Measurement of Light Absorption and Elemental Carbon in Atmospheric Aerosol Samples from Remote Locations
A new double beam, single detector integrating sphere photometer has been developed for light measurements on aerosol samples. The light measurements are completely digital (photon counting), controlled by a desk computer. The resolution of the digital photometer is such that it can detect a 10−5 difference between the sample and the reference signals. Taking a typical background aerosol sample (105 m length of air column swept by the filter), this results in a detection limit of 10−10 m−1 for the light absorption coefficient of the aerosol particles. This sensitivity is sufficient for the detection of elemental carbon in size segregated samples at ground level background locations or in stratospheric air.
the conventional absorption coefficient.
the pure light absorption of the particles independent of the filter they are sampled on and independent of their scattering properties.
The first results from size segregated aerosol samples inArctic haze on Spitsbergen show light absorption coefficients similar to those measured in Northern Alaska. The dominating part of the elemental carbon in Artic haze is located in particles smaller than 0.1 µm radius.
KeywordsAerosol Particle Elemental Carbon Soot Particle Light Absorption Coefficient Aerosol Sample
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