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

[摘要] Atmospheric aerosols play significant roles in climatic related phenomena.Size, density and shape of particles affect their fluid-dynamic parameterswhich in turn dictate their transport and lifecycle. Moreover, density andshape are also related to particles' optical properties, influencing theirregional and global radiative effects. In the present study we have measuredand compared the effective densities of humic like substances (HULIS)extracted from smoke and pollution aerosol particles to those of molecularweight-fractionated aquatic and terrestrial Humic Substances (HS). Theeffective density was measured by comparing the electro mobility and vacuumaerodynamic 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 theeffective density of these important environmental macromolecules. It issuggested that atmospheric aging processes increase the effective density ofHULIS due to oxidation, while packing due to the aromatic moieties playsimportant role in determining the density of the aquatic HS substances.

[学科分类] 大气科学