. Compendium of meteorology. Meteorology. ATMOSPHERIC POLLUTION 1141 numerical parameter with an average value of and a range from a minimum of for low turbulence to a maximum of for very turbulent air flow. Bosanquet and Pearson also give a formula for the ground-level concentration xo during a brief interval of time due to a continuous point source, in the form Xo = Q y/2Trpqux , exp -A vx y 2<fx- (2) where y is the distance crosswind from the axis of the smoke cloud, g is a second numerical parameter with an average value of , and the other symbols are as defined for e
. Compendium of meteorology. Meteorology. ATMOSPHERIC POLLUTION 1141 numerical parameter with an average value of and a range from a minimum of for low turbulence to a maximum of for very turbulent air flow. Bosanquet and Pearson also give a formula for the ground-level concentration xo during a brief interval of time due to a continuous point source, in the form Xo = Q y/2Trpqux , exp -A vx y 2<fx- (2) where y is the distance crosswind from the axis of the smoke cloud, g is a second numerical parameter with an average value of , and the other symbols are as defined for equation (1). In 1947, Sutton [84] extended his treatment to cover elevated point sources and assigned values to the various parameters involved. The general expression derived is X = Q exp {-y^/Clx' ") + exp (3) â iz + hf/Clx'-'']], where z is distance upward; Cy and C, are virtual diffusion coefficients for the crosswind and vertical directions, respectively; w is a numerical parameter whose value, lying between 0 and 1, is related to the diffusing power of the turbulence; and the other sym- bols are as given above. With z = 0, (3) gives the concentration at the surface as 2Q 1 vl + ^l pi "â " pi and its maximum as Xm 2Q eTTulv (I)' (4) (5) which occurs at a distance Xm from the source, given by .Tâ = {hyclY'''~''K (6) The parameter n, obtained by fitting the theoretical profile u = wis""'""' to the observed change of wind speed with height, has the value }.^ under average conditions of lapse rate, with a range from 14, for a large inversion to I/5 for a large lapse. For average con- ditions, Sutton gives values of Cy varying from for a source at the surface to for one at 100 m and values of Cz from to for the same range of heights of sources; for sources at 25 m and higher the values of C,, and C: are the same. For inversions the coefficients are smaller; for large lapse rates they are greater. The values of the numeri
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