CHARACTERIZATION OF INDIVIDUAL FINE-FRACTION PARTICLES FROM THE ARCTIC AEROSOL AT SPITSBERGEN, MAY-JUNE 1987

Aerosol particles collected in May and June 1987 at Ny Alesund, Spitsbergen, have been analysed with an automated electron microprobe for chemistry and size. Chemical data from about 30,000 individual particles in the fine fraction (0.1 to approximately 2.0-mu-m in average diameter) were subjected to nonhierarchical cluster analysis, resulting in the definition of over 30 distinct particle types. Principal component analysis of the 22 most abundant types indicates the presence of 11 components that account for most of the variance in the aerosol composition. Some of the particle types were associated with the end of an episode of polluted air from northern Eurasia during the first few days of sampling. The remaining types do not have any clear association with air masses from industrial areas, although a number are metal-bearing (with Cr, Fe, Ni, Cu, Zn, As or Pb) and probably of anthropogenic origin. After the end of the initial episode of polluted air, the sampling period probably represented "normal" conditions for late spring in the Arctic. Silicate particle types of probable crustal origin were the dominant group by volume through most of the period. Also important were particles of probable marine origin. However, marine particles have been so extensively modified by fractionation and reaction that the combined marine aerosol components bear little resemblance to sea salt. The individual-particle data clearly demonstrate the complexity of the aerosol at this remote Arctic site and the presence of crustal and anthropogenic pollutants during an "unpolluted" period.