Abstract: Severe pollutant concentrations, such as pollutants release by forest fires, have the (theoretical) potential to provoke a greenhouse effect resulting in an increase of the average global temperature of the planet. Lately, the rain forests in Africa, Asia and in the Amazon Region have been plagued by intense forest fires, many caused by expanding human occupations in these areas. A joint research project, between the Rio Scientific Center (IBM Brasil) and the Associated Laboratory for Computing and Applied Mathematics (LAC/INPE), is currently underway aiming at, among other topics, the study of the formation and dispersion of pollutants resulting from human provoked forest fires in the Amazon Region. In this paper a matrix approach is used to integrate the diffusion equation that governs CO_2 dispersion in the atmosphere. The method is based in the decomposition of the diffusion operator in one-dimensional components, one for each direction. The three-dimensional reconstruction is later obtained by using the Kronecker matrix product.