In-cloud multiphase behaviour of acetone in the troposphere: gas uptake, Henry's law equilibrium and aqueous phase photooxidation.

Acetone is ubiquitous in the troposphere. Several papers have focused in the past on its gas phase reactivity and its impact on tropospheric chemistry. However, acetone is also present in atmospheric water droplets where its behaviour is still relatively unknown.

Products and mechanisms of the reaction of oleic acid with ozone and nitrate radical.

The heterogeneous reactions of deposited, millimeter-sized oleic acid droplets with ozone and nitrate radicals are studied. Attenuated total reflectance infrared spectroscopy (ATR-IR), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS) are used for product identification and quantification. The condensed-phase products of the ozonolysis of oleic acid droplets are 1-nonanal (30 +/- 3% carbon yield), 9-oxononanoic acid (14 +/- 2%), nonanoic acid (7 +/- 1%), octanoic acid (1 +/- 0.

Ozonolysis of mixed oleic-acid/stearic-acid particles: reaction kinetics and chemical morphology.

The ozonolysis of mixed oleic-acid/stearic-acid (OL/SA) aerosol particles from 0/100 to 100/0 wt % composition is studied. The magnitude of the divergence of the particle beam inside an aerosol mass spectrometer shows that, in the concentration range 100/0 to 60/40, the mixed OL/SA particles are liquid prior to reaction. Upon ozonolysis, particles having compositions of 75/25 and 60/40 change shape, indicating that they have solidified during reaction.