A research program including a comparison between short term and long term emissions of MSW landfill started in 2006. The goal of that program was to access the human health chronic risk of three different waste disposal processes (anaerobic with/without leachate recirculation, with/without aerobic pretreatment) and to provide new criteria for the disposal site. A methodological approach using both calibration of the short term fluxes by in situ measurements and the prediction of long term fluxes by the use of exponential decreasing functions was explored. The identification of contaminant species was made by qualitative and quantitative concentration measurements done in a first stage on the landfill gas, and the collection of chemical leachate load measurements. At this stage of the study, the work did not show specific chemical contaminant species for the different waste disposal.