The contribution of C, N and S, as well as the isotopic composition of C and N of atmospheric pollutants, are assumed to be reflected in the organic compounds inbuilt into the lichen thallus. The chemical and isotopic analyses were carried out on lichen Hypogymnia physodes samples gathered from Picea abies and Larix decidua, collected in 13 sampling points located in Karkonoski National Park and its closest vicinity in 2011. The results for %C, %N and %S varied from 43.44 to 46.79%, from 0.86 to 1.85% and from 0.07 to 0.27 %, respectively. The δ13C values ranged from −26.6 to −24.6‰, whereas δ15N values varied from −13.0 to −6.8‰. The ranges in isotope composition suggest different sources of C and N for Karpacz compared to the remaining sampling sites. For Karpacz, the δ13C values suggest (in case the fractionation product-substrate does not exist and Δ=0) that the dominant sources are coal combustion processes, whereas for remaining sampling points, the δ13C values are ambiguous and are masked by many mixed natural and anthropogenic processes. With the same assumption that Δ=0, the δ15N values suggest that transport is not a dominant source of nitrogen within Karpacz city. Moreover, in this study we tested the possible fractionation (Δ) for carbon and nitrogen, assuming that within the investigated area, the source of carbon is probably CO2 and/or DIC (HCO3
−) dissolved in precipitation, while the source of nitrogen is NOx and/or NO3
− ion. The calculated fractionation factors were: (i) for gaseous carbon compounds ΔCO2-Corg value from −13.4 to −11.4‰, whereas for the ions form ΔHCO3−-Corg value from −16.6 to −14.6‰, (ii) for nitrogen gaseous compounds ΔNOx-Norg value between apx. −17 and −5‰, whereas for the ions form ΔNO3−-Norg value between −9.9 and −3.7‰.