Abstract: In studies of atmospheric diffusion,K-theory is very important. However,there hasn't been any generally accepted method to relate the turbulent diffusivityK to detectable meteorological,parameters,and space and time coordinates. Starting from the equations of pulsating fluxes of pollutants turbulence derived by C. P. Donaldson using the second order closure,we get a complete expression formfor the relationship between the gradients of mean concentration and the fluxes. Comparing it with K-theory,we obtain the turbulent diffusion coefficient.