d13 C of organic atmospheric dust deposited in Wrocław (SW Poland): critical remarks on the passive method

Abstract

This paper reports the results of the application of passive collectors to the collection of solid organic atmospheric particles (SOAP) in Wrocław (SW Poland) to carry out stable carbon isotope analyses. d¹³ C (SOAP) values collected during the vegetation-free period, from November to March, vary in a narrow range from -24.5 to -27.8. We show that d¹³ C (SOAP) is able to provide information about atmospheric pollution with respect to different emission sources. d¹³ C (SOAP) values collected during the period of vegetation growth, from April to October, show a wide range from -20.5 to -26.9. The most probable explanations for the 13 C-enriched values in summer are that: (i) the SOAP have been contaminated with fresh and decomposed organic matter in the passive collector and/or (ii) SOAP are derived from outside the city or from outside Poland (C4 plant particles). Therefore, the d¹³ C (SOAP) may not represent a strictly anthropogenic impact. The passive collector method for the (SOAP) collection should be applied only in areas with dry deposition of atmospheric dust where deposited organic matter is not decomposed in the water contained in collectors. We recommend the use of active sampling methods (hi-volume sampler) to collect SOAP useful for carbon isotope analyses.