Effect of rain on removal of a gaseous pollutant and two different particulate matters from the atmosphere of a city

A nonlinear five-dimensional mathematical model is proposed and analyzed to study the removal of a gaseous pollutant and two different particulate matters by rain from the atmosphere of a city. The atmosphere, during rain, is assumed to consist of five interacting phases namely, the raindrops phase, the gaseous pollutant phase, its absorbed phase and the phases of two different particulate matters, one being formed by the gaseous pollutant. We assume that the gaseous pollutant is removed from the atmosphere by the processes of absorption while the two particulate matters are removed only by the process of impaction with different removal rates. By analyzing the model, it is shown that under appropriate conditions, these pollutants can be removed from the atmosphere and their equilibrium levels, remaining in the atmosphere, would depend mainly upon the rates of emission of pollutants, growth rate of raindrops, the rate of raindrops falling on the ground, etc. It is found that if the rates of conversion of gaseous pollutant into the particulate matter and rainfall are very large, then the gaseous pollutants would be removed completely from the atmosphere.

[1]  S. Schwartz,et al.  In-cloud and below-cloud scavenging of Nitric acid vapor , 1982 .

[2]  Trevor D. Davies,et al.  Precipitation scavenging of sulphur dioxide in an industrial area , 1976 .

[3]  R. J. Engelmann.  THE CALCULATION OF PRECIPITATION SCAVENGING , 1965 .

[4]  J. Hales.  Fundamentals of the theory of gas scavenging by rain , 1972 .

[5]  J. B. Shukla,et al.  Modelling the depletion and conservation of forestry resources: effects of population and pollution , 1997 .

[6]  J. Pandey,et al.  Air pollutant concentrations in Varanasi, India , 1992 .

[7]  T. Y. Chang.  Rain and snow scavenging of HNO3 vapor in the atmosphere , 1984 .

[8]  B. Fisher.  The transport and removal of sulphur dioxide in a rain system , 1982 .

[9]  Wei Hsin Chen.  Atmospheric ammonia scavenging mechanisms around a liquid droplet in convective flow , 2004 .

[10]  B. Dubey,et al.  MODELING EFFECTS OF PRIMARY AND SECONDARY TOXICANTS ON RENEWABLE RESOURCES , 2003 .

[11]  S. Schwartz,et al.  Precipitation scavenging and atmosphere-surface exchange , 1992 .

[12]  Mihalis Lazaridis,et al.  Spatial Distribution of Gaseous And Particulate Matter Emissions in Greece , 2004 .

[13]  J. B. Shukla,et al.  EXISTENCE AND SURVIVAL OF TWO COMPETING SPECIES IN A POLLUTED ENVIRONMENT: A MATHEMATICAL MODEL , 2001 .

[14]  K. Moore.  Drop size-dependent chemical composition in clouds and fogs , 2004 .

[15]  Sudarshan Kumar.  An Eulerian model for scavenging of pollutants by raindrops , 1985 .

[16]  P. Rao,et al.  Measurements of wet and dry deposition at an urban location in India , 1992 .

[17]  R. Naresh.  Qualitative Analysis of a Nonlinear Model for Removal of Air Pollutants , 2003 .

[18]  J. Seinfeld,et al.  On the interaction between equilibration processes and wet or dry deposition , 1990 .

[19]  V. Sharma,et al.  Atmospheric pollution studies at Kanpur—suspended particulate matter , 1983 .

[20]  P. S. Prakasa Rao,et al.  Studies of Wet Deposition and Dustfall at Pune, India , 2001 .

[21]  Suman Mor,et al.  Variation in Spatial Pattern of Criteria Air Pollutants Before and During Initial Rain of Monsoon , 2003, Environmental monitoring and assessment.

[22]  Christer Johansson,et al.  Particulate matter in the underground of Stockholm , 2002 .

[23]  R. Naresh,et al.  Modeling the removal of gaseous pollutants and particulate matters from the atmosphere of a city , 2007 .

[24]  M. Hannigan,et al.  Drop size-dependent chemical composition of clouds and fogs. Part II: Relevance to interpreting the aerosol/trace gas/fog system , 2004 .

[25]  Joseph W.-H. So,et al.  Global stability and persistence of simple food chains , 1985 .