Mineralogical and oxygen isotope composition of inorganic dust-fall in Wrocław (SW Poland) urban area – test of a new monitoring tool

We have analysed the mineralogical and oxygen isotope composition of solid inorganic atmospheric particles (SIAP) in Wroclaw (SW Poland) to determine potential natural and anthropogenic sources of deposited dust. The mineralogical compositions of SIAP and local soils are very similar and quite typical. Dust sources were attributed to high emission sources (two large coal-fired power generation plants, i.e., "Wroclaw" and "Czechnica") and low emission sources (mostly small furnaces for home heating). A mullite phase was confirmed in the non-magnetic fraction of high emission dust. The delta O-18 (SIAP) values collected during the study period (from 20th November 2003 to 25th May 2005) vary between 8.6 and 21.8 parts per thousand.. The delta O-18 values of soil gathered nearest to the passive dust collector vary between 9.3 and 16.0 parts per thousand.. The delta O-18 values obtained for hypothetical anthropogenic sources of atmospheric inorganic particles are: (1) 7.4 parts per thousand for low emission and (2) from 13.4 to 16.1 parts per thousand. for high emission dust components. The range of delta O-18 values obtained for SIAP, soil and hypothetical anthropogenic sources do not allow the unambiguous partitioning of anthropogenic particles using isotopic mass balance. However, mineralogical and geochemical evidence suggests that a major source (natural or anthropogenic) of dust deposited in Wroclaw probably lies outside of the city. The predominant south-west wind direction suggests that agricultural areas, quarries, the Sudety Mountains, or industrial centres are possible origins of SIAP in Wroclaw. We also do not exclude hypothetical long-transport processes as a source of dust deposited in Wroclaw.