Recent progress in understanding physical and chemical properties of African and Asian mineral dust

摘要

This paper presents a review of recently acquired knowledge on thephysico-chemical properties of mineral dust from Africa and Asia based ondata presented and discussed during the Third International Dust Workshop,held in Leipzig (Germany) in September 2008.Various regional field experiments have been conducted in the last fewyears, mostly close to source regions or after short-range transport.Although significant progress has been made in characterising the regionalvariability of dust properties close to source regions, in particular themineralogy of iron and the description of particle shape and mixing state,difficulties remain in estimating the range of variability of thoseproperties within one given source region. As consequence, the impact ofthese parameters on aerosol properties like optical properties, solubility,hygroscopicity, etc. – determining the dust impact on climate – is onlypartly understood. Long-term datasets in remote regions such as the dustsource regions remain a major desideratum.Future work should also focus on the evolution of dust properties duringtransport. In particular, the prediction of the mineral dust sizedistribution at emission and their evolution during transport should beconsidered as a high-priority.From the methodological point of view, a critical assessment andstandardisation of the experimental and analytical techniques is highlyrecommended. Techniques to characterize the internal state of mixing of dustparticles, particularly with organic material, should be further developed.