ABSTRACT
This chapter is concerned with the deposition of the acid components of the increased emissions at large distances from their source. The real plume has an edge at a finite distance, but the plumes of the theories have no edge and fade to zero at infinite distance. The chapter deals with cases in which there is an absence of dilution, or even a mechanism of subsequent concentration of airborne pollution, so that higher concentrations than expected are found at large distances. Fumigation in the present context is the stirring up of the lowest layers of air by convection in the morning sunshine with the result that pollution which only existed in the higher levels is brought down to the ground by the mixing. A particular wind speed may select out a particular size of sand particle for transport along the ground, smaller ones becoming airborne and larger ones remaining scarcely moved.
