Theory Of Operation - MAGEE Scientific Aethalometer AE33 User Manual

Aethalometer
Model AE33

17. THEORY OF OPERATION

The Aethalometer Model AE33 has been developed with input from the research and
monitoring communities, and is designed for reliable operation under all conditions ranging
from state-of-the-art research to compliance monitoring.
The leading innovations incorporated into the Model AE33 include:
1. The DualSpot™ measurement method, which solves the effects common to all filter-
based real-time monitors, in which the instrumental response factor shows a dependence on
the loading of material on the filter.
2. Features for automatic 'dynamic zero' testing under a flow of internally-generated clean
air; 'span' testing of the response of the optical sources and detectors; calibration of the
response of the internal mass flow meters, if an external standard flow calibrator is connected;
and validation of the photometric response by use of a kit of 'Neutral Density' optical filters
whose properties may be traced to reference standards.
3. User and communications interfaces, permitting remote monitoring of operation; data
retrieval; performance of internal tests; and reporting of 'state-of-health' parameters.
4. Modular construction designed for ease of routine maintenance service.
In addition to the above features, the Aethalometer Model AE33 offers real-time aerosol
absorption analysis at up to ten optical wavelengths, with rapid time resolution to 1 second even
in 7-wavelength mode. This permits the measurement of optically-absorbing aerosols – 'Black'
Carbon and 'Brown' Carbon components of particulate matter – in applications including
routine monitoring of ambient air quality for regulatory purposes; measurements of the
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User's manual – Ver. 1.55 July 2017 131/146