Aerosols from far northwestern China have been investigated to characterize sulfur in relation to other elements in a northern hemisphere temperate latitude continental location remote form anthropogenic air pollution SO 2 sources. The importance of sulfur associated with soil-derived particles relative to any independently-occurring airborne sulfate was emphasized in the study. The first can result either from chemical and biological processes in uppermost soil layers during precipitation and evaporation or by attachment of gaseous sulfur species to suspended dust. The second, at least in polluted regions, can result from heterogeneous or homogeneous-atmospheric chemical reactions. The study was based on continuous time sequence aerosol sampling on 0.4 μm Nuclepore filter in a linear streaker and elemental analysis of 4-h steps by PIXE. Samples were collected August 8-22. 1980, in Xinjiang at Tianchi, a mountain lake resort near Urumqi high in the Bogda Shan of the Tian Shan Range situated above the semiarid Dzungarian plain that extends to the north. Statistical relationships in the set of 86 sequential measurements of 12 elements were found by absolute factor analysis, stepwise regression analysis, and Fourier analysis of time series. The study provides a test of alternative statistical methods for obtaining atmospheric process information from PIXE analysis data. Three distinct aerosol components could be distinguished. Two of these explained 95-99% of the variance of Mg. Al, Si, S, Cl, K, Ca, Ti. and Fc and 85% of Mn and P, indicating both the coherence of soil-related elements and a strong association of both S and Cl with them. Some S was also present as a constant background unrelated to concentration variations of dust. Zn, measured with less analytical accuracy than other elements, was not as well accounted for by these components. Of special interest is the presence of two distinct dust types, both of which were enriched in sulfur, chlorine, and phosphorus relative to average earth crust composition. The type with highest S, Cl, and P enrichments was also depleted in Fe, Mn, and Ti relative to average earth crust. It exhibited concentration maxima every 10-15 h and may be formed locally by dispersion of soil during turbulent wind conditions. The other type, which varied diurnally, may represent average aerosol over the Dzungarian plain that is transported by day during upslope northerly flow. The average measured sulfur concentration, as well as that calculated to be present in each of its three components, was higher than has been reported for southern hemisphere continental atmospheres. High concentrations of S, Cl, and P and their associations with crustal elements are consistent with an enrichment in soils before dust suspension by chemical or biological processes in soils under semiarid conditions. The scavenging of reactive gases by suspended particles may contribute as well, though to a limited degree, in this remote area. Since depostion and resuspension of dust over arid lands is considerable, a large flux of aerosol S and Cl exchange across the Xinjiang air-soil interface is implied.