Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Direct In-Situ Mass Specific Absorption Spectra of Biomass Burning Particles Generated from Smoldering Hard and Softwoods



Rian You, James Radney, Christopher D. Zangmeister, Michael R. Zachariah


Particles from smoldering biomass burning (BB) represent a major source of carbonaceous aerosol in the terrestrial atmosphere. In this study, mass specific absorption spectra of laboratory- generated smoldering wood particles (SWP) from 3 hardwood and 3 softwood species were measured in-situ. Absorption data spanning from λ = 500 nm to 840 nm were collected using a photoacoustic spectrometer coupled to a supercontinuum laser with a tunable wavelength and bandwidth filter. SWP were size- (electrical mobility) and mass-selected prior to optical characterization allowing data to be reported as mass-specific absorption cross sections (MAC). The median measured MAC at λ = 660 nm for smoldering oak particles was 1.1 (0.57/1.8) x 10-2 m2 g-1 spanning from 83 femtograms (fg) to 517 fg (500 nm ≤ mobility diameter ≤ 950 nm), MAC values in parenthesis are the 16th and 84th percentiles of the measured data (i.e. 1σ). The collection of all six wood species (Oak, Hickory, Mesquite, Western redcedar, Baldcypress and Blue spruce) had median MAC values ranging from 1.4 x 10-2 m2 g-1 to 7.9 x 10-2 m2 g-1 at λ = 550 nm with absorption Ångström exponents (AAE) between 3.5 and 6.2. Oak, Western redcedar and Blue spruce possessed statistically similar (p > 0.05) spectra while the spectra of Hickory, Mesquite and Baldcypress were distinct (p < 0.01) as calculated from a point-by-point analysis using the Wilcox rank-sum test.
Environmental Science & Technology


Aerosol, spectroscopy, biomass burning, photoacoustic


You, R. , Radney, J. , Zangmeister, C. and Zachariah, M. (2017), Direct In-Situ Mass Specific Absorption Spectra of Biomass Burning Particles Generated from Smoldering Hard and Softwoods, Environmental Science & Technology, [online],, (Accessed June 23, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created April 27, 2017, Updated October 12, 2021