Hygroscopicity and cloud droplet activation of mineral dust aerosol
Article first published online: 17 APR 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 8, April 2009
How to Cite
2009), Hygroscopicity and cloud droplet activation of mineral dust aerosol, Geophys. Res. Lett., 36, L08805, doi:10.1029/2009GL037348., , , , , and (
- Issue published online: 17 APR 2009
- Article first published online: 17 APR 2009
- Manuscript Accepted: 20 MAR 2009
- Manuscript Received: 16 JAN 2009
- mineral dust;
- cloud condensation nuclei
 Hygroscopicity and cloud condensation nucleus (CCN) activity were measured for three mineral dust samples: one from the Canary Islands, representing North African dust transported across the Atlantic; one from outside Cairo, representing North African dust transported to the eastern Mediterranean; and Arizona Test Dust, representing dust in the southwestern United States. To reaerosolize bulk samples, dust samples were either suspended in high purity water and particles generated by atomization, or samples were resuspended in dry air using a fluidized bed. Only the Canary Island sample generated from aqueous suspension showed appreciable hygroscopic growth at subsaturated conditions; all other samples exhibited diameter growth factors of less than 1.1 for relative humidities ≤90%. Despite their low hygroscopicities at subsaturated conditions, all samples activated as cloud droplets at supersaturations lower than required for insoluble particles. We suggest that the CCN activity of these mineral dusts are well-represented using the hygroscopicity parameter 0.01 ≤ κ ≤ 0.08.