Regular monitoring of CO2 anthropogenic emissions by megacities of our planet is very important since large cities contribute up to ~70 % of total anthropogenic CO2 emissions on Earth. In the work, the possibilities of quantitative assessment of Saint Petersburg anthropogenic contribution to CO2 emissions are studied by the analysis of spectroscopic measurements in Peterhof by stationary IR Furrier-spectrometer Bruker 125HR in 2018-2019. Analysis of the measurements of CO2 content during different wind directions has demonstrated that the Saint Petersburg anthropogenic contribution constituted 1.5-5.3 ppm in terms of average mixing ratio in dry atmosphere. The estimates obtained fit well with independent and highly accurate data on anthropogenic contribution calculated in the framework of EMME campaign in March-April 2019. To implement regular measurements of CO2 total content in Peterhof in some practical applications for emission estimates, the accuracy of the anthropogenic contribution estimation has to be increased significantly. This can be achieved due to additional differential measurements of CO2 total content using a stationary instrument and mobile Furrier-spectrometer Bruker EM27/SUN.