Atmospheric concentrations of carbon dioxide and its isotopic composition in Krakow (Southern Poland) based on one-year CoCO2 measurement campaign

Regular, monthly based, diurnal measurements of atmospheric carbon dioxide concentration and its carbon isotope composition (¹³C/¹²C and ¹⁴C/¹²C ratios) were performed between 9 February 2021 and 1^st February 2022 in Krakow, the second biggest city of Poland, populated by around 780,000 inhabitants. Spot air samples were collected in 3 l glass flasks every 4 hours from the roof of the building (50°04’ N 19°55’ E 220 AMSL, ∼ 20 m above the surface) during each measurement campaign. A total of 72 air samples were collected during 12 measurement campaigns. The samples were analyzed with Picarro G2101i (Picarro Inc., Santa Clara, California, USA) to determine the carbon dioxide. After that, the samples were analyzed with Isotope-Ratio Mass Spectrometry (IRMS) and Accelerator Mass Spectrometry (AMS) in order to determine δ¹³C and Δ¹⁴C composition. The carbon dioxide concentration during the campaign ranged from 404 ppm (7 September 2021) to 617 ppm (1 February 2022) with the one-year average of 463 ppm. δ¹³C ranged from -14.79 ‰ (1^st February 2022) to -8.5 ‰ (7^th September 2021). The one-year average results of Δ¹⁴C were -35 ‰.

Furthermore, measurement of gas concentration and its isotopic composition, along with the use of the isotope-mass balance, allowed determination of fossil fuel-related and biogenic contributions to the total measured CO₂ load during campaign days, allowing to characterise the diurnal and seasonal variability of those components in the urban environment. Based on the obtained results, a dataset dedicated for the validation of WRF-CHEM high-resolution simulations of the city atmosphere has been prepared.

 

ACKNOWLEDGEMENTS

The presented work was funded by the CoC02 project, which has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 958927 and the "Excellence Initiative - Research University" program at AGH University of Science and Technology.