AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Development of an Ultrafine Condensation Particle Counter (UCPC) for Measurements of Particles Down to 1 nm in Diameter
JUN ZHAO, Hee-Siew Han, Ashish Karn, Peter H. McMurry, University of Minnesota
Abstract Number: 714 Working Group: Instrumentation and Methods
Abstract Atmospheric nanoparticles formed by nucleation and their subsequent growth to cloud condensation nuclei may significantly affect cloud formation and global climate. To better understand this process will need to have the ability to measure particles down to the size of a nucleus (about 1-1.5 nm). In some industrial applications such as deposition in semiconductor and production of engineering nanoparticles, measurements of particles down to 1 nm are also needed. Conventional butanol or water-based ultrafine condensational particle counter (UCPC) can only measure particles as small as about 2.5 nm (D50=2.5 nm, mobility diameter) due to limitation of the physical properties of the working fluid. Here we present development and application of a diethylene glycol based UCPC (DEG-UCPC) that can measure atmospheric particles down to 1 nm in diameter. The DEG-UCPC was prototyped from a TSI UCPC 3776 with some noticeable modifications inside the hardware framework. The performance of the instrument was evaluated with several sets of saturator/condenser temperatures and with different saturator/capillary flows. The detection efficiencies of 1-30 nm NaCl particles were measured to determine the minimum size (D50, the size corresponds to 50% detection efficiency) and to invert the concentrations for data analysis. A minimum size of about 1.1 nm geometry diameter was achieved with saturator/capillary flows of 850/150 ccm and saturator/condenser temperatures of 62ºC/12ºC. Application of a prototyped DEG-SMPS (combined a TSI nano-DMA and a DEG-UCPC) for measurements of atmospheric nanoparticles in recent field campaigns was also presented.