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.

Light Source Effects on Aerosol Photoacoustic Spectroscopy Measurements

Published

Author(s)

James G. Radney, Christopher D. Zangmeister

Abstract

Photoacoustic spectroscopy measurements of flame-generated soot aerosol coated with small amounts of water yielded absorption enhancements that were dependent on the laser used: quasi- continuous wave (Q-CW, ≈ 650 ps pulse duration and 78 MHz repetition rate) versus continuous wave (CW). Water coating thickness was controlled by exposing the aerosol to a set relative humidity (RH). At ≈ 85 % RH, the mass of the soot particles increased by an amount comparable to a monolayer of water being deposited and enhanced the measured absorption by 36 % and 15 % for the Q-CW and CW lasers, respectively. Extinction measurements were also performed using a cavity ring-down spectrometer (extinction equals the sum of absorption and scattering) with a CW laser and negligible enhancement was observed at all RH. These findings demonstrate that source choice can impact measurements of aerosols with volatile coatings and that the absorption enhancements at high RH previously measured by Radney and Zangmeister (2015) [1] are the result of laser source used (Q-CW) and not from an increase in the particle absorption cross section.
Citation
Journal of Quantitative Spectroscopy and Radiative Transfer
Volume
187

Keywords

Photoacoustic, aerosol, soot, enhancement

Citation

Radney, J. and Zangmeister, C. (2016), Light Source Effects on Aerosol Photoacoustic Spectroscopy Measurements, Journal of Quantitative Spectroscopy and Radiative Transfer, [online], https://doi.org/10.1016/j.jqsrt.2016.09.026 (Accessed June 18, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created October 6, 2016, Updated November 10, 2018