Absorption Coefficient of the Vienna Aerosols: Comparison of Two Methods

Abstract

The absorption coefficient of the atmospheric aerosol average 20% light absorption and for the winter aerosol over Vienna has been determined by two independent with an average of 40% light absorption, they agree methods: the integrating plate method and by subtracting almost perfectly. When considering small corrections the light scattering coefficient obtained with an integratowing to truncation in the nephelometer, the light abing nephelometer from the light extinction coefficient sorption measured by the integrating plate is consistently obtained by telephotometer. The raw data are highly too high by 30%-40%. This is in agreement with previcorrelated and, both for the summer aerosol with an ously published results for other locations.

Response to “Comment on Measurement of Aerosol Absorption Coefficient from Teflon Filters Using Integrating Plate and Integrating Sphere Techniques by D. Campbell, S. Copeland, and T. Cahill,” by Antony Clarke, John Ogren & Robert Charlson

“…These measurements allow for such comparisons in all sorts of meterological and aerosol conditions. This same approach has been applied successfully (Horvath and Metzig 1990;Horvath and Habenreich 1989;Horvath 1993) for the original IPM, using Nuclepore filters, with the conclusion that the IPM systematically overestimates b,, by 20-30%, which is consistent with the various laboratory studies cited by Clarke, et al. An intensive evaluation of LIPM, using Teflo filters, was recently done during project MOHAVE , a large EPA sponsored study in which optical measurements and multiple filter samplers were co-located at Meadview, Arizona.…”

A Comprehensive Review on Study Methods of Aerosol Optical Properties in Different Dimensions

“…The extinction coefficient of aerosol is measured using an extinction meter or a far-light photometer, and the light scattering coefficient is measured using an integral turbidimeter. Subsequently, the difference between the two measured results is treated as the absorption coefficient of the aerosol [173,174]. However, for aerosols with low absorption, the difference between the extinction and scattering coefficients is small, requiring both values to be measured with high precision.…”

Deriving the basic cell-reciprocal integrating nephelometer equation and its use for calibration purposes: a comprehensive approach

“…Therefore, whatever volume-scattering coefficient is to be measured, it has to be corrected in order to obtain the true or real value of this coefficient. In doing so, a correction factor f c must be defined as [44,60]…”