Denjean C. auteur aut IRD Caquineau Sandrine auteur aut IRD Desboeufs K. auteur aut IRD Laurent B. auteur aut IRD Maille M. auteur aut IRD Rosado M. Q. auteur aut IRD Vallejo P. auteur aut IRD Mayol-Bracero O. L. auteur aut IRD Formenti P. auteur aut IRD text journalArticle eng text/pdf reformatted digital access We present the first direct evidence that the hygroscopic properties of super micron (>1 mu m) African dust particles did not change despite undergoing long-range transport across the Atlantic toward the Caribbean. Concurrent measurements of chemical composition show that most of mineral dust was chemically unprocessed and externally mixed. A minor portion of mineral dust was internally mixed with sulfate and chloride (similar to 13-24% by number) or aggregated with sea-salt particles (similar to 3-6%). Only dust particles aggregated with sea salt showed significant hygroscopic growth above 75% relative humidity (RH), resulting in a decrease in extinction mass efficiency by up to a factor 2.2. All other dust particles did not take up significant amounts of water when exposed to up to 94% RH. These results demonstrate that the direct radiative effect of African dust in this region remained independent of RH and an external mixing state could be considered for evaluating the climate effects of dust. specialized mineral dust long-range transport hygroscopicity optical properties particle shape mixing state CARAIBE PORTO RICO ATLANTIQUE MAURITANIE SAHARA ALGERIE 032 064 42 18 7835-7843 2015 0094-8276 https://www.documentation.ird.fr/hor/fdi:010065402 10.1002/2015gl065693 0094-8276 [F B010065402] https://www.documentation.ird.fr/hor/fdi:010065402 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers16-11/010065402.pdf IRD - Base Horizon / Pleins textes 2015-12-04 2021-10-17 fdi:010065402 fre