The density of humic acids and humic like substances (HULIS) from fresh and aged wood burning and pollution aerosol particles E. Dinar1, T. F. Mentel2, and Y. Rudich1 1Department of Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel 2Institute for Tropospheric Chemistry, Research Center Jülich, Jülich, Germany
Abstract. Atmospheric aerosols play significant roles in climatic related phenomena.
Size, density and shape of particles affect their fluid-dynamic parameters
which in turn dictate their transport and lifecycle. Moreover, density and
shape are also related to particles' optical properties, influencing their
regional and global radiative effects. In the present study we have measured
and compared the effective 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
effective density was measured by comparing the electro mobility and vacuum
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
effective density of these important environmental macromolecules. It is
suggested that atmospheric aging processes increase the effective density of
HULIS due to oxidation, while packing due to the aromatic moieties plays
important role in determining the density of the aquatic HS substances.
Citation: Dinar, E., Mentel, T. F., and Rudich, Y.: The density of humic acids and humic like substances (HULIS) from fresh and aged wood burning and pollution aerosol particles, Atmos. Chem. Phys., 6, 5213-5224, doi:10.5194/acp-6-5213-2006, 2006.