Chemical composition of tropospheric aerosols

Modern bulk analysis methods make possible non-destructive chemical identification, which means that the sample remains intact after the analysis. Such a procedure is provided by electron microprobe or X-ray fluorescence analyses, in which the sample is irradiated by electron beams or X-rays and the elemental composition is determined on the basis of induced characteristic X-ray emissions. These methods have been successfully employed to study both stratospheric (Junge, 1963) and tropospheric (Gillette and Blifford, 1971) aerosol particles. Neutron activation analysis is also widely used to identify the chemical composition of atmospheric particulate matter (e.g. Duceef ai, 1966 Rahn etal., 1971) this is also a non-destructive procedure. 

The chemical composition of aerosol particles in the troposphere results from the interaction of many formation and dynamic (e.g. coagulation) processes. For this reason particles are often composed of several materials and the composition varies... 

Chemical composition of aerosol particles in the upper troposphere over the Philippine Islands on November 19, 1969, from the aircraft measurements of... 

In the last subsection the relation between short-wave radiative transfer and tropospheric composition changes has been presented. The aim of this subsection is to discuss the interaction between infrared radiation emitted by the Earth s surface and variations in the chemical composition of the troposphere. Since the influence of aerosol particles on infrared radiative transfer is not clear and is sometimes neglected,4 this paragraph is devoted to the effects of the carbon dioxide increase, which seems to be a very important environmental factor. 

Because a great variety of sources contribute materials to the tropospheric aerosol, it represents a complex mixture of marry substances that additionally depends on the size of the particles. Source characteristics are preserved only in the vicinity of somces. The mixtirre may be divided into three fractiorts water-solirble inorganic salts (electrolytes), water-irrsoluble minerals, and organic compoimds, both soluble in water and insoluble. Table II shows the chemical composition of two boimdary layer aerosols that are typical of marine and of rural continental air. 

Lee, C., Kim, Y.J., Tanimoto, H., Bobrowski, N., Platt, U., Mori, T., Yamamoto, K., Hong, C.S. High CIO and ozone depletion observed in the plume of Sakurajima volcano, Japan. Geophys. Res. Lett. 32, L21809 (2005). doi 10.1029/2005GL023785 Lehrer, E., Wagenbach, D., Platt, U. Aerosol chemical composition during tropospheric ozone depletion at Ny Alesund/Svalbard. Tellus B 49,486-495 (1997)... 

Atmospheric particles in the troposphere are composed of a complex mixture of highly water-soluble inorganic salts, insoluble mineral dust, and carbonaceous material (which includes organic compounds plus elemental carbon) (Jacobson et al., 2000). Studies in which the chemical composition has been determined as a function of particle size demonstrate a correlation between the chemical composition and the size mode of atmospheric aerosols (Meszaros et al., 1997 Krivacsy and Molnar, 1998 Alves et al.,2000 Maenhaut et al.,2002 Smolik et al., 2003 Samara andVoutsa, 2005). 

The observational program included getting information about the content and properties of atmospheric aerosol and most substantial optically active MGCs (03, CO, NOx, S02, etc.), but concentrated on aerosol studies to retrieve data on direct and indirect aerosol RF (ARF). The most interesting (and in many respects unexpected) results were connected with detection of a thick aerosol layer in the troposphere (an important feature of aerosol chemical composition consisted in the presence of a considerable black carbon component) and distinct manifestations of the long-range transport of both aerosol and MGCs. 

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