Analysis of the Influence of Sources on the Spatial Variation in Atmospheric Methane Concentrations in the City of Tandil, Argentina

Abstract There is an overall trend in urban methane (CH4) emissions due to the presence of several sources; however, differences exist between cities, and therefore further local research should be undertaken. The present study analyzes the spatiotemporal variation in atmospheric CH4 concentrations during a year at ten sampling sites in the urban core of a medium-sized city. The mean annual atmospheric CH4 concentrations varied between 2.02 ppm and 5.45 ppm; the maximum concentrations were found in a site close to a wastewater treatment plant (WWTP), presenting a significant increase toward the summer. In the rest of the sites, the maximum concentrations were recorded in the coldest months due to the influence of combustion sources dependent on natural gas (NG). An exploratory regression analysis was performed, in which the variables “homes connected to the gas network” and “distance from compressed NG stations” each explained 66 and 65% of the spatial variation of the atmospheric CH4 concentrations at the 9 sites (excluding that one nearest the WWTP). The results show the need to prevent NG leaks in all urban areas to reduce the emissions of this potent greenhouse gas, which, at the same time, will provide economic benefits for the sectors involved.