A multi-angle laser scattering based single particle aerosol monitoring device and method

Abstract

The application discloses a kind of single particle aerosol monitoring device and method based on multi-angle laser scattering, it is related to single particle aerosol monitoring field, the device includes the sampling module, optical module and analysis module connected in turn, sampling module is used to separate stable airflow from ambient air, and the stable airflow is focused, forms single particle particle stream, optical module is used to irradiate single particle particle stream and obtain the multi-angle scattering light information of particle in single particle particle stream, analysis module is used to process the multi-angle scattering light information, identify effective particle, and output effective particle characteristic and concentration data, the application can realize to single particle aerosol particle high precision, high reliability Real-time monitoring and analysis.

Description

Technical Field

[0001] This application relates to the field of single-particle aerosol monitoring, and in particular to a single-particle aerosol monitoring device and method based on multi-angle laser scattering. Background Technology

[0002] Aerosols are stable or quasi-stable systems composed of solid or liquid particles with sizes ranging from 0.001 micrometers to 100 micrometers suspended in a gaseous medium. Based on their biological properties, they can be divided into bioaerosols (such as pollen, spores, viruses, bacteria, etc.) and abiotic aerosols (such as sulfates, nitrates, black carbon, heavy metals, etc.). Aerosols have a profound impact on human health and the ecological environment. In terms of health, inhalable particulate matter (especially PM2.5) poses a significant risk. 2.5 and PM 10 Aerosols can enter and deposit in the human respiratory tract and alveoli through respiration, causing diseases of the respiratory and cardiovascular systems. In terms of the environment, aerosols are a direct cause of reduced atmospheric visibility and the formation of smog. They also participate in complex climate processes by scattering or absorbing solar radiation (such as the cooling effect of sulfates and the warming effect of black carbon). At the same time, some of their components are also major precursors to acid rain.

[0003] Given the widespread impact of aerosols, real-time and accurate monitoring of their physicochemical properties is crucial. Currently, optical scattering technology is the mainstream method in real-time monitoring scenarios outside of laboratories. Its basic principle is: to use a laser to illuminate the particle to be measured, to detect the scattered light pulse signal generated by the particle, and to roughly distinguish and count the particles based on the physical information (such as particle size, shape, surface structure, etc.) contained in the scattered light at different angles.

[0004] However, existing monitoring schemes based on scattering technology have two major drawbacks:

[0005] First, in optical detection systems, traditional equipment often employs a limited-angle scattered light detection scheme that combines side-facing and forward-facing lasers. Due to the limited number of scattered light detectors, the detection range can only cover 50% to 75% of the particle's surface area, failing to acquire omnidirectional scattered light pulse signals. This "incomplete information" makes it difficult for the system to accurately invert the particle's true shape, surface structure, and other key physical characteristics, thus limiting its ability to precisely distinguish between bioaerosols and non-bioaerosols, as well as between different types of aerosols, ultimately affecting the accuracy of particle classification.

[0006] Secondly, traditional aerosol sampling systems often employ simple straight-path designs. A high-flow-rate suction pump directly introduces and transports ambient aerosols to the optical detection cavity. This design lacks a pre-processing step of aerodynamic focusing or dilution dispersion of particles before laser irradiation, making it difficult to effectively prevent multiple particles from simultaneously entering the detection area (i.e., the "particle stacking" phenomenon). When multiple particles pass through the laser beam simultaneously, they may be misidentified by the optical module as a single, larger particle, leading to statistical distortion of particle count, aberration of particle size distribution, and severely impacting the accuracy of subsequent particle concentration calculations.

[0007] Therefore, existing technologies cannot meet the needs for high-precision and high-reliability monitoring and analysis of single aerosol particles. Summary of the Invention

[0008] The purpose of this application is to provide a single-particle aerosol monitoring device and method based on multi-angle laser scattering, which can perform high-precision and high-reliability monitoring and analysis of single-particle aerosol particles.

[0009] To achieve the above objectives, this application provides the following solution:

[0010] In a first aspect, this application provides a single-particle aerosol monitoring device based on multi-angle laser scattering, the multi-angle laser scattering single-particle aerosol real-time monitoring device comprising: a sampling module, an optical module and an analysis module connected in sequence;

[0011] The sampling module is used to separate a stable airflow from the ambient air and focus the stable airflow to form a single-particle stream;

[0012] The optical module is used to irradiate the single-particle stream and acquire multi-angle scattered light information of the particles in the single-particle stream; the optical module includes: a semiconductor laser, multiple single-angle scattered light detectors and a spectral detector connected in sequence.

[0013] The semiconductor laser emits a forward laser beam and a side laser beam, which respectively irradiate the particles, generating scattered light;

[0014] The plurality of single-angle scattering light detectors are used to detect the scattered light from multiple angles and generate multi-angle scattered light pulse signals; the plurality of single-angle scattering light detectors include: Backscattering light detector Backscattering light detector Backscattering photodetector and Backscattering light detector;

[0015] Among them, the forward laser beam irradiation direction, the side laser beam irradiation direction, Detection direction of the backscattering light detector Detection direction of the backscattering light detector and The direction of the backscattering light detector is in the same plane; The direction of the backscattering light detector is related to the direction of the forward laser beam illumination and the direction of the lateral laser beam illumination. Detection direction of the backscattering light detector Detection direction of the backscattering light detector and The direction of the backscattering light detector is not in the same plane;

[0016] The spectral detector is used to perform spectral detection on the multi-angle scattered light pulse signal to obtain multi-angle scattered light information of particles in the single-particle stream.

[0017] The analysis module is used to process the multi-angle scattered light information, identify effective particles, and output effective particle characteristics and concentration data.

[0018] Optionally, the sampling module includes: an air pump and a material nozzle connected in sequence;

[0019] The air intake pump is used to draw ambient air into the main road channel to obtain a stable airflow;

[0020] The material nozzle is used to capture the stable airflow and focus the stable airflow to form the single-particle stream, and to deliver the single-particle stream to the bypass channel.

[0021] Optionally, the analysis module includes: a data receiving unit and a data processing unit;

[0022] The data receiving unit is used to receive multi-angle scattered light information of particles in the single-particle particle stream;

[0023] The data processing unit is used to process the multi-angle scattered light information of particles in the single particle stream, identify effective particles, and output the characteristics and concentration data of the effective particles.

[0024] Optionally, the analysis module further includes a display unit; the display unit is used to display the effective particle characteristics and concentration data.

[0025] Optionally, the forward laser beam is emitted from the semiconductor laser in a horizontal direction; the lateral laser beam is emitted from the semiconductor laser along a direction perpendicular to the forward laser beam, at a 90° counterclockwise angle to the forward laser beam; The direction of the backscattering light detector is 115° counterclockwise from the direction of the lateral laser beam illumination; The direction of the backscattering light detector is the same as the direction of the backscattering light detector. The direction of the light scattering detector is 140° counterclockwise; The direction of the backscattering light detector is the same as the direction of the backscattering light detector. The direction of the light scattering detector is 70° counterclockwise; The direction of the backscattering light detector is the same as the direction of the backscattering light detector. The direction of the light scattering detector is 120° clockwise.

[0026] Secondly, this application provides a method for monitoring single-particle aerosols based on multi-angle laser scattering, the method comprising:

[0027] Obtain a single-particle stream;

[0028] The particles in the single-particle stream are irradiated with forward and lateral laser beams to generate scattered light;

[0029] The scattered light is detected from multiple angles to obtain multi-angle scattered light pulse signals;

[0030] Spectral detection is performed on the multi-angle scattered light pulse signal to obtain multi-angle scattered light information of particles in a single particle stream; the multi-angle scattered light information includes: scattering light pulse, scattering light pulse, scattering light pulse and Information on the width, height, area, and depolarization ratio of the outscattered light pulse; including the forward laser beam illumination direction, the lateral laser beam illumination direction, and so on. In the direction of the scattered light pulse, The direction of the scattered light pulse and The directions of the scattered light pulses are in the same plane; The direction of the scattered light pulse is related to the forward laser beam irradiation direction and the lateral laser beam irradiation direction. In the direction of the scattered light pulse, The direction of the scattered light pulse and The directions of the scattered light pulses are not in the same plane;

[0031] The multi-angle scattered light information of particles in the single particle stream is processed to determine whether the particles in the single particle stream are effective, and the characteristics and concentration data of effective particles are obtained.

[0032] Optionally, the The direction of the scattered light pulse is 115° counterclockwise from the direction of the lateral laser beam irradiation; The direction of the scattered light pulse is related to the The direction of the scattered light pulse is 140° counterclockwise; The direction of the scattered light pulse is related to the The direction of the scattered light pulse is 70° counterclockwise; The direction of the scattered light pulse is related to the The direction of the scattered light pulse is 120° clockwise.

[0033] Optionally, the effective particle characteristics include: particle size, quantity, shape, surface structure, and type of effective particles.

[0034] Optionally, the multi-angle scattered light information of particles in the single-particle particle stream is processed to determine whether the particles in the single-particle particle stream are effective, and effective particle characteristics and concentration data are obtained, specifically including:

[0035] Based on the multi-angle scattered light information, particles in the single-particle particle stream are extracted. , , , Width, height, area, and depolarization ratio of the four-way scattered light pulse;

[0036] Based on the particles in the single-particle particle stream , , , The width of the four-way scattered light pulse is used to determine whether there is particle stacking in the single particle stream; if so, it is discarded; if not, it is determined to be a valid particle.

[0037] Based on the particles in the single-particle particle stream , , , The width, height, area, and depolarization ratio of the four-way scattered light pulse are used to obtain the effective particles. , , , Width, height, area, and depolarization ratio of the four-way scattered light pulse;

[0038] Based on the effective particles , , , The width, height, area, and depolarization ratio of the four-way scattered light pulses are used to obtain the particle size, number, shape, and surface structure of the effective particles.

[0039] Based on the effective particles , , , The area and depolarization ratio of the four-way scattered light pulse are compared with a preset "microparticle fingerprint database" to identify the type of aerosol.

[0040] Based on the number of effective particles and the volume of a single sampling, the number of effective particles within a unit sampling volume is counted, and the aerosol concentration in the air is calculated.

[0041] Optionally, based on the particles in the single-particle particle stream , , , The width of the four-way scattered light pulse is used to determine whether there is particle stacking in the single-particle particle stream; if so, it is discarded; if not, it is determined to be a valid particle, specifically including:

[0042] If particles in a single-particle stream , , , If the width of any pulse in the four-way scattered light pulse exceeds a preset threshold, it is determined to be a stacked particle and is discarded.

[0043] If particles in a single-particle stream , , , If the width of the four-way scattered light pulse does not exceed the preset threshold, it is determined to be a valid particle.

[0044] According to the specific embodiments provided in this application, this application has the following technical effects:

[0045] This application provides a single-particle aerosol monitoring device and method based on multi-angle laser scattering. The device includes a sampling module, an optical module, and an analysis module. The sampling module can focus particles in the airflow to obtain a single-particle particle stream. The optical module causes the particles in the single-particle particle stream to generate scattered light, acquires the multi-angle scattered light pulse signals of the particles, and analyzes them. The analysis module can determine whether the particles are effective based on the particle stacking situation, and processes the multi-angle scattered light information containing information on particle size, quantity, shape, surface structure, and type to finally obtain effective particle characteristics and concentration data, realizing high-precision and high-reliability monitoring and analysis of single-particle aerosol particles. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1A schematic diagram of the functional modules of a single-particle aerosol monitoring device based on multi-angle laser scattering provided in an embodiment of this application;

[0048] Figure 2 for Figure 1 A detailed functional module diagram of the sampling module in a single-particle aerosol monitoring device based on multi-angle laser scattering;

[0049] Figure 3 This is a schematic diagram of the multi-angle scattered light detection direction;

[0050] Figure 4 This is a flowchart illustrating a single-particle aerosol monitoring method based on multi-angle laser scattering, provided as an embodiment of this application. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] In one exemplary embodiment, such as Figure 1 As shown, a single-particle aerosol monitoring device based on multi-angle laser scattering is provided. The multi-angle laser scattering single-particle aerosol real-time monitoring device includes a sampling module, an optical module, and an analysis module connected in sequence.

[0054] The sampling module is used to separate a stable airflow from the ambient air and focus the stable airflow to form a single-particle stream.

[0055] Specifically, such as Figure 2 As shown, the sampling module includes an air intake pump and a material nozzle connected in sequence. The air intake pump is used to draw ambient air into the main channel to obtain a stable airflow; the material nozzle is used to capture the stable airflow and focus it to form the single-particle stream, and then deliver the single-particle stream to the bypass channel.

[0056] In this embodiment, the suction pump draws ambient air into the main channel at a constant flow rate (approximately 10 L / min) to form a stable airflow, allowing airborne particles to be captured. The material nozzle captures single particles (sample gas) from the airflow in the main channel at a flow rate of ≤1 L / min and directs them into the bypass channel. The material nozzle includes a pneumatic focusing unit, whose core structure and working principle are based on the "aerodynamic focusing" technology in fluid mechanics. The pneumatic focusing unit generates a sheath gas flow in the material nozzle, which acts as a "carrier" fluid, flowing stably at a certain flow rate to form an invisible "tube wall" that envelops the sample gas. This focuses the broad, diffuse sample gas flow into a narrow, collimated, and stable particle flow within the bypass channel, which ultimately enters the optical module.

[0057] In this embodiment, the particles in the particle stream are collimated into a sequence of single particles by a material nozzle and then irradiated by a semiconductor laser beam, ensuring that each laser beam irradiates only one single particle at a time.

[0058] The optical module is used to irradiate the single-particle stream and acquire multi-angle scattered light information of the particles in the single-particle stream.

[0059] Specifically, the optical module includes: a semiconductor laser, multiple single-angle scattered light detectors, and a spectral detector connected in sequence; the semiconductor laser is used to irradiate the particles in the single-particle stream with laser light to generate scattered light; the multiple single-angle scattered light detectors are used to detect the scattered light from multiple angles to generate multi-angle scattered light pulse signals; the spectral detector is used to perform spectral detection on the multi-angle scattered light pulse signals to obtain multi-angle scattered light information of the particles in the single-particle stream.

[0060] In this embodiment, the semiconductor laser is used to emit two laser beams, which illuminate the particles. When the particles pass through the laser beams, they generate scattered light in various directions. The height, width, area, and depolarization ratio of the scattered light pulses are closely related to the particle size, shape, and surface structure.

[0061] Specifically, in this embodiment, the semiconductor laser in the optical module emits two laser beams: a forward laser beam and a side laser beam. The forward laser beam is emitted horizontally from the laser and illuminates the particles. The side laser beam is emitted perpendicular to the forward laser beam, at a 90° angle, and illuminates the particles. Each particle passing through the laser beam generates four sets of electrical signals: one... A scattered light pulse, one A scattered light pulse, one A scattered light pulse, one The scattered light pulses. The spectral detector in the optical module records the height, width, area, and depolarization ratio of these four pulses.

[0062] In this embodiment, four single-angle scattering light detectors are used to detect scattered light and obtain scattered light pulse signals, which can help to determine the particle stacking situation, so as to distinguish individual particles and accurately measure the particle size, shape, quantity and other characteristics.

[0063] Specifically, such as Figure 3 As shown, , , The backscattering photodetector is in the same plane as the forward and lateral laser beams. The backscattering photodetector is rotated 115° counterclockwise to the direction of the lateral laser beam. The larger the particle size, The greater the height of the scattered light pulse, the stronger the detection signal. The detection signal is relatively stable and is very sensitive to particle size.

[0064] Backscattering photodetector and The direction of the backscattering light detector is 140° counterclockwise, and 25° counterclockwise from the direction of the lateral laser beam. If the particles are regularly shaped and symmetrical... The closer the depolarization ratio of the scattered light pulse is to The depolarization ratio of the scattered light pulse. If the particle shape is irregular and asymmetrical, The depolarization ratio of the scattered light pulse and The depolarization ratios of the scattered light pulses differ significantly. The scattered light detection is very sensitive to the shape of the particles.

[0065] Backscattering photodetector and The direction of the backscattered light detector is 70° counterclockwise, 45° clockwise with the direction of the lateral laser beam, and 45° counterclockwise with the direction of the forward laser beam. Within the plane of the outward-scattering photodetector. For particles with rough surfaces and complex internal structures (such as pollen grains or cavities), The depolarization ratio of the scattered light pulse is higher. This signal is more sensitive to the surface structure and internal features of particles, and can also supplement the "blind zone" image features of the limited-angle scattered light detection scheme that combines side-laser and forward-laser.

[0066] Backscattering photodetector and , , The backscattering photodetectors are not on the same plane, and The direction of the backscattering light detector is 120°. For particles that are not completely separated from the material nozzle and are stacked, The outward-scattered light pulse width will be wider. For particles that are completely separated from the material nozzle, without any stacking, the particle surface is regular and consists of a single particle. The width and depolarization ratio of the outscattered light pulse are equal to or slightly smaller than the width and depolarization ratio of other outscattered light pulses.

[0067] The multiple single-angle scattering light detectors in this embodiment can, on the one hand, realize multi-directional scattering light detection of particles, solving the blind zone problem of limited-angle scattering light detection combined with lateral and forward lasers. On the other hand, by detecting scattering light from multiple angles, the particle stacking situation can be determined, reducing the risk of misjudging particle type due to large scattering signals caused by particle stacking. This enables accurate measurement of particle size, quantity, shape, stacking properties, surface structure, type, and other items, improving the accuracy of particle monitoring.

[0068] The analysis module is used to process the multi-angle scattered light information, identify effective particles, and output effective particle characteristics and concentration data.

[0069] Specifically, the analysis module includes a data receiving unit and a data processing unit; the data receiving unit is used to receive multi-angle scattered light information of particles in the single-particle particle stream; the data processing unit is used to process the multi-angle scattered light information of particles in the single-particle particle stream, identify effective particles, and output the characteristics and concentration data of the effective particles.

[0070] In this embodiment, the data processing module is used to convert the received multi-angle scattered light information into digital signals, and filter and amplify the electrical signals according to preset thresholds and algorithms to eliminate background noise and other interference signals; then, by performing integration, counting or fitting on the electrical signals, the stacked particle signals are excluded, and information such as the particle size, number, shape, surface structure and type of single particles are retained and calculated.

[0071] In this embodiment, the data processing module is also used to count the number of single particles of different categories in real time and calculate the number of particles per cubic meter of air, thereby providing particle concentration data.

[0072] Specifically, the analysis module further includes a display unit; the display unit is used to display the effective particle characteristics and concentration data in digital or graphical form.

[0073] The single-particle aerosol monitoring device based on multi-angle laser scattering described in the above embodiments of this application includes a sampling module, an optical module, and an analysis module. It aims to achieve accurate identification and concentration calculation of single aerosol particles to support the particulate matter characteristic data needs in public health, environmental monitoring, and meteorological fields.

[0074] Traditional samplers use an air pump to draw in air at a fixed flow rate (approximately 10 L / min), relying solely on gravity sedimentation to allow particles to settle onto a placed glass slide. Traditional methods are incapable of quantitative analysis and are highly susceptible to wind speed and terrain variations, resulting in poor representativeness. This application employs a dual-channel sampling system. The main channel draws in air at a constant flow rate (approximately 10 L / min), creating a stable airflow. A material nozzle then captures single particles in the airflow at a flow rate ≤1 L / min, focusing the particles into an extremely fine particle stream. This particle stream enters a bypass sampling channel, and only after bypassing the bypass can it enter the optical module, ensuring that each laser beam illuminates only one particle at a time, significantly improving air sampling efficiency.

[0075] In traditional multi-angle laser scattering detection, only a limited number of scattered light directions are detected by combining lateral and forward laser beams. Because the number of scattered light detection directions is small, and the coverage area of ​​these directions is only about 50-75% of the particle surface, it is difficult to completely cover the particle surface. Therefore, it is difficult to accurately measure particle size, quantity, shape, surface structure, and type, and cannot effectively identify particles. This application passes... Towards, Towards, Xianghe Single-angle scattered light detection enables multi-angle and multi-directional scattered light detection of particles, solving the blind zone problem of traditional two-angle scattered light detection. At the same time, multi-angle scattered light detection can effectively identify particle stacking, solving the problem that the large volume of stacked particles and abnormally high scattered light pulse width and height caused by particle surface adhesion or electrostatic forces can affect particle monitoring results.

[0076] Based on the same inventive concept, this application also provides a method for use in the aforementioned single-particle aerosol monitoring device based on multi-angle laser scattering. The solution provided by this method is similar to the solution described in the aforementioned device. Therefore, the specific limitations in one or more embodiments of the single-particle aerosol monitoring method based on multi-angle laser scattering provided below can be found in the limitations of the single-particle aerosol monitoring device based on multi-angle laser scattering described above, and will not be repeated here.

[0077] In one exemplary embodiment, such as Figure 4 As shown, a method for monitoring single-particle aerosols based on multi-angle laser scattering is provided, including the following steps:

[0078] Step 1: Obtain a single-particle stream.

[0079] Step 2: Irradiate the particles in the single-particle stream with forward and lateral laser beams to generate scattered light.

[0080] Step 3: Detect the scattered light from multiple angles to obtain multi-angle scattered light pulse signals.

[0081] Step 4: Perform spectral detection on the multi-angle scattered light pulse signal to obtain multi-angle scattered light information of particles in the single-particle stream; the multi-angle scattered light information includes: scattering light pulse, scattering light pulse, scattering light pulse and Information on the width, height, area, and depolarization ratio of the outscattered light pulse; including the forward laser beam illumination direction, the lateral laser beam illumination direction, and so on. In the direction of the scattered light pulse, The direction of the scattered light pulse and The scattered light pulses are in the same plane; The direction of the scattered light pulse is 115° counterclockwise from the direction of the lateral laser beam irradiation; The direction of the scattered light pulse is related to the The direction of the scattered light pulse is 140° counterclockwise; The direction of the scattered light pulse is related to the Rotate counterclockwise by 70° towards the direction of the scattered light pulse; The direction of the scattered light pulse is related to the forward laser beam irradiation direction and the lateral laser beam irradiation direction. In the direction of the scattered light pulse, The direction of the scattered light pulse and The directions of the scattered light pulses are not in the same plane, and are different from those of the above. The direction of the scattered light pulse is 120° clockwise.

[0082] Step 5: Process the multi-angle scattered light information of the particles in the single-particle stream to determine whether the particles in the single-particle stream are effective, and obtain the effective particle characteristics and concentration data. The effective particle characteristics include: particle size, number, shape, surface structure, and type of effective particles.

[0083] Specifically, the multi-angle scattered light information of particles in the single-particle particle stream is processed to determine whether the particles in the single-particle particle stream are effective, and effective particle characteristics and concentration data are obtained, including:

[0084] Step 501: Based on the multi-angle scattered light information, extract the particles from the single-particle particle stream. , , , Width, height, area, and depolarization ratio of the four-way scattered light pulse.

[0085] Step 502: Based on the particles in the single-particle particle stream , , , The width of the four-way scattered light pulse is used to determine whether there is particle stacking in the single particle stream; if so, it is discarded; if not, it is determined to be a valid particle.

[0086] The specific judgment rule is as follows: if the particles in a single-particle particle stream... , , , If the width of any pulse in the four-way scattered light pulse exceeds a preset threshold, it is determined to be a stacked particle and is discarded; if the particle in the single-particle stream... , , , If the width of the four-way scattered light pulse does not exceed the preset threshold, it is determined to be a valid particle.

[0087] In this embodiment, , , , The width (duration), height (peak intensity), and area (total energy) of a four-way scattered light pulse contain crucial information for determining whether stacking has occurred, measuring particle size, and classifying particle types. , , , The depolarization ratio of a four-way scattered light pulse contains crucial information for determining the regularity of particle shape, surface structure, and internal structure. Under fixed airflow velocity and laser beam width, the time it takes for a single particle to pass through the laser beam (i.e., the pulse width) is a relatively stable value. If multiple particles pass through the laser beam sequentially or side-by-side, the pulse duration changes, forming "wide pulses" or "high pulses." The data processing module sets a maximum permissible pulse width. Any signal with a pulse width exceeding the maximum permissible pulse width is marked as an "overlapping event" and removed from the valid count.

[0088] Step 503: Based on the particles in the single-particle particle stream , , , The width, height, area, and depolarization ratio of the four-way scattered light pulse are used to obtain the effective particles. , , , Width, height, area, and depolarization ratio of the four-way scattered light pulse.

[0089] Step 504: Based on the effective particles , , , The width, height, area, and depolarization ratio of the four-way scattered light pulses are used to obtain the particle size, number, shape, and surface structure of the effective particles.

[0090] Specifically, by analyzing multiple parameters of each pulse (pulse width, area, pulse height, etc.) and setting a "window", the effective pulse signals that conform to the characteristics of aerosol pulses are counted. Each effective pulse represents a single aerosol particle, and the number of effective particles is finally obtained.

[0091] By analyzing each effective particle , , , Peak detection is performed on the four-way scattered light pulse to find the highest point of the pulse. The value of the highest point of the pulse (i.e., the pulse height) corresponds to the particle size of the aerosol, and finally the particle size of the effective particles is obtained.

[0092] By measuring effective particles , , , The four-way scattered light pulse contains components parallel and perpendicular to the polarization direction of the incident light, i.e., the depolarization ratio (depolarization ratio = perpendicular component / parallel component), which ultimately yields the surface structure and shape of the effective particles. A higher depolarization ratio indicates a more irregular particle shape. Spherical particles can better maintain the polarization direction of the incident light, while irregularly shaped or complex-structured particles will cause significant depolarization of the scattered light.

[0093] Step 505: Based on the effective particles , , , The area and depolarization ratio of the four-way scattered light pulse are compared with a preset "microparticle fingerprint database" to identify the type of aerosol.

[0094] Specifically, by... , , , The area and depolarization ratio of the four-way scattered light pulses are compared with the "particle fingerprint database" built into the data processing module. Towards, Towards, Xianghe By comparing the scattered light pulse area and depolarization ratio pairwise, the type of aerosol, and even the specific species of aerosol particle, can be determined. For bioaerosols, they can also be categorized into different size classes based on signal characteristics (e.g., distinguishing between pollen, bacteria, and spores). A particle fingerprint database contains information on the scattered light pulse area and depolarization ratio of known aerosols. By comparing the scattered light pulse area and depolarization ratio in the fingerprint database, aerosol particle classification can be achieved.

[0095] Step 506: Based on the number of effective particles and the single sampling volume, count the number of effective particles within a unit sampling volume and calculate the aerosol concentration in the air.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A multi-angle laser scattering based single particle aerosol monitoring device, characterized in that, The single-particle aerosol monitoring device based on multi-angle laser scattering comprises a sampling module, an optical module and an analysis module connected in sequence; The sampling module is used for separating a stable airflow from ambient air and focusing the stable airflow to form a single-particle particle flow; The optical module is used for irradiating the single-particle particle flow and acquiring multi-angle scattering light information of particles in the single-particle particle flow; the optical module comprises a semiconductor laser, a plurality of single-angle scattering light detectors and a spectrum detector connected in sequence; The semiconductor laser emits a forward laser beam and a lateral laser beam, which irradiate onto particles respectively to generate scattering light; The multiple single-angle scattered light detectors are used for multi-angle detection of the scattered light to generate multi-angle scattered light pulse signals; the multiple single-angle scattered light detectors comprise: to a scattered light detector, to a scattered light detector, to a scattered light detector, and to a scattered light detector; The forward laser beam irradiation direction, the lateral laser beam irradiation direction, The forward laser beam irradiation direction, the lateral laser beam irradiation direction, The forward laser beam irradiation direction, the lateral laser beam irradiation direction, The forward laser beam irradiation direction, the lateral laser beam irradiation direction, The forward laser beam irradiation direction, the lateral laser beam irradiation direction, The forward laser beam irradiation direction, the lateral laser beam irradiation direction, The forward laser beam irradiation direction, the lateral laser beam irradiation direction, The forward laser beam irradiation direction, the lateral laser beam irradiation direction, The spectrum detector is used for spectrum detection on the multi-angle scattering light pulse signal to obtain the multi-angle scattering light information of the particles in the single-particle particle flow; The analysis module is used for processing the multi-angle scattering light information, identifying effective particles and outputting effective particle characteristics and concentration data.

2. The multi-angle laser scattering based single particle aerosol monitoring device of claim 1, wherein, The sampling module comprises an air suction pump and a substance nozzle connected in sequence; The air suction pump is used for sucking ambient air into a main path channel to obtain a stable airflow; The substance nozzle is used for capturing the stable airflow, focusing the stable airflow to form the single-particle particle flow and delivering the single-particle particle flow to a bypass channel.

3. The multi-angle laser scattering based single particle aerosol monitoring device of claim 1, wherein, The analysis module comprises a data receiving unit and a data processing unit; The data receiving unit is used for receiving the multi-angle scattering light information of the particles in the single-particle particle flow; The data processing unit is used for processing the multi-angle scattering light information of the particles in the single-particle particle flow, identifying effective particles and outputting effective particle characteristics and concentration data.

4. The multi-angle laser scattering based single particle aerosol monitoring device of claim 1, wherein, The analysis module further comprises a display unit; the display unit is used for displaying the effective particle characteristics and concentration data.

5. The multi-angle laser scattering based single particle aerosol monitoring device of claim 1, wherein, The forward laser beam is emitted horizontally by the semiconductor laser; the side laser beam is emitted by the semiconductor laser along a direction perpendicular to the direction of the forward laser beam, 90° counterclockwise to the forward laser beam; the The direction of the scattered light detector is 115° counterclockwise to the direction of the side laser beam; the The direction of the scattered light detector is 140° counterclockwise to the direction of the side laser beam; the The direction of the scattered light detector is 140° counterclockwise to the direction of the side laser beam; the The direction of the scattered light detector is 140° counterclockwise to the direction of the side laser beam; the The direction of the scattered light detector is 70° counterclockwise to the direction of the side laser beam; the The direction of the scattered light detector is 70° counterclockwise to the direction of the side laser beam; the The direction of the scattered light detector is 120° clockwise to the direction of the side laser beam.

6. A multi-angle laser scattering-based single-particle aerosol monitoring method, characterized by, The single-particle aerosol monitoring method based on multi-angle laser scattering comprises: Acquiring a single-particle particle flow; Irradiating particles in the single-particle particle flow with forward and lateral laser beams to generate scattering light; Multi-angle detecting the scattering light to obtain a multi-angle scattering light pulse signal; The multi-angle scattered light pulse signal is subjected to spectral detection to obtain multi-angle scattered light information of the particles in the single-particle particle flow; the multi-angle scattered light information includes: The width, height, area and depolarization ratio information of the forward scattering light pulse, The width, height, area and depolarization ratio information of the side scattering light pulse, The width, height, area and depolarization ratio information of the backward scattering light pulse, and The width, height, area and depolarization ratio information of the side scattering light pulse; wherein the forward laser beam irradiation direction, the side laser beam irradiation direction, The forward scattering light pulse direction, The side scattering light pulse direction, and The backward scattering light pulse direction are in the same plane; The forward scattering light pulse direction is not in the same plane with the forward laser beam irradiation direction, the side laser beam irradiation direction, The side scattering light pulse direction, The backward scattering light pulse direction, and The side scattering light pulse direction. Processing multi-angle scattering light information of the particles in the single-particle particle flow, judging whether the particles in the single-particle particle flow are effective and obtaining effective particle characteristics and concentration data.

7. The multi-angle laser scattering based single particle aerosol monitoring method according to claim 6, wherein, The to the direction of the scattered light pulse counterclockwise 115° from the direction of the lateral laser beam illumination; the to the direction of the scattered light pulse counterclockwise 140° from the direction of the lateral laser beam illumination; the to the direction of the scattered light pulse counterclockwise 140° from the direction of the lateral laser beam illumination; the to the direction of the scattered light pulse counterclockwise 70° from the direction of the lateral laser beam illumination; the to the direction of the scattered light pulse counterclockwise 70° from the direction of the lateral laser beam illumination; the to the direction of the scattered light pulse counterclockwise 70° from the direction of the lateral laser beam illumination; the to the direction of the scattered light pulse clockwise 120° from the direction of the lateral laser beam illumination.

8. The multi-angle laser scattering based single particle aerosol monitoring method according to claim 7, wherein, The effective particle characteristics include particle size, number, shape, surface structure and type of effective particles.

9. The multi-angle laser scattering based single particle aerosol monitoring method according to claim 8, wherein, Processing the multi-angle scattering light information of the particles in the single-particle particle flow, judging whether the particles in the single-particle particle flow are effective and obtaining effective particle characteristics and concentration data specifically comprises: Based on the multi-angle scattered light information, extract the particle in the single-particle particle flow 、 、 、 The width, height, area and depolarization ratio of the four-way scattered light pulse; Based on the particles in the single-particle particle stream , , , The width of the four-way scattered light pulse is used to determine whether there is particle stacking in the single particle stream; if so, it is discarded; if not, it is determined to be a valid particle. based on the width, height, area, and depolarization ratio of the four-way scattered light pulses of the effective particles 、 、 、 width, height, area, and depolarization ratio of the four-way scattered light pulses; and 、 、 、 width, height, area, and depolarization ratio of the four-way scattered light pulses. based on the effective particles , , , width, height, area and depolarization ratio of the four-way scattered light pulse, the particle size, quantity, shape and surface structure of the effective particles are obtained; based on the effective particles 、 、 、 The area and depolarization ratio of the four-way scattered light pulse are combined with a preset "particle fingerprint library" for comparison to identify the aerosol type. Based on the number of effective particles and the volume of single sampling, the number of effective particles in a unit sampling volume is counted to calculate the aerosol concentration in the air.

10. The multi-angle laser scattering based single particle aerosol monitoring method according to claim 9, characterized in that, determining whether a particle stack exists in the single-particle particle stream based on a width of the four-way scattered light pulse of the particle in the single-particle particle stream 、 、 、 determining whether a particle stack exists in the single-particle particle stream based on a width of the four-way scattered light pulse of the particle in the single-particle particle stream If yes, it is rejected; if no, it is determined as an effective particle, specifically comprising: If the particle in the single-particle stream , , , If the width of any of the four-way scattered light pulses exceeds a preset threshold, it is determined that the particle is a stacked particle, and is rejected. If the particle , , , The four-way scattered light pulse width does not exceed the preset threshold, and it is determined as an effective particle.

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