Carbon aerosol light absorption

Filter substrates were chosen that were suited for subsequent determinations of aerosol mass, total carbon, elemental carbon, trace metals and aerosol light absorption coefficient The three filter assemblies contained, a 47 mm Pallflex Tissuquartz filter (2500 QAO), a 47 mm Nuclepore polycarbonate filter (0.40 ym pore size) and a 13 mm Pallflex Tissuquartz filter (2500 QAO). 

An upper limit to the absorption efficiency of the elemental carbon particles sampled can be obtained if it is assumed that all aerosol light absorption is due to elemental carbon. In that case the specific absorption from the slope of the line in Figure 5 is about 11.9 0.9 m g. That value is higher than would be... 

Huffman, H. D., Comparison of the Light Absorption Coefficient and Carbon Measures for Remote Aerosols An Independent Analysis of Data from the Improve Network—I, Atmos. Environ., 30, 73-83 (1996). 

Clarke, A. D., Weiss, R. E., and Charlson, R. J. (1984) Elemental carbon aerosols in the urban, rural and remote-marine troposphere and in the stratosphere. Interferences from light absorption data and consequences regarding radiative transfer, Sci. Total Environ., 36, 97-102. 

Those oxides with wide band gaps, such as y-Al203, MgO, etc., are also known to be efficient photocatalysts for the oxidation of ammonia, nitrogen oxides, and hydrocarbons [23-26]. When evaluating the possible role of these most abundant components of continental aerosols in the tropospheric photochemistry, their importance may be due to their photoactivity under irradiation not only in their main absorption bands, but also in the bands of surface chemisorbed species. For example, for dispersed Sn02, it was found that surface carbonates were formed upon CO2 adsorption, which in turn sensitized some surface photoreactions to light quanta with energies less than 2eV (below 600 nm) [27]. 

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