A measurement method has been developed and applied in order to measure and help to minimize the impacts of landfills on the atmosphere and to reduce greenhouse gases emissions. The studied method is the accumulation chamber, which resulted suitable for the quantification of non collected emissions of landfill gas (LFG). The measure campaigns have been carried out with different size of the sampling grid. These measurements have been performed in order to evaluate the sensitivity with respect to these parameters and consequently to understand the reliability of the accumulation chamber method. The accumulation chamber method supplies useful information also for the application of atmospheric pollutants dispersion models properly calibrated and validated in reference to specific case studies. The integrated application of these different tools allows the evaluation of the impacts on air quality in the surroundings of a landfill.