Carbon dioxide, methane, and carbon monoxide are the carbon cycle gases, the data on their emissions are needed when monitoring air pollution and developing methods for reducing anthropogenic emissions to the atmosphere and for climate forecasting. The estimates of nocturnal area fluxes for CO ₂, CH ₄, and CO presented for a suburb of Saint Petersburg (Peterhof) are obtained using the box model and continuous observations of concentration of these gases. The mean values of CH ₄, CO ₂, and CO fluxes estimated for Peterhof for 2014–2015 are 44 ± 27, 6100 ± 4000, and 90 ± 100 t/(km ² year), respectively. The intensity of the CO area flux has pronounced seasonal variations characterized by the maximum of ~(160 ± 120) t/(km ² year) in November—February and by the minimum of ~(30 ± 20) t/(km ² year) in June-July. The analysis of the ratio of CO/CO ₂ fluxes identified the main types of anthropogenic sources typical of Peterhof: motor transport, natural gas combustion, and the use of wood stoves for the heating of private low-rise buildings (in the cold season).