The SootScan™ 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.
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:
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).
Title | Type | Download |
---|---|---|
SootScan OT21 Transmissometer spec sheet A4 | SPEC SHEET | LINK |
Frank (NAMC 2009) Optical Analysis of FRM filters | PRESENTATION | LINK |
Hu (2011) Real-time and filter-based BC measurements for vehicle emissions | POSTER | LINK |
First measurements of aerosol black carbon in a very humid area | PRESENTATION | LINK |
Title | Author | Publication | Year | Link |
---|---|---|---|---|
Filter Light Attenuation as a Surrogate for Elemental Carbon | Judith C. Chow | Journal of the Air & Waste Management Association Volume 60, 2010 - Issue 11 | 2012 | LINK |
Measurement of black carbon (BC) by an optical method and a thermal-optical method: Intercomparison for four sites | TanveerAhmed | Volume 43, Issue 40, December 2009, Pages 6305-6311 | 2009 | LINK |
Gundel (1984) ATN vs BC - SciTotEnv | Gundel | Printed in the Netherlands | 1984 | LINK |
The Neutral Density Optical Kit provides a validation of the reproducibility of the photometric detectors.
The reproducibility of the optical attenuation method employed by the SootScan™ OT21 Optical Transmissometer may be validated by the use of the Neutral Density Optical Kit. This kit consists of Neutral Density optical glass elements with stable optical absorbances referenced back to traceable photometric standards. The kit is used to verify that the optical performance of the instrument is constant with time, relative to its original manufacturing certification.
Magee_Scientific_Sootscan_OT_21_Optical_Analysis_of_Standards_for_Validation_and_Calibration
Additional filter adapter for small area analysis (10 mm center, 14 mm outer diameter).