The first objective of this study was to discuss the applicability of the

ratio method in order to assess

oxidation efficiency. To achieve this objective, a comparison between

ratios and the mass balance method was conducted. The second objective of this study was to estimate the

oxidation efficiency in an interim landfill soil cover and assess how a

influx influences the

oxidation efficiency. The results showed that despite the

problems brought by respiration, the

oxidation efficiencies obtained by the

ratio method led to similar results compared to the mass balance method. In this respect, the

ratio method can be an indicator of the

oxidation efficiencies for landfill cover soils. The

oxidation efficiencies derived in this study through the

ratio method ranged between 46% and 64%, and between 41% and 62% through the mass balance method. The results imply that the Intergovernmental Panel on Climate Change's (IPCC) default value of 10% for the

oxidation efficiency is an underestimation for landfill cover soils.

oxidation efficiency tends to be negatively correlated with

influx. Therefore,

influx reaching a landfill cover should be limited in order to increase the

oxidation efficiency.