A new particle size magnifier (PSM) for detection of nano-CN as small as ∼1 nm in mobility diameter was developed, calibrated and tested in atmospheric measurements. The working principle of a PSM is to mix turbulently cooled sample flow with heated clean air flow saturated by the working fluid. This provides a high saturation ratio for the working fluid and activates the seed particles and grows them by condensation of the working fluid. In order to reach high saturation ratios, and thus to activate nano-CN without homogeneous nucleation, diethylene glycol was chosen as the working fluid. The PSM was able to grow nano-CN to mean diameter of 90 nm, after which an ordinary condensation particle counter was used to count the grown particles (TSI 3010). The stability of the PSM was found to be good making it suitable for stand-alone field measurements. Calibration results show that the detection efficiency of the prototype PSM + TSI 3010 for charged tetra-alkyl ammonium salt molecules having mobility equivalent diameters of 1.05, 1.47, 1.78, and 2.57 nm are 25, 32, 46, and 70%, respectively. The commercial version of the PSM (Airmodus A09) performed even better in the smallest sizes the detection efficiency being 51% for 1.47 nm and 67% for 1.78 nm.

The surface tension of adipic aqueous solutions was measured as a function of temperature (T=278-313 K) and adipic acid mole fraction (X=0.000-0.003) using the Wilhelmy plate method. A parametrization fitted to these data is presented. The evaporation rates of binary water-malonic and water-adipic acid droplets were measured with a TDMA technique at different temperatures (T=293-300 K) and relative humidities (58-80%), and the saturation vapor pressures of subcooled liquid malonic and adipic acids were derived from the data using a binary evaporation model. The temperature dependence of the vapor pressures was obtained as least-squares fits to the derived vapor pressures: ln(Psat,l) (Pa)=220.2389-22634.96/T (K)-26.66767 ln T (K) for malonic acid and ln(Psat,l) (Pa)=140.6704-18230.97/T (K)-15.48011 ln T (K) for adipic acid.