Laboratory-measured Nucleation Rates of Sulfuric Acid and Water from the SO2 + OH Reaction
Binary homogeneous nucleation of H2SO4/H2O is the most basic nucleation system, yet its nucleation mechanisms are poorly understood. Here, we present results of the laboratory study of this binary nucleation system. H2SO4was produced through the reaction of SO2 + OH→ HSO3 (R1) in the presence of SO2, OH, O2, and H2O in a fast flow reactor at 288K and atmospheric pressure. OH was produced from the photolysis of H2O. The power dependence of the nucleation rate (J) on sulfuric acid concentration ([H2SO4]) was 2–10 in the [H2SO4] range from 3 × 106− 2 × 109 cm−3. This power dependence increased with decreasing RH and increasing nucleation time. The measured aerosol sizes ranged from 4–20 nm. These aerosol sizes were larger at higher [H2SO4] and higher RH, and with higher nucleation times. The effects of RH on aerosol growth were also more pronounced at higher [H2SO4] and with higher nucleation times.
Keywords Binary nucleation, sulfuric Acid, CIMS
KeywordsAcidity Sulfuric Acid Dition Photolysis Librium
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