This is absolutely new for me

Please give examples

And how would you know the mass absorption coefficient without measurements

more information about Mie theory and applications are available on the following paper: Aerosol light absorption and its measurement : Areview.

H. Moosmuller et al. / Journal of Quantitative Spectroscopy & Radiative Transfer 110(2009)844–878.

I know that publication very well!

Tell us how can we know how the Black Carbon is aggregated

Is it in separate particles

Is it mixed with non-absorbing material and where is it

In the core at the surface

I've never taken those questions into consideration !!!

I focus on the BC concentration calculation results from an optical measurement, using either Aethalometer or Multi-wavelength Absorption Black Carbon Instrument.

So, I need the mass absorption coefficient for that purpose, and I choose the assumptions that the black carbon particles on the filter are spherical in shape and are distributed in the same plane.

I suggest you read more publications

because black carbon is NOT a single sphere

it is only a small fraction of the aerosol typically 5% - 10% imbedded in organics and ammonium sulphate/nitrate

Great discussion, thank you.

Could we get the mass absorption coefficient characteristic of our case study with only an optical measurement (neither thermal nor chemical methods were used) ?

In Northern Morocco, the black carbon fraction of the aerosol is almost 60% and typically embedded in PM2.5.

60%?

Not even in diesel emissions

Mie theory assumes that particles are perfect spheres (balls). BC is far from that. But there is Matlab code if you want to play with Mie equations.

BC is embedded in organic carbon and in the atmosphere coated with secondary aerosol. This material can act as a lens thus increasing the light-absorption

abstract Mie calculations based on a single sphere gives just an estimate of the absorption

The aethalometer has another problem. There is internal reflection in the filter so that the absorption is much higher than the calculated value. And there is a loading effect: the attenuation does not increase linearly with the loading and this has to be corrected. There is literature on this correction

These problems are the reason that the MAAP is used in the network in the Netherlands