One-year spatial and temporal monitoring of concentration and carbon isotopic composition of atmospheric CO2 in a Wroclaw (SW Poland) city area

The main aim of this study was to assess the natural and anthropogenic contributions of CO2 in the urban atmosphere of Wroclaw City (SW Poland) using combined quantitative (CO2 concentrations) and qualitative analysis (delta C-13 of CO2). Between 21 January 2011 and 22 December 2011, 17 sampling campaigns were performed at 3-week intervals and in total 255 samples were collected. The mean CO2 concentration was 469 +/- 71 ppm and the mean delta C-13(CO2) was -10.8 +/- 1 parts per thousand. The measured delta C-13(CO2) values of major end-members for two winter heating seasons (-25.7 parts per thousand in January-March of 2011 and -27.6 parts per thousand in October-December of 2011) and for one vegetative season (-20.4 parts per thousand in April-September of 2011) suggest soil respiration as a main source of atmospheric CO2 during the vegetative season, and a very significant impact of fossil fuel combustion during the winter heating seasons. There were significant increases of CO2 concentrations at many sampling locations after the opening of a new motorway on 31 August 2011. The authors hypothesise that the new motorway contributes to the increase of CO2 across the city. (C) 2013 Elsevier Ltd. All rights reserved.