Uni-Bayreuth grafik-uni-bayreuth



Kinetic and mechanistic studies on seasalt activation and halogenation of organic aerosol

Natalja Balzer1, Sergej Bleicher1, Cornelius Zetzsch1
1 Forschungsstelle Atmosphärische Chemie, Uni Bayreuth

P 4.3 in Klimaforschung

Field experiments and laboratory studies show that atomic Br and Cl are produced from sea-salt aerosol. The halogen release is based on the uptake of gaseous HOX on aqueous, acidified salt surfaces. Br and Cl play an important role in atmospheric ozone depletion and destruction of hydrocarbons. Secondary organic aerosol and HULIS (humic like substances) may take part in these reaction cycles by halogenation and production of volatile organic halogens.  

Aerosol smog-chamber facilities (coolable down to -25°C) enable us to simulate the halogen release mechanism under arctic and troposphere conditions. Mechanistic and kinetic studies will be carried out to investigate the influence of secondary organic aerosols (SOA) and HULIS on bromine explosion and to determine possible halogenated gaseous and solid organic products through sea-salt activation. To verify our model of the gaseous and heterogeneous kinetic reactions we use computer-simulations. 

At the present time we have the following results: Using the technique of the radical clock we have measured the photolysis constant of Cl2→2Cl· to calibrate our smog-chamber's solar simulator. Afterwards the activation and the release of halogenated species (ClO, BrO) from humid inorganic aerosol where observed under environmental relevant conditions. The role of HOBr as an important factor for the Cl-activation was approved in this measurements.    

The formation of the secondary organic aerosol and the determination of possible halogenated gaseous and solid organic products are studied using longpath-FTIR, DRIFTS, ATR, GC-MS, DMA-CNC, GC-ECD, GC-FID, IC.  

Letzte Änderung 26.03.2009