AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
A New Mobility Particle Size Spectrometer Capable of Measuring the Size Tange from 1.1 to 55nm
GERHARD STEINER, Joonas Vanhanen, Joonas Enroth, Lothar Keck, Minna Väkevä, Grimm Aerosol Technik Ainring
Abstract Number: 183 Working Group: Instrumentation and Methods
Abstract In order to understand the basic mechanisms of new particle formation (NPF) as well as the formation rate and growth rate of the particles (e.g. Kulmala et al., 2013), it is crucial to measure aerosol number size distributions starting from the sub 2 nm size range. Current state of the art aerosol instrumentation is capable of detecting particles down to almost 1 nm (Vanhanen et al. 2011, Jiang et al. 2011), but commercial electrical mobility spectrometers are still lacking the necessary sensitivity in the sub 2 nm size range (Kangasluoma et al. 2017).
In this study, the Airmodus A10 Particle Size Magnifier (PSM, Vanhanen et al. 2011) is combined with the Grimm SMPS+C system in order to increase its sensitivity for the particles in the size range < 4 nm. The system consists of a soft x-ray neutralizer (Grimm 5524-X), a short Differential Mobility Analyzer (Grimm S-DMA), the diethylene glycol-based PSM (Airmodus A10) and a butanol-based CPC (Grimm 5416). The S-DMA was operated with an aerosol sample flow rate of 2.5 L/min and a sheath flow rate of 10 L/min, allowing size distribution measurements from 1.1-55 nm. The Grimm 5416 CPC was operated at a modified aerosol inlet flowrate of 1 L/min. The system was characterized using monodisperse particles produced with the Grimm WOx generator 7860 and electrospray generated molecular mobility standards (Ude & Fernández de la Mora, 2005).
The first results show that the new SMPS+PSM is capable of detecting small molecular ions < 2nm originating from the ionizing processes in the soft x-ray neutralizer and with its scan time of < 1min also of tracking very fast nucleation events. We will give details about the instrument’s specifications and its performance for laboratory and ambient aerosol number size distribution measurements.