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CFCs have useful properties such as coolant liquids in refrigerators and aerosol sprays but studies in the 1980s revealed that they are the cause of destroying the Earths ozone layer. How was this problem addressed?
Introduction
Halogen derivatives are new compounds acquired when one or multiple hydrogen atoms of acyclic hydrocarbons are exchanged for an equivalent number of halogen atoms of alkenes or alkanes. Chlorofluorocarbons (CFCs )such as chlorine (Cl), carbon (C), hydrogen (H), and fluorine (F) are halogenated hydrocarbons that are known for contributing to ozone depletion on a global scale ( Chlorofluorocarbon | Chemical Compound | Britannica ). Their purpose was to act as non-flammable and non-toxic refrigerants (Sehested). At first, they were useful and they were used in creating aerosol sprays, fire extinguishers, and coolant liquids. They were banned in 1996 once studies showed that they were harmful to the environment, mostly the earths ozone layer. When CFCs are released, the process of destroying and forming ozone in the atmosphere is affected negatively, increasing the chance of depletion. Once the ozone layer is destroyed, UV radiation is able to reach the earths surface adversely affecting human, animal, and plant life and exposing them to various complications and diseases. This is because once chlorofluorocarbons are released into the atmosphere, they rise up to the ozone layer and the ultraviolet rays are able to hit the chlorine (Cl) atom and cause it to break away from the CFCs. Chlorine atom(s) come into contact with an ozone molecule and gains an oxygen (O) molecule, leading to the formation of chlorine monoxide.
- CFCl3 + UV ’ CFCl2 + Cl
- Cl + O3 ’ ClO + O2
- ClO + O ’ Cl + O2
( The Ozone Hole )
Chlorine is harmful and it proceeds to destroy the ozone. Tropospheric ozone is dangerous to human beings because it can lead to various conditions and infections (Stubbings). The equations below show its formation which occurs when electrical discharge arises from high-voltage appliances.
- O2 Â 2O
- O2 + O Â O3
Stratospheric ozone is the principal protective layer and it provides the energy to split oxygen molecules into atoms (Stubbings).
- O2 Â 2O (UV radiation)
- Equation displaying reaction with oxygen to form ozone: O + O2 Â O3
- Equation displaying absorption of UV radiation: O3 Â O2 + O
Since these chlorofluorocarbons were already in use, an environmentally friendly compound needed to be obtained in order to replace them. Hydrofluorocarbons (HFCs) were found to be the best alternative. Although they also contribute to the destruction of the earths ozone layer, it does so to a less harmful extent.
HFCs are organic compounds containing hydrogen (H), fluorine (F), and carbon (C). While the properties of CFCs consist of low toxicity, low flammability, and stability hydrofluorocarbons have a shorter lifetime in terms of the length of atmospheric pollution which makes them a better alternative (Sehested). Unlike CFCs, they do not contain chlorine (Cl) which means the ozone layer is less susceptible to depletion.
The economy was evidently affected by the introduction of HFCs. Industries, production companies, and various institutions faced challenges and had concerns about how the replacement of CFCs would impact them economically. For instance, production industries found that deciding how to market and influence people to dispose of their old CFC refrigerants and other products proved to be a challenge. They had to figure out how to recover their money. If we take refrigerators as an example, the coolant liquids in them contain CFCs which had already been banned. The producers still had unsold refrigerators worth millions. Knowing how to begin going about making new appliances without having a profit from the previous one required a lot of investments and was considered a big risk to the economy. During the transitional stage from CFCs to HFCs, environmentalists insisted on an immediate ban. Chemical companies argued that if the economy was to transition that fast, a shortage of coolant liquids would be a threat. This not only affected people at home but also health institutions and morgues where certain things have to be preserved through refrigeration; if cadavers or blood and organs were not preserved these institutions would face a major loss which would put them at risk both financially and legally.
As the production level of CFCs lowered, scientists worries also heightened due to the fear of a research hiatus (Holusha). They were hesitant to plan far ahead and to give estimates for years to come concerning the production and the positive and negative effects of the new alternatives. This is because they feared a repetition of loss of research like what happened when CFCs were found to be harmful. HFCs are less damaging than CFCs but this doesnt mean that they have no negative effects at all. Hydrofluorocarbons are global warming gases. Damaging gases are still released into the atmosphere but in controllable amounts. Scientists still need to find a better solution because according to a study done by NASA, damage to the stratosphere will eventually increase over time due to the build-up of concentration of the chemicals and by the year 2050, 5 types of HFCs will contribute to global warming ( HFC Impact ).
In October 2016, the Montreal Protocol Kigali Agreement addressed the problem and came forward with the suggestion of the gradual ban of HFCs. More than 170 countries signed and it was effective from January 2019. It was agreed that developed countries should start the process of cutting down the use of HFCs in 2019 and developing countries should begin between 2024 and 2028.
A possible alternative to HFCs is hydrofluoroolefins (HFOs) which have a short atmospheric lifetime but they produce toxic chemicals when broken down. The most shocking alternative suggested was CO2. It is non-flammable and non-toxic and it is a weaker greenhouse gas in comparison to HFCs (Fisher and Wilson). So far, this seems to be the best option for refrigerants.
Conclusion
The problem was addressed by applying a ban on the usage of CFCs and finding an environmentally safer alternative. HFCs were seen to be the best solution but studies then showed that they had a lasting atmospheric lifetime which would contribute to global warming in the years to come. Therefore, the problem was not completely solved but the magnitude of the problem was decreased from the initial effect of CFCs on the ozone layer. This is why the 2016 Montreal Protocol Kigali Amendment was put forward in order to find more efficacious replacements and work towards a lower-impact alternative. In conclusion, the positive effects of HFCs outweigh the negative ones but as soon as the Montreal Protocol Kigali Amendment is in full effect, the alternatives provided will work towards a safer ozone layer.
Works Cited
- Chlorofluorocarbon | Chemical Compound | Britannica. Encyclopædia Britannica, 2020, www.britannica.com/science/chlorofluorocarbon.
- Fisher, Jenny, and Stephen Wilson. Explainer: Hydrofluorocarbons Saved the Ozone Layer, so Why Are We Banning Them? The Conversation, theconversation.com/explainer-hydrofluorocarbons-saved-the-ozone-layer-so-why-are-we-banning-them-86672. Accessed 30 Apr. 2020.
- Holusha, John. Ozone Issue: Economics of a Ban. The New York Times, 11 Jan. 1990, www.nytimes.com/1990/01/11/business/ozone-issue-economics-of-a-ban.html. Accessed 16 Apr. 2020.
- Hurwitz, Margaret M., et al. Ozone Depletion by Hydrofluorocarbons. Geophysical Research Letters, vol. 42, no. 20, 22 Oct. 2015, pp. 86868692, 10.1002/2015gl065856. Accessed 16 Apr. 2020.
- Hydrofluorocarbon | Definition, Characteristics, & Facts | Britannica. Encyclopædia Britannica, 2020, www.britannica.com/science/hydrofluorocarbon.
- Hydrofluorocarbon – an Overview | ScienceDirect Topics. Www.Sciencedirect.Com, www.sciencedirect.com/topics/earth-and-planetary-sciences/hydrofluorocarbon. Accessed 16 Apr. 2020.
- Pearce, Fred. Saving the Ozone Layer Is Warming the Planet but It Can Be Fixed. New Scientist, www.newscientist.com/article/2097581-saving-the-ozone-layer-is-warming-the-planet-but-it-can-be-fixed/. Accessed 16 Apr. 2020.
- Phillips, Guy D. CFCs in the Developing Nations: A Major Economic Development Opportunity. Will the Institutions Help or Hinder? Ambio, vol. 19, no. 6/7, 1990, pp. 316320, www.jstor.org/stable/4313725?seq=1. Accessed 16 Apr. 2020.
- Sehested, Jens. Atmospheric Chemistry of Hydrofluorocarbons and Hydrochlorofluorocarbons. 1995.
- SVS: Ozone Depletion by Hydrofluorocarbons. Svs.Gsfc.Nasa.Gov, svs.gsfc.nasa.gov/4389. Accessed 16 Apr. 2020.
- The Montreal Protocol Evolves to Fight Climate Change | UNIDO. Www.Unido.Org, www.unido.org/our-focus-safeguarding-environment-implementation-multilateral-environmental-agreements-montreal-protocol/montreal-protocol-evolves-fight-climate-change.
- The Ozone Hole. Theozonehole.Com, 2019, www.theozonehole.com/ozonedestruction.htm.
- US EPA, OAR. Substitutes in Refrigeration and Air Conditioning. US EPA, 4 Nov. 2014, www.epa.gov/snap/substitutes-refrigeration-and-air-conditioning. Accessed 16 Apr. 2020.
- We Saved the Ozone Layer. We Can Save the Climate. We Saved the Ozone Layer. We Can Save the Climate. NRDC, 19 Apr. 2019, www.nrdc.org/experts/david-doniger/we-saved-ozone-layer-we-can-save-climate.
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