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Last edited 19 Sep 2018
Ozone depleting substances
Ozone depleting substances are man-made chemicals that damage the ozone layer in the upper atmosphere (the stratosphere). They are also referred to as 'halogen source gases'. Ozone is destroyed by chlorine and bromine atoms within ozone depleting substances.
The ozone layer protects the earth from ultraviolet radiation emitted by the sun and its depletion could lead to increases in the incidence of skin cancer and cataracts, as well as having an adverse effect on crops, plants and ocean plankton (ref UNEP 2010).
Ozone depleting substances have contributed to the formation of the 'ozone hole' over the Antarctic.
 Control of ozone depleting substances – Montreal Protocol
The emissions of ozone depleting substances increased in the middle to late 20th century, peaking in the late 1980s. This was linked to the increased use of chemicals such as Chlorofluorocarbons (CFCs) in refrigeration, industrial cleaning, foam blowing and air conditioning (ref UNEP 2010).
As a result of the threat of increased ozone depletion, an international agreement was formulated in 1987, known as the Montreal Protocol on Substances that Deplete the Ozone Layer. The protocol was ratified by all 196 United Nations members. Its main purpose was to reduce the worldwide use of ozone depleting substances. It has since had various amendments and adjustments.
The treaty has been successful. The use of ozone depleting substances is decreasing and ozone depletion is no longer increasing. It is anticipated that in the late 21st century, the ozone layer will have substantially recovered (ref UNEP 2010). This success has largely been attributed to the development of ‘ozone friendly’ substitutes for ozone depleting substances.
 Examples of ozone depleting substances
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 UNEP 2010).
The main ozone depleting substances include:
- Chlorofluorocarbons (CFCs).
- Hydrochlorofluorcarbons (HCFCs).
- Methyl Chloroform.
- Carbon Tetrachloride (the main precursor of CFCs).
- Methyl Bromide.
 Sources of ozone depleting substances
Ozone depleting substances have many historic uses including:
- Air conditioning.
- Foam blowing agents.
- Aerosol propellants.
- Fire fighting fluids.
- Fumigation substances.
- Soil sterilisation substances.
 European Union (EU) and UK obligations
- Regulation (EC) 1005/2009 on substances that deplete the ozone layer.
- Amended by Commission Regulation 744/2010 on the critical uses of halons.
- Environmental Protection (Controls on Ozone-Depleting Substances) Regulations 2011 (SI 2011/1543)
- The Ozone-Depleting Substances (Qualifications) Regulations 2009 (SI 2009/216)
Specific activities that have been included within the regulations to help reduce the emissions of ozone depleting substances include (Defra 2014):
- Banning the use of CFCs.
- Limited the critical use of Halons (used in fire protection).
- Banning the use of HCFCs: from 2001 in new equipment and from 2015 for existing equipment.
- Control and licensing of the production, import and export of ozone depleting substances by the European Commission.
- Only essential use of ozone depleting substances in laboratory and analytical purposes and subject to registration.
 Compliance with ozone depleting substances regulations
The Environment Agency helps businesses comply with the UK regulations and enforces compliance. Specific guidance is provided for individuals who work with high voltage switchgear, solvents, stationary refrigeration, air conditioning, heat pumps, fire extinguishers and mobile air conditioning (ref Environment Agency 2014).
 Related articles on Designing Buildings Wiki
- BREEAM Impact of refrigerants.
- Climate change act.
- Construction 2025.
- Deleterious materials.
- Greenhouse gases.
- Montreal Protocol.
- R22 phase out.
- Refrigerant selection.
- Sustainable materials.
 External references
- Controlling ozone-depleting substances and fluorinated greenhouse gases, Defra 2014.
- European Commission.
- Managing fluorinated gases and ozone-depleting substances: guidance for industry, Environment Agency 2014.
- The 2010 Assessment of the Scientific Assessment Panel(UNEP 2010).
- The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer (UNEP).
- Environmental Protection (Controls on Ozone-Depleting Substances) Regulations 2011 (SI 2011/1543).
- The Ozone-Depleting Substances (Qualifications) Regulations 2009 (SI 2009/216).
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