The density of humic acids and humic like substances (HULIS) from fresh and aged wood burning and pollution aerosol particles

E. Dinar (1) , T. F. Mentel (2) , Y. Rudich (1)

1 Department of Environmental Sciences
2 Institute for Tropospheric Chemistry

Atmospheric aerosols play significant roles in climatic related phenomena. The density and shape of particles dominates their fluid-dynamic parameters which in turn dictate their transport and lifecycle. Moreover, density and shape are also related to the particles optical properties, influencing their regional and global radiative effects. In the present study we have measured and compared the densities of humic like substances (HULIS) extracted from smoke and pollution aerosol particles to those of molecular weight-fractionated aquatic and terrestrial Humic Substances (HS). The density was measured by comparing the mobility and aerodynamic diameter of aerosol particles composed of these compounds. Characterization of chemical parameters such as molecular weight, aromaticity and elemental composition allow us to test how they affect the density of these important environmental macromolecules. It is found that atmospheric aging processes increase the density of HULIS due to the oxidation, while packing due to the aromatic moieties plays important role in determining the density of the aquatic HS substances.

Domaines: Océan, Atmosphère

E. Dinar, T. F. Mentel, Y. Rudich. The density of humic acids and humic like substances (HULIS) from fresh and aged wood burning and pollution aerosol particles. Atmospheric Chemistry and Physics Discussions, 2006, 6 (4), pp.7835-7867. ⟨hal-00302064⟩