Ionisation nanoparticle detector based on modified smoke detector to measure neutralised and non-neutralised aerosol concentrations

Abstract

Innovation in nanotechnology should be accompanied by advances in the monitoring of nanomaterials, especially the concentration of nanoparticles in the air, because of the risk to human health that their use may pose. Current solutions for determining nanoparticle concentrations are mainly used in research laboratories. Firstly, purchase and secondly conservation, maintenance and servicing of these devices are high costs that companies cannot afford on a larger scale. There is therefore a growing demand for monitoring devices suitable for larger-scale use. The aim of the research was to verify the proposed detector’s suitability as a stand-alone measuring device for the determination of the nanoparticles’ number concentration. An electronic circuit has been developed that is responsible for reading the measured voltage, the necessary conversions and controlling the operation of the detector. A simple menu was developed for the user to configure basic measurement options. Detector tests were done in two stages: with and without aerosol neutralisation. They indicate that the ionisation nanoparticle detector measurements strongly correlate with those obtained with the reference device (r > 0.90 and r > 0.85, respectively). Statistical analysis confirmed the capability of the investigated ionisation nanoparticle detector to estimate the number concentration of nanoparticles (strong correlations) by following concentration changes (non-normal distribution of measured voltage, Shapiro-Wilk test, p < 0.05 for both stages). However, the aerosol neutralisation affected the measurement data obtained from this device (Mann-Whitney U test, p = 4.519 × 10−7), while the reference device did not (Mann-Whitney U test, p = 7.182 × 10−2).