Measurements of the composition of aerosol partitioned into two size fractions, fine (particle aerodynamic equivalent diameter, dp≤2.5&mgr;m) and coarse (2.56000 km. So-called pristine marine air from the central Indian Ocean is shown to contain aged and recirculated Si that could only have been derived from land areas after transport over long distances. The nature of the aerosols measured on Mount Kenya depends critically on regional patterns of aerosol transport. Interregional transfers seem to be a feature of the transport climatology. Likewise, interhemispheric transport across the equator in east Africa is observed. ¿ 2001 American Geophysical Union