Abstract: The mixing ratio of carbon dioxide CO₂ from the CAMS database is compared with in situ and remote measurements carried out at Peterhof in 2018 (St. Petersburg, Russia). The analysis shows strong annual variations in the difference in the surface CO₂ concentration from CAMS and measurements, and in the correlation coefficients. Ground-based and satellite spectroscopic measurements of the column-averaged CO₂ mixing ratio are in a good agreement with CAMS, which shows the possibility of using CAMS data to solve the inverse problems of estimating anthropogenic emissions for the territory of St. Petersburg and its suburbs.