A New Method for Measuring Aerosol Absorption

Abstract

A new technique has recently been developed to measure aerosol absorption by means of a microdensitometer. Black particulate material is collected into six spots on membrane filters by a laboratory-tested impaction{sol}concentration technique. Follow-up analysis of the collected specimens enables us to determine the physical and chemical characteristics of the aerosol. The optical absorption coefficient of the well-characterized aerosol material can be determined in a matter of minutes by a rapid light extinction method using the microdensitometer. Further analysis of size, shape, and elemental composition can be obtained by SEM{sol}EDXA (scanning electron microcopy with energy-dispersive x-ray analysis). This technique is well suited for urban aerosol measurements. In the Arctic and Antarctic, this technique may prove most beneficial, where highly sensitive techniques are needed to measure the soot component of the aerosol on a time scale comparable to the variation of meteorological events.