Laboratory investigation of chemical and physical properties of soot-containing aerosols

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dc.contributor.advisor Zhang , Renyi en_US
dc.contributor.committeeMember Collins , Don en_US
dc.creator Zhang , Dan en_US 2006 -08 -16T19 :12 :00Z 2014 -02 -19T19 :25 :56Z 2006 -08 -16T19 :12 :00Z 2014 -02 -19T19 :25 :56Z 2003 -05 en_US 2006 -08 -16T19 :12 :00Z
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /3977
dc.description.abstract Soot particles released from fossil fuel combustion and biomass burning have a large impact on the regional /global climate by altering the atmospheric radiative properties and by serving as cloud condensation nuclei (CCN ) . However , the exact forcing is affected by the mixing of soot with other aerosol constituents , such as sulfuric acid . In this work , experimental studies have been carried out focusing on three integral parts : (1 ) heterogeneous uptake of sulfuric acid on soot ; (2 ) hygroscopic growth of H2SO4 -coated soot aerosols ; (3 ) effect of H2SO4 coating on scattering and extinction properties of soot particles . A low -pressure laminar -flow reactor , coupled to ion driftchemical ionization mass spectrometry (ID -CIMS ) detection , is used to study uptake coefficients of H2SO4 on combustion soot . The results suggest that uptake of H2SO4 takes place efficiently on soot particles , representing an important route to convert hydrophobic soot to hydrophilic aerosols . A tandem differential mobility analyzing (TDMA ) system is employed to determine the hygroscopicity of freshly generated soot in the presence of H2SO4 coating . It is found that fresh soot particles are highly hydrophobic , while coating of H2SO4 significantly facilitates water uptake on soot even at sub -saturation relative humidities . The results indicate that aged soot particles in the atmosphere can potentially be an efficient source of CCN . Scattering and extinction coefficient measurements of the soot -H2SO4 mixed particles are conducted using a threewavelength Nephelometer and a multi -path extinction cell . Coating of H2SO4 is found to increase the single scattering albedo (SSA ) of soot particles which has impact on the aerosol direct radiative effect . Other laboratory techniques such as transmission electron microscopy (TEM ) and Fourier transform infrared spectrometry (FTIR ) are utilized to examine the morphology and chemical composition of the soot -H2SO4 particles . This work provides critical information concerning the heterogeneous interaction of soot and sulfuric acid , and how their mixing affects the hygroscopic and optical properties of soot . The results will improve our ability to model and assess the soot direct and indirect forcing and hence enhance our understanding of the impact of anthropogenic activities on the climate . en_US
dc.format.extent 11678399 bytes
dc.format.medium electronic en_US
dc.format.mimetype application /pdf
dc.language.iso en _US en_US
dc.publisher Texas A &M University en_US
dc.subject soot en_US
dc.title Laboratory investigation of chemical and physical properties of soot -containing aerosols en_US
dc.type Book en
dc.type.genre Electronic Dissertation en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US


Laboratory investigation of chemical and physical properties of soot-containing aerosols. Available electronically from http : / /hdl .handle .net /1969 .1 /3977 .

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