HUMAN ACTIVITY RECORDED IN CARBON ISOTOPIC COMPOSITION OF ATMOSPHERIC CO2 IN GLIWICE URBAN AREA AND SURROUNDINGS (SOUTHERN POLAND) IN THE YEARS 2011-2013

In this paper, a record of the C-14 and C-13 isotope content of atmospheric CO2 for Gliwice is presented for samples collected on a weekly basis in the years 2011-2013. In addition, measurements were performed on the early and late wood from the annual rings of pine trees from five sites located 3-6 km from the atmospheric CO2 sampling point. The concentration of C-14 in CO2 samples from the air was much lower relative to the concentration of this isotope in "clean air," indicating a pronounce Suess effect, with a mean Delta C-14 lower by ca. 60%0 than Jungfraujoch data when the 15% of the highest differences are excluded, which leads to the FFCO2 estimate of 5.8%. In winter, the main source of fossil CO2 was fuel combustion, as confirmed by significant correlations with air pollutants. In the vegetation seasons, the Delta C-14 was highly variable due to biogenic influence and more variable winds. The isotopic results were also affected by an additional significant CO2 source for the Gliwice air, which was a closed mine shaft. The Delta C-14 and delta C-13 in tree rings did not record a strong Suess effect in the years 2008-2013 in woodland areas around Gliwice city.