There is the problem in determining the background of urban area in estimation of the contribution of large enterprises in the air pollution. In this study, a statistical approach was used to evaluate the anthropogenic geochemical background using the method of moss-biomonitors. The concentrations of elements from natural origins effect large remote sources and many surface sources (e.g., dust, traffic, mini-boilers), can be described as normal or lognormal distribution. In this case, the mean ± 2 standard deviation can be used for anthropogenic geochemical background for the calculation of this area. This method was applied in an urban area (Tomsk, Russia) for the epiphytic moss Pylaisia polyanth, which has a high accumulating capacity. The moss was collected in 2011 and was taken from the bark of poplars at a height of 1.5 … 2 meters above the ground. The concentrations of 21 chemical elements were determined by neutron activation analysis at the research reactor of the Tomsk Polytechnic University (Russia.) The hypothesis of normal distribution was tested with the χ2 criterion. All the chemical elements except cobalt ranges of concentrations were determined using normal or lognormal distribution. Calcium concentrations had a bimodal distribution. Calculated anthropogenic background concentrations were compared to natural concentrations obtained from the moss collected in remote areas from settlements (more than 100 km away.) Natural concentrations of chemical elements were either below or within the range of the mean value ± 2σ. The effect of region’s power station leads to the exceedance of up to 8 times more in concentrations of Ce, Eu, Fe, Yb and up to 10 times of Br, Cs over anthropogenic the background.