Development of a mini- aerosol Faraday cage for personal nanoparticle monitor

Li Huang (1), Da-ren Chen (1)

(1) Washington University in St. Louis

     Abstract Number: 656
     Last modified: May 14, 2010

Abstract
Particles in submicrometer and nanometer size ranges are considered as the building blocks for aanotechnology. The expected increase of nanopowder production in the future raises the concerns of their health effects and environmental impacts. The demand for miniature particle detectors enabling to monitor submicrometer particles at the personal level and for spatial distribution monitoring is consequently increasing. Methods based on the light scattering technique have been applied in miniature devices for monitoring submicrometer particles. These optical devices often suffer from the optical contamination from both the presence of large particles in sampled air and working fluids, e.g., alcohol, in addition to their limited capability of detecting particles with the sizes less than 80 nm. Miniature particles monitors based on the electrical detection technique is therefore proposed to carry out the monitoring task. Measuring the charges associated with particles in electrical detection technique is often accomplished by an aerosol electrometer, consisting of the aerosol Faraday cage and electrometer. The objective of this study is thus to develop a miniature aerosol Faraday cage to be used in the miniature particles monitors.

In this study we have developed a miniature aerosol Faraday cage which can be used as a part of mini- aerosol electrometer via its combination with a sensitive electrometer. Various cage sizes, filter material and filter porous sizes were tested to optimize the performance of the mini- cage while keeping its feature size as compact as possible. The performance of prototype mini- aerosol Faraday cage was evaluated by DMA-classified particles and using CPC as the reference particle counter. The detailed design of this mini- aerosol Faraday cage and the result of its experimental evaluation will be described in this presentation.