aerosol particles in the atmosphere, while ‘c’ refers to a
reference material. Usually, Al, Si or Fe are chosen as reference
elements. In our study, Fe was correlated with elements
generally associated with anthropogenic sources and Si was
below the detection limit. Thus, Al has been used as a reference
element. Due to the lack of data on regional soil composition,
crustal concentrations were obtained from Wedepohl (1995).