The Magee Scientific Aethalometer® measures the "black" or "elemental"
carbon components of aerosols in ambient air, indoor and occupational environments.
This species is a tracer for combination emissions and is a major component
of PM2.5 in urban areas. The instrument is self-contained, and is designed
for automatic, unattended monitoring in environments ranging from urban
settings to remote locations. No consumables are required other than a
roll of tape that usually lasts more than a year.
The Aethalometer is based on two decades of experience in the measurement
of optically absorbing aerosols, with hundreds of predecessor units installed
worldwide. Numerous independent field studies have validated its calibration
against standard chemical analysis.
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Rackmounted Model |
Portable Model |
Special Options Upon Request
- Mass Flow Controller
- High Flow Options: 0-20 SLPM, 0-50 SLPM
- High Capacity Pump
- Memory Card
- Weather Proof Enclosure
- Data Output Options: 4-20 ma. RS422/485, Memory card substituted for floppy
disk.
AE1 Series Specifications
Sample Flow Rate:
2-6 SLPM, user adjustable, 0-10 SLPM mass flow meter standard
Analysis Time Base:
2 seconds - 1 hour
Pump:
Internal diaphragm pump
Optoelectronics:
Analysis at 880 nm, 22 bit A/D
Temperature stabilization:
Electronics board
Display:
4 line LCD panel with keyboard and status indicator lamps.
Processor:
Embedded 386 - class computer, program and operating parameters
stored in EPROM.
Dimensions:
19" rack mount, 10.5" H, 12.5" D, 20 Ibs
Power Requirements:
110 VAC, 60 HZ, 100W (100 & 220-240 VAC available)
Data Output:
3.5" floppy disk, RS232 COM port, analog outputs
Principle
The Magee Scientific Aethalometer collects the aerosol on a quartz fibre tape,
and measures the optical absorption continuously while the aerosol spot
accumulates. Since "elemental" or "black" carbon is the dominant optically
absorbing species in the atmosphere, the spot blackness maybe equated to
a mass of according to calibration performed by intercomparisons with standard
chemical analysis techniques. The rate of increase of optical absorption
is due to the mass of BC collected per time base period, user selected
from 15 seconds to 1 hour, combined with the air flow rate measured by
the mass flow meter. Sample collection proceeds on a 1 cm2 spot
until a threshold optical density is reached, at which time the tape automatically
advances. The optical measurement is ratiometric and no external calibration
materials are required: filter tape is the only material used. The instrument
runs automatically from power-up, recovers from outages and presents data
directly as BC concentration in micrograms per cubic meter.
Analytical Performance
The Aethalometer can detect an increment of less than 1 nanogram
of BC on the filter. At a flow rate of 4 SLPM and a time base of ten minutes,
this corresponds to a resolution of 0.025 ug/m3, to be compared with typical
urban BC concentrations of 5 to 25 ug/m3. Time base and air flow rate may
be varied by the user to optimize sensitivity versus tape use, with temporal
resolution selectable from 1 hour down to 2 seconds.
Filtration Medium
Quartz fibre tape, supplied in 15 meter rolls. At full flow, one roll is
sufficient for two to three months of unattended operation in urban environments,
several years at remote locations. The "Tape Saver" features can be selected
from the menu to reduce tape consumption by up to a factor of 10.
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