Tracing atmospheric carbon: applications to climate change studies and related methodological issues

Human activities have disrupted the natural carbon cycle and led to the accumulation of pollutants, altering the Earth’s radiative balance and contributing to global warming. Therefore, tracers and precise methods are required to monitor these changes. This thesis combines empirical studies and experimental approaches to enhance our understanding of the impact of human activities on the global carbon cycle, focusing on both gaseous and particulate carbon in the atmosphere.Key tracers for assessing these impacts include carbon isotopes (12C, 13C, and 14C) and atmospheric oxygen (O₂). These tracers help to identify and quantify carbon sources and sinks, such as fossil fuels, oceans, and the terrestrial biosphere.This thesis addresses methodological challenges such as the interference of N₂O in isotopic measurements of CO₂ using isotope ratio mass spectrometry (IRMS). A method is proposed to correct for N₂O interference, thereby improving measurement accuracy.The study also analyzed data from sampling stations in Ireland and the Netherlands, revealing trends and seasonal variations in CO₂ and O₂.Finally, it focuses on carbonaceous aerosols, which affect climate and health. A case study in Naples, Italy used 14C isotopic analysis to distinguish between fossil and non-fossil carbon sources in urban air pollution.By integrating experimental results with case studies, this thesis enhances our understanding of human impacts on the carbon cycle and provides steppingstones for further research.