Atmospheric and Water Quality Essay Example | Topics and Well Written Essays - 2250 words

Atmospheric and Water Quality - Essay ExampleMoreover, it also included the set up of ground reflectiveness on the plume. (Sutton, 1947) The basis for this model and various other models is the Generalized Dispersion equality for A Continuous Point Source Plume. (Beychok, 2005) This equation is Where is the cross wind dispersion parameter stipulation as is the upright dispersion parameter tending(p) as Where is the vertical dispersion with no reflection, is the vertical dispersion for reflection from the ground, is the vertical dispersion for reflection from an inversion aloft and be abandoned as is the concentration of emissions given up in g/m3 at any given receptor that is located at meters downwind of the emission source, meters crosswind from the emission plume centreline and meters above the level of the ground. is the emission rate of the source pollutant given in g/s is the horizontal wind velocity along the plumes centreline given in m/s is the height of the emission plumes centreline above the ground given in m is the vertical standard deviation of the emissions distribution given in m is the horizontal standard deviation of the emissions distribution given in m is the height of the inversion alofts bottom from the ground The equation pledgeed above compensates for upward reflection from ground as well as for downward reflection from the bottom of any inversion lids present within the atmosphere. The exponential terms in g3 converge rapidly and in most circumstances anticipate m as 1, 2 and 3 provide acceptable solutions. as well as are representative functions of atmospheric stability and delineate the turbulence of the ambient atmosphere and of the downwind distance to the particular(prenominal) receptor. Within this arrangement, the most important variables are the degree of atmospheric turbulence and the height of the emission source. in general dispersion is directly related to the turbulence. Q2. a. Describe the natural chemical reac tions by which stratospheric ozone is created and destroyed. 10 marks Ozone is produced in the atmosphere as the photochemical decomposition of oxygen molecules occurs. (Science Fun, 2011) As diatomic oxygen absorbs ultra violet radiation with wavelengths of slight than 240 nm it tends to disintegrate as O2 ? 2O* (reaction 1) The resulting free oxygen atoms combine with more oxygen molecules to generate ozone as below O + O2 ? O3 Another mechanism is when ozone molecules decompose when treated with ultraviolet radiation with a wavelength of less(prenominal) than 290 nm. The reaction is as under O3 ? O2 + O* (reaction 2) b. Explain the link that is believed to exist between pollution and ozone bottom depletion. 10 marks Myriad chemicals released into the air are k instantlyn to react with ozone causing its depletion. The greatest danger stems from chlorofluorocarbons (CFCs) which are disintegrated by the action of ultraviolet light as below CFCl3 + hv ? CFCl2 + Cl* (reaction 1) The activated chlorine atom now reacts with an ozone molecule to give off oxygen and chlorine oxide as under Cl + O3 ? ClO + O2 (reaction 2) The chlorine oxide moreover promotes disintegration of ozone as under ClO + O3 ? Cl* + 2O2 (reaction 3) This reaction tends to persist as reactions 2 and 3 grow and cause further ozone molecules to disintegrate into oxygen molecules. The net reaction for reactions 1, 2 and 3 becomes