The components of the Arctic aerosol

Atmospheric aerosol samples have been collected through a year at five locations in Greenland. The samples have been analyzed by PIXE to determine the elemental composition of the Arctic aerosol. The results for one of the stations are described in detail and related to those obtained at the other sites. Annual and monthly geometric means of the concentrations in the aerosol of the elements Al, Si, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Sr and Pb are reported. The results have been subjected to factor analyses, which show that the Arctic aerosol can be considered to be composed of at most five different components, the characteristics of which are described. The components consist of three different anthropogenic and a crustal component and, in addition, a sea salt component at sites exposed to open seas within mesoscale distances. Possible origins of the various components are discussed in view of the seasonal variations of the factor estimates, their statistical independence, and their relation to a selection of synoptic situations. It is concluded that the high Arctic troposphere in winter constitutes a well mixed aerosol reservoir which in most cases masks the origins in distant source areas.