Light Scattering Intensity Field Imaging Sensor for In Situ Aerosol Analysis

Aerosol plays an important role in a broad range of scientific disciplines, such as atmospheric chemistry and physics, fuel combustion, and human health. Current particle sizing instruments are usually bulky, complicated, and expensive, while the portable ones cannot provide sufficient measurement channels to describe the particle size distribution accurately. To address this challenge, we propose an optical sensing method to analyze the particle size distribution of aerosols based on the light scattering intensity field (LSIF). The LSIF is a set of scattering lights in all directions around the particles, which contains the scattering light signals in different observing angles. Then, the particle size distribution of the aerosol samples is retrieved by the Tikhonov regularization algorithm. A portable and low-cost aerosol sizing prototype sensor is designed to image part of the LSIF signals, where the LSIF is collected by a parabolic reflector and projected on the image sensor as an image with telecentric lenses. According to the experimental result of di-ethyl-hexyl-sebacate aerosol test, the relative measurement error of LSIF can be controlled to ±10%. With an integrated and cost-effective design, this particle sizing sensor shows great potential for routine field measurements outside of the laboratory.