AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Design and Characterization of a Multiwavelength Thermal/Optical Carbon Analyzer
XIAOLIANG WANG, Benjamin Sumlin, Sierra Mayorga, Steven Gronstal, L.-W. Antony Chen, Judith Chow, John Watson, Desert Research Institute
Abstract Number: 285 Working Group: Instrumentation and Methods
Abstract A multiwavelength thermal/optical carbon analyzer (DRI Model 2015) was developed. Seven lasers in the wavelength range of 405-980 nm are used to monitor the spectral reflectance (R) and transmittance (T) signals of filter samples during thermal analysis. The R and T signals are calibrated with transfer standards traceable to absolute R and T measured by a UV/VIS spectrometer. It is demonstrated that R and T calibration is independent of the sample type using ambient and source (e.g., diesel exhaust, flaming biomass, and smoldering biomass) samples with a wide range of optical depth. Tests on ambient and source samples show that total carbon (TC), organic carbon (OC), and elemental carbon (EC) are equivalent to those from legacy thermal/optical carbon analyzers (DRI Model 2001) using the earlier hardware design and 633 nm laser for pyrolysis correction. The thermal spectral analysis provides additional information that evaluates black carbon (BC) and brown carbon (BrC) contributions and their optical properties in the near-ultraviolet to near-infrared solar spectrum. It provides insight into the charring process and improves the charring correction, leading to more accurate OC and EC measurements for climate, visibility, or health studies.