title: Efflorescence transitions of ammonium sulfate particles coated with secondary organic aerosol.
abstract: Ammonium sulfate particles were generated by atomization and introduced into a smog chamber where they were coated with secondary organic aerosol from ozonolysis of limonene or alpha-pinene. These mixed particles were then sampled with a humidified Tandem-DMA system where a monodisperse aerosol population was selected, humidified, and dried to observe the relative humidity (RH) at which the particles returned to the original dry diameter. The volume fraction of secondary organic aerosol (SOA) in the mixed particles ranged from 0.59 to 0.94 for limonene SOA and 0.54 to 0.72 for alpha-pinene SOA. Efflorescence RHs for our mixed aerosols were in the range of 28-34%, similar to our observation of 32% ERH for pure ammonium sulfate nanoparticles. These findings indicate that the effect of SOA on the ERH of inorganic salts in the atmosphere may be negligible.
authors: Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
authors: Satoshi
authors: S
authors: Takahama
authors: Ravi K
authors: RK
authors: Pathak
authors: Spyros N
authors: SN
authors: Pandis
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D000645:Ammonium Sulfate / Q000737:chemistry*; D001272:Atmosphere / Q000737:chemistry*; D000081008:Bicyclic Monoterpenes; D053138:Cyclohexenes; D006813:Humidity; D000077222:Limonene; D039821:Monoterpenes; D044367:Phase Transition; D012044:Regression Analysis; D012905:Smog / Q000032:analysis*; D013729:Terpenes; D014867:Water / Q000737:chemistry*
chemical_list: D000336:Aerosols; D000081008:Bicyclic Monoterpenes; D053138:Cyclohexenes; D039821:Monoterpenes; D012905:Smog; D013729:Terpenes; D014867:Water; D000077222:Limonene; C005451:alpha-pinene; D000645:Ammonium Sulfate