A New Angular Light Scattering Measurement of Particulate Matter Mass Concentration for Homogeneous Spherical Particles

Abstract

Under the condition of ultra-low emission for power plants, the particulate matter concentration is significantly lower than that of typical power plants a decade ago, which posed new challenges for the particulate matter monitoring of stationary emission. The monitoring of particulate matter mass concentration based on ensemble light scattering has been found affected by particle size. Thus, this study develops a method of using the scattering angular distribution to obtain the real-time particle size, and then correct the particulate matter concentration with the real-time measured particle size. In this study, a real-time aerosol concentration and particle size measurement setup is constructed with a fixed detector at the forward direction and a rotating detector. The mass concentration is measured by the fixed detector, and the particle size is measured from the intensity ratio of the two detectors. The simulations show that the particle size has power law functionality with the angular spacing of the ripple structure according to Mie theory. Four quartz aerosols with different particle size are tested during the experiment, and the particle size measured from the ripple width is compared with the mass median size measured by an electrical low pressure impactor (ELPI). Both techniques have the same measurement tendency, and the measurement deviation by the ripple width method compared with ELPI is less than 15%. Finally, the measurement error of the real-time mass concentration is reduced from 38% to 18% with correction of the simultaneously measured particle size when particle size has changed.

Small-Angle Particle Counting Coupled Photometry for Real-Time Detection of Respirable Particle Size Segmentation Mass Concentration

“…Figure 4 shows the Mie scattering characteristics of the four kinds of particles varying in particle size from 0.1 to 10 μm at a detection angle of 20 ± 5°. Since standard spherical particles are used for simulation in the calculation, there are more oscillations on the curve [ 35 ]. The oscillations will be significantly reduced when some irregular particles are used in the real environment.…”

Real-time Monitoring of Suspended Particulate Matter in Indoor Air: Validation and Application of a Light-scattering Sensor

“…This instrument has to be evaluated in the laboratory and collocated for comparison with a Federal Reference Method (FRM) or Federal Equivalent Method (FEM) in the field campaigns each time a new type of aerosol matrix is introduced. Another limitation of the aerosol monitor might be a lack of sensitivity to particles smaller than 0.1 or larger than 15 µm, where light-scattering response is no longer sensitive (Chen et al, 2019;Di Biagio et al, 2019). Mass concentrations of high-volatility compounds might be underestimated by the DustTrak DRX due to the nature of aerosol and slow response of the instrument.…”

A low-cost, label-free microfluidic scanning flow cytometer for high-accuracy quantification of size and refractive index of particles

“…custom flow cells, rotating detectors, motorized iris diaphragms, or numerous photomultiplier tubes) which makes them unsuitable for integration with other lab-on-chip technologies or for pointof-care (POC) applications. [31][32][33] Here, we describe a simple, low-cost microfluidic scanning flow cytometry (μSFC) system for the high-throughput measurement of size and refractive index of single cells. The proposed system uses a single photoreceiver to perform an SFC measurement within a standard polydimethylsiloxane (PDMS) microchip exploiting a linearly variable optical density (OD) filter to reduce the dynamic range of the signal and to increase its signal-to-noise ratio (SNR).…”

“…custom flow cells, rotating detectors, motorized iris diaphragms, or numerous photomultiplier tubes) which makes them unsuitable for integration with other lab-on-chip technologies or for point-of-care (POC) applications. 31–33…”