A method and system for measuring the spatial field of aerosol distribution

Abstract

This invention belongs to the field of optical measurement technology, specifically relating to a method and system for measuring the spatial field of aerosol distribution. The method includes: dividing a square region inscribed within a measurement area into several squares, where the aerosol concentration and particle size distribution function are denoted as in each square; distributing multiple lasers at or outside the boundary of the measurement area, with the laser beams pointing to different combinations of squares, and all combinations covering the entire measurement area; sequentially activating each laser, and receiving scattered light intensity through multiple photoelectric conversion devices distributed at or outside the boundary of the measurement area for each laser activation; constructing a formula for the scattered light intensity received by each photoelectric conversion device based on the scattered light intensity of the aerosol particle group in each square; and obtaining the sum of the values ​​for each square by solving a system of equations. This invention can reconstruct the spatial field of aerosol distribution within a non-negligible measurement area.

Description

Technical Field

[0001] This invention belongs to the field of optical measurement technology, and more specifically, relates to a method and system for measuring the spatial field of aerosol distribution. Background Technology

[0002] Aerosols are solid or liquid particles suspended in a gaseous medium, typically ranging in size from a few nanometers to tens of micrometers. The concentration, size distribution, and spatial evolution of aerosols directly impact climate change, air quality, and public health, and are closely linked to the environment and human health. Aerosol distribution field measurement technology will contribute to advancements in areas such as urban smog early warning, cleanroom cleanliness monitoring, weather forecasting, pesticide spraying measurement, detection of toxic fumes and biochemical threats, and fuel combustion efficiency testing. Therefore, accurate measurement of aerosol distribution fields is crucial for scientific research and engineering applications.

[0003] Traditional methods for measuring aerosol concentration and particle size parameters include gravimetric analysis, beta-ray diffraction, scanning electromigration, aerodynamic analysis, electron microscopy, and light scattering. However, gravimetric analysis, beta-ray diffraction, scanning electromigration, aerodynamic analysis, and electron microscopy all suffer from drawbacks such as long sampling times, poor real-time performance, and susceptibility to external interference, making them unsuitable for real-time online monitoring. Furthermore, the equipment used for these methods is expensive, complex to operate, and can only be used in laboratory environments, making them unsuitable for field measurements.

[0004] More importantly, the above methods are only applicable to laboratory sampling and contact measurements, and are point measurement methods, which cannot be used for measuring the spatial field of aerosol distribution. Light scattering measurement, as a non-contact measurement method, has gradually become the mainstream method in the field of aerosol measurement due to its advantages such as high real-time performance, wide measurement range, and ease of operation, and has the potential for field measurement. Light scattering can invert the spatial field of aerosol distribution (including aerosol concentration and particle size distribution) by using the scattering characteristics of aerosol particles to incident light and the measured scattered light intensity information. However, due to the superposition and coupling problem of scattered light throughout the entire optical path when the optical path is long, existing research on light scattering aerosol measurement methods is mostly focused on measuring physical parameters such as aerosol concentration and particle size distribution in small areas and single points, and still lacks methods for measuring the spatial aerosol distribution field with a non-negligible measurement area. Summary of the Invention

[0005] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a method and system for measuring the spatial field of aerosol distribution, the purpose of which is to realize the spatial reconstruction of the aerosol concentration and particle size distribution field within a non-negligible measurement area.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for measuring the spatial field of aerosol distribution is provided, comprising:

[0007] The square region inscribed within the measurement area is divided into several squares, and the aerosol concentration in each square is... The particle size distribution function is ;

[0008] Multiple lasers are distributed in a distributed manner at the boundary of the measurement area and / or in the area outside the boundary, and the orientation of the multiple lasers satisfies the following condition: the combination of squares pointed to by each laser beam is different, and all the square combinations cover the entire measurement area.

[0009] Each laser is turned on in sequence. For each laser turned on, multiple photoelectric conversion devices distributed in the boundary and / or outside the boundary of the measurement area receive the scattered light intensity. The scattered light intensity received by each photoelectric conversion device is the sum of the scattered light intensity of the aerosol particle group in each grid through which the current laser beam passes.

[0010] The intensity of light scattered by the aerosol particle group in each square is expressed as: multiplying the intensity of light scattered by a single particle in the square by... Then, the scattered light intensity of particles with different sizes was summed, and the summation result was compared with... Multiplication; constructing a formula for the scattered light intensity received by each photoelectric conversion device based on the scattered light intensity of the aerosol particle group in each square; obtaining the value of each square by solving the system of equations. and The spatial field measurement of aerosol distribution was completed.

[0011] Furthermore, different lasers emit beams with different wavelengths, with each laser emitting a beam in the range of 450-1550nm.

[0012] Furthermore, the number of lasers and photoelectric conversion devices, as well as the optical path arrangement, are obtained through iterative optimization using machine learning algorithms.

[0013] Furthermore, the formula for the intensity of scattered light received by each photoelectric conversion device is:

[0014]

[0015] In the formula, This indicates that the photoelectric converter received the first... The intensity of light scattered by a group of particles in a square grid. For the first The concentration of aerosols in each square. The first photoelectric converter received In each square The dimensionless particle size is , refractive index The intensity of light scattered by a single aerosol particle. This indicates that the photoelectric converter receives the first... The angle at which the scattered light is received by each square. , The wavelength of the laser beam Indicates the particle size of a single particle.

[0016] According to another aspect of the present invention, an aerosol distribution spatial field measurement system is provided, comprising: multiple lasers, multiple photoelectric conversion devices, a signal amplification and filtering module, an analog-to-digital converter, and a main controller;

[0017] In this system, multiple lasers are distributed and positioned at the boundary of the measurement area and / or outside the boundary, and the orientation of the multiple lasers satisfies the following conditions: the combination of squares pointed to by each laser beam is different, and all the square combinations cover the entire measurement area; each square is obtained by dividing the measurement area into square regions inscribed within it.

[0018] Multiple photoelectric conversion devices are distributed in the measurement area boundary and / or outside the boundary. Each photoelectric converter is used to receive the scattered light intensity of the square through which the beam of a single laser is turned on, and convert the scattered light intensity into an electrical signal. The scattered light intensity received by each photoelectric conversion device is the sum of the scattered light intensity of the aerosol particle group in each square through which the current laser beam passes.

[0019] The signal amplification and filtering module is used to amplify and smooth the electrical signal before inputting it into the analog-to-digital converter; the analog-to-digital converter is used to perform analog-to-digital conversion on the received data to obtain a digital signal.

[0020] The main controller is used to control the sequential activation of multiple lasers, and upon receiving a digital signal, it constructs a formula for the intensity of scattered light received by each photoelectric conversion device. By solving a system of equations, it obtains the intensity of light in each square. and Complete the spatial field measurement of aerosol distribution; the scattered light intensity of aerosol particles in each square is expressed as: multiplying the scattered light intensity of a single particle in the square by... Then, the scattered light intensity of particles with different sizes was summed, and the summation result was compared with... Multiply.

[0021] Furthermore, different lasers emit beams with different wavelengths, with each laser emitting a beam in the range of 450-1550nm.

[0022] Furthermore, the number of lasers and photoelectric conversion devices, as well as the optical path arrangement, are obtained through iterative optimization using machine learning algorithms.

[0023] Furthermore, the formula for the intensity of scattered light received by each photoelectric conversion device constructed by the main controller is as follows:

[0024]

[0025] In the formula, This indicates that the photoelectric converter received the first... The intensity of light scattered by a group of particles in a square grid. For the first The concentration of aerosols in each square. The first photoelectric converter received In each square The dimensionless particle size is , refractive index The intensity of light scattered by a single aerosol particle. This indicates that the photoelectric converter receives the first... The angle at which the scattered light is received by each square. , The wavelength of the laser beam Indicates the particle size of a single particle.

[0026] In summary, compared with the prior art, the technical solutions conceived by this invention have the following main advantages:

[0027] 1. This invention proposes a method for measuring the spatial field of aerosol distribution. First, the measurement area is divided into multiple squares, with the aerosol concentration in each square being [missing information]. The particle size distribution function is This invention achieves spatial discretization of aerosol distribution. Compared to traditional overall averaging measurement methods, spatial discretization of aerosol distribution reveals the non-uniform spatial distribution characteristics of aerosol concentration and particle size. To avoid potential measurement blind spots when irradiated by a single beam, this invention employs a distributed arrangement of multiple lasers, with each laser beam irradiating a different grid, ensuring that the laser beam covers all grids within the measurement area and improving the spatial resolution of the aerosol distribution field within the measurement area. Furthermore, by receiving scattered light intensity through multiple photoelectric conversion devices, and based on Mie scattering theory and combining the weighted summation of the scattered light intensity of a single particle with the particle size distribution within each grid, a mathematical model is established from scattered light intensity to aerosol concentration and particle size distribution. By solving this set of equations, the aerosol spatial field is reconstructed, effectively solving the problem of inverting multi-parameter aerosol distribution from optical measurement signals, and achieving spatial reconstruction of the aerosol concentration and particle size distribution field within a non-negligible measurement area.

[0028] 2. This invention also proposes to use lasers of different wavelengths to emit beams. This fully utilizes the differences in scattering characteristics of aerosol particles to different wavelengths of light, enhancing the ability to identify aerosol particle size distribution. Through multi-wavelength laser irradiation, changes in aerosol particle size distribution can be reflected from scattering characteristics, effectively improving the accuracy and sensitivity of particle size differentiation. The laser wavelength covers a wide spectral range from 450 nm (blue light) to 1550 nm (near-infrared). The interaction between light of different wavelengths and aerosol particles varies significantly. Shorter wavelengths (around 450 nm) are more sensitive to scattering of smaller particles (such as fine particulate matter PM2.5), while longer wavelengths (near-infrared) are more suitable for penetrating dense aerosols and have a stronger response to larger particles. Using lasers in the 450-1550 nm range can adapt to various environments such as clean air, complex atmospheric pollution, fire smoke, and dust storms. In particular, the near-infrared wavelength has advantages in energy transmission efficiency and atmospheric transmittance. The wide band coverage significantly improves the detection and identification capabilities of aerosols with multiple particle size ranges. Attached Figure Description

[0029] Figure 1 A flowchart of a method for measuring the spatial field of aerosol distribution provided in an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram showing the arrangement of the laser and photoelectric converter in a square measurement area provided in an embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram showing the arrangement of the laser and photoelectric converter in an irregular measurement area provided in an embodiment of the present invention.

[0032] Figure 4 This is a schematic diagram showing the arrangement of M lasers and N photoelectric converters in an irregular measurement area provided in an embodiment of the present invention.

[0033] Figure 5 A block diagram of an aerosol distribution spatial field measurement system provided in an embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Example 1

[0036] A method for measuring the spatial field of aerosol distribution, such as Figure 1 As shown, it includes:

[0037] The square region inscribed within the measurement area is divided into several squares, and the aerosol concentration in each square is... The particle size distribution function is ;

[0038] Multiple lasers are distributed in a distributed manner at the boundary of the measurement area and / or in the area outside the boundary, and the orientation of the multiple lasers satisfies the following condition: the combination of squares pointed to by each laser beam is different, and all the square combinations cover the entire measurement area.

[0039] Each laser is turned on in sequence. For each laser turned on, multiple photoelectric conversion devices distributed in the boundary and / or outside the boundary of the measurement area receive the scattered light intensity. The scattered light intensity received by each photoelectric conversion device is the sum of the scattered light intensity of the aerosol particle group in each grid through which the current laser beam passes.

[0040] The intensity of light scattered by the aerosol particle group in each square is expressed as: multiplying the intensity of light scattered by a single particle in the square by... Then, the scattered light intensity of particles with different sizes was summed, and the summation result was compared with... Multiplication; constructing a formula for the scattered light intensity received by each photoelectric conversion device based on the scattered light intensity of the aerosol particle group in each square; obtaining the value of each square by solving the system of equations. and The spatial field measurement of aerosol distribution was completed.

[0041] When a beam of light shines on aerosol particles, optical scattering occurs. The intensity of the scattered light depends on parameters such as the incident light intensity, the incident light wavelength, the observation angle of the scattered light, and the particle size of the aerosol particles. According to optical scattering theory:

[0042]

[0043]

[0044] in, To observe the scattering angle The intensity of light scattered by the particle group at that location. The concentration of aerosols. Let be the particle size distribution function. The particle size of the aerosol particles is denoted as . The intensity of scattered light from a single particle is related to the incident light wavelength, detection distance, and the angle of observation of the scattered light. Dimensionless particle size and aerosol refractive index The intensity of the scattered light from the particle group can be obtained by integrating over a single particle.

[0045] In the above equation For measured values, and The unknown to be measured Since the unknowns in the equation are known quantities, solving the equation requires solving multiple sets of equations simultaneously. Therefore, multiple sets of measured values ​​are needed. .

[0046] To solve this problem, a measurement system is deployed in space. The laser is placed at or outside the boundary of the measurement area, and the photoelectric conversion device is also placed at or outside the boundary of the measurement area. The measurement area is divided into several small squares of equal size, with an aerosol concentration of [missing information - likely a specific value]. The particle size distribution function is When a laser beam passes through the area to be measured, it passes through several small squares. The intensity of the scattered light received by the photoelectric conversion device is the sum of the scattered light intensities of aerosol particles in all the small squares through which the laser beam passes.

[0047] For ease of calculation, the integral calculation in equation (1) is simplified to the summation operation in equation (3). When the number of grids through which the laser beam passes is At that time, the intensity of the scattered light received by the photoelectric converter It can be represented as:

[0048]

[0049] In the formula, This indicates that the photoelectric converter received the first... The intensity of light scattered by a group of particles in a square grid. For the first The concentration of aerosols in each square. The first photoelectric converter received In each square The dimensionless particle size is , refractive index The intensity of light scattered by a single aerosol particle. This indicates that the photoelectric converter receives the first... The angle at which the scattered light from the nth square is received can also be called the nth square. The angle of observation of scattered light in each grid , The wavelength of the laser beam Indicates the particle size of a single particle.

[0050] In order to detect the scattered light intensity of all small squares in the measurement area, the measurement system should include several lasers and several photoelectric converters. When there is a photoelectric converter in the measurement system, equation (3) can be written in the form of the following matrix.

[0051]

[0052] When there is When using a single laser, one can obtain... A matrix equation similar to equation (3) can be obtained by solving these equations to obtain the aerosol concentration and particle size distribution in each small square, and thus obtain the aerosol concentration and particle size distribution field.

[0053] Lasers can have multiple wavelengths, and a single laser can also emit laser beams of multiple wavelengths, which can be preferred. Different lasers emit beams with different wavelengths, and the wavelength of the beam emitted by each laser is in the range of 450-1550nm.

[0054] While ensuring that the laser beam passes through each small grid, the design of the measurement system can be simplified by reducing the number of lasers and photoelectric converters. Furthermore, the angle at which the scattered light intensity of the photoelectric converter is received can be a spatial angle, meaning the laser and photoelectric converter do not need to be on the same horizontal plane, or they can be within a planar angle, ensuring flexibility in system setup.

[0055] Preferably, the number of lasers and photoelectric conversion devices and the arrangement of optical paths are obtained through iterative optimization using machine learning algorithms.

[0056] like Figure 2 As shown, when the measurement area is square, it can be divided into 16 small squares. The laser and photoelectric converter can be arranged as shown in the figure. The laser beam passes through squares 1, 5, 9, and 13. The scattered light intensity received by photoelectric converter 1 is the sum of the scattered light intensities at photoelectric converter 1 from these four small squares. (Upper and lower limits in the particle size distribution function) and The wavelengths are taken as 1000 nm and 10 nm respectively. Examples of laser wavelengths selectable are 450 nm, 650 nm, 850 nm, and 1050 nm. Examples of photodiodes can be used as photoconverters, specifically PTSMD3528 or BPV10. Particle size distribution function... This can be described using a log-normal distribution model:

[0057]

[0058] in, and These represent the median particle size and standard deviation, respectively.

[0059] Therefore, solving the particle size distribution function can be transformed into solving the median particle size in the normal distribution model. and standard deviation .

[0060] Scattered light intensity The original encoding of the analog-to-digital converter (ADC) can be used instead; if the ADC resolution is 12 bits, then... The intensity of scattered light from a single particle. It can be calculated using Mie scattering theory or the discrete dipole approximation (DDA) method.

[0061] The aerosol distribution field can be measured by following these steps:

[0062] The first step is to measure the background signal of each photoelectric converter in an aerosol-free environment. The background signal is generally the dark current or bias voltage of the photoelectric converter. The analog-to-digital converter converts the background signal into a digital signal, denoted as . In subsequent sampling, the sampled value needs to be subtracted from the corresponding background signal.

[0063] The second step involves sequentially turning on all lasers. After each laser is turned on and stabilized, the voltage signals from all photoelectric converters are collected. These signals are then output as digital signals via analog-to-digital converters. The measurement result is subtracted from the background signal obtained in the first step to obtain the final result. ;

[0064] Third step: Construct the following equation based on the measured data:

[0065]

[0066] For equation (6) Find the inverse, and you will get Multiply by the right on both sides It can be found The median particle size in the log-normal distribution model was obtained. and standard deviation This leads to the determination of the aerosol distribution field.

[0067] like Figure 3 As shown, even when the measurement area is irregularly shaped, small squares can still be used to divide the measurement area, and the laser and photoelectric converter can be arranged on the boundary of the squares.

[0068] like Figure 4 As shown, even when the measurement area is irregularly shaped, small squares can still be used to divide the measurement area, and the laser and photoelectric converter can be placed outside the boundary of the measurement area.

[0069] Example 2

[0070] An aerosol distribution spatial field measurement system includes: multiple lasers, multiple photoelectric conversion devices, a signal amplification and filtering module, an analog-to-digital converter, and a main controller;

[0071] In this system, multiple lasers are distributed and positioned at the boundary of the measurement area and / or outside the boundary, and the orientation of the multiple lasers satisfies the following conditions: the combination of squares pointed to by each laser beam is different, and all the square combinations cover the entire measurement area; each square is obtained by dividing the measurement area into square regions inscribed within it.

[0072] Multiple photoelectric conversion devices are distributed in the measurement area boundary and / or outside the boundary. Each photoelectric converter is used to receive the scattered light intensity of the square through which the beam of a single laser is turned on, and convert the scattered light intensity into an electrical signal. The scattered light intensity received by each photoelectric conversion device is the sum of the scattered light intensity of the aerosol particle group in each square through which the current laser beam passes.

[0073] The signal amplification and filtering module is used to amplify and smooth the electrical signal before inputting it into the analog-to-digital converter; the analog-to-digital converter is used to perform analog-to-digital conversion on the received data to obtain a digital signal.

[0074] The main controller is used to control the sequential activation of multiple lasers, and upon receiving a digital signal, it constructs a formula for the intensity of scattered light received by each photoelectric conversion device. By solving a system of equations, it obtains the intensity of light in each square. and Complete the spatial field measurement of aerosol distribution; the scattered light intensity of aerosol particles in each square is expressed as: multiplying the scattered light intensity of a single particle in the square by... Then, the scattered light intensity of particles with different sizes was summed, and the summation result was compared with... Multiply.

[0075] In practical implementation, the measurement of the spatial field of aerosol distribution can be achieved by following these steps:

[0076] The first step is to measure the background signal of each photoelectric converter in an aerosol-free environment. The background signal is generally the dark current or bias voltage of the photoelectric converter. The analog-to-digital converter converts the background signal into a digital signal, denoted as . In subsequent sampling, the sampled value needs to be subtracted from the corresponding background signal.

[0077] The second step involves the main controller sequentially activating all lasers. After each laser activation and stabilization period, the voltage signals from all photoelectric converters are collected. The analog-to-digital converter outputs a digital signal to the main controller. The measurement result is then subtracted from the background signal obtained in the first step to obtain the final result. ;

[0078] The third step is for the main controller to solve the matrix equation shown in equation (4) based on the measured data, thereby obtaining the aerosol distribution parameters. This is done by applying the matrix equation shown in equation (4) to the main controller. Find the inverse, and you will get Multiply by the right on both sides It can be found This leads to the determination of the aerosol distribution field.

[0079] like Figure 5 The diagram shows the overall block diagram of the aerosol distribution spatial field measurement system. The main controller controls whether the laser group emits a laser beam by controlling the laser driver. The laser group consists of multiple lasers. The photoelectric converter group consists of multiple photoelectric converters. The voltage (current) signal output by the converter is amplified and filtered before being sent to the analog-to-digital converter (ADC). The main controller is responsible for controlling the ADC to convert the analog voltage signal into a digital signal and save it into the main controller's memory unit.

[0080] Preferably, different lasers emit beams with different wavelengths, with each laser emitting a beam in the range of 450-1550nm.

[0081] Preferably, the number of lasers and photoelectric conversion devices and the arrangement of optical paths are obtained through iterative optimization using machine learning algorithms.

[0082] Preferably, the formula for the intensity of scattered light received by each photoelectric conversion device constructed by the main controller is:

[0083]

[0084] In the formula, This indicates that the photoelectric converter received the first... The intensity of light scattered by a group of particles in a square grid. For the first The concentration of aerosols in each square. The first photoelectric converter received In each square The dimensionless particle size is , refractive index The intensity of light scattered by a single aerosol particle. This indicates that the photoelectric converter receives the first... The angle at which the scattered light is received by each square. , The wavelength of the laser beam Indicates the particle size of a single particle.

[0085] The relevant technical solutions are the same as in Embodiment 1, and will not be repeated here.

[0086] In summary, this embodiment proposes a spatial field measurement method for aerosol distribution based on multi-wavelength and multi-angle optical scattering. Through innovative hardware architecture and algorithm co-design, it realizes the spatial reconstruction of aerosol concentration and particle size distribution fields.

[0087] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring the spatial field of aerosol distribution, characterized in that, include: The square region inscribed within the measurement area is divided into several squares, and the aerosol concentration in each square is... The particle size distribution function is ; Multiple lasers are distributed in a distributed manner at the boundary of the measurement area and / or in the area outside the boundary, and the orientation of the multiple lasers satisfies the following condition: the combination of squares pointed to by each laser beam is different, and all the square combinations cover the entire measurement area. Each laser is turned on in sequence. For each laser turned on, multiple photoelectric conversion devices distributed in the boundary and / or outside the boundary of the measurement area receive the scattered light intensity. The scattered light intensity received by each photoelectric conversion device is the sum of the scattered light intensity of the aerosol particle group in each grid through which the current laser beam passes. The intensity of light scattered by the aerosol particle group in each square is expressed as: multiplying the intensity of light scattered by a single particle in the square by... Then, the scattered light intensity of particles with different sizes was summed, and the summation result was compared with... Multiplication; constructing a formula for the scattered light intensity received by each photoelectric conversion device based on the scattered light intensity of the aerosol particle group in each square; obtaining the value of each square by solving the system of equations. and Complete the spatial field measurement of aerosol distribution; The number of lasers and photoelectric conversion devices and the arrangement of optical paths are obtained through iterative optimization using machine learning algorithms. While ensuring that each small grid has a laser beam passing through, the design of the measurement system is simplified by reducing the number of lasers and photoelectric conversion devices. The scattered light intensity receiving angle of the photoelectric conversion device is a spatial angle, that is, the laser and photoelectric conversion device are on or not on the same horizontal plane. The formula for the intensity of scattered light received by each photoelectric conversion device is: In the formula, This indicates that the photoelectric converter received the first... The intensity of light scattered by a group of particles in a square grid. For the first The concentration of aerosols in each square. The first photoelectric converter received In each square The dimensionless particle size is , refractive index The intensity of light scattered by a single aerosol particle. This indicates that the photoelectric converter receives the first... k The angle at which the scattered light is received by each square. , The wavelength of the laser beam Indicates the particle size of a single particle; Particle size distribution function The model is a log-normal distribution. When there are n photoelectric converters, the intensity of scattered light received by the n photoelectric converters can be written in the form of the following matrix equation: When there are M lasers, M matrix equations are obtained. By solving these equations, the aerosol concentration and particle size distribution in each small square can be obtained, and thus the aerosol concentration and particle size distribution field can be obtained. A single laser can emit laser beams of multiple wavelengths. Different lasers emit beams of different wavelengths, with each laser emitting a beam in the range of 450-1550nm.

2. A spatial field measurement system for aerosol distribution, characterized in that, include: Multiple lasers, multiple photoelectric conversion devices, signal amplification and filtering modules, analog-to-digital converters, and a main controller; In this system, multiple lasers are distributed and positioned at the boundary of the measurement area and / or outside the boundary, and the orientation of the multiple lasers satisfies the following conditions: the combination of squares pointed to by each laser beam is different, and all the square combinations cover the entire measurement area; each square is obtained by dividing the measurement area into square regions inscribed within it. Multiple photoelectric conversion devices are distributed in the measurement area boundary and / or outside the boundary. Each photoelectric converter is used to receive the scattered light intensity of the square through which the beam of a single laser is turned on, and convert the scattered light intensity into an electrical signal. The scattered light intensity received by each photoelectric conversion device is the sum of the scattered light intensity of the aerosol particle group in each square through which the current laser beam passes. The signal amplification and filtering module is used to amplify and smooth the electrical signal before inputting it into the analog-to-digital converter; the analog-to-digital converter is used to perform analog-to-digital conversion on the received data to obtain a digital signal. The main controller is used to control the sequential activation of multiple lasers, and upon receiving a digital signal, it constructs a formula for the intensity of scattered light received by each photoelectric conversion device. By solving a system of equations, it obtains the intensity of light in each square. and Complete the spatial field measurement of aerosol distribution; the scattered light intensity of aerosol particles in each square is expressed as: multiplying the scattered light intensity of a single particle in the square by... Then, the scattered light intensity of particles with different sizes was summed, and the summation result was compared with... Multiply; The number of lasers and photoelectric conversion devices and the arrangement of optical paths are obtained through iterative optimization using machine learning algorithms. While ensuring that each small grid has a laser beam passing through, the design of the measurement system is simplified by reducing the number of lasers and photoelectric conversion devices. The scattered light intensity receiving angle of the photoelectric conversion device is a spatial angle, that is, the laser and photoelectric conversion device are on or not on the same horizontal plane. The formula for the intensity of scattered light received by each photoelectric conversion device constructed by the main controller is: In the formula, This indicates that the photoelectric converter received the first... The intensity of light scattered by a group of particles in a square grid. For the first The concentration of aerosols in each square. The first photoelectric converter received In each square The dimensionless particle size is , refractive index The intensity of light scattered by a single aerosol particle. This indicates that the photoelectric converter receives the first... k The angle at which the scattered light is received by each square. , The wavelength of the laser beam Indicates the particle size of a single particle; Particle size distribution function The model is a log-normal distribution. When there are n photoelectric converters, the intensity of scattered light received by the n photoelectric converters can be written in the form of the following matrix equation: When there are M lasers, M matrix equations are obtained. By solving these equations, the aerosol concentration and particle size distribution in each small square can be obtained, and thus the aerosol concentration and particle size distribution field can be obtained. A single laser can emit laser beams of multiple wavelengths. Different lasers emit beams of different wavelengths, with each laser emitting a beam in the range of 450-1550nm.

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