Ozone, an allotrope of oxygen, with the chemical formula O3, is ‘a gas that occurs both in the Earth’s upper atmosphere and at ground level. Ozone can be “good” or “bad” for people’s health and for the environment, depending on its location in the atmosphere’ (Ozone 2010, para. 1).
The ground-level ozone (ozone of the troposphere) has some negative effects on health, crops and vegetation in general. One of its negative effects on health is that it enhances manifestations of asthma.
I will give consideration to the stratospheric or “good” ozone further in this work.
The ‘ozone layer extends upward from about 6 to 30 miles and protects life on Earth from the sun’s harmful ultraviolet (UV) rays’ (Ozone 2010, para. 3), acting as a filter. It happens due to the ozone-oxygen cycle that results in converting the radiation to heat. Andrew Dessler makes the following statement about the significance of ozone: ‘the role O3 plays in absorbing these photons is crucial because a photon of 250 nm wavelength has an energy … enough to break chemical bonds in DNA or interfere in other ways in biological processes’ (2), causing skin cancer, cataracts, or weakening immune systems. The most obvious thing is that ozone layer protects people from sunburn.
Chipperfield notes that ozone is formed in the stratosphere by ‘dissociation of O2 molecules by short-wavelength ultraviolet radiation’, and that ‘the distribution of ozone in the atmosphere is maintained by a balance between photochemical production, transport and photochemical loss’ (169). There are several causes of defection of this balance. The main of them are: emission of chlorofluorocarbons (CFCs) and hydrofluorocarbons (HCFCs), and other substances that deplete the ozone layer. These substances are used widely as solvents, refrigerants, insulating foams, and so on. Thus, the depletion happens due to human-factor aspect, not due to some natural sources, as people used to think and blame volcanoes or oceans in releasing large amounts of chlorine. Nevertheless, this natural chlorine is easily dissolved in water, in contrast to CFCs.
This problem of ozone degradation or of the depletion of the ozone layer has become a major concern of many scientists and governments nowadays. Today there exist various regulatory programs, the aim of which is safeguarding of the ozone layer. People started thinking about the need of control over chemicals and sign regional and international protocols. In the preface by Intergovernmental Panel on Climate Change it is written, that this international process has resulted in
- elimination of production of most CFCs, methyl chloroform, and halons,
- the increased use of existing hydrochlorofuorocarbons (HCFCs),
- the new production of a wide range of industrial fluorine containing chemicals including new types of HCFCs …,
- use of non-halogenated chemical substitutes such as hydrocarbons, carbon dioxide … (Intergovernmental Panel on Climate Change IX).
By now, more than 190 countries have approved the treaty to accelerate the phaseout of CFCs, HCFCs, and other substances, that are harmful for the ozone layer, and have combined their efforts in this important issue of safeguarding of the ozone layer. Other programs are: Stationary Refrigeration and Air-Conditioning, Motor Vehicle Air-Conditioning programs, The Phaseout of Methyl Bromide.
We can protect the ozone layer, vital for our safety, only if all countries participate in such programs, and every person conducts consciously and does everything possible to lessen emission of deleterious substances into the environment.
Works Cited
Chipperfield, M.P. ‘‘Mid-latitude Ozone Depletion’’. Stratospheric Ozone Depletion and Climate Change. Ed. Rolf Muller. London: Royal Society of Chemistry, 2012. 169-189. Print.
Dessler, Andrew. Chemistry and Physics of Stratospheric Ozone, San Diego, CA: Academic Press, 2000. Print.
Intergovernmental Panel on Climate Change. Safeguarding the Ozone Layer and the Global Climate System: Special Report of the Intergovernmental Panel on Climate Change, Cambridge, England: Cambridge University Press, 2005. Print.
Ozone 2010. Web.