Figure 2: First addition of DMA.
From: The effect of acid–base clustering and ions on the growth of atmospheric nano-particles
(a) Sulphuric acid monomer concentration (red line) measured by the CIMS as a function of time. In the beginning of the experiment (14:00–16:00) no dimethylamine was added to the chamber and the DMA concentration was below detection limit. After addition of DMA (the DMA flow was started around 16:00, after which it took some time to reach the chamber) the measured H2SO4 monomer concentration decreased, although the production rate of H2SO4 remained constant. After 19:30 the ultra violet light intensity (blue shaded area) was stepwise increased to increase production of sulphuric acid. (b) Concentrations of selected DMA–H2SO4 clusters measured with the CI-APi-TOF for the same time period.
