Abstract: Pollutant dispersion problem in the atmosphere is knowly a hard issue. In some practical situations, it is important to have available a tool capable of identifying the pollutant source emission strength on the basis of measured concentrations only. Therefore, the goal here is to identify the strength of pollutant sources punctual and source/sink of area. A Langrangian particle model, based on the Langevin equation, is used to simulate the forward problem, while the inverse problem is formulated as an optimization problem. The optimizer methods employed are deterministic and stochastic approaches. The stochastic method find good inverse solution.