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Updated: May 27, 2026
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Split Point Analysis and Uncertainty Quantification of Thermal-Optical Organic/Elemental Carbon Measurements
Published on: September 7, 2019
Validating a nondestructive optical method for apportioning colored particulate matter into black carbon and
Beizhan Yan1, Daniel Kennedy, Rachel L Miller
1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York.
Atmospheric Environment (Oxford, England : 1994)
|November 30, 2011
Summary
This study refines optical methods for measuring black carbon (BC) and second-hand smoke (SHS) in air samples. The improved technique accurately quantifies BC and SHS, enhancing air quality assessment.
Area of Science:
- Environmental Science
- Analytical Chemistry
- Atmospheric Science
Background:
- Black carbon (BC) exposure is linked to adverse health effects, necessitating accurate measurement methods.
- Existing optical methods for BC estimation often misattribute absorption from other colored particulate matter (PM).
- Previous methods for distinguishing BC from second-hand smoke (SHS) lacked validation and optimization for complex samples.
Purpose of the Study:
- To refine and validate an optical reflectance method for quantifying black carbon (BC) and second-hand smoke (SHS).
- To characterize the spectral absorption of various PM components, including iron oxides and ammonium sulfate.
- To assess the accuracy and reliability of the refined method compared to established techniques.
Main Methods:
- A lab-modified integrating sphere was used for continuous absorption measurements from 350 nm to 1000 nm.
- The absorption spectra of ammonium sulfate, hematite, goethite, and magnetite were characterized on PM(2.5) filters.
- Synthesized data and environmental samples were used to optimize wavelengths and validate the method against Aethalometer, Smoke-stain Reflectometer (SSR), and EC measurements.
Main Results:
- Optimizing wavelength selection significantly reduced computational errors in apportionment models from over 10% to less than 2%.
- The refined method accurately estimated airborne BC and SHS levels but was less sensitive to iron oxides and sulfate mass loadings.
- Measurements showed high reproducibility for duplicate NYC samples (R(2) = 0.95) and strong correlation with EC (R(2) = 0.7).
Conclusions:
- The validated optical method effectively quantifies black carbon (BC) from archived Teflon filters.
- The technique shows promise for providing additional information on airborne particulate matter components.
- This improved method enhances the assessment of BC and SHS exposure and their associated health risks.
