other products.
• Ozone layer protection efforts have also contributed to the fight against climate change by averting an estimated 135 billion tonnes of carbon dioxide equivalent emissions, from 1990 to 2010.
• Part of the ozone layer has recovered at a rate of 1-3% per decade since 2000, and it is expected to return to pre-1980 levels by 2050.

• According to the UN, the Montreal Protocol has led to the phase-out of 99% of ozone-depleting chemicals in refrigerators, air-conditioners and many other products.
• Ozone layer protection efforts have also contributed to the fight against climate change by averting an estimated 135 billion tonnes of carbon dioxide equivalent emissions, from 1990 to 2010.
• Part of the ozone layer has recovered at a rate of 1-3% per decade since 2000, and it is expected to return to pre-1980 levels by 2050.