Harmful particulate matter mass concentration and oxidation potential on-line intelligent monitoring system and method

Abstract

The invention discloses an on-line intelligent monitoring system and method for mass concentration and oxidation potential of harmful particulate matters. The system is characterized in that a particulate matter sampling subsystem comprises a particle size separator, a vacuum pump, a mixing pipeline and an HEPA (High Efficiency Particulate Air) filter; the particulate matter mass concentration detection subsystem comprises an optical detection chamber, a laser, a light trap, a collimating lens, a focusing lens and a photodiode; the particulate matter atomization trapping subsystem comprises an atomization trapping chamber, a buffer trapping liquid chamber and an ultrasonic nozzle atomizer; the particulate matter oxidation potential detection subsystem comprises a first stirring device, a PH sensor, a DTT chamber, a PH buffer solution chamber, a second stirring device, a first liquid pump, a DTNB chamber, an optical fiber probe and a light absorption luminoscope. According to the method, accurate sampling, particulate matter concentration measurement and quantitative detection operation of the oxidation potential are achieved through the system. According to the system and the method, the concentration of atmospheric particulates can be detected in real time by utilizing a light scattering technology, and quantitative detection of oxygen potential can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent monitoring, and specifically relates to an online intelligent monitoring system and method for the mass concentration and oxidative potential of harmful particulate matter. Background Art

[0002] With the rapid advancement of industrialization and urbanization, the problem of air pollution has become increasingly severe. Among them, the concentration of fine particulate matter (such as PM2.5 and PM 10 ) has become an important indicator for evaluating air quality. A large number of studies have shown that long-term exposure to high-concentration particulate matter environments will significantly increase the risk of cardiovascular, respiratory, and other chronic diseases. However, the impact of particulate matter on health is not only closely related to its concentration, but its chemical composition and biological activity also play a decisive role. Metal ions, organic substances, and other active components present in particulate matter can induce oxidative stress in the body, leading to cell damage and inflammatory reactions. Oxidative Potential (OP), as an important parameter reflecting the ability of particulate matter to induce oxidative stress, can more intuitively reveal its toxicity and harm degree. Therefore, simultaneously monitoring the mass concentration and oxidative potential of harmful particulate matter in real-time online can not only provide more comprehensive data support for environmental quality evaluation, but also provide a scientific basis for pollution warning and health risk assessment.

[0003] Currently, the detection of particulate matter concentration mainly uses the gravimetric method of offline sampling, the β-ray attenuation method of online real-time monitoring, and light scattering technology, etc. Among them, although the gravimetric method is accurate, it has the problems of long sampling period and cumbersome on-site operation; the β-ray attenuation method and light scattering technology can achieve rapid online detection, but their sensitivity, calibration stability, and dependence on environmental conditions (such as humidity, temperature) are relatively large in low-concentration environments. In addition, equipment maintenance and long-term operation stability are also often concerned. At the same time, the detection of particulate matter oxidative potential currently mainly relies on laboratory offline methods such as the DTT method, antioxidant enzyme method, and electron spin resonance method. Although these methods can accurately measure the oxidation activity of samples under laboratory conditions, due to the need for cumbersome extraction, pretreatment, and offline chemical reaction processes after sample collection, the real-time performance is insufficient, and component loss or change is likely to occur during sampling, processing, and transportation, thus affecting the accuracy and continuity of the detection results. In addition, the existing technologies as a whole have large equipment volume, complex operation, and high maintenance costs, and it is difficult to meet the current requirements for rapid dynamic response and long-term monitoring of air pollution.

[0004] To overcome the deficiencies of the existing technology, there is an urgent need to provide a comprehensive system that integrates online intelligent monitoring of particulate matter concentration and oxidative potential. Summary of the Invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides an on-line intelligent monitoring system and method for the mass concentration and oxidation potential of harmful particulate matter. The system can collect samples at set time intervals and continuously monitor the mass concentration and oxidation potential of particulate matter without interruption, achieving the continuity and stability of measurement. The method has the advantages of fast real-time response, high automation degree, simple operation process, high detection accuracy and low implementation cost. It can use light scattering technology to detect the concentration of atmospheric particulate matter in real time and realize the quantitative detection of oxygen potential.

[0006] To achieve the above object, the present invention provides an on-line intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter, including a particulate matter sampling subsystem, a particulate matter mass concentration detection subsystem, a particulate matter atomization and capture subsystem, a particulate matter oxidation potential detection subsystem, a waste liquid treatment subsystem and a control subsystem;

[0007] The particulate matter sampling subsystem includes a main intake air pipeline, a particle size separator, a first vacuum pump, a mixing pipeline, a first auxiliary intake air pipeline, a second vacuum pump, a first HEPA filter, a second auxiliary intake air pipeline, a third vacuum pump and a second HEPA filter. The particle size separator is connected in series at the inlet end of the main intake air pipeline. The inlet of the first vacuum pump is connected to the outlet end of the main intake air pipeline. The mixing pipeline is arranged vertically, and its inlet end is connected to the outlet of the first vacuum pump. The mixing pipeline includes an outer pipeline and an inner pipeline. The outer pipeline is a variable-diameter pipeline, which successively includes a large-diameter section, a conical transition section and a small-diameter section from top to bottom. Auxiliary air inlets one and two are respectively arranged on the upper part of the large-diameter section on opposite sides. The lower end of the small-diameter section is used as the outlet end of the mixing pipeline. The inner pipeline is coaxially inserted inside the large-diameter section, its lower end extends to the inlet end of the conical transition section, and its upper end extends above the upper end of the large-diameter section and serves as the inlet end of the mixing pipeline. At the same time, an annular flow channel is formed between the inner pipeline and the large-diameter section. The first auxiliary intake air pipeline is arranged horizontally, and its outlet end is connected to the outer pipeline through the auxiliary air inlet one. The first HEPA filter and the second vacuum pump are respectively connected in series at the inlet end and the middle section of the first auxiliary intake air pipeline. The second auxiliary intake air pipeline is arranged horizontally, and its outlet end is connected to the outer pipeline through the auxiliary air inlet two. The second HEPA filter and the third vacuum pump are respectively connected in series at the inlet end and the middle section of the second auxiliary intake air pipeline.

[0008] The particulate matter mass concentration detection subsystem includes an optical detection chamber, a laser, an optical trap, a collimating lens, a focusing lens, and a photodiode; the optical detection chamber is horizontally arranged, and a detection inlet and a detection outlet are oppositely opened at the upper and lower ends of its central detection area; the detection inlet of the optical detection chamber is connected to the outlet end of the mixing pipeline; the laser and the optical trap are oppositely installed on the left and right side walls inside the optical detection chamber; the collimating lens and the focusing lens are sequentially installed at intervals from left to right inside the optical detection chamber and are located between the laser and the detection inlet, and the focal point of the focusing lens is located in the central detection area; the photodiode is installed on the front side wall in the middle section of the optical detection chamber, and its detection center forms a 90° angle with the laser emission direction of the laser;

[0009] The particulate matter atomization and capture subsystem includes an atomization and capture chamber, a buffer capture liquid chamber, an ultrasonic nozzle atomizer, and a main discharge pipeline; the upper and lower ends of the middle section of the atomization and capture chamber are oppositely provided with an atomization inlet and an atomization outlet, and two installation ports are oppositely provided on the left and right sides of the middle section thereof; the atomization and capture chamber is arranged below the optical detection chamber, and its atomization inlet is connected to the detection outlet of the optical detection chamber through a vertical communication pipeline; the two buffer capture liquid chambers are distributed on both sides of the atomization and capture chamber and both store buffer capture liquid; the two ultrasonic nozzle atomizers are oppositely inserted into the two installation ports, and their outlet ends oppositely extend into the interior of the atomization and capture chamber, and their inlet ends are respectively connected to the liquid outlet ports of the two buffer capture liquid chambers through two liquid supply pipelines; the main discharge pipeline is vertically arranged, and its inlet end is connected to the atomization and capture chamber through the atomization outlet;

[0010] The particulate matter oxidation potential detection subsystem includes a first stirring device, a pH sensor, a DTT chamber, a first high-precision injection pump, a pH buffer chamber, a second high-precision injection pump, a second stirring device, a first liquid pump, a DTNB chamber, a third high-precision injection pump, an optical fiber probe, and an absorption fluorometer; the first stirring device is installed below the atomization and trapping chamber, and it includes a first constant-temperature stirring table, a reaction chamber, and a first stirring assembly. The reaction chamber is installed at the upper end of the first constant-temperature stirring table and is located below the atomization and trapping chamber. The reaction chamber is a closed structure, and its upper end is successively provided with a first filling port, a second filling port, and a third filling port from left to right, and its right side is provided with a liquid outlet. Among them, the first filling port is connected to the outlet end of the main discharge pipeline; the first stirring assembly is installed inside the reaction chamber, and its lower end is connected to the driving mechanism in the first constant-temperature stirring table after passing through the bottom of the reaction chamber; the pH sensor is installed inside the reaction chamber; the DTT chamber is arranged above the reaction chamber, and DTT solution is stored inside it. Its bottom outlet is connected to the second filling port through a vertically arranged DTT filling pipeline, and the first high-precision injection pump is connected in series in the middle section of the DTT filling pipeline; the pH buffer chamber is arranged above the reaction chamber, and pH buffer solution is stored inside it. Its bottom outlet is connected to the third filling port through a vertically arranged pH liquid filling pipeline, and the second high-precision injection pump is connected in series in the middle section of the pH liquid filling pipeline; the second stirring device is installed adjacent to the right side of the first stirring device, and it includes a second constant-temperature stirring table, a flow detection chamber, and a second stirring assembly. The flow detection chamber is installed at the upper end of the second constant-temperature stirring table and is located on the right side of the reaction chamber. The upper end of the flow detection chamber is open, its right side is provided with a liquid discharge port, and its left side is provided with a liquid inlet corresponding to the liquid outlet, and the liquid inlet is connected to the liquid outlet through a horizontal communication pipeline; the first liquid pump is connected in series in the middle section of the horizontal communication pipeline; the DTNB chamber is arranged above the flow detection chamber, and DTNB solution is stored inside it. Its bottom outlet is connected to a vertically arranged DTNB filling pipeline, and the third high-precision injection pump is connected in series in the middle section of the DTNB filling pipeline; the optical fiber probe is arranged inside the flow detection chamber; the absorption fluorometer is arranged on the outer side of the flow detection chamber and is connected to the optical fiber probe;

[0011] The waste liquid treatment subsystem includes a drain pipeline and a second liquid pump. The inlet end of the drain pipeline is connected to the flow detection chamber through the liquid discharge port, and the second liquid pump is connected in series in the middle section of the drain pipeline;

[0012] The control subsystem is respectively connected to a photodiode, a pH sensor, an absorptiometric fluorometer, a particle size separator, a first vacuum pump, a second vacuum pump, a third vacuum pump, a laser, an ultrasonic nozzle atomizer, a first high-precision syringe pump, a second high-precision syringe pump, a first liquid pump, a third high-precision syringe pump, a second liquid pump, a first constant temperature stirring table and a second constant temperature stirring table.

[0013] Further, in order to achieve the rapid installation and separation of the particle size separator, a quick-connect joint is used to connect between the particle size separator and the main intake pipeline.

[0014] Further, in order to effectively reduce the deposition rate of particulate matter on the inner wall surface, the inner surface of the optical detection chamber is coated with a functional coating with low surface energy and excellent anti-adhesion performance.

[0015] Further, in order to effectively reduce the adhesion rate of droplets on the wall surface, the inside of the atomization capture chamber is coated with a hydrophobic coating.

[0016] Further, in order to achieve light-tight storage, effectively reduce the degradation rate of DTNB, and ensure the accuracy of the color reaction, the DTT chamber is made of light-impermeable material; the DTNB chamber is made of light-impermeable material.

[0017] As a preference, the control subsystem includes a controller, a communication module and a power module.

[0018] In the present invention, by installing a particle size separator at the inlet end of the main intake pipeline, it is convenient to classify the particle size of particulate matter, thereby ensuring that the particulate matter entering the detection system is of the target particle size. Thus, accurate sampling of particulate matter in a specific particle size range is achieved, ensuring the accuracy of subsequent detection results. In the mixing pipeline, the outer pipeline is a variable-diameter pipeline. At the same time, a conical filter section is provided between the large-diameter section and the small-diameter section. On this basis, the inner pipeline is coaxially inserted into the large-diameter section to form an annular flow channel. In this way, when the airflow entering from the annular flow channel passes through the contraction area of the conical filter section, the flow velocity of the airflow will increase due to the gradual reduction of the flow channel cross-sectional area, and at the same time, a flow field constraint effect will be generated, forcing the airflow entering from the inner pipeline to radially contract in the central area, thereby forming a sheath flow, reducing the diffusion amplitude and diffusion probability of particulate matter in the airflow in the radial direction. In this way, after entering the optical detection chamber, the particulate matter can be concentrated in the central detection area, ensuring the accuracy of subsequent detection. On both sides of the upper part of the large-diameter section, the first and second auxiliary intake pipelines are respectively connected. Then, a vacuum pump and a HEPA filter are sequentially connected to the auxiliary intake pipelines, and the clean air filtered by the HEPA filter can be supplied into the annular flow channel by using the negative pressure provided by the vacuum pump. In the optical detection chamber, a laser, a collimating lens, a focusing lens, an optical trap, and a photodiode are sequentially arranged. The laser can be used to emit a monochromatic and highly coherent laser beam in the direction of the collimating lens, and the collimating lens can be used to adjust the shape of the laser beam so that the adjusted beam propagates parallelly in the direction of the focusing lens. Then, the focusing lens is used to focus the parallelly propagating beam, and thus a high-energy density light spot can be formed in the central detection area in the middle section of the optical detection chamber. In this way, the detection light spot formed by the focusing lens can be matched with the spatial position of the dust-containing airflow entering from the mixing pipeline, and thus when the particulate matter passes through the high-light-intensity area in the central detection area, it can be fully irradiated by the laser, thereby improving the detection efficiency and measurement accuracy of the light scattering signal; the detection center of the photodiode is at a 90° angle to the emission direction of the laser, which can effectively reduce the interference of background light and improve the signal-to-noise ratio. Thus, the scattered light signal generated when the light spot irradiates the particulate matter can be efficiently and accurately collected, and the scattered light signal can be converted into an electrical signal. By setting the optical trap, the laser irradiating the right side wall can be absorbed, and thus the adverse effect of the reflected light on the detection result can be avoided.Since the ultrasonic nozzle atomizer can use ultrasonic energy to atomize the buffer trapping liquid in the buffer trapping liquid chamber into micron-sized droplets, the atomization inlet of the atomization trapping chamber is connected to the detection outlet of the optical detection chamber through a vertical connecting pipeline. At the same time, two ultrasonic nozzle atomizers are inserted on its opposite sides. Then, while introducing the detection gas flow, atomized droplets can be synchronously introduced, and thus a mixed environment with gas-liquid interaction can be formed inside the atomization trapping chamber. When ambient air carrying particulate matter enters the buffer trapping liquid chamber, it will collide and diffuse with the atomized droplets. In this way, the particulate matter in the gas flow can fully contact and combine with the droplets, and then the particulate matter can be transferred from the gas phase to the liquid phase. The two ultrasonic nozzles are symmetrically arranged, which can ensure the uniform distribution of the trapping liquid in the atomization chamber, thus forming a uniform micron-sized fog field, avoiding the problem of uneven gas-liquid distribution caused by single-sided spraying. At the same time, it can ensure that the particulate matter concentration in the liquid phase is more uniform, avoiding the local particulate matter concentration deviation caused by uneven atomization, and improving the reliability and accuracy of analysis results such as oxidation potential. The first stirring device mainly consists of a first constant temperature console and a reaction chamber. It is not only convenient to accurately control the reaction temperature in the reaction chamber by using the first constant temperature console, ensuring that the reaction system can proceed under the set temperature conditions, so that the kinetic characteristics of the DTT oxidation reaction can always remain stable. At the same time, the stirring function of the first constant temperature console can also promote the full mixing of the particulate matter in the DTT solution, PH buffer solution and atomization trapping liquid. Through the stirring action, the sedimentation of particulate matter in the chamber can be reduced, which is beneficial to improving the uniformity of the reaction solution, thus ensuring that the measurement process of the DTT consumption rate can proceed more stably and reliably. Therefore, through the combined action of constant temperature and stirring, the equilibrium state of the DTT reaction can be accelerated, the reaction time is reduced, the detection efficiency of the detection system is improved, and the detection accuracy can also be improved. Among them, the reaction chamber adopts a closed structure design, which can prevent the buffer solution from overflowing due to evaporation and other reasons, thus ensuring that no PH value drift occurs, and improving the long-term stability and detection accuracy of the system.By connecting a first high-precision injection pump in series on the DTT filling pipeline communicating with the DTT chamber, the filling volume of the DTT solution can be accurately controlled, ensuring that the DTT concentration in the reaction chamber remains within a stable range; by connecting a second high-precision injection pump in series on the pH buffer solution filling pipeline communicating with the pH buffer chamber, the filling volume of the pH buffer solution can be precisely controlled, ensuring the stability of the pH value in the system and avoiding the spontaneous degradation of DTT due to pH factors or abnormal oxidation reaction rates; through the setting of the pH sensor, it is convenient to monitor the pH value data in the reaction chamber in real time; on this basis, combined with the monitoring data of the pH value of the mixed solution in the reaction chamber by the pH sensor, the flow rate of the second high-precision injection pump is closed-loop controlled, and the pH buffer solution can be accurately supplemented into the reaction chamber to keep the pH value data in the reaction solution stable within a constant range, significantly improving the automation level of the system and the stability of long-term reactions. An outlet is provided on the right side of the reaction chamber. At the same time, an inlet is provided on the left side of the flow detection chamber. Then, the outlet and the inlet are connected by a horizontal communication pipeline, and a first liquid pump is connected in series on the horizontal communication pipeline. The first liquid pump can be used to transport the reaction liquid in the reaction chamber to the flow detection chamber. By performing staged transportation actions at different reaction time nodes, the DTT samples at different reaction time nodes can be efficiently transported to the flow detection chamber for subsequent detection operations. The second stirring device mainly consists of a second constant temperature stirring table and a flow detection chamber. It is not only convenient to accurately control the reaction temperature in the flow detection chamber by using the second constant temperature control console, ensuring that the reaction system can proceed under the set temperature conditions, and then maintaining the constant temperature of the color reaction through constant temperature control to ensure the stability of the DTNB color reaction system. At the same time, the stirring function of the second constant temperature control console can also be used to promote the uniform mixing of the reaction liquid, improving the accuracy and repeatability of optical detection. By connecting a third high-precision injection pump in series on the DTNB filling pipeline communicating with the DTNB chamber, after the reaction in the DTT oxidation stage ends, the reaction solution can be first transported to the flow detection chamber, and then the DTNB solution can be accurately and quantitatively filled into the flow detection chamber by the third high-precision injection pump. Furthermore, the color reaction between DTT and DTNB can occur. By precisely controlling the filling volume of DTNB, the color error caused by excessive or insufficient reagents can be avoided, ensuring the stability of the color reaction.Meanwhile, it can also ensure the consistency of the initial DTNB concentration in each measurement process, improving the repeatability of optical determination. By setting the optical fiber probe in the flow detection chamber, it is convenient to collect the optical signals in the flow detection chamber in real time and transmit them to the absorptiometric fluorometer without loss. Then, the absorptiometric fluorometer can measure the absorbance after the reaction of DTT and DTNB in the flow detection chamber based on the received optical signals, and calculate the DTT consumption rate through the absorbance, thereby quantifying the oxidation potential of the particulate matter. By directly measuring the solution in the flow detection chamber in this way, it ensures the accurate measurement of absorbance, can effectively reduce the interference factors of the environment, improve the collection efficiency of optical signals, effectively reduce the light loss rate in the optical system, and improve the sensitivity of absorbance and fluorescence measurement. By connecting a drain pipeline to the drain port of the flow detection chamber and connecting a second liquid pump in series on the drain pipeline, the waste liquid in the flow detection chamber can be quickly drained, preventing the accumulation of liquid in the chamber from affecting the subsequent liquid inlet flow of the sample and the stability of subsequent detection. Thus, using this system, samples can be collected at set time intervals, and the DTT consumption rate can be detected in different reaction stages in stages, enabling continuous and stable measurement.

[0019] The present invention can realize the automation and continuous operation of the whole process of real-time sampling, detection, reaction and analysis of particulate matter. Different from the traditional off-line detection method, this system can continuously monitor the mass concentration and oxidation potential of particulate matter without interruption, providing real-time and continuous data updates, thus greatly improving the monitoring efficiency and data timeliness. In the continuous working mode, this system can ensure the seamless connection between multiple stages such as sampling, optical detection, chemical reaction, and color reaction by periodically controlling the working states of each subsystem, avoiding the monitoring interruption or data loss caused by operation intervals or sampling stops. Especially during the measurement of the oxidation potential of particulate matter, the consumption rate of DTT can be tracked in real time through precise time control, and data can be automatically collected and analyzed at different time points to ensure the accuracy and stability of the measurement results.

[0020] The present invention also provides an on-line intelligent monitoring method for the mass concentration and oxidation potential of harmful particulate matter. Using an on-line intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter, it includes the following steps:

[0021] Step 1: Select a particle size separator within the target particle size range and connect it to the main intake pipeline through a quick-connect joint. Meanwhile, inject buffer trapping liquid, DTT solution, pH buffer solution, and DTNB solution into the buffer trapping liquid chamber, DTT chamber, pH buffer solution chamber, and DTNB chamber respectively.

[0022] Step 2: Control the particle size separator, the first vacuum pump, the second vacuum pump, and the third vacuum pump to start working synchronously for the time of a measurement cycle; during this measurement cycle, use the continuous suction force provided by the first vacuum pump to make the air in the environment enter the particle size separator. At the same time, use the particle size separator to preliminarily screen the particle sizes of the particulate matter in the air, so that the particulate matter within the target particle size range enters the inner pipeline in the mixing pipeline along with the air flow. Use the continuous suction force provided by the second vacuum pump to make the clean air flow after being filtered by the first HEPA filter enter the annular flow channel in the mixing pipeline. Use the continuous suction force provided by the third vacuum pump to make the clean air flow after being filtered by the second HEPA filter enter the annular flow channel in the mixing pipeline;

[0023] Step 3: Use the conical filter section to accelerate the air flow in the annular flow channel and generate a flow field constraint effect, radially constrain the particulate matter in the air flow discharged from the inner pipeline to the central area of the air flow, and make the air flow containing particulate matter enter the central detection area from the detection inlet on the optical detection chamber along the small-diameter section and discharge from the detection outlet; at the same time, control the laser to emit a monochromatic and highly coherent laser beam, use the collimating lens to correct the shape of the laser beam into a parallel beam, use the focusing lens to focus the parallel beam on the central detection area, and form a tiny laser spot with a high energy density in the central detection area. Under the irradiation of the laser spot, the surface of the particulate matter passing through the central detection area undergoes a scattering phenomenon. Synchronously, use the photodiode to capture the scattered light signal and convert it into a scattered electrical signal and send it to the control subsystem. The control subsystem analyzes the particulate matter composition based on the scattered electrical signals received in the current measurement cycle, and then obtains the concentration and particle size distribution data of the particulate matter in the current measurement cycle;

[0024] Step 4: Use the vertical communication pipeline to divert the air flow containing particulate matter to the atomization capture chamber. During the process of the air flow containing particulate matter entering the buffer capture liquid chamber, synchronously control the two ultrasonic nozzle atomizers to start working. The ultrasonic nozzle atomizers atomize the buffer capture liquid in the buffer capture liquid chamber into micron-sized droplets by using the ultrasonic excitation effect and supply them into the interior of the atomization capture chamber to form a micron-sized fog field inside the atomization capture chamber; during the process of the particulate matter in the air flow passing through the fog field, it collides and contacts with the atomized droplets and combines with the droplets to form a capture liquid containing particulate matter;

[0025] Step 5: Use the main discharge pipeline to divert all the formed capture liquid containing particulate matter to the reaction chamber. At the same time, control the first constant temperature stirring table in the first stirring device to start working, so that the reaction temperature in the reaction chamber is maintained within the set temperature range, and at the same time, continuously stir the liquid in the reaction chamber evenly;

[0026] Synchronously, the control subsystem controls the first high-precision injection pump to quantitatively inject DTT solution into the reaction chamber based on the concentration and particle size distribution data of particulate matter in the current measurement cycle, so that DTT molecules undergo redox reactions with oxidizing substances attached to the surface of particulate matter; during the redox reaction process, the PH sensor is used to collect the PH value data in the reaction solution in real time and send it to the control subsystem, and the control subsystem controls the second high-precision injection pump to quantitatively inject PH buffer solution into the reaction chamber according to the PH value data, so that the PH value data in the reaction solution is stabilized within a constant range;

[0027] During the redox reaction process, the control subsystem controls the intermittent operation of the first liquid pump at set time intervals to quantitatively transport the reaction solution in the reaction chamber to the flow detection chamber for stage detection at different reaction time nodes. During the stage detection process, the control subsystem synchronously controls the second constant temperature stirring table in the second stirring device to start working, so that the reaction temperature in the flow detection chamber is maintained within the set temperature range. At the same time, the liquid in the flow detection chamber is continuously and evenly stirred. Meanwhile, the control subsystem controls the third high-precision injection pump to quantitatively inject DTNB solution according to the injection volume of the reaction solution entering the flow detection chamber, so that a color reaction occurs between DTNB and DTT, and a colored compound with specific light absorption characteristics is generated. During the color reaction process, the optical signal of the reaction solution is collected in real time by the optical fiber probe and transmitted to the absorbance fluorometer. The absorbance fluorometer analyzes the received optical signal to obtain the absorbance value, and calculates the current consumption rate of DTT based on the obtained absorbance value. At the end of the color reaction, the control subsystem controls the second liquid pump to start working for a set time, and discharges the reaction waste liquid in the flow detection chamber through the drain pipeline. Repeat the above process to obtain the DTT consumption rate at different reaction time nodes through the stage detection process;

[0028] Step six, repeat steps one to five to perform the monitoring operation for the next measurement cycle.

[0029] Furthermore, in order to effectively reduce the non-specific oxidation of DTT and effectively ensure the detection accuracy, in step one, the PH buffer solution is a buffer solution pretreated by removing trace metal ions.

[0030] The present invention can use light scattering technology to detect the concentration of atmospheric particulate matter in real time. At the same time, it adopts a technical means combining liquid capture and on-line DTT reaction, and quickly "quenches" the reaction by automatically injecting DTNB. Then, the absorbance change is monitored in real time through the color reaction, so as to accurately calculate the DTT consumption rate and realize the quantification of oxygen potential. Compared with traditional methods, this method has the advantages of fast real-time response, high automation degree, simple operation process, high detection accuracy and low implementation cost, and can provide efficient and reliable technical support for dynamic monitoring of air pollution and health risk assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic structural diagram of the present invention;

[0032] Figure 2 is a schematic structural diagram of the mixing pipeline in the present invention;

[0033] Figure 3 is a principle block diagram of the circuit part in the present invention.

[0034] In the figure: 1, particle size separator; 2, first vacuum pump; 3, second vacuum pump; 4, third vacuum pump; 5, mixing pipeline; 6, optical detection chamber; 7, laser; 8, collimating lens; 9, focusing lens; 10, optical trap; 11, atomization capture chamber; 12, ultrasonic nozzle atomizer; 13, buffer capture liquid chamber; 14, reaction chamber; 15, first constant temperature stirring table; 16, DTT chamber; 17, first high-precision injection pump; 18, PH buffer solution chamber; 19, second high-precision injection pump; 20, PH sensor; 21, first liquid pump; 22, DTNB chamber; 23, third high-precision injection pump; 24, flow detection chamber; 25, optical fiber probe; 26, absorbance fluorometer; 27, second liquid pump; 28, second constant temperature stirring table; 29, first HEPA filter; 30, second HEPA filter; 31, main air inlet pipeline; 32, auxiliary air inlet pipeline 1; 33, auxiliary air inlet pipeline 2; 34, inner pipeline; 35, outer pipeline; 36, large diameter section; 37, tapered transition section; 38, small diameter section; 39, auxiliary air inlet 1; 40, auxiliary air inlet 2; 41, vertical communication pipeline; 42, main discharge pipeline; 43, DTT filling pipeline; 44, PH liquid filling pipeline; 45, horizontal communication pipeline; 46, DTNB filling pipeline; 47, liquid discharge pipeline. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will be further described below with reference to the accompanying drawings.

[0036] As Figures 1 to 3 shown, the present invention provides an online intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter, including a particulate matter sampling subsystem, a particulate matter mass concentration detection subsystem, a particulate matter atomization capture subsystem, a particulate matter oxidation potential detection subsystem, a waste liquid treatment subsystem, and a control subsystem;

[0037] The particulate sampling subsystem includes a main intake pipeline 31, a particle size separator 1, a first vacuum pump 2, a mixing pipeline 5, a first auxiliary intake pipeline 32, a second vacuum pump 3, a first HEPA filter 29, a second auxiliary intake pipeline 33, a third vacuum pump 4, and a second HEPA filter 30; the particle size separator 1 is connected in series at the inlet end of the main intake pipeline 31, and the air inlet of the first vacuum pump 2 is connected to the outlet end of the main intake pipeline 31; the mixing pipeline 5 is vertically arranged, and its inlet end is connected to the outlet end of the first vacuum pump 2. The mixing pipeline 5 includes an outer pipeline 35 and an inner pipeline 34; the outer pipeline 35 is a variable-diameter pipeline, which successively includes a large-diameter section 36, a tapered transition section 37, and a small-diameter section 38 from top to bottom. The upper part of the large-diameter section 36 is respectively provided with a first auxiliary air inlet 39 and a second auxiliary air inlet 40 on opposite sides; the lower end of the small-diameter section 38 serves as the outlet end of the mixing pipeline 5; the inner pipeline 34 is coaxially inserted inside the large-diameter section 36, its lower end extends to the inlet end of the tapered transition section 37, and its upper end extends above the upper end of the large-diameter section 36 and serves as the inlet end of the mixing pipeline 5. At the same time, an annular flow channel is formed between the inner pipeline 34 and the large-diameter section 36, and the upper end of the large-diameter section 36 and the inner pipeline 36 can be hermetically connected through an annular end plate; the first auxiliary intake pipeline 32 is horizontally arranged, and its outlet end is connected to the outer pipeline 35 through the first auxiliary air inlet 39; the first HEPA filter 29 and the second vacuum pump 3 are respectively connected in series at the inlet end and the middle section of the first auxiliary intake pipeline 32. The first HEPA filter 29 is connected to the external environment and is used to achieve efficient filtration of air, so that the air flow entering the first auxiliary intake pipeline 32 is clean air flow; the second auxiliary intake pipeline 33 is horizontally arranged, and its outlet end is connected to the outer pipeline 35 through the second auxiliary air inlet 40; the second HEPA filter 30 and the third vacuum pump 4 are respectively connected in series at the inlet end and the middle section of the second auxiliary intake pipeline 33. The second HEPA filter 30 is connected to the external environment and is used to achieve efficient filtration of air, so that the air flow entering the second auxiliary intake pipeline 33 is clean air flow;

[0038] The particulate matter mass concentration detection subsystem includes an optical detection chamber 6, a laser 7, an optical trap 10, a collimating lens 8, a focusing lens 9, and a photodiode; the optical detection chamber 6 is horizontally arranged, and a detection inlet and a detection outlet are relatively provided at the upper and lower ends of its central detection area; the detection inlet of the optical detection chamber 6 is connected to the outlet end of the mixing pipeline 5; the laser 7 and the optical trap 10 are relatively installed on the left and right side walls inside the optical detection chamber 6; the collimating lens 8 and the focusing lens 9 are successively installed at intervals inside the optical detection chamber 6 from left to right and are located between the laser 7 and the detection inlet. The focal point of the focusing lens 9 is located in the central detection area; the photodiode is installed on the front side wall in the middle section of the optical detection chamber 6, and its detection center forms a 90° angle with the laser emission direction of the laser 7;

[0039] The particulate atomization and capture subsystem includes an atomization and capture chamber 11, a buffer capture liquid chamber 13, an ultrasonic nozzle atomizer 12, and a main discharge pipeline 42; at the upper and lower ends of the middle section of the atomization and capture chamber 11, an atomization inlet and an atomization outlet are relatively provided, and two installation openings are relatively provided on the left and right sides of the middle section thereof; the atomization and capture chamber 11 is arranged below the optical detection chamber 6, and its atomization inlet is connected to the detection outlet of the optical detection chamber 6 through a vertical communication pipeline 41; the two buffer capture liquid chambers 13 are distributed on both sides of the atomization and capture chamber 11, and both store buffer capture liquid; wherein, the buffer capture liquid has appropriate solubility and surface tension, enabling the particulate matter in the aerosol to be efficiently transferred to the liquid phase, which is beneficial to improving the capture efficiency, and the buffer capture liquid is also beneficial to maintaining the reaction activity of DTT. The atomization and capture chamber 11 is the main area of gas-liquid interaction. When ambient air carrying particulate matter enters the chamber, it will collide and diffuse with the atomized droplets, causing the particulate matter to transfer from the gas phase to the liquid phase; the ultrasonic nozzle atomizer 12 has a liquid suction function, and it can atomize the capture liquid into micron-sized droplets by using ultrasonic energy. In this way, after the air flow enters the atomization and capture chamber 11, a uniformly distributed gas-liquid mixed environment can be formed, enabling the particulate matter in the air flow to fully contact and combine with the droplets;

[0040] The two ultrasonic nozzle atomizers 12 are relatively inserted into the two installation openings, and the outlet ends thereof relatively extend into the interior of the atomization and capture chamber 11, and the inlet ends thereof are connected to the liquid outlet of the two buffer capture liquid chambers 13 through two liquid supply pipelines respectively; the main discharge pipeline 42 is vertically arranged, and its inlet end is connected to the atomization and capture chamber 11 through the atomization outlet; as a preference, a grid is installed at the outlet of the ultrasonic nozzle atomizer 12. Thus, it is beneficial to optimize the distribution of the droplet size, further improve the capture efficiency of the particle diameter, avoid the situation of reduced capture efficiency caused by uneven droplet size, and can uniformly distribute the atomized droplets, reduce the locally high-concentration droplet area, reduce the situation of droplet agglomeration, help to increase the specific surface area of the droplets, make it easier for the particulate matter to enter the liquid phase, and improve the overall detection accuracy;

[0041] The particulate matter oxidation potential detection subsystem includes a first stirring device, a pH sensor 20, a DTT chamber 16, a first high-precision injection pump 17, a pH buffer chamber 18, a second high-precision injection pump 19, a second stirring device, a first liquid pump 21, a DTNB chamber 22, a third high-precision injection pump 23, an optical fiber probe 25, and an absorption fluorescence spectrometer 26; the first stirring device is installed below the atomization and capture chamber 11, and it includes a first constant-temperature stirring table 15, a reaction chamber 14, and a first stirring assembly. The reaction chamber 14 is installed at the upper end of the first constant-temperature stirring table 15 and is located below the atomization and capture chamber 11. The reaction chamber 14 is a closed structure, and its upper end is successively provided with a first filling port, a second filling port, and a third filling port from left to right. Its right side is provided with a liquid outlet. Among them, the first filling port is connected to the outlet end of the main discharge pipeline 42; the first stirring assembly is installed inside the reaction chamber 14, and its lower end is connected to the driving mechanism in the first constant-temperature stirring table 15 after passing through the bottom of the reaction chamber 14; the pH sensor 20 is installed inside the reaction chamber 14; the DTT chamber 16 is arranged above the reaction chamber 14, and DTT solution is stored inside it. Its bottom outlet is connected to the second filling port through a vertically arranged DTT filling pipeline 43, and the first high-precision injection pump 17 is connected in series in the middle section of the DTT filling pipeline 43; the pH buffer chamber 18 is arranged above the reaction chamber 14, and pH buffer is stored inside it. Its bottom outlet is connected to the third filling port through a vertically arranged pH liquid filling pipeline 44, and the second high-precision injection pump 19 is connected in series in the middle section of the pH liquid filling pipeline 44;

[0042] As a preference, the pH buffer is pretreated to remove trace metal ions, which can effectively reduce the non-specific oxidation of DTT and improve the experimental accuracy;

[0043] The second stirring device is installed adjacent to the right side of the first stirring device, and it includes a second constant-temperature stirring table 28, a flow detection chamber 24, and a second stirring assembly. The flow detection chamber 24 is installed at the upper end of the second constant-temperature stirring table 28 and is located on the right side of the reaction chamber 14. The upper end of the flow detection chamber 24 is open, its right side is provided with a liquid discharge port, and its left side is provided with a liquid inlet corresponding to the liquid outlet, and the liquid inlet is connected to the liquid outlet through a horizontal communication pipeline 45; the first liquid pump 21 is connected in series in the middle section of the horizontal communication pipeline 45; the DTNB chamber 22 is arranged above the flow detection chamber 24, and DTNB solution is stored inside it. Its bottom outlet is connected with a vertically arranged DTNB filling pipeline 46, and the third high-precision injection pump 23 is connected in series in the middle section of the DTNB filling pipeline 46; the optical fiber probe 25 is arranged inside the flow detection chamber 24; the absorption fluorescence spectrometer 26 is arranged on the outer side of the flow detection chamber 24 and is connected to the optical fiber probe 25;

[0044] The waste liquid treatment subsystem includes a liquid discharge pipeline 47 and a second liquid pump 27. The liquid inlet end of the liquid discharge pipeline 47 is connected to the flow detection chamber 24 through a liquid discharge port, and the second liquid pump 27 is connected in series in the middle section of the liquid discharge pipeline 47;

[0045] The control subsystem is respectively connected to a photodiode, a pH sensor 20, an absorption fluorometer 26, a particle size separator 1, a first vacuum pump 2, a second vacuum pump 3, a third vacuum pump 4, a laser 7, an ultrasonic nozzle atomizer 12, a first high-precision injection pump 17, a second high-precision injection pump 19, a first liquid pump 21, a third high-precision injection pump 23, a second liquid pump 27, a first constant temperature stirring table 15 and a second constant temperature stirring table 28.

[0046] Before the start of the detection operation, it is necessary to inject pre-prepared buffer trapping liquid, DTT solution, pH buffer solution and DTNB solution into the buffer trapping liquid chamber 1, DTT chamber 16, pH buffer solution chamber 18 and DTNB chamber 22 respectively, and ensure that the solutions in the system are stored sufficiently and meet the detection requirements at the same time.

[0047] In order to achieve the rapid installation and separation of the particle size separator 1, a quick connector is used to connect the particle size separator 1 and the main intake pipeline 31. In this way, it is convenient to quickly replace different particle size separators 1 according to different detection target particle sizes.

[0048] In order to effectively reduce the deposition rate of particulate matter on the inner wall surface, the inner surface of the optical detection chamber 6 is coated with a functional coating with low surface energy and excellent anti-adhesion performance. In this way, it can effectively prevent particulate matter from accumulating inside the optical detection chamber during the measurement process, which may otherwise affect the accuracy and repeatability of optical detection.

[0049] In order to effectively reduce the adhesion rate of droplets on the wall surface, the inside of the atomization trapping chamber 11 is coated with a hydrophobic coating. In this way, the droplets can gather towards the bottom more quickly, which is beneficial to improving the integrity of liquid-phase sampling. And the hydrophobic coating can effectively reduce the adhesion rate of particulate matter on the inner wall of the chamber, which helps the particulate matter to enter the liquid phase more efficiently, thereby improving the sampling consistency and reducing the measurement error;

[0050] In order to achieve light-proof storage and effectively reduce the spontaneous oxidation of DTT, the DTT chamber 16 is made of light-proof material. Further preferably, the DTT chamber 16 can have a temperature regulation function, and further reduce the DTT degradation rate by providing a low-temperature storage environment to ensure the stability of the DTT solution concentration.

[0051] In order to achieve light - proof storage, effectively reduce the degradation rate of DTNB, and ensure the accuracy of the color - developing reaction, the DTNB chamber 22 is made of light - impermeable material.

[0052] As a preference, the control subsystem includes a controller, a communication module, and a power module. The communication module is used to establish a communication connection between the controller and external devices.

[0053] In the present invention, by installing a particle size separator at the inlet end of the main intake pipeline, it is convenient to classify the particle size of the particulate matter, thereby ensuring that the particulate matter entering the detection system is of the target particle size. Thus, accurate sampling of particulate matter in a specific particle size range is achieved, ensuring the accuracy of subsequent detection results. In the mixing pipeline, the outer pipeline is a variable-diameter pipeline. At the same time, a conical filter section is provided between the large-diameter section and the small-diameter section. On this basis, the inner pipeline is coaxially inserted into the large-diameter section to form an annular flow channel. In this way, when the airflow entering from the annular flow channel passes through the contraction area of the conical filter section, the flow velocity of the airflow will increase due to the gradual reduction of the cross-sectional area of the flow channel, and at the same time, a flow field constraint effect will be generated, forcing the airflow entering from the inner pipeline to radially contract in the central area, thereby forming a sheath flow, reducing the diffusion amplitude and diffusion probability of the particulate matter in the airflow in the radial direction. In this way, after entering the optical detection chamber, the particulate matter can be concentrated in the central detection area, ensuring the accuracy of subsequent detection. The auxiliary intake pipelines I and II are respectively connected to both sides of the upper part of the large-diameter section, and then a vacuum pump and a HEPA filter are successively connected to the auxiliary intake pipelines. The negative pressure provided by the vacuum pump can be used to supply the clean air filtered by the HEPA filter into the annular flow channel. In the optical detection chamber, a laser, a collimating lens, a focusing lens, an optical trap, and a photodiode are successively arranged. A monochromatic and highly coherent laser beam can be emitted by the laser in the direction of the collimating lens, and the collimating lens can be used to adjust the shape of the laser beam so that the adjusted beam propagates parallelly in the direction of the focusing lens. Then, the focusing lens is used to focus the parallelly propagating beam, and thus a high-energy density light spot can be formed in the central detection area in the middle section of the optical detection chamber. In this way, the detection light spot formed by the focusing lens can be matched with the spatial position of the dust-containing airflow entering from the mixing pipeline, so that when the particulate matter passes through the high-light-intensity area in the central detection area, it can be fully irradiated by the laser, thereby improving the detection efficiency and measurement accuracy of the light scattering signal; the detection center of the photodiode is at a 90° angle to the emission direction of the laser, which can effectively reduce the interference of background light and improve the signal-to-noise ratio. Therefore, the scattered light signal generated when the light spot irradiates the particulate matter can be efficiently and accurately collected, and the scattered light signal can be converted into an electrical signal. By setting the optical trap, the laser irradiated on the right side wall can be absorbed, thereby avoiding the adverse effect of the reflected light on the detection result.Since the ultrasonic nozzle atomizer can use ultrasonic energy to atomize the buffer trapping liquid in the buffer trapping liquid chamber into micron-sized droplets, the atomization inlet of the atomization trapping chamber is connected to the detection outlet of the optical detection chamber through a vertical connecting pipeline. At the same time, two ultrasonic nozzle atomizers are inserted on its opposite sides. Then, while introducing the detection gas flow, atomized droplets can be synchronously introduced, and thus a mixed environment with gas-liquid interaction can be formed inside the atomization trapping chamber. When ambient air carrying particulate matter enters the buffer trapping liquid chamber, it will collide and diffuse with the atomized droplets. In this way, the particulate matter in the gas flow can fully contact and combine with the droplets, and then the particulate matter can be transferred from the gas phase to the liquid phase. The two ultrasonic nozzles are symmetrically arranged, which can ensure the uniform distribution of the trapping liquid in the atomization chamber, thus forming a uniform micron-sized fog field, avoiding the problem of uneven gas-liquid distribution caused by unilateral spraying. At the same time, it can ensure that the particulate matter concentration in the liquid phase is more uniform, avoiding local particulate matter concentration deviation caused by uneven atomization, and improving the reliability and accuracy of analysis results such as oxidation potential. The first stirring device mainly consists of a first constant temperature control console and a reaction chamber. It can not only facilitate the precise control of the reaction temperature in the reaction chamber by using the first constant temperature control console, ensuring that the reaction system can proceed under the set temperature conditions, so that the kinetic characteristics of the DTT oxidation reaction can always remain stable. At the same time, it can also use the stirring function of the first constant temperature control console to promote the full mixing of the particulate matter in the DTT solution, PH buffer solution and atomization trapping liquid. Through the stirring action, the sedimentation of particulate matter in the chamber can be reduced, which is beneficial to improving the uniformity of the reaction solution, thus ensuring that the measurement process of the DTT consumption rate can proceed more stably and reliably. Therefore, through the combined action of constant temperature and stirring, the equilibrium state of the DTT reaction can be accelerated, the reaction time required can be reduced, the detection efficiency of the detection system can be improved, and the detection accuracy can also be improved. Among them, the reaction chamber adopts a closed structure design, which can prevent the buffer solution from overflowing due to evaporation and other reasons, thus ensuring that no PH value drift occurs, and improving the long-term stability and detection accuracy of the system.By connecting a first high-precision injection pump in series on the DTT filling pipeline connected to the DTT chamber, the filling volume of the DTT solution can be accurately controlled, ensuring that the DTT concentration in the reaction chamber remains within a stable range; by connecting a second high-precision injection pump in series on the pH buffer solution filling pipeline connected to the pH buffer chamber, the filling volume of the pH buffer solution can be precisely controlled, ensuring that the pH value in the system remains stable and avoiding the spontaneous degradation of DTT due to pH factors or abnormal oxidation reaction rates; through the setting of the pH sensor, it is convenient to monitor the pH value data in the reaction chamber in real time; on this basis, combining the monitoring data of the pH value of the mixed solution in the reaction chamber by the pH sensor, the flow rate of the second high-precision injection pump is closed-loop controlled, and the pH buffer solution can be accurately supplemented into the reaction chamber to make the pH value data in the reaction solution stable within a constant range, significantly improving the automation level of the system and the stability of long-term reactions. An outlet is provided on the right side of the reaction chamber. At the same time, an inlet is provided on the left side of the flow detection chamber. Then, the outlet and the inlet are connected by a horizontal connecting pipeline, and a first liquid pump is connected in series on the horizontal connecting pipeline. The first liquid pump can be used to transport the reaction liquid in the reaction chamber to the flow detection chamber. By performing phased transportation actions at different reaction time nodes, the DTT samples at different reaction time nodes can be efficiently transported to the flow detection chamber for subsequent detection operations. The second stirring device mainly consists of a second constant temperature stirring table and a flow detection chamber, which not only facilitates the precise control of the reaction temperature in the flow detection chamber by using the second constant temperature control console, ensuring that the reaction system can proceed under the set temperature conditions, and then maintaining the constant temperature of the color reaction through constant temperature control to ensure the stability of the DTNB color reaction system. At the same time, the stirring function of the second constant temperature control console can also be used to promote the uniform mixing of the reaction liquid, improving the accuracy and repeatability of optical detection. By connecting a third high-precision injection pump in series on the DTNB filling pipeline connected to the DTNB chamber, after the reaction in the DTT oxidation stage ends, the reaction solution can be first transported to the flow detection chamber, and then the DTNB solution can be accurately and quantitatively added to the flow detection chamber by the third high-precision injection pump. Furthermore, the DTT and DTNB can undergo a color reaction. By precisely controlling the addition amount of DTNB, the color error caused by excessive or insufficient reagents can be avoided, ensuring the stability of the color reaction.Meanwhile, it can also ensure the consistency of the initial DTNB concentration in each measurement process, improving the repeatability of optical determination. By setting the optical fiber probe in the flow detection chamber, it is convenient to collect the optical signals in the flow detection chamber in real time and transmit them to the absorptiometric fluorometer without loss. Then, the absorptiometric fluorometer can measure the absorbance after the reaction of DTT and DTNB in the flow detection chamber based on the received optical signals, and calculate the DTT consumption rate through the absorbance, thereby quantifying the oxidation potential of the particulate matter. By directly measuring the solution in the flow detection chamber in this way, it ensures the accurate measurement of absorbance, effectively reduces the interference factors of the environment, improves the collection efficiency of optical signals, effectively reduces the light loss rate in the optical system, and improves the sensitivity of absorbance and fluorescence measurement. By connecting a drain pipeline to the drain port of the flow detection chamber and connecting a second liquid pump in series on the drain pipeline, the waste liquid in the flow detection chamber can be quickly drained, preventing the accumulation of liquid in the chamber from affecting the subsequent sample inlet flow and the stability of subsequent detection. Therefore, by using this system, samples can be collected at set time intervals, and the DTT consumption rate can be detected at different reaction stages in stages, realizing the continuity and stability of measurement.

[0054] The present invention can realize the automation and continuous operation of the whole process of real-time sampling, detection, reaction and analysis of particulate matter. Different from the traditional offline detection method, this system can continuously monitor the mass concentration and oxidation potential of particulate matter without interruption, providing real-time and continuous data updates, thus greatly improving the monitoring efficiency and data timeliness. In the continuous working mode, this system can ensure the seamless connection between multiple stages such as sampling, optical detection, chemical reaction, and color reaction by periodically controlling the working states of each subsystem, avoiding the monitoring interruption or data loss caused by operation intervals or sampling stops. Especially during the measurement of the oxidation potential of particulate matter, the consumption rate of DTT can be tracked in real time through precise time control, and data can be automatically collected and analyzed at different time points to ensure the accuracy and stability of the measurement results.

[0055] The present invention also provides an online intelligent monitoring method for the mass concentration and oxidation potential of harmful particulate matter. Using an online intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter, it includes the following steps:

[0056] Step 1: Select a particle size separator 1 within the target particle size range and connect it to the main intake pipeline 31 through a quick connector. Meanwhile, inject buffer capture liquid, DTT solution, pH buffer solution, and DTNB solution into the buffer capture liquid chamber 13, DTT chamber 16, pH buffer solution chamber 18, and DTNB chamber 22 respectively.

[0057] Step 2: Control the particle size separator 1, the first vacuum pump 2, the second vacuum pump 3, and the third vacuum pump 4 to start working synchronously for the time of a measurement cycle; during this measurement cycle, use the continuous suction force provided by the first vacuum pump 2 to allow the air in the environment to enter the particle size separator 1. At the same time, use the particle size separator 1 to preliminarily screen the particle sizes of the particulate matter in the air, so that the particulate matter within the target particle size range enters the inner pipeline 34 in the mixing pipeline 5 along with the air flow. Use the continuous suction force provided by the second vacuum pump 3 to allow the clean air flow filtered by the first HEPA filter 29 to enter the annular flow channel in the mixing pipeline 5. Use the continuous suction force provided by the third vacuum pump 4 to allow the clean air flow filtered by the second HEPA filter 30 to enter the annular flow channel in the mixing pipeline 5;

[0058] Step 3: Use the conical filter section 37 to accelerate the air flow in the annular flow channel and generate a flow field constraint effect, radially constrain the particulate matter in the air flow discharged from the inner pipeline 34 to the central region of the air flow, and make the air flow containing particulate matter enter the central detection region from the detection inlet on the optical detection chamber 6 along the small diameter section 38 and discharge from the detection outlet; at the same time, control the laser 7 to emit a monochromatic and highly coherent laser beam, use the collimating lens 8 to correct the shape of the laser beam into a parallel beam, use the focusing lens 9 to focus the parallel beam on the central detection region, and form a tiny laser spot with a high energy density in the central detection region. Under the irradiation of the laser spot, the surface of the particulate matter passing through the central detection region undergoes a scattering phenomenon. Synchronously, use the photodiode to capture the scattered light signal and convert it into a scattered electrical signal and send it to the control subsystem. The control subsystem analyzes the particulate matter composition based on the scattered electrical signals received during the current measurement cycle, and then obtains the concentration and particle size distribution data of the particulate matter during the current measurement cycle;

[0059] Step 4: Use the vertical connection pipeline 41 to divert the air flow containing particulate matter to the atomization capture chamber 11. During the process of the air flow containing particulate matter entering the buffer capture liquid chamber 13, synchronously control the two ultrasonic nozzle atomizers 12 to start working. The ultrasonic nozzle atomizers 12 use the ultrasonic excitation effect to atomize the buffer capture liquid in the buffer capture liquid chamber 13 into micron-sized droplets and supply them into the interior of the atomization capture chamber 11 to form a micron-sized fog field inside the atomization capture chamber 11; during the process of the particulate matter in the air flow passing through the fog field, it collides and contacts with the atomized droplets and combines with the droplets to form a capture liquid containing particulate matter;

[0060] Step 5: Use the main discharge pipeline 42 to divert all the formed capture liquid containing particulate matter to the reaction chamber 14. At the same time, control the first constant temperature stirring table 15 in the first stirring device to start working, so that the reaction temperature in the reaction chamber 14 is maintained within the set temperature range, and at the same time, continuously stir the liquid in the reaction chamber 14 evenly;

[0061] Synchronously, the control subsystem controls the first high-precision injection pump 17 to quantitatively inject DTT solution into the reaction chamber 14 based on the concentration and particle size distribution data of the particulate matter in the current measurement cycle, so that the DTT molecules undergo a redox reaction with the oxidizing substances attached to the surface of the particulate matter; during the redox reaction, the PH sensor 20 is used to collect the PH value data in the reaction solution in real time and send it to the control subsystem, and the control subsystem controls the second high-precision injection pump 19 to quantitatively inject PH buffer solution into the reaction chamber 14 according to the PH value data, so that the PH value data in the reaction solution is stabilized within a constant range;

[0062] During the redox reaction, the control subsystem controls the first liquid pump 21 to work intermittently at a set time interval to quantitatively transport the reaction solution in the reaction chamber 14 to the flow detection chamber 24 for stage detection at different reaction time nodes. During the stage detection process, the control subsystem synchronously controls the second constant temperature stirring table 28 in the second stirring device to start working, so that the reaction temperature in the flow detection chamber 24 is maintained within the set temperature range. At the same time, the liquid in the flow detection chamber 24 is continuously and evenly stirred. Meanwhile, the control subsystem controls the third high-precision injection pump 23 to quantitatively inject DTNB solution according to the injection volume of the reaction solution entering the flow detection chamber 24, so that a color reaction occurs between DTNB and DTT, and a colored compound with specific light absorption characteristics is generated. During the color reaction, the optical signal of the reaction solution is collected in real time by the optical fiber probe 25 and transmitted to the absorbance fluorometer 26. The absorbance fluorometer 26 analyzes the received optical signal to obtain the absorbance value, and calculates the current consumption rate of DTT based on the obtained absorbance value. At the end of the color reaction, the control subsystem controls the second liquid pump 27 to start working for a set time, and discharges the reaction waste liquid in the flow detection chamber 24 through the drain pipeline 47. Repeat the above process to obtain the DTT consumption rate at different reaction time nodes through the stage detection process;

[0063] Step six, repeat steps one to five to perform the monitoring operation for the next measurement cycle.

[0064] In order to effectively reduce the non-specific oxidation of DTT and effectively ensure the detection accuracy, in step one, the PH buffer solution is a buffer solution pretreated by removing trace metal ions.

[0065] The present invention can utilize light scattering technology to detect the concentration of atmospheric particulate matter in real time. At the same time, it adopts a technical means combining liquid trapping and on-line DTT reaction, and quickly "quenches" the reaction by automatically adding DTNB. Then, the change of absorbance is monitored in real time through a color reaction, so as to accurately calculate the DTT consumption rate and realize the quantification of oxygen potential. Compared with the traditional method, this method has the advantages of fast real-time response, high automation degree, simple operation process, high detection accuracy and low implementation cost, and can provide efficient and reliable technical support for dynamic monitoring of air pollution and health risk assessment.

Claims

1. An online intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter, including a particulate matter sampling subsystem, characterized in that: It also includes a particle mass concentration detection subsystem, a particle atomization capture subsystem, a particle oxidation potential detection subsystem, a waste liquid treatment subsystem and a control subsystem; The particle sampling subsystem comprises a main air intake pipeline (31), a particle size separator (1), a first vacuum pump (2), a mixing pipeline (5), an auxiliary air intake pipeline 1 (32), a second vacuum pump (3), a first HEPA filter (29), an auxiliary air intake pipeline 2 (33), a third vacuum pump (4) and a second HEPA filter (30); the particle size separator (1) is connected in series to the inlet end of the main air intake pipeline (31), and the air inlet of the first vacuum pump (2) is connected to the main air intake pipeline (31). The mixing pipeline (5) is vertically arranged, and its inlet end is connected to the outlet of the first vacuum pump (2). The mixing pipeline (5) comprises an outer pipeline (35) and an inner pipeline (34). The outer pipeline (35) is a variable diameter pipeline, which comprises a large diameter section (36), a conical transition section (37) and a small diameter section (38) from top to bottom. The upper opposite sides of the large diameter section (36) are respectively provided with auxiliary air inlet 1 (39) and auxiliary air inlet 2 (40); the lower end of the small diameter section (38) serves as the outlet end of the mixing pipe (5); the inner pipe (34) is coaxially inserted into the interior of the large diameter section (36), its lower end extending to the inlet end of the conical transition section (37), its upper end extending above the upper end of the large diameter section (36), and serving as the inlet end of the mixing pipe (5), and at the same time, an annular flow channel is formed between the inner pipe (34) and the large diameter section (36); the auxiliary air intake pipe (32) is arranged transversely, and its outlet The first end of the auxiliary air inlet (39) is connected to the outer pipeline (35); the first HEPA filter (29) and the second vacuum pump (3) are respectively connected in series to the inlet end and the middle section of the auxiliary air inlet pipeline (32); the second auxiliary air inlet pipeline (33) is arranged horizontally, and its outlet end is connected to the outer pipeline (35) through the auxiliary air inlet (40); the second HEPA filter (30) and the third vacuum pump (4) are respectively connected in series to the inlet end and the middle section of the auxiliary air inlet pipeline (33); The particle mass concentration detection subsystem comprises an optical detection chamber (6), a laser (7), a light trap (10), a collimating lens (8), a focusing lens (9) and a photodiode; the optical detection chamber (6) is arranged horizontally, and a detection inlet and a detection outlet are oppositely opened at the upper and lower ends of the central detection area; the detection inlet of the optical detection chamber (6) is connected to the outlet end of the mixing pipe (5); the laser (7) and the light trap (10) are oppositely installed on the left and right walls inside the optical detection chamber (6); the collimating lens (8) and the focusing lens (9) are installed in the optical detection chamber (6) in sequence from left to right, and are located between the laser (7) and the detection inlet, and the focus of the focusing lens (9) is located in the central detection area; the photodiode is installed on the front side wall of the middle section of the optical detection chamber (6), and its detection center is 90 degrees with the laser emission direction of the laser (7); The particle atomization capture subsystem comprises an atomization capture chamber (11), a buffer capture liquid chamber (13), an ultrasonic nozzle atomizer (12) and a main discharge pipeline (42); an atomization inlet and an atomization outlet are provided at the upper and lower ends of the middle section of the atomization capture chamber (11), and two installation ports are provided at the left and right sides of the middle section; the atomization capture chamber (11) is arranged below the optical detection chamber (6), and its atomization inlet is connected to the detection outlet of the optical detection chamber (6) through a vertical connecting pipeline (41). connection; two buffer capture liquid chambers (13) are distributed on both sides of the atomizing capture chamber (11), and both store buffer capture liquid; two ultrasonic nozzle atomizers (12) are relatively inserted into the two installation ports, and their outlet ends relatively extend into the interior of the atomizing capture chamber (11), and their inlet ends are respectively connected to the liquid outlets of the two buffer capture liquid chambers (13) through two liquid supply pipelines; the main discharge pipeline (42) is vertically arranged, and its inlet end is connected to the atomizing capture chamber (11) through the atomizing outlet; The particle oxidation potential detection subsystem comprises a first stirring device, a pH sensor (20), a DTT chamber (16), a first high-precision injection pump (17), a pH buffer chamber (18), a second high-precision injection pump (19), a second stirring device, a first liquid pump (21), a DTNB chamber (22), a third high-precision injection pump (23), an optical fiber probe (25) and an absorption fluorescence instrument (26); the first stirring device is installed below the atomization capture chamber (11), and comprises a first constant temperature stirring platform (15), a reaction chamber (14) and a first stirring assembly; the reaction chamber (14) is installed at the upper end of the first constant temperature stirring platform (15) and is located below the atomization capture chamber (11); the reaction chamber (14) The chamber (14) is a closed structure, and a first filling port, a second filling port and a third filling port are sequentially opened at its upper end from left to right, and a liquid outlet is opened on its right side, wherein the first filling port is connected to the outlet end of the main discharge pipeline (42); the first stirring component is installed inside the reaction chamber (14), and its lower end is connected to the driving mechanism in the first constant temperature stirring table (15) after passing through the bottom of the reaction chamber (14); the pH sensor (20) is installed inside the reaction chamber (14); the DTT chamber (16) is arranged above the reaction chamber (14), and DTT solution is stored inside it, and its bottom outlet is connected to the second filling port through a vertically arranged DTT filling pipeline (43), and the first high-precision injection pump ( 17) is connected in series to the middle section of the DTT filling pipeline (43); the pH buffer chamber (18) is arranged above the reaction chamber (14), and pH buffer is stored therein, and its bottom outlet is connected to the third filling port through a vertically arranged pH liquid filling pipeline (44), and the second high-precision injection pump (19) is connected in series to the middle section of the pH liquid filling pipeline (44); the second stirring device is installed adjacent to the right side of the first stirring device, and includes a second constant temperature stirring table (28), a flow detection chamber (24) and a second stirring assembly, the flow detection chamber (24) is installed at the upper end of the second constant temperature stirring table (28) and is located on the right side of the reaction chamber (14), the upper end of the flow detection chamber (24) is open, and its right A liquid discharge port is provided on the side thereof, and a liquid inlet is provided on the left side thereof corresponding to the liquid outlet, and the liquid inlet is connected to the liquid outlet through a transverse connecting pipeline (45); the first liquid pump (21) is connected in series to the middle section of the transverse connecting pipeline (45); the DTNB chamber (22) is arranged above the flow detection chamber (24), and a DTNB solution is stored therein, and a vertically arranged DTNB filling pipeline (46) is connected to the bottom outlet thereof, and the third high-precision injection pump (23) is connected in series to the middle section of the DTNB filling pipeline (46); the optical fiber probe (25) is arranged inside the flow detection chamber (24); the absorbance fluorescence instrument (26) is arranged on one side outside the flow detection chamber (24) and is connected to the optical fiber probe (25); The waste liquid treatment subsystem comprises a liquid discharge pipeline (47) and a second liquid pump (27), wherein the liquid inlet end of the liquid discharge pipeline (47) is connected to the flow detection chamber (24) via a liquid discharge port, and the second liquid pump (27) is connected in series to the middle section of the liquid discharge pipeline (47); The control subsystem is respectively connected to a photodiode, a pH sensor (20), an absorption fluorescence instrument (26), a particle size separator (1), a first vacuum pump (2), a second vacuum pump (3), a third vacuum pump (4), a laser (7), an ultrasonic nozzle atomizer (12), a first high-precision injection pump (17), a second high-precision injection pump (19), a first liquid pump (21), a third high-precision injection pump (23), a second liquid pump (27), a first constant temperature stirring platform (15) and a second constant temperature stirring platform (28).

2. The online intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter according to claim 1 is characterized in that: The particle size separator (1) and the main air intake pipeline (31) are connected by a quick connection joint.

3. The online intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter according to claim 1 or 2, characterized in that: The inner surface of the optical detection chamber (6) is coated with a functional coating with low surface energy and excellent anti-adhesion performance.

4. The online intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter according to claim 3 is characterized in that: The interior of the atomization and collection chamber (11) is coated with a hydrophobic coating.

5. The online intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter according to claim 4 is characterized in that: The DTT chamber (16) is made of a light-proof material; and the DTNB chamber (22) is made of a light-proof material.

6. The online intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter according to claim 1 or 2, characterized in that: The control subsystem includes a controller, a communication module and a power module.

7. A method for online intelligent monitoring of the mass concentration and oxidation potential of harmful particulate matter, using an online intelligent monitoring system for the mass concentration and oxidation potential of harmful particulate matter as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Select a particle size separator (1) within a target particle size range and connect it to a main air intake pipeline (31) via a quick-connect connector; at the same time, inject a buffer capture liquid, a DTT solution, a pH buffer solution and a DTNB solution into a buffer capture liquid chamber (13), a DTT chamber (16), a pH buffer solution chamber (18) and a DTNB chamber (22) respectively; Step 2: Control the particle size separator (1), the first vacuum pump (2), the second vacuum pump (3), and the third vacuum pump (4) to start working synchronously for a measurement cycle; during the measurement cycle, the continuous suction force provided by the first vacuum pump (2) is used to allow air in the environment to enter the particle size separator (1); at the same time, the particle size separator (1) is used to preliminarily screen the particle size of particles in the air, so that particles within the target particle size range enter the inner pipe (34) of the mixing pipe (5) along with the airflow; the continuous suction force provided by the second vacuum pump (3) is used to allow the clean airflow filtered by the first HEPA filter (29) to enter the annular flow channel in the mixing pipe (5); and the continuous suction force provided by the third vacuum pump (4) is used to allow the clean airflow filtered by the second HEPA filter (30) to enter the annular flow channel in the mixing pipe (5); Step 3: Use the conical filter section (37) to accelerate the airflow in the annular flow channel and generate a flow field constraint effect, so that the particles in the airflow discharged from the inner pipe (34) are radially constrained in the central area of ​​the airflow, and the airflow containing the particles is allowed to enter the central detection area from the detection inlet on the optical detection chamber (6) along the small diameter section (38) and be discharged from the detection outlet; at the same time, control the laser (7) to emit a monochromatic and highly coherent laser beam, and use the collimating lens (8) to correct the shape of the laser beam into a parallel beam, use the focusing lens (9) to focus the parallel beam on the central detection area, and form a small laser spot with high energy density in the central detection area. Under the irradiation of the laser spot, the surface of the particles passing through the central detection area is scattered, and the scattered light signal is captured by the photodiode simultaneously, and converted into a scattered electrical signal and sent to the control subsystem. The control subsystem analyzes the composition of the particles based on the scattered electrical signal received in the current measurement cycle, and then obtains the concentration and particle size distribution data of the particles in the current measurement cycle; Step 4: using the vertical connecting pipe (41) to guide the airflow containing particulate matter into the atomizing and capturing chamber (11); in the process of the airflow containing particulate matter entering the buffer capturing liquid chamber (13), the two ultrasonic nozzle atomizers (12) are synchronously controlled to start working; the ultrasonic nozzle atomizer (12) uses the ultrasonic excitation effect to atomize the buffer capturing liquid in the buffer capturing liquid chamber (13) into micron-sized droplets, and supplies them into the interior of the atomizing and capturing chamber (11), thereby forming a micron-sized fog field inside the atomizing and capturing chamber (11); in the process of the particulate matter in the airflow passing through the fog field, the particulate matter collides with the atomized droplets and combines with the droplets to form a capturing liquid containing particulate matter; Step 5: Using the main discharge pipeline (42), all the captured liquid containing particulate matter is drained into the reaction chamber (14); at the same time, the first constant temperature stirring table (15) in the first stirring device is controlled to start working, so that the reaction temperature in the reaction chamber (14) is maintained within a set temperature range, and at the same time, the liquid in the reaction chamber (14) is continuously stirred uniformly; Synchronously, the control subsystem controls the first high-precision injection pump (17) to quantitatively inject DTT solution into the reaction chamber (14) based on the concentration and particle size distribution data of the particles in the current measurement cycle, so that the DTT molecules undergo a redox reaction with the oxidizing substances attached to the surface of the particles; during the redox reaction, the pH value data in the reaction liquid is collected in real time by using the pH sensor (20) and sent to the control subsystem, and the control subsystem controls the second high-precision injection pump (19) to quantitatively inject pH buffer into the reaction chamber (14) based on the pH value data, so that the pH value data in the reaction liquid is stabilized within a constant range; During the redox reaction, the control subsystem controls the first liquid pump (21) to work intermittently at set time intervals, so as to quantitatively transport the reaction liquid in the reaction chamber (14) to the flow detection chamber (24) for staged detection at different reaction time nodes. During the staged detection process, the control subsystem synchronously controls the second constant temperature stirring table (28) in the second stirring device to start working, so that the reaction temperature in the flow detection chamber (24) is maintained within the set temperature range. At the same time, the injection body in the flow detection chamber (24) is continuously stirred uniformly. At the same time, the control subsystem controls the third high-precision injection pump (23) to quantitatively inject DTNB according to the injection amount of the reaction liquid entering the flow detection chamber (24). The solution is used to cause a color reaction between DTNB and DTT, and a colored compound with specific light absorption characteristics is generated. During the color reaction, the optical signal of the reaction solution is collected in real time by using an optical fiber probe (25), and is transmitted to an absorption fluorescence meter (26). The absorption fluorescence meter (26) analyzes the received optical signal and obtains an absorbance value, and calculates the current DTT consumption rate based on the obtained absorbance value. When the color reaction is finished, the control subsystem controls the second liquid pump (27) to start working for a set time, and discharges the reaction waste liquid in the flow detection chamber (24) through a drainage pipeline (47). The above process is repeated, and the DTT consumption rate at different reaction time nodes is obtained through a phased detection process. Step 6: Repeat steps 1 to 5 to perform monitoring operations for the next measurement cycle.

8. The method for online intelligent monitoring of the mass concentration and oxidation potential of harmful particulate matter according to claim 7, characterized in that: In step 1, the pH buffer is a buffer pretreated to remove trace metal ions.

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