Analysis of Mixing Ratios of Greenhouse Carbon-Containing Gases at the Atmospheric Monitoring Station of St. Petersburg State University

In order to study temporal variations in the mixing ratios of greenhouse carbon-containing gases and factors influencing them, local measurements of CO₂, CH₄ (January 2013–January 2020), and CO (January 2013–January 2019) mixing ratios in atmospheric air at the monitoring station of St. Petersburg State University are analyzed taking into account trends and seasonal fluctuations. Linear trends for CO₂, CH₄, and CO, which are 2.42 ppm/year (0.60%), 8.6 ppb/year (0.49%), and −3.8 ppb/year (−2.2%), respectively, are in a good agreement with independent estimates of both global/background changes and changes in urban areas. The analysis of the CO/CO₂ emission ratio confirmed that motor vehicles are the dominant anthropogenic source affecting the composition of atmospheric air near the monitoring station of St. Petersburg State University. The results can be used for validation of atmospheric models and independent estimation of greenhouse gas fluxes.