A theoretical treatment is developed for the deposition and transport of an aerosol in a multicompartment system in which there exists a pressure-induced gas flow. Based on a solution of the relevant gas equations, the aerosol equation is first formulated and then solved numerically by both discretization and moments techniques. The former method is more accurate, but the complex nature of the problem means that the computing time required can be prohibitive, especially when the number of compartments is large. The moments technique, based on a gamma or lognormal distribution, requires substantially less computing time, and to estimate its accuracy, a validation comparison has been made with the discretization method. The technique was then applied to two multicompartment accident situations. Results show that the moments method based on the gamma distribution is significantly more accurate than the lognormal-based one and is also in close agreement with the results from the AEROSIM code.