Methane emission of the Amsterdam urban area

Within the Dutch National Research Programme on Climate Change, the emission of methane from urban areas was considered to be one of the uncertain sources in the national methane budget. Amsterdam was chosen to be a representative urban area for methane emission assessment. An emission inventory was made and concentration fields were calculated using the Danish OML model. Calculated concentration values were compared to concentrations measured continuously at a site near Amsterdam and corrected for background concentrations, The methane emission of the Amsterdam area is low. Main sources are traffic emissions (1.3 ktons y(-1)) and the gas distribution network (0.44 ktons y(-1)). The background corrected outdoor concentrations are a factor of twenty higher than the calculated outdoor concentrations. The most probable sources for this discrepancy are uncertainty in background concentration and the choice of the roughness length in modelling.