During cruise No. 32 of RV ''Meteor'', 6.Nov.-6.Dec. 1973 across the Atlantic at 15¿N, samples of Aitken nuclei were taken and the chemical composition determined by an X-ray fluorescence technique. The samples consisted mainly of sulfur with concentration of 0.2 &mgr;g/m3 in pure Atlantic air and about double this value in air influenced by the Sahara. The concentrations of the elements chlorine, calcium and potassium were about one order of magnitude lower and suggest the absence of sea salt in the Aitken particle range. The elements vanadium, selenium and bromineray were just below the positive detection limits but seemed to be present, since all values were higher than the blank values but within the error limits. The results show that in clean air conditions the dynamics of the Aitken particles are closely related to the sulfur cycle.