2 research outputs found
Photochemical Aging Induces Changes in the Effective Densities, Morphologies, and Optical Properties of Combustion Aerosol Particles
Effective density (ρeff) is an important
property
describing particle transportation in the atmosphere and in the human
respiratory tract. In this study, the particle size dependency of
ρeff was determined for fresh and photochemically
aged particles from residential combustion of wood logs and brown
coal, as well as from an aerosol standard (CAST) burner. ρeff increased considerably due to photochemical aging, especially
for soot agglomerates larger than 100 nm in mobility diameter. The
increase depends on the presence of condensable vapors and agglomerate
size and can be explained by collapsing of chain-like agglomerates
and filling of their voids and formation of secondary coating. The
measured and modeled particle optical properties suggest that while
light absorption, scattering, and the single-scattering albedo of
soot particle increase during photochemical processing, their radiative
forcing remains positive until the amount of nonabsorbing coating
exceeds approximately 90% of the particle mass
Photochemical Aging Induces Changes in the Effective Densities, Morphologies, and Optical Properties of Combustion Aerosol Particles
Effective density (ρeff) is an important
property
describing particle transportation in the atmosphere and in the human
respiratory tract. In this study, the particle size dependency of
ρeff was determined for fresh and photochemically
aged particles from residential combustion of wood logs and brown
coal, as well as from an aerosol standard (CAST) burner. ρeff increased considerably due to photochemical aging, especially
for soot agglomerates larger than 100 nm in mobility diameter. The
increase depends on the presence of condensable vapors and agglomerate
size and can be explained by collapsing of chain-like agglomerates
and filling of their voids and formation of secondary coating. The
measured and modeled particle optical properties suggest that while
light absorption, scattering, and the single-scattering albedo of
soot particle increase during photochemical processing, their radiative
forcing remains positive until the amount of nonabsorbing coating
exceeds approximately 90% of the particle mass