The article presents the measurements results of the concentration and fluxes of carbon dioxide in the air of the Belgorod agglomeration, carried out by the eddy covariance method at the carbon polygon of the Belgorod National Research University in 2023. The measurements were made on a tower 48.6 m high, at two levels: 10 m and 48 m using LI-COR stations, based on a closed-type infrared gas analyzer (model LI-7200RSF). The first level characterizes the carbon balance of atmospheric air on the territory of the botanical garden of the Belgorod National Research University, the second level – the air of the entire city. Data are presented as monthly averages, with variation assessed. Maximum concentrations and fluxes were recorded in the autumn. Carbon dioxide absorption was maximum in May and June, but it compensated for emissions only at the level of tree crowns. In the remaining months, emissions prevailed. In the green areas of the city, emission reaches 2.7 µmol/m2 s, and absorption 1.4 µmol/m2 s. In general, for the city, the emission of carbon dioxide can reach 6.1 µmol/m2•s, on average for the year 3.5 µmol/m2•s. Green spaces in the city are not able to completely compensate for CO2 emissions, but they can reduce them by more than 2 times in nature-like ecosystems, such as the botanical garden of the Belgorod National Research University.