SOOTSCAN™ MODEL OT21 OPTICAL TRANSMISSOMETER
SOOTSCAN™ MODEL OT21
The SootScan™ Model OT21 Optical Transmissometer benchtop analyzer is a simple and robust instrument that measures the Black Carbon content of an aerosol sample collected on a filter, either from ambient air or from source emissions.
The SootScan™ Model OT21 Optical Transmissometer can analyze aerosol samples quickly and easily in the field or the laboratory to determine optical attenuation and BC / BrC mass results. The analysis is performed at two wavelengths (880 nm, definitive for “Black” Carbon; and 370 nm, where enhanced optical absorption may indicate the presence of “Brown” Carbon aerosol derived from biomass combustion.)
The analysis is non-contact, non-contaminating, and non-destructive. It may therefore be performed before other laboratory techniques are applied to the sample. The analysis method requires no support gases or consumables. A neutral density photometric standard kit is available for verifying instrument calibration and validating the instrument response.
The SootScan™ Model OT21 Optical Transmissometer bench top analyzer has been developed as a simple and robust way of measuring the Black Carbon content of particulate matter (PM) collected on sample filters. The analysis can be easily performed in the field or the laboratory and provides optical attenuation and BC mass results in only a few seconds. The analysis is non-contact, non-contaminating, and non-destructive. It may therefore be performed before other laboratory techniques are applied to the sample. It requires no support gases or consumables. A neutral density photometric standard kit is available for verifying instrument calibration and validating the instrument response.
Since the method does not alter, contaminate or destroy the sample during analysis, the OT21 can be used to quickly determine BC from samples collected specifically for US EPA PM-2.5 Federal Reference Method (FRM), Method 5 / 201A stationary source, and mobile source compliance determination.
Importantly, because Black Carbon is a non-volatile component of particulate matter, the analysis can be performed not only on freshly collected samples, but also on historically archived filters in order to detect long-term trends.
The instrument contains a 2 wavelength light source: 880 nm providing the quantitative measurement of Black Carbon PM and a 370 nm for qualitative assessment of certain aromatic organic compounds, often described as ‘Brown Carbon’ and usually associated with biomass combustion emissions.
This 2-wavelength data provides additional information which is important for determining:
- source apportionment of ambient PM samples (i.e., wood smoke vs. diesel PM) or
- the mechanical status of an internal combustion engine (i.e., black smoke = poor combustion efficiency, fuel system needs adjustment; blue smoke = mechanical wear, oil entering combustion chamber).
The instrument is supplied with sample holders which accept 15, 25, 37, or 47mm diameter filters comprised of Teflon, quartz fiber, glass fiber, or Teflon-coated glass fiber media. Punches may be taken of samples collected on large-size filters (e.g.. 8 x 10″ high volume filter or 70mm or larger source sample filter).