Tuija Jokinen

Molecular steps of neutral sulfuric acid and dimethylamine nucleation in CLOUD

We have run a set of experiments in the CLOUD chamber at CERN, Switzerland, studying the effect of dimethylamine (DMA) on sulfuric acid (SA)-water nucleation using a nitrate based Chemical Ionization Atmospheric Pressure ionization Time-Of-Flight Mass Spectrometer (CI-APi-TOF). Experiment was designed to produce neutral high m/z SA-DMA clusters in close to atmospherically relevant conditions to be detected and characterized by the CI-APi-TOF. We aimed in filling up the gap in measurement techniques from molecular level up to climatically relevant aerosol particles and thus improve our understanding of the role of sulfuric acid and DMA in atmospheric nucleation.

Nucleation of H_2SO_4 and oxidized organics in CLOUD experiment

The research of atmospheric new particle formation has proceeded lately as the role of sulphuric acid has been established. Still, the roles of other atmospheric compounds in nucleation remain largely unclear. To clarify the first steps of atmospheric new particle formation extensive nucleation experiments were performed in CLOUD chamber in 2012. Especially the role of oxidations products of α-pinene was studied in detail. The experiments provided new information about the part of oxidized organics in nucleation.

Sulphur dioxide and sulphuric acid concentrations in the vicinity of Kilpilahti industrial area

Industrial activity is a major source of sulphur compound emissions. The sulphuric acid and sulphur dioxide measurements in the vicinity of the industrial area and the oil refinery in Kilpilahti expressed great variation in concentration. The hourly mean values of concentration were categorized according to the area from where the air mass was travelling towards the measurement site. The statistical characteristics and diurnal behavior of emissions between these areas were significantly different.

Chemistry of stabilized Criegee intermediates in the CLOUD chamber

In atmospheric conditions the oxidation of sulphur dioxide to sulphuric acid in gas phase has been considered to be determined by the concentration of hydroxyl radical. Recently the significance of stabilized Criegee intermediate as an oxidizer of sulphuric acid has been brought out. In this study we investigated the oxidation of sulphur dioxide in the CLOUD chamber in conditions where the hydroxyl radical was removed. The concentration of formed sulphuric acid was measured with a chemical ionization atmospheric pressure interface time-offlight mass spectrometer and it was compared with the calculated yield of sulphuric acid.