As part of the 7 Southeast Asian Studies Program, an intensive operations period was performed in the northern South China Sea to understand regional aerosol chemical, microphysical and transport phenomenology. Centered around the remote Taiwanese Dongsha Island (aka Pratas Island), comprehensive measurements were made of atmospheric properties. In this paper, we present XRF elemental data from an 8 stage Davis Rotating Drum impactor (DRUM) operating from 30 March-9 May, 2010, at the sea-level Dongsha monitoring site. Size-resolved chemical composition data with three-hour temporal resolution were obtained for elements Mg and heavier. The results of a principal components analysis of the DRUM data showed the variable influence of several aerosol types, including dust, sea salt, and pollution aerosols, that were consistent with satellite imagery and other information on dust storms and biomass burning in the region. Backtrajectories from the HYSPLIT model were computed for each of the factors and agreed with expected origins for specific periods of the study. Finally, aerosol types and AOD variations seen in AERONET data and predicted by the operational Navy Aerosol Analysis and Prediction System (NAAPS) model also supported our interpretation of the DRUM data.