Estimation of 14CO2 amount in the atmosphere

Carbon from fossil CO2 emissions, without a significant presence of C-14, causes dilution of C-14 in the carbon isotopic mixture (Suess effect). Reported C-14 activities are usually connected to radiocarbon amount in the carbon isotopic mixture. Our paper is aimed on estimation of C-14/(CO2)-C-14 amount in the atmosphere (and its trend), utilizing calculation of a C-14 activity concentration. A parameter connected only with a C-14 quantity in the volume or mass unit of air is not influenced by a fossil carbon amount. Such a "robust" parameter can be influenced only by processes connected with C-14 emissions/depositions.