Ozone is a gas that consists of three oxygen atoms. The ozone gas occurs in both the Earth’s lower atmosphere and the upper atmosphere. At the lower atmosphere, ozone is considered as an air pollutant as it is a main ingredient of the urban smog. It has harmful effects on the animals’ respiratory systems, and burns sensitive crops and plants. In the upper atmosphere, ozone layer is beneficial as it prevents the damaging radiations from reaching the surface of the earth. Ozone therefore shields the Earth from the harmful ultraviolet rays.
Ozone is not directly emitted into the air. At ground-level, ozone is created from a chemical reaction between the oxides of nitrogen and the volatile organic compounds. Such a reaction requires sunlight. The industrial emissions, chemical solvents, motor vehicle exhaust, gasoline vapors, among others, emit nitrogen oxides and volatile organic compounds that react to form ozone. Harmful concentrations of ground-level ozone forms in the presence of hot weather and sunlight.
In the upper atmosphere, ozone is naturally produced; however, human actions gradually destroy it. Some chemicals that are used in fire extinguishers, coolants, pesticides, and solvents, such as hydrochlorofluorocarbons, methyl bromide, methyl chloroform, and carbon tetrachloride among others, destroy the ozone and are referred to as ODS (ozone-depleting substances). When released into the air, these substances move slowly to the upper ozone layer where they are broken down and chlorine and bromine molecules that destroy ozone are released.
Ozone depletion has made scientist look for best possible actions that provide solution to the problem. Some of the actions include the use of alternatives to Chlorofluorocarbons (CFCs) in refrigeration industry. This, however, has not been successful and the research continues. Scientists have come up with non-azeotropic mixture of HFC-23 and HFC-134a to replace HCFC-22 which is a CFC. This has been very successful, as the mixture does not deplete ozone i.e. the ODP of the mixture is zero.
Human must ensure that ozone level is not depleted. The depletion of the ozone can result in increased skin cancer, impaired immune systems, and cataracts. At the same time, crops can be damaged and there can be adverse consequences on human food supply.
In the cities and suburbs, there is great concentration of cars, trucks, various engines, factories, etc. whose exhaust pollutes the air. This worsens the depletion. To address the problem, such pollution should be reduced. Also, the household and garden chemicals should be used wisely.
In an attempt to reduce the production of ozone, various challenges exist. Some of the air pollutants cannot be done away with. The use of cars cannot be reduced, which means that emission will still continue. Industries also continue to operate, emitting the pollutants. Some citizens are not aware of the effects of their actions, which might continue to pollute the air.
As an individual, I shall always minimize the emission of pollutants into the atmosphere. This can be achieved through the use of public transportation, reduction of driving, use of bicycle or walking. It is also important that I use chemicals wisely. I also use the approved refrigerants.
Ground-level Ozone. Retrieved at http://www.epa.gov/air/ozonepollution
Hoigné, J. (1998). Handbook of Environmental Chemistry, Vol. 5 part C. Berlin: Springer-Verlag. pp. 83–141.
National Ambient Air Quality Standards for Ozone AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. Retrieved at http://www.epa.gov/air/ozonepollution/fr/20100119.pdf
United States Environmental Protection Agency (2003). Ozone. Retrieved at http://www.epa.gov/oar/oaqps/gooduphigh/ozone.pdf