BPIT, Inc. - Optical Transmissometer SootScan™ Model OT21

Optical Transmissometer SootScan™ Model OT21

By: Magee Scientific


It is a simple and robust instrument which measures the Black Carbon content of an aerosol sample collected on a filter, either from  ambient air or from source emissions.


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• 2-Wavelength operation: UV (370nm) & IR (880nm)

• Non-contact, non-destructive, non-contaminating

• Accepts 25, 37 or 47 mm diameter filters

• Analyzes glass fiber, quartz fiber, Teflon filters


MEASUREMENT PRINCIPLE

Measurement of the attenuation of transmitted light due to an aerosol deposit previously collected on the filter.Simultaneous analysis at 370 nm and 880 nm.

 

INTERPRETATION

Light absorption measurement at 880 nm interpreted asBlack Carbon (‘BC’, also called ‘Elemental Carbon – EC’). Measurement at 370 nm designated as ‘UVPM’, interpretedas a ‘Brown Carbon’ (‘BrC’) indicator of aromatic organic compounds such as are found in smoke from biomass burning.

 

DATA FORMAT

Attenuation ( 100 * ln[I0/I] ) in ‘ATN units’ at two wavelengths.

 

SPECIFITY

No other aerosol species absorbs light even 0.001 times as much as Black Carbon in the visible range.

 

INTERCOMPARISON

Light absorption measurements can be converted to BC or EC equivalents.

 

SENSITIVITY

1 ATN unit, equivalent to 0.06 μg/cm² BC on filter. If collected on a 47 mm diameter filter at a 16.7 LPM flow rate for 24 hours, this represents a Limit Of Detection for BC of 0.075 μg/m³.

 

MEASUREMENT RANGE

Maximum loading of 125 ATN units is optimal, equivalent to an average BC concentration of 3.1 μg/m³ collected on a 47 mm diameter filter at 16.7 LPM for 24 hours. At higher ATN values , the linearity may be impaired. The Data Reduction Template suggests other choices of filter collection area, sampling flow rate and sample collection time to permit accurate data over a very wide range of BC concentrations.

 

SAMPLE MEDIUM

Quartz fiber, T60 Teflon coated borosilicate glass fiber, or Teflon membrane filters may be analyzed. For the use of other substrates contact Magee Scientific.

 

SAMPLE ANALYSIS AREA

Accommodates 25 mm, 37 mm, and 47 mm diameter filter media.

 

SAMPLE RETENTION

Analysis is non-destructive, non-contact and non-contaminating. Filters are unaffected for subsequent laboratory analysis.

 

VALIDATION

NIST-traceable neutral density filter kit option available.

 

DATA OUTPUT

Digital data available via rear RS-232 (COM) and USB ports.

 

DISPLAY AND INTERFACE

2-line display screen with keypad.

 

PHYSICAL SPECIFICATIONS:

• Dimensions (HxWxD): 102 x 270 x 274 mm

• Weight: 5.5 kg

• Electrical Power supply: 100-230VAC, 50/60Hz (auto-switching)

• Temperature: 0-40 °C