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The Aethalometer :

Real-Time Measurement of Aerosol Black Carbon ('BC' or 'EC')

The Aethalometer is an instrument that uses a continuous filtration and optical transmission technique to measure the concentration of BC in near-real-time. This technique was developed in the late 1970's by Dr. Tony Hansen, who founded Magee Scientific Company in 1986 to manufacture the instrument and promote its use in a wide range of research applications. More than a hundred instruments were distributed in the first few years, primarily to research laboratories and research stations at remote locations.
 
 

The Aethalometer is fully automatic and completely self-contained.  It is constructed in a standard 19-inch enclosed chassis and includes the filtration and analysis chamber with automatically-advancing quartz fiber tape; the sample aspiration pump and air mass flow meter or controller (typical flowrates are 2 to 6 LPM); and temperature-stabilized optics and electronics.  The instrument is operated by an embedded computer with display screen and keypad that controls all instrument functions and records the data to built-in 3.5" floppy diskette.  There is a COM-port digital data stream output and an analog voltage terminal that can be programmed either to represent the measured concentration or to function as an on/off threshold alarm.

The Aethalometer operates automatically upon power-up and can be left unattended for long periods of time.  Power consumption is approximately 100 W at either 115 or 230 VAC.  Weight is approximately 35 lbs. (15 kg.) and dimensions are 19" rack width, 11" (26 cm.) height and 12" (30 cm.) depth.
 

There are presently 3 models of Aethalometer (see 'Model Series') that differ only in terms of the optical analysis wavelengths: all are identical in terms of mechanical, electrical and aerosol handling features.  These models were previously designated by Magee Scientific as the AE-1x series ('BC only'), the AE-2x series ('UV + BC'), and the AE-3x series ('7-wavelength Spectrum').

Worldwide distribution of all models of the Aethalometer is now handled exclusively by Andersen Instruments Inc.   See the Sales link for contact information.  The Andersen designation for the various models is as follows:
    Andersen RTAA-800     =  Magee Scientific AE-16   ("Classic" BC-only)
    Andersen RTAA-900     =  Magee Scientific AE-20   (" UV + BC ")
    Andersen RTAA-1000 =  Magee Scientific AE-30   (" Spectrum ")

Applications

In the indoor environment, the Aethalometer can be used to monitor the infiltration and trapping of emissions in a building as well as the production and circulation of internal emissions. (The 'classic' example is that of a building whose air intake is next to the truck unloading dock). The Model AE2x series Aethalometer (Andersen RTAA-900) was specially designed to respond to UV-absorbing filterable material, which is found to include components present in tobacco smoke.

In urban locations, the Aethalometer monitors combustion-derived particulates when high concentrations due to traffic and other emissions may threaten public health. The Model AE1x series Aethalometer (Andersen RTAA-800) is ideally suited for automatic, unattended monitoring operation. Its rapid response allows data to be collected on a (typical) 3- or 5-minute timebase, providing immediate identification of source strength and dispersion patterns.  The speciation of inhalable aerosol particulates (PM2.5) in real time is a current topic of considerable interest to the US EPA and governmental air quality management organizations in U.S. states. A standard for allowable BC concentrations has been legislated by the German Government, and instruments are being installed across Germany with matching interest in other European countries.

At remote sites, the presence of BC in the atmosphere is an indicator of the long-range distribution of combustion-derived pollution. The high sensitivity of the Model AE1x series Aethalometer (Andersen RTAA-800) allows valid data to be acquired on a 1-hour timebase even in the cleanest atmospheres. Aethalometers have been installed in the Arctic, on remote islands and wind-swept ocean coasts, on the periphery of the Antarctic and even at the South Pole.

Aethalometer Model Series

The 'classic' Aethalometer (AE1x series, Andersen RTAA-800) measures BC ("Elemental Carbon") using optical absorption at 880 nm. Aerosol Black Carbon is the only commonly-found species that has a strong absorption: the absorption is quantitative and the instrument's response can be calibrated as a mass concentration of BC.
 

The 'dual channel' AE2x series (Andersen RTAA-900) combines this measurement with a simultaneous measurement of optical absorption at 350 nm in the near ultraviolet. Many aromatic organic species have strong absorbance at this wavelength, and the UV channel responds very strongly to species such as those present in tobacco smoke, fresh diesel exhaust, etc.
 

The 'Spectrum' AE3x series (Andersen RTAA-1000) performs the measurement simultaneously at 7 wavelengths from 350 nm (UV) to 950 nm (near IR). This instrument is used for studies of atmospheric optical properties, radiative transfer, etc. Deviations from uniformity of absorption can yield information about aerosol size and composition.
 

For more information on the 'standard' Aethalometer, click here

For more information on the full line of Aethalometers, click here

Aethalometer Sales Information

    Andersen RTAA-800     =  Magee Scientific AE-16   ("Classic" BC-only)
    Andersen RTAA-900     =  Magee Scientific AE-20   (" UV + BC ")
    Andersen RTAA-1000 =  Magee Scientific AE-30   (" Spectrum ")

Delivery of new units is usually less than 4 weeks from order date.
Please contact Andersen at 1-(800) 241-6898:  is reponsible for U.S. sales, for international sales.

Examples and Illustrations of Aethalometer Data

Aethalometer 24-hour Data Chart Template

Click here to download a convenient utility charting program written in Microsoft Excel.  This template accepts data pasted in from the instrument's "BCmmddyy.CSV" data file, smooths it (if desired), and produces a standardized chart on a 24-hour axis.  The chart can be printed out full-page size, or saved as a GIF file for posting as a web page or for compact e-mail transmission.

Aethalometer Documentation

For the Aethalometer full manual, including discussion of Aerosol Black Carbon, theory of operation, description of measurement principle, etc:

Responses to Frequently Asked Questions

Click here to go to a page of correspondence in response to users' Frequently Asked Questions.

'Quick-Start Guide' for operating the Aethalometer

Click here to go to a page of simplified instructions designed to help you get an Aethalometer operating as quickly as possible.

Aethalometer Software Upgrade

Click here to download the compressed software upgrade file: Version 065 (approx. 290 Kbyte)

Click here for the text file containing installation instructions (approx. 2 Kbyte)

Aethalometer Software Recovery

Click here for the text file with Original Program Disk re-load instructions (approx. 3 kb)

The "Original Program Disk" is shipped with the instrument. If for any reason it is missing or damaged, it may be re-created by downloading a 'ZIP'-compressed file, expanding it and using its components to re-create a bootable disk. You will need a blank diskette, formatted to 1.44 Mb capacity.

Click here for the text file with "Create OPD" instructions (approx. 5 kb)

After reading the "Create OPD" instructions, click here to download the compressed file (approx. 390 kb)

Aerosol Science Journal Article References

The first of these compared the Aethalometer with the thermal-optical analysis of filter samples collected in parallel. (see figures presented in the 'Examples' page). The reference is:

The second of these compared Aethalometer data with that from a photoacoustic spectrometer operating at two different wavelengths. The reference is:

Extensive historical reference lists were compiled by William Grant of NASA Langley in early 1993. Please acknowledge him if you use the material.

Click here for W. Grant tropospheric aerosol references (RTF text format, approx. 520 Kbyte)

Click here for W. Grant biomass burning aerosol references (RTF text format, approx. 24 Kbyte)
 
 

Magee Scientific Co. maintains a set of references that pertain to Aerosol Black Carbon. Copies may be requested from our office.

Click here for the list of Magee Scientific aerosol black carbon references (RTF text format, approx. 12 Kbyte)
 
 

Dr. L. A. Gundel of the Lawrence Berkeley National Laboratory has worked in the area of organic aerosols.

Click here for a list of references that pertain to the determination of aerosol elemental carbon (RTF text format, approx. 6 Kbyte)
 

If you work in this field, or if you know of references that are relevant, we would like to add these to a "User's List".
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To The South Pole

To follow Tony to the South Pole and back, click here.

For Further Information about the Aethalometer