Study on polarization scattering applied in aerosol recognition in the air

Li, Da; Chen, Fei; Zeng, Nan; Qiu, Zhigang; He, Honghui; He, Yonghong; Ma, Hui

doi:10.1364/oe.27.00a581

Cited by 31 publications

(17 citation statements)

References 45 publications

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“…To investigate the effect of sensor number on the information content, we varied θ over a range that encompasses the sensor numbers of instruments previously reported in the literature. Examples at either end are the instrument described by Li et al (2019) with four sensors and laser imaging polar nephelometers with a maximal angular resolution of θ ≈1 • (Dolgos and Martins, 2014). The range of simulated θ values is shown in Table 2, along with the corresponding N θ values for base case truncation angles, i.e.…”

Section: Angular Characteristics: Number Of Probed Angles Assuming Ev...mentioning

confidence: 99%

“…Multidetector nephelometers can have either very basic designs (e.g. four angles and only one wavelength; Li et al, 2019), or more complex designs, such as the instruments introduced by Barkey et al (2007) and Nakagawa et al (2016), which measure both PF and PPF at 21 and 17 angles, respectively. A third design class is the laser imaging nephelometer (Dolgos and Martins, 2014;Ahern et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

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Information content and aerosol property retrieval potential for different types of in situ polar nephelometer data

Moallemi

Modini²,

Lapyonok³

et al. 2022

Atmos. Meas. Tech.

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Abstract. Polar nephelometers are in situ instruments used to measure the angular distribution of light scattered by aerosol particles. These types of measurements contain substantial information about the properties of the aerosol being probed (e.g. concentrations, sizes, refractive indices, shape parameters), which can be retrieved through inversion algorithms. The aerosol property retrieval potential (i.e. information content) of a given set of measurements depends on the spectral, polarimetric, and angular characteristics of the polar nephelometer that was used to acquire the measurements. To explore this issue quantitatively, we applied Bayesian information content analysis and calculated the metric degrees of freedom for signal (DOFS) for a range of simulated polar nephelometer instrument configurations, aerosol models and test cases, and assumed levels of prior knowledge about the variances of specific aerosol properties. Assuming a low level of prior knowledge consistent with an unconstrained ambient/field measurement setting, we demonstrate that even very basic polar nephelometers (single wavelength, no polarization capability) will provide informative measurements with a very high retrieval potential for the size distribution and refractive index state parameters describing simple unimodal, spherical test aerosols. As expected, assuming a higher level of prior knowledge consistent with well-constrained laboratory applications leads to a reduction in potential for information gain via performing the polarimetric measurement. Nevertheless, we show that in this situation polar nephelometers can still provide informative measurements: e.g. it can be possible to retrieve the imaginary part of the refractive index with high accuracy if the laboratory setting makes it possible to keep the probed aerosol sample simple. The analysis based on a high level of prior knowledge also allows us to better assess the impact of different polar nephelometer instrument design features in a consistent manner for retrieved aerosol parameters. The results indicate that the addition of multi-wavelength and/or polarimetric measurement capabilities always leads to an increase in information content, although in some cases the increase is negligible, e.g. when adding a fourth, near-IR measurement wavelength for the retrieval of unimodal size distribution parameters or if the added polarization component has high measurement uncertainty. By considering a more complex bimodal, non-spherical-aerosol model, we demonstrate that performing more comprehensive spectral and/or polarimetric measurements leads to very large benefits in terms of the achieved information content. We also investigated the impact of angular truncation (i.e. the loss of measurement information at certain scattering angles) on information content. Truncation at extreme angles (i.e. in the near-forward or near-backward directions) results in substantial decreases in information content for coarse-aerosol test cases. However for fine-aerosol test cases, the sensitivity of DOFS to extreme-angle truncation is noticeably smaller and can be further reduced by performing more comprehensive measurements. Side angle truncation has very little effect on information content for both the fine and coarse test cases. Furthermore, we demonstrate that increasing the number of angular measurements generally increases the information content. However, above a certain number of angular measurements (∼20–40) the observed increases in DOFS plateau out. Finally, we demonstrate that the specific placement of angular measurements within a nephelometer can have a large impact on information content. As a proof of concept, we show that a reductive greedy algorithm based on the DOFS metric can be used to find optimal angular configurations for given target aerosols and applications.

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Section: Angular Characteristics: Number Of Probed Angles Assuming Ev...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Information content and aerosol property retrieval potential for different types of in situ polar nephelometer data

Moallemi

Modini²,

Lapyonok³

et al. 2022

Atmos. Meas. Tech.

View full text Add to dashboard Cite

show abstract

“…At the same time, the polarized light path need not be designed separately, as long as the current dynamic light scattering light path-polarizing element can be added. At present, it has been applied to biomedicine ( Xiang-Yu et al, 2019 ; He et al, 2021 ; Meng et al, 2021 ; Shen et al, 2021 ; Song et al, 2021 ), marine microbial detection ( Wang et al, 2018 ; Li et al, 2020; Liu et al, 2020 ; Wang et al, 2020 ; Li et al, 2021 ), atmospheric detection ( Li et al, 2019 ; Qizhi et al, 2021 ), etc. It is believed that with the introduction of polarized light technology, the accuracy, measurable parameters, and applicable range of the dynamic light scattering method will be greatly improved.…”

Section: Online Detection Of Nanoparticlesmentioning

confidence: 99%

Detection Methods of Nanoparticles Synthesized by Gas-Phase Method: A Review

Zhang

Zhao

et al. 2022

Front. Chem.

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The detection of nanoparticles is the basis of the study of synthesis mechanism, active regulation of the synthesis process, and the study of nanoparticle properties after synthesis. It is significantly meaningful to the academia and engineering industry. Although there are many relevant detection methods at present, each method has its own advantages and disadvantages, and their measurement quantity and application conditions are also different. There is a lack of unified sorting and generalization. In this paper, the significance of detection of nanoparticles synthesized by a gas-phase method is introduced, the development of detection technology is reviewed, and the future is prospected. It is hoped that this paper will provide a reference for the detection of nanoparticles under various conditions and for the development of new detection methods.

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“…To investigate the effect of sensor number on the information content, we varied Δθ 250 over a range that encompasses the sensor numbers of instruments previously reported in the literature. Examples at either end are the instrument described by Li et al (2019) with four sensors, or laser imaging polar nephelometers with a maximal angular resolution of Δθ≈1˚ (Dolgos and Martins, 2014). The range of simulated Δθ values is shown in Table 2, along with the corresponding Nθ values for base case truncation angles, i.e., α = 5˚ and β = 0˚.…”

Section: Angular Characteristics: Number Of Probed Angles Assuming Ev...mentioning

confidence: 99%

“…Here we assess how the information content increases with increasing number of angular data points for the angular configurations of four polar nephelometer designs previously reported in the literature (Li et al, 2019;Nakagawa et al, 2016;Dolgos and Martins, 2014;Dick et al, 2007). For each of these angular configurations, different spectral and polarimetric capabilities are considered (specifically, all four combinations of data sets that would be obtained with single/triple wavelength and radiometric/polarimetric measurements).…”

Section: Dependence Of Information Content On the Angular Configurati...mentioning

confidence: 99%

Information content and aerosol property retrieval potential for different types of in situ polar nephelometer data

Moallemi

Modini

Lapyonok

et al. 2022

Preprint

View full text Add to dashboard Cite

Abstract. Polar nephelometers are in situ instruments used to measure the angular distribution of light scattered by aerosol particles. These type of measurements contain substantial information about the properties of the aerosol being probed (e.g. concentrations, sizes, refractive indices, shape parameters), which can be retrieved through inversion algorithms. The aerosol property retrieval potential (i.e., information content) of a given set of measurements depends on the spectral, polarimetric and angular characteristics of the polar nephelometer that was used to acquire it. To explore this issue quantitatively, we applied Bayesian information content analysis and calculated the metric Degrees of Freedom for Signal (DOFS) for a range of simulated polar nephelometer instrument configurations, aerosol models and test cases, and assumed levels of prior knowledge about the variances of specific aerosol properties. Assuming a low level of prior knowledge consistent with an unconstrained ambient/field measurement setting, we demonstrate that even very basic polar nephelometers (single wavelength, no polarization capability) will provide informative measurements with very high retrieval potential for the size distribution and refractive index state parameters describing simple unimodal, spherical test aerosols. As expected, assuming a higher level of prior knowledge consistent with well constrained laboratory applications leads to a reduction in potential for information gain via performing the polarimetric measurement. This analysis allows us to better assess the impact of different polar nephelometer instrument design features in a consistent manner for retrieved aerosol parameters. The results indicate that the addition of multi-wavelength and/or polarimetric measurement capabilities always leads to an increase in information content, although in some cases the increase is negligible: e.g. when adding a fourth, near-IR measurement wavelength for the retrieval of unimodal size distribution parameters, or if the added polarization component has high measurement uncertainty. By considering a more complex bimodal, non-spherical aerosol model, we demonstrate that performing the more comprehensive spectral and/or polarimetric measurements leads to very large benefits in terms of the achieved information content. We also investigated the impact of angular truncation (i.e., the loss of measurement information at certain scattering angles) on information content. Truncation at extreme angles (i.e., in the near-forward or –backward directions) results in substantial decreases in information content for coarse aerosol test cases. However for fine aerosol test cases, the sensitivity of DOFS to extreme angle truncation is noticeably smaller and can be further reduced by performing more comprehensive measurements. Side-angle truncation has very little effect on information content for both the fine and coarse test cases. Furthermore, we demonstrate that increasing the number of angular measurements generally increases the information content. However, above a certain number of angular measurements (~20–40) the observed increases in DOFS plateau out. Finally, we demonstrate that the specific placement of angular measurements within a nephelometer can have a large impact on information content. As a proof-of-concept, we show that a reductive greedy algorithm based on the DOFS metric can be used to find optimal angular configurations for given target aerosols and applications.

show abstract

Study on polarization scattering applied in aerosol recognition in the air

Cited by 31 publications

References 45 publications

Information content and aerosol property retrieval potential for different types of in situ polar nephelometer data

Information content and aerosol property retrieval potential for different types of in situ polar nephelometer data

Detection Methods of Nanoparticles Synthesized by Gas-Phase Method: A Review

Information content and aerosol property retrieval potential for different types of in situ polar nephelometer data

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