Solutions of the two‐dimensional diffusion equations

General solutions of the two dimensional diffusion equation are derived following the work of Sutton and the profiles of Deacon. These solutions apply to (1) diffusion of gases and aerosols from sources infinite in cross‐wind extent located at arbitrary heights and having arbitrary initial distributions; (2) diffusion of particles with non‐zero free fall velocity; and (3) diffusion of gases and aerosols under an atmospheric lid as at the base of an inversion. These solutions are then applied to several types of sources and the down‐wind concentrations are presented in graphical form.