Chlorofluorocarbons CFCs - Revision history

Designing Buildings at 08:20, 1 April 2022

2022-04-01T08:20:07Z

← Older revision		Revision as of 08:20, 1 April 2022
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	= Related articles on Designing Buildings =		= Related articles on Designing Buildings =

−	* Chiller units	+	* Chiller units.
		+	* Fluorocarbon.
	* Greenhouse gases.		* Greenhouse gases.
	* Halocarbons.		* Halocarbons.

Editor at 18:38, 25 January 2022

2022-01-25T18:38:47Z

← Older revision		Revision as of 18:38, 25 January 2022
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	During the phase out, certain refrigerants were introduced as CFC substitutes. Some of these too became restricted under the Kyoto Protocol in 1997.		During the phase out, certain refrigerants were introduced as CFC substitutes. Some of these too became restricted under the Kyoto Protocol in 1997.

−	For more information see: HFC phase out and R22 phase out.	+	For more information see: HFC phase out and R22 phase out and Hydrochlorofluorocarbons HCFCs.

	The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) is an international agreement which commits participants to internationally binding greenhouse gas emission reduction targets. It also assists countries in adapting to climate change through the Adaptation Fund by facilitating the development and deployment of technologies to increase resilience.		The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) is an international agreement which commits participants to internationally binding greenhouse gas emission reduction targets. It also assists countries in adapting to climate change through the Adaptation Fund by facilitating the development and deployment of technologies to increase resilience.
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	* Chiller units		* Chiller units
	* Greenhouse gases.		* Greenhouse gases.
−	* Halocarbons	+	* Halocarbons.
−	* HFC phase out	+	* HFC phase out.
		+	* Hydrochlorofluorocarbons HCFCs.
	* Intergovernmental Panel on Climate Change IPCC.		* Intergovernmental Panel on Climate Change IPCC.
	* Kyoto Protocol.		* Kyoto Protocol.
	* Montreal Protocol on Substances that Deplete the Ozone Layer.		* Montreal Protocol on Substances that Deplete the Ozone Layer.
	* Ozone-depleting substances.		* Ozone-depleting substances.
−	* R22 phase out	+	* R22 phase out.
	* Refrigerants in buildings.		* Refrigerants in buildings.

Designing Buildings at 08:04, 21 December 2021

2021-12-21T08:04:41Z

← Older revision		Revision as of 08:04, 21 December 2021
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	= Introduction =		= Introduction =

−	Chlorofluorocarbons (commonly referred to as CFCs) are a type of halocarbon ~~that is~~ formulated from carbon, chlorine and fluorine. Halocarbons are defined by the [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ Intergovernmental Panel on Climate Change] as ‘A collective term for the group of partially halogenated organic species which includes…chlorofluorocarbons'.	+	Chlorofluorocarbons (commonly referred to as CFCs) are a type of halocarbon formulated from carbon, chlorine and fluorine. Halocarbons are defined by the [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ Intergovernmental Panel on Climate Change] as ‘A collective term for the group of partially halogenated organic species which includes…chlorofluorocarbons'.

	= History of CFCs =		= History of CFCs =

−	CFCs were first discovered by a Belgian chemist ~~named~~ Frédéric Swarts in the 1890s. The connection between CFCs and refrigeration was made in 1928, prompted by safety issues associated with early forms of mechanical refrigeration.	+	CFCs were first discovered by the Belgian chemist Frédéric Swarts in the 1890s. The connection between CFCs and refrigeration was made in 1928, prompted by safety issues associated with early forms of mechanical refrigeration.

−	In the late 1800s and early 1900s, refrigerators used dangerous gases for cooling ~~purposes~~. The combination of ammonia (NH3), methyl chloride (CH3Cl) and sulfur dioxide (SO2) was linked to fatal accidents due to leakage, which prompted several refrigeration corporations to push for the development of a safer alternative.	+	In the late 1800s and early 1900s, refrigerators used dangerous gases for cooling. The combination of ammonia (NH3), methyl chloride (CH3Cl) and sulfur dioxide (SO2) was linked to fatal accidents due to leakage, which prompted several refrigeration corporations to push for the development of a safer alternative.

−	In 1928, a team of researchers led by the American chemist Thomas Midgley, Jr. on behalf of General Motors (the parent company of Frigidaire - a major United States manufacturer of refrigerators) found that Swarts’ discovery could be put to practical use after some modifications were made. General Motors subsequently patented a device that used the new type of CFC, and in 1930 the company formed ~~another~~ division to produce the modified substance - trademarked under the name Freon - on a large commercial scale.	+	In 1928, a team of researchers led by the American chemist Thomas Midgley, Jr. on behalf of General Motors (the parent company of Frigidaire - a major United States manufacturer of refrigerators) found that Swarts’ discovery could be put to practical use after some modifications were made. General Motors subsequently patented a device that used the new type of CFC, and in 1930 the company formed a division to produce the modified substance - trademarked under the name Freon - on a large commercial scale.

	From the 1930s, CFCs became widely used in the United States for residential, commercial and automotive air conditioning systems. They were also commonly used as a propellant in various products - ranging from pesticides to healthcare items.		From the 1930s, CFCs became widely used in the United States for residential, commercial and automotive air conditioning systems. They were also commonly used as a propellant in various products - ranging from pesticides to healthcare items.
Line 15:		Line 15:
	= Safety of CFCs called into question =		= Safety of CFCs called into question =

−	Initially, CFCs were thought to be completely safe due to their non flammable characteristics, low toxicity and stability. Furthermore, they had no impact on the lower atmosphere.	+	Initially, CFCs were thought to be completely safe due to their non flammable characteristics, low toxicity and stability. Furthermore, they had no impact on the lower atmosphere. However, in the 1970s, scientists discovered that the potential impact of emissions from CFCs on the upper atmosphere (or stratosphere) might be cause for concern. Research conducted by University of California chemists Professor F. Sherwood Rowland and Dr Mario Molina found that CFCs emit significant amounts of inorganic chlorine in the upper atmosphere, and this was seen as a contributing factor to ozone depletion.
−		+
−	In the 1970s, scientists discovered that the potential impact of emissions from CFCs on the upper atmosphere (or stratosphere) might be cause for concern. Research conducted by University of California chemists Professor F. Sherwood Rowland and Dr Mario Molina found that CFCs emit significant amounts of inorganic chlorine in the upper atmosphere, and this was seen as a contributing factor to ozone depletion.	+

	= CFCs and damage to the ozone layer =		= CFCs and damage to the ozone layer =
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	The research conducted by Rowland and Molina on the decomposition of ozone (caused by CFC emissions in particular) - along with contributions from researchers at the Max Planck Institute for Chemistry - received the 1995 Nobel Prize for Chemistry. It also formed the basis of the Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol).		The research conducted by Rowland and Molina on the decomposition of ozone (caused by CFC emissions in particular) - along with contributions from researchers at the Max Planck Institute for Chemistry - received the 1995 Nobel Prize for Chemistry. It also formed the basis of the Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol).

−	Montreal Protocol was agreed on 16 September 1987 and came into effect on 1 January 1989. It came after a series of rigorous meetings and crucial negotiations at the Headquarters of the International Civil Aviation Organisation in Montreal, Quebec, in Canada and was ratified by all 196 United Nations members. Its framework was defined by the Vienna Convention for the Protection of the Ozone Layer in 1985.	+	The Montreal Protocol was agreed on 16 September 1987 and came into effect on 1 January 1989. It came after a series of rigorous meetings and crucial negotiations at the Headquarters of the International Civil Aviation Organisation in Montreal, Quebec, in Canada and was ratified by all 196 United Nations members. Its framework was defined by the Vienna Convention for the Protection of the Ozone Layer in 1985.

−	It was developed ~~in order~~ to reduce the production of ozone depleting substances such as CFCs. The definition of ozone depleting substances only includes halogen source gases emitted by human activities and controlled by the Montreal Protocol. Those gases that have only natural sources are not classed as ozone depleting substances. Most ozone depleting substances are also ~~GHG~~ that contribute to global warming (ref [https://ozone.unep.org/sites/default/files/2019-05/00-SAP-2010-Assement-report.pdf United Nations Environment Programme 2010]).	+	It was developed to reduce the production of ozone depleting substances such as CFCs. The definition of ozone depleting substances only includes halogen source gases emitted by human activities and controlled by the Montreal Protocol. Those gases that have only natural sources are not classed as ozone depleting substances. Most ozone depleting substances are also greenhouse gases that contribute to global warming (ref [https://ozone.unep.org/sites/default/files/2019-05/00-SAP-2010-Assement-report.pdf United Nations Environment Programme 2010]).

	The Protocol introduced an incremental reduction of the manufacture, import, export and consumption of CFCs and other substances that deplete the ozone layer. In 1990, an amendment to the Protocol escalated the commitment to cease production of CFCs by 2000. In 1996, the production ban in major countries came into effect.		The Protocol introduced an incremental reduction of the manufacture, import, export and consumption of CFCs and other substances that deplete the ozone layer. In 1990, an amendment to the Protocol escalated the commitment to cease production of CFCs by 2000. In 1996, the production ban in major countries came into effect.

−	During the phase out, certain refrigerants were introduced as CFC substitutes. ~~These~~ too became ~~severely~~ restricted under the Kyoto Protocol in 1997.	+	During the phase out, certain refrigerants were introduced as CFC substitutes. Some of these too became restricted under the Kyoto Protocol in 1997.
		+
		+	For more information see: HFC phase out and R22 phase out.

−	The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) is an international agreement which commits participants to internationally binding ~~GHG~~ emission reduction targets. It also assists countries in adapting to climate change through the Adaptation Fund by facilitating the development and deployment of technologies to increase resilience.	+	The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) is an international agreement which commits participants to internationally binding greenhouse gas emission reduction targets. It also assists countries in adapting to climate change through the Adaptation Fund by facilitating the development and deployment of technologies to increase resilience.

	= Related articles on Designing Buildings =		= Related articles on Designing Buildings =
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	* Montreal Protocol on Substances that Deplete the Ozone Layer.		* Montreal Protocol on Substances that Deplete the Ozone Layer.
	* Ozone-depleting substances.		* Ozone-depleting substances.
		+	* R22 phase out
	* Refrigerants in buildings.		* Refrigerants in buildings.

Editor at 09:24, 20 December 2021

2021-12-20T09:24:04Z

Editor at 18:38, 17 December 2021

2021-12-17T18:38:04Z

← Older revision		Revision as of 18:38, 17 December 2021
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	= Introduction =		= Introduction =

−	Chlorofluorocarbons (commonly referred to as CFCs) are a type of halocarbon that is formulated from carbon, chlorine and fluorine. Halocarbons are defined by the [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ Intergovernmental Panel on Climate Change] as ‘A collective term for the group of partially halogenated organic species which includes…chlorofluorocarbons ~~(CFCs)~~.	+	Chlorofluorocarbons (commonly referred to as CFCs) are a type of halocarbon that is formulated from carbon, chlorine and fluorine. Halocarbons are defined by the [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ Intergovernmental Panel on Climate Change] as ‘A collective term for the group of partially halogenated organic species which includes…chlorofluorocarbons'.

	= History of CFCs =		= History of CFCs =
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	The Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol) was agreed on 16 September 1987 and came into effect on 1 January 1989. It came after a series of rigorous meetings and crucial negotiations at the Headquarters of the International Civil Aviation Organisation in Montreal, Quebec, in Canada and was ratified by all 196 United Nations members. Its framework was defined by the Vienna Convention for the Protection of the Ozone Layer in 1985.		The Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol) was agreed on 16 September 1987 and came into effect on 1 January 1989. It came after a series of rigorous meetings and crucial negotiations at the Headquarters of the International Civil Aviation Organisation in Montreal, Quebec, in Canada and was ratified by all 196 United Nations members. Its framework was defined by the Vienna Convention for the Protection of the Ozone Layer in 1985.

−	It was developed in order to reduce the production of ozone-depleting substances such as CFCs. The definition of ozone depleting substances only includes halogen source gases emitted by human activities and controlled by the Montreal Protocol. Those gases that have only natural sources are not classed as ozone depleting substances Most ozone depleting substances are also greenhouse gases that contribute to global warming (ref United Nations Environment Programme 2010).	+	It was developed in order to reduce the production of ozone-depleting substances such as CFCs. The definition of ozone depleting substances only includes halogen source gases emitted by human activities and controlled by the Montreal Protocol. Those gases that have only natural sources are not classed as ozone depleting substances Most ozone depleting substances are also greenhouse gases that contribute to global warming (ref [https://ozone.unep.org/sites/default/files/2019-05/00-SAP-2010-Assement-report.pdf United Nations Environment Programme 2010]).

	The Protocol introduced an incremental reduction of the manufacture, import, export and consumption of CFCs and other substances that deplete the ozone layer. In 1990, an amendment to the Protocol escalated the commitment to cease production of CFCs by 2000. In 1996, the production ban in major countries came into effect.		The Protocol introduced an incremental reduction of the manufacture, import, export and consumption of CFCs and other substances that deplete the ozone layer. In 1990, an amendment to the Protocol escalated the commitment to cease production of CFCs by 2000. In 1996, the production ban in major countries came into effect.
Line 56:		Line 56:

	* Intergovernmental Panel on Climate Change, Climate Change 2021, [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ The Physical Science Basis].		* Intergovernmental Panel on Climate Change, Climate Change 2021, [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ The Physical Science Basis].
−	* The 2010 Assessment of the Scientific Assessment Panel (UNEP 2010).	+	* [https://ozone.unep.org/sites/default/files/2019-05/00-SAP-2010-Assement-report.pdf The 2010 Assessment of the Scientific Assessment Panel] (UNEP 2010).
		+
		+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:DCN_Regulation]] [[Category:Definitions]] [[Category:International]] [[Category:Regulations]] [[Category:Sustainability]] [[Category:Products_/_components]]

Editor at 18:33, 17 December 2021

2021-12-17T18:33:10Z

← Older revision		Revision as of 18:33, 17 December 2021
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	* Intergovernmental Panel on Climate Change, Climate Change 2021, [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ The Physical Science Basis].		* Intergovernmental Panel on Climate Change, Climate Change 2021, [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ The Physical Science Basis].
		+	* The 2010 Assessment of the Scientific Assessment Panel (UNEP 2010).

Editor: Created page with "= Introduction = Chlorofluorocarbons (commonly referred to as CFCs) are a type of halocarbon that is formulated from carbon, chlorine and fluorine. Halocarbons are defined by th..."

2021-12-17T18:24:21Z

Created page with "= Introduction = Chlorofluorocarbons (commonly referred to as CFCs) are a type of halocarbon that is formulated from carbon, chlorine and fluorine. Halocarbons are defined by th..."

New page

= Introduction =

Chlorofluorocarbons (commonly referred to as CFCs) are a type of halocarbon that is formulated from carbon, chlorine and fluorine. Halocarbons are defined by the [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ Intergovernmental Panel on Climate Change] as ‘A collective term for the group of partially halogenated organic species which includes…chlorofluorocarbons (CFCs).

= History of CFCs =

CFCs were first discovered by a Belgian chemist named Frédéric Swarts in the 1890s. The connection between CFCs and refrigeration was made in 1928, prompted by safety issues associated with early forms of mechanical refrigeration.

In the late 1800s and early 1900s, refrigerators used dangerous gases for cooling purposes. The combination of ammonia (NH3), methyl chloride (CH3Cl), and sulfur dioxide (SO2) was associated with fatal accidents due to leakage, and this prompted several corporations to join together to support the development of a safer alternative.

In 1928, a team of researchers led by the American chemist Thomas Midgley, Jr. on behalf of General Motors (the parent company of Frigidaire - a major United States manufacturer of refrigerators) found that Swarts’ discovery could be put to practical use after some modifications to the substance were made. General Motors subsequently patented a device that used the new type of CFC, and in 1930 the company formed another division to produce the substance - trademarked under the name Freon - on a large commercial scale.

From the 1930s, CFCs became widely used in the United States for residential, commercial and automotive air conditioning systems. It was also commonly used as a propellant in various products - ranging from pesticides to healthcare products.

= Safety of CFCs called into question =

Initially, CFCs were considered safe due to their non flammable characteristics, low toxicity and stability. Furthermore, they had no impact on the lower atmosphere.

In the 1970s scientists discovered that the potential impact of CFCs on the upper atmosphere (or stratosphere) could be cause for concern. Research conducted by University of California chemists, Professor F. Sherwood Rowland and Dr Mario Molina found that CFCs emit significant amounts of inorganic chlorine in the upper atmosphere, and this was linked to ozone depletion.

= CFCs and damage to the ozone layer =

The high-altitude stratospheric ozone layer acts as a shield in the atmosphere, protecting life from harmful ultraviolet (UV) radiation emitted by the sun. Scientific evidence shows that certain compounds can cause considerable damage to and weakening of the earth’s ozone layer, leading to increases in the incidence of skin cancer and cataracts, as well as having an adverse effect on crops, plants and ocean plankton.

The use of ozone depleting chemicals such as CFCs peaked by the 1980s. But after greenhouse gas emissions associated with CFCs were linked to the formation of the 'ozone hole' over the Antarctic, a global effort was made to decrease the use of this (and other) fluorocarbon refrigerants.

Greenhouse gases allow sunlight to enter the atmosphere and heat the Earth’s surfaces. These surfaces then re-radiate that heat as long-wave infrared radiation, which greenhouse gases tend to absorb rather than transmit. The result is that the long-wave infrared radiation is ‘trapped’ and heat accumulates in the atmosphere causing a warming process.

= Ceasing the production of CFCs =

The work of Rowland and Molina on the decomposition of ozone (and CFCs in particular) - along with contributions from researchers at the Max Planck Institute for Chemistry - received the 1995 Nobel Prize for Chemistry. It also formed the basis of the Montreal Protocol.

The Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol) was agreed on 16 September 1987 and came into effect on 1 January 1989. It came after a series of rigorous meetings and crucial negotiations at the Headquarters of the International Civil Aviation Organisation in Montreal, Quebec, in Canada and was ratified by all 196 United Nations members. Its framework was defined by the Vienna Convention for the Protection of the Ozone Layer in 1985.

It was developed in order to reduce the production of ozone-depleting substances such as CFCs. The definition of ozone depleting substances only includes halogen source gases emitted by human activities and controlled by the Montreal Protocol. Those gases that have only natural sources are not classed as ozone depleting substances Most ozone depleting substances are also greenhouse gases that contribute to global warming (ref United Nations Environment Programme 2010).

The Protocol introduced an incremental reduction of the manufacture, import, export and consumption of CFCs and other substances that deplete the ozone layer. In 1990, an amendment to the Protocol escalated the commitment to cease production of CFCs by 2000. In 1996, the production ban in major countries came into effect.

During the phase out, certain refrigerants were introduced as CFC substitutes. These too became severely restricted under the Kyoto Protocol.

The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) is an international agreement which commits participants to internationally binding greenhouse gas (GHG) emission reduction targets. It also assists countries in adapting to climate change through the Adaptation Fund by facilitating the development and deployment of technologies to increase resilience. It was adopted in Kyoto, Japan, on 11 December 1997.

= Related articles on Designing Buildings =

* Chiller units
* Greenhouse gases.
* Halocarbons
* HFC phase out
* Intergovernmental Panel on Climate Change IPCC.
* Kyoto Protocol.
* Montreal Protocol on Substances that Deplete the Ozone Layer.
* Ozone-depleting substances.
* Refrigerants in buildings.

= External resources =

* Intergovernmental Panel on Climate Change, Climate Change 2021, [https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ The Physical Science Basis].

← Older revision		Revision as of 09:24, 20 December 2021
Line 7:		Line 7:
	CFCs were first discovered by a Belgian chemist named Frédéric Swarts in the 1890s. The connection between CFCs and refrigeration was made in 1928, prompted by safety issues associated with early forms of mechanical refrigeration.		CFCs were first discovered by a Belgian chemist named Frédéric Swarts in the 1890s. The connection between CFCs and refrigeration was made in 1928, prompted by safety issues associated with early forms of mechanical refrigeration.

−	In the late 1800s and early 1900s, refrigerators used dangerous gases for cooling purposes. The combination of ammonia (NH3), methyl chloride (CH3Cl), and sulfur dioxide (SO2) was ~~associated with~~ fatal accidents due to leakage, ~~and this~~ prompted several corporations to ~~join together to support~~ the development of a safer alternative.	+	In the late 1800s and early 1900s, refrigerators used dangerous gases for cooling purposes. The combination of ammonia (NH3), methyl chloride (CH3Cl) and sulfur dioxide (SO2) was linked to fatal accidents due to leakage, which prompted several refrigeration corporations to push for the development of a safer alternative.

−	In 1928, a team of researchers led by the American chemist Thomas Midgley, Jr. on behalf of General Motors (the parent company of Frigidaire - a major United States manufacturer of refrigerators) found that Swarts’ discovery could be put to practical use after some modifications ~~to the substance~~ were made. General Motors subsequently patented a device that used the new type of CFC, and in 1930 the company formed another division to produce the substance - trademarked under the name Freon - on a large commercial scale.	+	In 1928, a team of researchers led by the American chemist Thomas Midgley, Jr. on behalf of General Motors (the parent company of Frigidaire - a major United States manufacturer of refrigerators) found that Swarts’ discovery could be put to practical use after some modifications were made. General Motors subsequently patented a device that used the new type of CFC, and in 1930 the company formed another division to produce the modified substance - trademarked under the name Freon - on a large commercial scale.

−	From the 1930s, CFCs became widely used in the United States for residential, commercial and automotive air conditioning systems. ~~It was~~ also commonly used as a propellant in various products - ranging from pesticides to healthcare ~~products~~.	+	From the 1930s, CFCs became widely used in the United States for residential, commercial and automotive air conditioning systems. They were also commonly used as a propellant in various products - ranging from pesticides to healthcare items.

	= Safety of CFCs called into question =		= Safety of CFCs called into question =

−	Initially, CFCs were ~~considered~~ safe due to their non flammable characteristics, low toxicity and stability. Furthermore, they had no impact on the lower atmosphere.	+	Initially, CFCs were thought to be completely safe due to their non flammable characteristics, low toxicity and stability. Furthermore, they had no impact on the lower atmosphere.

−	In the 1970s scientists discovered that the potential impact of CFCs on the upper atmosphere (or stratosphere) ~~could~~ be cause for concern. Research conducted by University of California chemists, Professor F. Sherwood Rowland and Dr Mario Molina found that CFCs emit significant amounts of inorganic chlorine in the upper atmosphere, and this was ~~linked~~ to ozone depletion.	+	In the 1970s, scientists discovered that the potential impact of emissions from CFCs on the upper atmosphere (or stratosphere) might be cause for concern. Research conducted by University of California chemists Professor F. Sherwood Rowland and Dr Mario Molina found that CFCs emit significant amounts of inorganic chlorine in the upper atmosphere, and this was seen as a contributing factor to ozone depletion.

	= CFCs and damage to the ozone layer =		= CFCs and damage to the ozone layer =

−	The high-altitude stratospheric ozone layer acts as a shield in the atmosphere, protecting life from harmful ultraviolet (UV) radiation emitted by the sun. Scientific evidence shows that certain compounds can cause considerable damage to and weakening of the earth’s ozone layer, leading to increases in the incidence of skin cancer and cataracts, as well as having an adverse effect on crops, plants and ocean plankton.	+	The high-altitude stratospheric ozone layer acts as a shield in the atmosphere, protecting life from harmful ultraviolet (UV) radiation emitted by the sun. Scientific evidence shows that certain compounds can cause considerable damage to - and weakening of - the earth’s ozone layer, leading to increases in the incidence of skin cancer and cataracts, as well as having an adverse effect on crops, plants and ocean plankton.

−	The use of ozone depleting chemicals such as CFCs peaked by the 1980s. But after greenhouse gas emissions associated with CFCs were linked to the formation of the 'ozone hole' over the Antarctic, a global effort was made to decrease the use of this (and other) fluorocarbon refrigerants.	+	The use of ozone depleting chemicals such as CFCs peaked by the 1980s. But after greenhouse gas (GHG) emissions associated with CFCs were linked to the formation of the ozone hole over the Antarctic, a global effort was made to decrease the use of this (and other) fluorocarbon refrigerants.

−	~~Greenhouse gases allow~~ sunlight to enter the atmosphere and heat the Earth’s surfaces. These surfaces then re-radiate that heat as long-wave infrared radiation, which greenhouse gases tend to absorb rather than transmit. The result is that the long-wave infrared radiation is ~~‘trapped’~~ and heat accumulates in the atmosphere causing a warming process.	+	The emission of GHGs allows sunlight to enter the atmosphere and heat the Earth’s surfaces. These surfaces then re-radiate that heat as long-wave infrared radiation, which greenhouse gases tend to absorb rather than transmit. The result is that the long-wave infrared radiation is trapped and heat accumulates in the atmosphere causing a warming process.

	= Ceasing the production of CFCs =		= Ceasing the production of CFCs =

−	The ~~work of~~ Rowland and Molina on the decomposition of ozone (~~and CFCs~~ in particular) - along with contributions from researchers at the Max Planck Institute for Chemistry - received the 1995 Nobel Prize for Chemistry. It also formed the basis of the Montreal Protocol.	+	The research conducted by Rowland and Molina on the decomposition of ozone (caused by CFC emissions in particular) - along with contributions from researchers at the Max Planck Institute for Chemistry - received the 1995 Nobel Prize for Chemistry. It also formed the basis of the Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol).

−	~~The~~ Montreal Protocol ~~on Substances that Deplete the Ozone Layer (the Montreal Protocol)~~ was agreed on 16 September 1987 and came into effect on 1 January 1989. It came after a series of rigorous meetings and crucial negotiations at the Headquarters of the International Civil Aviation Organisation in Montreal, Quebec, in Canada and was ratified by all 196 United Nations members. Its framework was defined by the Vienna Convention for the Protection of the Ozone Layer in 1985.	+	Montreal Protocol was agreed on 16 September 1987 and came into effect on 1 January 1989. It came after a series of rigorous meetings and crucial negotiations at the Headquarters of the International Civil Aviation Organisation in Montreal, Quebec, in Canada and was ratified by all 196 United Nations members. Its framework was defined by the Vienna Convention for the Protection of the Ozone Layer in 1985.

−	It was developed in order to reduce the production of ozone-depleting substances such as CFCs. The definition of ozone depleting substances only includes halogen source gases emitted by human activities and controlled by the Montreal Protocol. Those gases that have only natural sources are not classed as ozone depleting substances Most ozone depleting substances are also ~~greenhouse gases~~ that contribute to global warming (ref [https://ozone.unep.org/sites/default/files/2019-05/00-SAP-2010-Assement-report.pdf United Nations Environment Programme 2010]).	+	It was developed in order to reduce the production of ozone depleting substances such as CFCs. The definition of ozone depleting substances only includes halogen source gases emitted by human activities and controlled by the Montreal Protocol. Those gases that have only natural sources are not classed as ozone depleting substances. Most ozone depleting substances are also GHG that contribute to global warming (ref [https://ozone.unep.org/sites/default/files/2019-05/00-SAP-2010-Assement-report.pdf United Nations Environment Programme 2010]).

	The Protocol introduced an incremental reduction of the manufacture, import, export and consumption of CFCs and other substances that deplete the ozone layer. In 1990, an amendment to the Protocol escalated the commitment to cease production of CFCs by 2000. In 1996, the production ban in major countries came into effect.		The Protocol introduced an incremental reduction of the manufacture, import, export and consumption of CFCs and other substances that deplete the ozone layer. In 1990, an amendment to the Protocol escalated the commitment to cease production of CFCs by 2000. In 1996, the production ban in major countries came into effect.

−	During the phase out, certain refrigerants were introduced as CFC substitutes. These too became severely restricted under the Kyoto Protocol.	+	During the phase out, certain refrigerants were introduced as CFC substitutes. These too became severely restricted under the Kyoto Protocol in 1997.

−	The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) is an international agreement which commits participants to internationally binding ~~greenhouse gas (~~GHG) emission reduction targets. It also assists countries in adapting to climate change through the Adaptation Fund by facilitating the development and deployment of technologies to increase resilience~~. It was adopted in Kyoto, Japan, on 11 December 1997~~.	+	The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) is an international agreement which commits participants to internationally binding GHG emission reduction targets. It also assists countries in adapting to climate change through the Adaptation Fund by facilitating the development and deployment of technologies to increase resilience.

	= Related articles on Designing Buildings =		= Related articles on Designing Buildings =