Abstract
Here we present the bulk and size resolved mass concentrations of dust, nitrate, non-sea salt sulfate, and oxalate that corresponds to the manuscript “African dust transported to Barbados in the wintertime lacks indicators of chemical aging”
The chemical processing (“aging”) of mineral dust is thought to increase dust light scattering efficiency, cloud droplet activation, and nutrient solubility. However, the extent of African dust aging during long-range transport to the western Atlantic is poorly understood. Here, we explore African dust aging in wintertime samples collected from Barbados when dust is transported at lower altitudes. Ion chromatography (IC) analysis indicates that the mass concentrations of bulk nitrate, sulfate, and oxalate increase, relative to background conditions, when African dust reaches Barbados after transatlantic transport, indicating dust aging. However, aerosol mixing state analysis from computer-controlled scanning electron microscopy with energy dispersive x-ray spectroscopy (CCSEM/EDX) indicates that approximately 67% of dust particles are internally mixed with sea salt, while only about 26% of dust particles contain no internally mixed components. SEM/EDX elemental mapping and time-of-flight secondary ion mass spectrometry (TOF-SIMS) reveals that within internally mixed dust and sea salt particles, only sea salt components contain signs of aging as indicated by the loss of chloride and acquisition of nitrate and/or sulfate.
This data is associated with the article: Royer, H.M., Sheridan, M.T., Elliott, H.E., Blades, E., Lata, N.N., Cheng, Z., China, S., Zhu, Z., Ault, A.P, Gaston, C.J. African dust transported to Barbados in the wintertime lacks indicators of chemical aging.