Laboratory Studies of Aerosol Optical Properties. R.F. Niedziela DePaul University Department of Chemistry Chicago, IL 23 Oct 01. Particle Size. Atmospheric background aerosols. Average atmospheric aerosols. Smallest detectable particles. Atoms and small molecules. Very fine aerosols.
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Department of Chemistry
23 Oct 01
Atmospheric background aerosols
Average atmospheric aerosols
Smallest detectable particles
Atoms and small molecules
Very fine aerosols
VOAG in action. (Courtesy of TSI, Inc.)
Adapted from Lovejoy, et al., J. Geophys. Res., 100, 18775-18,780, (1995).
Jenkin, et al., Atmos. Env., 34, 2837-2850, (2000)
Xu, et al., J. Phys. Chem. B, 102, 7462-7469, (1998).
Disselkamp, et al., J. Phys. Chem., 100, 9127-9137, (1996).
Collect a non scattering spectrum
k() = K()
Collect several scattering spectra
corresponding to different particle sizes
Select a scattering spectrum and guess the particle size
Use the Kramers-Kronig relationship to calculate n()
Vary particle size
Use Mie scattering theory to calculate the scattering spectrum
Vary scaling factor K
Compare calculated and experimental spectra – good fit?
Correct k() if necessary
Report final refractive index set
Quality control checks
Niedziela, et al., J. Phys. Chem. A, 102(32), 6477, (1998)
Toon, et al., J. Geophys. Res., 99, 25631, (1994)
Clapp, et al., J. Geophys. Res., 102(D7), 8899, (1997)
Phase diagram: Gable et al., J. Am. Chem. Soc., 72, 1445-1448, (1950)
Trajectory: Steele and Hamill, J. Aerosol Sci., 12, 517-528, (1981)
From Milham and Querry (unpublished). See D.F. Flannigan, Tech. Rep. ERDEC-TR-416 (Edgewood Research, Development, and Engineering Center, Aberdeen Proving Ground, Aberdeen, MD 1997), Appendix B