HR: 13:55h
AN: A43E-02 INVITED    [Abstracts]
TI: The Role of Organics in Atmospheric New Particle Formation and Growth
AU: * Zhang, R
EM: zhang@ariel.met.tamu.edu
AF: Department of Atmospheric Sciences, Texas A&M University, 1204 Eller O&M Building 3150 TAMU, College Station, TX 77843-3150, United States
AU: Zhang, J
EM: jzhao@neo.tamu.edu
AF: Department of Atmospheric Sciences, Texas A&M University, 1204 Eller O&M Building 3150 TAMU, College Station, TX 77843-3150, United States
AU: Khalizov, A F
EM: khalizov@neo.tamu.edu
AF: Department of Atmospheric Sciences, Texas A&M University, 1204 Eller O&M Building 3150 TAMU, College Station, TX 77843-3150, United States
AB: Atmospheric aerosols impair visibility and human health, interfere with radiative transfer, and alter cloud formation. The major contributors include sulfate and organic aerosols from anthropogenic and biogenic activities, which are produced through a multitude of complex multiphase atmospheric processes by photochemical oxidation of emitted sulfur dioxide and volatile organic compounds (VOCs) into less volatile forms and gas-to-particle conversion. Aerosol nucleation events have been frequently observed under various tropospheric conditions and account for a major fraction of the total aerosol population, but the fundamental chemical processes responsible for aerosol nucleation and growth remain poorly understood. New particle formation occurs in two distinct stages, nucleation to form thermodynamically stable clusters and subsequent growth of the newly nucleated clusters by condensation or heterogeneous reactions to detectable particles that competes with capture and removal by coagulation with pre-existing particles. Sulfuric acid has been identified as a key species in new particle formation, but it is commonly recognized that binary nucleation of water and sulfuric acid is not efficient enough to explain measured nucleation events. Considerable uncertainty exists regarding the identity of other condensable species responsible for nucleation and growth of new particles. Currently available results of aerosol nucleation and growth from experimental, theoretical, and field studies are rather conflicting, hindering efforts to model formation and growth of secondary aerosols on the regional and global scales and to assess their atmospheric impacts. This talk will summarize recent progress in the understanding of the contributions of organics to atmospheric aerosol nucleation and growth. New experimental and theoretical results on this subject will be presented.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0320 Cloud physics and chemistry
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting