Characterisation of organic contaminants in the CLOUD chamber at CERN
Atmos. Meas. Tech., 7, 2159-2168, 2014
Effect of ions on the measurement of sulfuric acid in the CLOUD experiment at CERN
Atmos. Meas. Tech., 7, 3849-3859, 2014
On the composition of ammonia–sulfuric-acid ion clusters during aerosol particle formation
Summary: We used an ion mass spectrometer at CERN's CLOUD chamber to investigate the detailed composition of ammonia--sulfuric acid ion clusters (of both polarities) as they initially form and then grow into aerosol particles, at atmospherically relevant conditions. We found that these clusters’ composition is mainly determined by the ratio of the precursor vapors and ranges from ammonia-free clusters to clusters containing > 1 ammonia per sulfuric acid. Acid--base bindings are a key formation mechanism.
Atmos. Chem. Phys., 15, 55-78, 2015
Elemental composition and clustering behaviour of α-pinene oxidation products for different oxidation conditions
Summary: Our study shows, based on data from three atmospheric pressure interface time-of-flight mass spectrometers measuring in parallel charged and neutral molecules and molecular clusters, how oxidised organic compounds bind to inorganic ions (e.g. bisulfate, nitrate, ammonium). This ionisation is selective for compounds with lower molar mass due to their limited amount and variety of functional groups. We also found that extremely low volatile organic compounds (ELVOCs) can be formed immediately.
Atmos. Chem. Phys., 15, 4145-4159, 2015
Experimental investigation of ion–ion recombination under atmospheric conditions
Summary: The ion-ion recombination coefficient was measured at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the CLOUD chamber at CERN. We observed a strong dependency on temperature and on relative humidity, which has not been reported previously. No dependency of the ion-ion recombination coefficient on ozone concentration was observed and a weak variation with sulfur dioxide concentration was also observed.
Atmos. Chem. Phys., 15, 7203-7216, 2015