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Compact Real-Time Monitor for Particle-Bound
Polycyclic Aromatic Hydrocarbons (PAH)
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Detects particle-bound Polycyclic Aromatic
Hydrocarbons on ultrafine particulate matter in real-time
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Lightweight, compact and ruggedized
construction
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Battery powered with onboard data storage
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Applications related to personal exposure in
various environments (homes, workplace, automobiles, tunnels etc.)
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Companion product to the DC
2000CE --- the DC 2000CE measures ALL particulate matter, the PAS 2000CE
measures PAH (primarily on carbonaeous matter)
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The Photoelectric Aerosol Sensor (PAS) works on the principle of
photoionization of particle-bound PAH.
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Using an Excimer lamp the aerosol flow is
exposed to UV radiation. The Excimer lamp offers a high intensity, narrow
band source of UV radiation. The wavelength of the light is chosen such that
only the PAH coated aerosols are ionized, while gas molecules and non-carbon
aerosols remain neutral.
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The aerosol particles which have PAH
molecules adsorbed on the surface emit electrons which are subsequently
removed when an electric field is applied.
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The remaining positively charged particles
are collected on a filter inside an electrometer, where the charge is
measured. The resulting electric current establishes a signal which is
proportional to the concentration of total particle- bound PAH. Also by
operating the Excimer lamp in a chopped mode, the PAS 2000 can eliminate the
back-ground signal which is sometimes found very close to combustion
sources.
The analyzer signal is a measure of total PAH adsorbed on carbon
particles and does not speciate the sample.
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Source-specific calibration curves are available or can be
generated where the monitor output is compared to an analytically determined PAH
concentration. A site-specific calibration curve can provide greater accuracy
for the particle size, charge and PAH distribution specific to the source. In
addition to the site-specific curves, an approximate universal calibration curve
can be used for screening and real-time trending applications.
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Display
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16
characters with 2 lines LED
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Power
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115
volts AC / 60 Hz & 220
volts AC / 50 HzMax.
Battery
15 volts Lithium Metal Hydride
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Range
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0
to 1000 ng / m3
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Sensitivity
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~
10 ng / m3 (actual calibration is site-specific)
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Lower
Threshold
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~
10 ng / m3 total particle-bound PAH
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Response
time
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<
10 seconds (adjustable)
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Digital
Output
Analog
Output
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RS
- 232 (for data download and program upload)
0
to 10 volts
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Sample
gas
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Built-in
pump with flowrate controlled at 1 L/min
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Operating
temp
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40
to 104 ºF (5 to 40ºC)
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Dimensions
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Height
x Width x Depth = 3in x 7in x 5in ( 68mm x 175mm x 124mm )
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Weight
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3
lb. ( 1.5 kg )
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Data
Storage
Data
Download
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8000
data points (each
data point consisting of : Time, Value )
User-friendly
PC-compatible graphical software used for downloading the collected data.
Flat ASCII file output can also be generated for further analysis (e.g.
Microsoft Excel format).
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