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Fire Technology

, Volume 51, Issue 2, pp 247–269 | Cite as

Quantification of Optical and Physical Properties of Combustion-Generated Carbonaceous Aerosols (< PM2.5) Using Analytical and Microscopic Techniques

  • Inoka Eranda PereraEmail author
  • Charles D. Litton
Article

Abstract

A series of experiments were conducted to quantify and characterize the optical and physical properties of combustion-generated aerosols during both flaming and smoldering combustion of three materials common to underground mines—Pittsburgh Seam coal, Styrene Butadiene Rubber (a common mine conveyor belt material), and Douglas-fir wood—using a combination of analytical and gravimetric measurements. Laser photometers were utilized in the experiments for continuous measurement of aerosol mass concentrations and for comparison to measurements made using gravimetric filter samples. The aerosols of interest lie in the size range of tens to a few hundred nanometers, out of range of the standard photometer calibration. To correct for these uncertainties, the photometer mass concentrations were compared to gravimetric samples to determine if consistent correlations existed. The response of a calibrated and modified combination ionization/photoelectric smoke detector was also used. In addition, the responses of this sensor and a similar, prototype ionization/photoelectric sensor, along with discrete angular scattering, total scattering, and total extinction measurements, were used to define in real time the size, morphology, and radiative transfer properties of these differing aerosols that are generally in the form of fractal aggregates. SEM/TEM images were also obtained in order to compare qualitatively the real-time, continuous experimental measurements with the visual microscopic measurements. These data clearly show that significant differences exist between aerosols from flaming and from smoldering combustion and that these differences produce very different scattering and absorption signatures. The data also indicate that ionization/photoelectric sensors can be utilized to measure continuously and in real time aerosol properties over a broad spectrum of applications related to adverse environmental and health effects.

Keywords

Carbonaceous aerosols Flaming Smoldering Photometry Particulate matter Smoke 

List of Symbols

dg

Number mean Diameter

Df

Fractal dimension

dp

Diameter of primary particles (nm)

d10

Count mean diameter (cm)

Di

Ion diffusion coefficient (cm3/s)

I0

Incident intensity of the light

I

Reduced intensity of light

kf

Fractal pre-factor

l

Path length (m)

M

Aerosol mass concentration (mg/m3)

Ma

Mass of a fractal aggregate

np

Number of primary particles per aggregate

N

Number of aggregate per cm3

Rg

Radius of gyration

xp

Size parameter

σext

Mass specific extinction (m2/g)

σsca

Mass specific scattering (m2/g)

σabs

Mass specific absorption (m2/g)

λ

Wavelength (nm)

ρp

Particle density (g/m3)

Notes

Acknowledgments

The authors would like to acknowledge Diane Schwegler-Berry at the National Institute for Occupational Safety and Health (NIOSH), Morgantown, WV, for her help in SEM/TEM imaging.

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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.Pittsburgh Research Laboratory, Fires and Explosions Branch, Office of Mine Safety and Health ResearchNational Institute for Occupational Safety and Health, Centers for Disease Control & Prevention, U. S. Department of Health & Human ServicesPittsburghUSA

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