Detection of Airborne Nanoparticles through Enhanced Light Scattering Images

Abstract

A new method is proposed in this paper to detect airborne nanoparticles, detecting the light scattering caused by both the particle and the surrounding molecules, which can surpass the limitations of conventional laser optical methods while maintaining simplicity and cost-effectiveness. This method is derived from a mathematical analysis that describes the particle light scattering phenomenon more exactly by including the influence of light scattered from surrounding gas molecules. The analysis shows that it is often too much of a simplification to consider only light scattering from the detected nanoparticle, because light scattering from the surrounding gas molecules, whether visible or invisible to the sensor, is important for nanoparticle detection. An image detection approach utilizing the light scattering from surrounding air molecules is described for the detection of airborne nanoparticles. Tests using monodisperse nanoparticles confirm that airborne particles of around 50 nm in size can even be detected using a low-cost testing device. This shows further that even when using a simple image processing code, captured particle light scattering images can be converted digitally into instantaneous particle counts or concentrations. The factors limiting conventional pulse detection are further discussed. This new method utilizes a simple static light scattering (SLS) approach to enable the development of new devices with better detection capabilities, paving the way for the further development of nanoparticle detection technology.

Single-step detection of toxic airborne metallic nanoparticles using Goos–Hänchen effect in photonic Bragg grating structures

“…In parallel with other methods, alternative platforms which seem to be far from most of the abovementioned limitations are the optical sensors. The variety of these techniques is very large but the most important ones are based on fluorescence or luminescence spectroscopy, dynamic/static scatterometry, surfaceenhanced Raman spectroscopy (SERS), laser heating of the atmosphere under study and tracking the changes of the optical features, plasmonic imaging, and optical fiber-based sensing [9][10][11]. Although each of these valuable approaches has its own advantages and has been able to increase hope in the possibility of HMNP detection, they have also some challenges to be implemented in practice.…”