Chlorofluorocarbons (CFC) are gases used for various purposes including solvents, refrigerants and aerosol sprays. They are organic chemicals and contain carbon, (sometimes hydrogen,) chlorine, and fluorine. They were much used in the middle 20th century, replacing chemicals that were toxic or flammable or had traits that were generally harmful to human health.
Chlorofluorocarbons have a direct impact on the environment as a whole. As a result, they are an important concept for the Environment and Ecology segment of the UPSC Syllabus.
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What are the applications of CFC?
Chlorofluorocarbons are used in a variety of applications because of their low toxicity, reactivity and flammability. Every permutation of fluorine, chlorine and hydrogen-based on methane and ethane has been examined and most have been commercialized.
Furthermore, many examples are known for higher numbers of carbon as well as related compounds containing bromine. Uses include refrigerants, blowing agents, propellants in medicinal applications and degreasing solvents.
How do CFCs impact the environment?
However, the atmospheric impacts of CFCs are not limited to their role as ozone-depleting chemicals. Infrared absorption bands prevent heat at that wavelength from escaping the earth’s atmosphere. CFCs have their strongest absorption bands from C-F and C-Cl bonds in the spectral region of 7.8–15.3 µm—referred to as “atmospheric window” due to the relative transparency of the atmosphere within this region.
The strength of CFC absorption bands and the unique susceptibility of the atmosphere at wavelengths where CFCs (indeed all covalent fluorine compounds) absorb creates a “super” greenhouse gas (GHG) effect from CFCs and other unreactive fluorine-containing gases such as perfluorocarbons, HFCs, HCFCs, bromofluorocarbons.
Use of certain chloroalkanes as solvents for large-scale application, such as dry cleaning, have been phased out, for example, by the IPPC directive on greenhouse gases in 1994 and by the volatile organic compounds (VOC) directive of the European Union in 1997. Permitted chlorofluoro alkane uses are medicinal only.
According to scientific communities, the hole in the ozone layer has begun to recover as a result of CFC bans. India is one of the few countries that are pioneers in the use of non-Ozone Depleting technologies and have a low Global Warming Potential (GWP).
Hydrochlorofluorocarbon (HCFC)-141 b
India has successfully phased out Hydrochlorofluorocarbon (HCFC)-141 b. HCFC-141 b is one of the most powerful ozone-depleting chemicals after Chlorofluorocarbons (CFCs). It is not produced domestically but the requirements are met through imports. It is mainly used as a blowing agent in the foam manufacturing industries.
The issuance of import license for HCFC-141b is prohibited from 1st January 2020 under Ozone Depleting Substances (Regulation and Control) Amendment Rules, 2019, a notified by the Ministry of Environment, Forest and Climate Change. Read more on Ozone Layer Depletion and Preservation on the given link. This step is among the first at this scale in Article 5 (special status of developing countries) parties under the Montreal Protocol.
- Ozone Depleting Substances (Regulation and Control) Amendment Rules, 2019 have been issued under the Environment Protection Act, 1986.
Trichlorofluoromethane (CFC 11)
An international team of researchers has said that the rogue emissions of a gas (CFC-11) that harm the ozone layer come from eastern China.
- CFC-11 – trichlorofluoromethane is one of a number of chlorofluorocarbons (CFC) chemicals that were initially developed as refrigerants during the 1930s. One tonne of CFC-11 is equivalent to around 5,000 tonnes of CO2, leading not only to a decline in the ozone layer but also an increase in the earth’s overall temperature.
- It took many decades for scientists to discover that when CFCs break down in the atmosphere, they release chlorine atoms that are able to rapidly destroy the ozone layer which protects us from ultraviolet light. (A gaping hole in the ozone layer over Antarctica was discovered in the mid-1980s.)
- Excessive amounts of some types of UV radiation can cause skin cancer and eye damage in people and are harmful to crops and other vegetation.
- The international community agreed the Montreal Protocol in 1987 which outlawed chlorofluorocarbons for almost all uses. The Montreal Protocol on Substances that Deplete the Ozone Layer is an important Multilateral Agreement regulating the production, consumption, and emissions of ozone-depleting substances (ODSs). Read more on Montreal Protocol on the linked page.
Aspirants can find the list of Important Environment Conventions and Protocols at the linked article.
CFC – UPSC Notes:- Download PDF Here
Frequently Asked Questions for RBI Admit Card
Q 1. How can we reduce chlorofluorocarbons?
Q 2. What are some of the well-known examples of CFC’s?
Q 3. Why were CFCs banned?