Institut für Physik der AtmosphäreAtmosphärische Aerosole

Deutsches Zentrum für Luft- und Raumfahrt e.V. German Aerospace Center

The Multi-Angle Absorption Photometer for theDetermination of Black Carbon in Ambient Aerosol

CARUSSO

A. Petzold 1 , M. Schönlinner 2 , H.Kramer 2 and H. Schloesser 2

1 Institut für Physik der Atmosphäre,    Deutsches Zentrum für Luft- und Raumfahrt Oberpfaffenhofen, 82234 Wessling, Germany

2 ESM Andersen Instruments, Frauenauracher Str. 96, 91056 Erlangen, Germany

Institut für Physik der AtmosphäreAtmosphärische Aerosole

Deutsches Zentrum für Luft- und Raumfahrt e.V. German Aerospace Center

Determination of the black carbon (BC)

content in ambient aerosol by means of

an extinction measurement on filter-

deposited aerosol samples.

Measurement of transmitted and reflected

radiation in angular-resolved mode.

Reduction of measurement uncertainties,

which are related to multiple scattering of

radiation by aerosol particles and

between the aerosol layer and the filter

substrate, by applying a radiative transfer

scheme to the data analysis.

The Multi-Angle Absorption Photometer for theDetermination of Black Carbon in Ambient Aerosol

1

Optical sensor head

Institut für Physik der AtmosphäreAtmosphärische Aerosole

Deutsches Zentrum für Luft- und Raumfahrt e.V. German Aerospace Center

The aerosol is deposited in the top layer of a fiber filter matrix, which is

termed as aerosol-filter layer.

A two-stream approximation is applied to calculate the radiative

properties of the aerosol-filter layer from the radiative transfer equation.

Required input values are the measured filter transmittance trans and

reflectance ref.

The algorithm determines

optical thickness of the aerosol-filter layer L

single-scattering albedo of the aerosol-filter layer 0

Derived properties are

aerosol-filter layer absorbance ABS = 100 L ( 1 - 0 )

BC mass loading of the filter ABS = ABS S BC

Data Analysis Algorithm

Institut für Physik der AtmosphäreAtmosphärische Aerosole

Deutsches Zentrum für Luft- und Raumfahrt e.V. German Aerospace Center

The instrument is set up as a filter tape device.

time resolution 2 minsampling volume 0.5 - 1 m 3 h -1

detection limit (1 m3 h -1, 2 min) 10 -6 m -1 100 ng m -3

Instrument Capabilities

Institut für Physik der AtmosphäreAtmosphärische Aerosole

Deutsches Zentrum für Luft- und Raumfahrt e.V. German Aerospace Center

Design of the Multi Angle Absorption Photometer - CARUSSO