Atmospheric particulate matter water-soluble ion analysis instrument calibration system and calibration method

Abstract

The application provides an atmospheric particulate matter water-soluble ion analysis instrument calibration system and a calibration method, and belongs to the technical field of atmospheric particulate matter metrology. The system comprises an atmospheric environment simulation measurement device and a portable calibration device. The atmospheric environment simulation measurement device simulates actual environmental conditions through an aerosol mixing cabin in a thermostat, and is equipped with various sensors to monitor temperature, air pressure and humidity. The portable calibration device is internally provided with an aerosol generator, an equal-speed flow divider, a particulate sensor and the like, and can generate aerosol samples on site for calibration. The calibration method comprises two parts of constructing a standard parameter database and on-site calibration, and ensures calibration accuracy by comparing particulate matter sensor measurement values and particle size spectra. The application adopts the atmospheric particulate matter water-soluble ion analysis instrument calibration system and the calibration method, solves the problem that traditional calibration equipment is large in size and cannot be calibrated on site, and provides reliable technical support for on-site calibration of atmospheric particulate matter water-soluble ion analysis instruments.

Description

Technical Field

[0001] This invention relates to the field of atmospheric particulate matter measurement technology, and in particular to a calibration system and calibration method for an atmospheric particulate matter water-soluble ion analyzer. Background Technology

[0002] Atmospheric particulate matter is a significant component of ambient air pollutants, and the content of its water-soluble ionic components is crucial foundational data for particulate matter source apportionment. Currently, particulate matter water-soluble ion analyzers typically employ ion chromatography to determine the composition and content of these ions. These instruments generally consist of an aerosol sampling unit, a particulate matter collection unit, a liquid sample collection unit, an ion chromatography analysis unit, a waste liquid collection unit, and a data processing unit. Due to their large size and complex piping connections, they are usually fixedly installed at monitoring stations and difficult to move. Therefore, calibration cannot be performed at the monitoring station like conventional instruments, which can be transported to a calibration laboratory.

[0003] Particulate matter water-soluble ion analyzers require direct aerosol sample collection for analysis during operation, which means conventional water-soluble ion standard solutions cannot be used for instrument calibration. Instead, aerosol particulate matter samples must be generated on-site at the monitoring station to serve as the calibration basis. The content of water-soluble ions in particulate matter is usually expressed as atmospheric mass concentration, with units of μg / m³. 3 Therefore, the mass concentration of particulate matter in aerosol form has become a core measurement in the instrument calibration process. However, traditional metrological standards for the mass concentration of water-soluble ions in particulate matter are mostly based on the method of sample collection using filter membrane sampling and balance weighing. These devices are bulky and cannot be transported to monitoring sites. Therefore, it is necessary to use a portable generator capable of producing particulate matter samples of specific concentrations as a transfer standard for on-site calibration.

[0004] In actual calibration, factors such as ambient temperature and atmospheric pressure at the monitoring site must also be considered. These factors are uncontrollable, but they can affect the performance of the aerosol generator and may cause changes in the concentration and morphology of particulate matter during pipeline transport, thus altering the particulate matter concentration. Therefore, it is essential to establish the relationship between ambient temperature, atmospheric pressure, and particulate matter concentration, and to verify the operating status of the portable generator in a real-world environment to ensure the accuracy and reliability of the calibration. Summary of the Invention

[0005] The purpose of this invention is to provide a calibration system and method for atmospheric particulate matter water-soluble ion analyzers, so as to solve the problems of accurate generation and concentration correction of particulate matter aerosols during on-site calibration.

[0006] To achieve the above objectives, the present invention provides a calibration system for an atmospheric particulate matter water-soluble ion analyzer, including an atmospheric environment simulation measurement device and a portable calibration device;

[0007] The atmospheric environment simulation and measurement device includes:

[0008] The constant temperature chamber has an aerosol mixing chamber inside, which includes a first compartment and a second compartment.

[0009] The first barometer and the first thermometer are installed on the side wall of the first compartment, and their outlets are connected to the second compartment through a double-flare structure.

[0010] The second cabin is equipped with a first thermometer and hygrometer and a second barometer, and the top is equipped with a sampling tube and an exhaust tube.

[0011] The portable calibration device includes a housing, inside which are:

[0012] The aerosol generator has its input end connected to the compressed air inlet and its output end connected to the input end of the constant velocity splitter.

[0013] The constant velocity splitter has a first output end connected to a particle sensor and a second output end connected to an aerosol outlet pipeline.

[0014] The second temperature and humidity meter is installed on the pipeline before the constant velocity shunt.

[0015] The third barometer is installed inside the chamber and is used to measure the ambient air pressure inside the chamber.

[0016] An ambient temperature gauge interface is provided on the outside of the enclosure for installing a second thermometer;

[0017] The control system is connected to the interfaces of the aerosol generator, particle sensor, second temperature and humidity meter, third barometer and ambient temperature meter respectively;

[0018] An isokinetic sampling head can be detachably installed at the end of the aerosol outlet pipeline, and the isokinetic sampling head is equipped with an air vent.

[0019] Preferably, the sampling tube adopts a constant velocity sampling design, that is, the gas flow rate entering the sampling port is the same as the gas flow rate not entering the sampling port. The sampling tube extends to the sampling port outside the constant temperature chamber and is connected to a standard aerosol particle size analyzer and a standard particulate matter water-soluble ion analyzer respectively through a switching valve. The gas extraction tube extends to the gas extraction port outside the constant temperature chamber and is connected to the input end of the pressure-stabilized gas extraction pump. The control end of the pressure-stabilized gas extraction pump receives the measurement signal from the first barometer.

[0020] Preferably, either of the flares in the double-flare structure is a conical flare, and the angle between the generatrix of the conical flare and its height is... satisfy:

[0021] ;

[0022] In a double-flare structure, any one of the flares is a non-conical flare. The normal cross-sectional radius of the non-conical flare at any point on the gas trajectory is... With trajectory length satisfy:

[0023] .

[0024] Preferably, the inner diameter of the pipe between the double bell mouths satisfy:

[0025] ;

[0026] in, This indicates the lowest achievable air pressure inside the first compartment during the simulation measurement process. This indicates the highest temperature that can be reached during the simulation measurement process. This represents the lowest aerosol input flow rate during the simulation measurement process.

[0027] Preferably, the second compartment is a cylinder of constant diameter, with an inner diameter of... satisfy:

[0028] ;

[0029] In the second compartment, the distance from the end of the horn-shaped opening to the top of the sampling port... satisfy:

[0030] ;

[0031] Distance from the top of the sampling port to the top of the air extraction port satisfy:

[0032] .

[0033] This invention also provides a calibration method for an atmospheric particulate matter water-soluble ion analyzer, which uses the above-mentioned atmospheric particulate matter water-soluble ion analyzer calibration system and includes the following steps:

[0034] Step S1: Construct a standard parameter database for portable calibration devices;

[0035] Step S2: Perform on-site calibration using a portable calibration device.

[0036] Preferably, step S1 specifically includes:

[0037] Step S11: Connect the aerosol outlet of the portable calibration device to the aerosol inlet on the constant temperature chamber. The portable calibration device is not equipped with an isokinetic sampling head.

[0038] Step S12, prepare the mixture containing a The dust source solution contains each component, and the composition of each component is recorded. ~ and its concentration ~ Add the dust source solution to the aerosol generator of the portable calibration device and set the aerosol generation parameters. ~ Aerosol generation occurs;

[0039] Step S13: Adjust the temperature and air pressure stabilization device of the constant temperature chamber;

[0040] Step S14: After the aerosol temperature, aerosol humidity, and output values ​​of the particle sensor for each particle size range measured by the portable calibration device have stabilized, and the measured values ​​of the first barometer and the first thermometer in the atmospheric environment simulation measurement device have stabilized, record the aerosol temperature measured by the portable calibration device. aerosol humidity Output values ​​of particle sensors for various particle size ranges ~ The measured value of the first barometer in the atmospheric environment simulation measurement device simulates the atmospheric pressure of the environment. The thermometer readings simulate ambient temperature. The second barometer measures atmospheric pressure. The first temperature and humidity meter measured the sampling temperature. and sampling humidity ;

[0041] Step S15: Obtain the aerosol standard particle size distribution by adjusting the switching valve. and the mass concentration of each component of the aerosol under sampling conditions ~ ;

[0042] Step S16: Calculate the standard mass concentration of each component. ~ Sensor-particle size spectrum difference for various particle size ranges ~ Sensor-particle size ratio ;

[0043] Step S17: When sampling humidity When the humidity does not exceed the preset sampling threshold, the dust source solution used for aerosols will be affected by various components. ~ and its concentration ~ Aerosol generation parameters ~ Simulated ambient atmospheric pressure Simulated ambient temperature Aerosol standard particle size distribution Particle sensor-particle size spectrum difference for various particle size ranges ~ Sensor-particle size ratio and the standard mass concentration of each component ~ Enter into the database; when sampling humidity When the preset sampling humidity threshold is exceeded, all data is invalidated and not entered into the database;

[0044] Step S18: Change the dust source solution ratio, air inlet flow rate, generation parameters, constant temperature chamber temperature, and air pressure stabilization device target pressure respectively to make the above parameters cover all conditions of the expected calibration work, and measure and record according to steps S12 to S17 to build a standard parameter database for the portable calibration device.

[0045] Preferably, step S2 specifically includes:

[0046] Step S21: Place the second thermometer of the portable calibration device next to the sampling port of the instrument being calibrated, connect the instrument connection port of the isokinetic sampling head to the sampling port of the instrument being calibrated, connect the isokinetic sampling head to the aerosol outlet of the portable calibration device using a pipeline, and start the instrument being calibrated to enter the working state.

[0047] Step S22, prepare the mixture containing a The dust source solution contains each component, and the composition of each component is recorded. ~ and its concentration ~ ;

[0048] Step S23: Add the dust source solution to the aerosol generator and set the aerosol generation parameters. ~ Aerosol generation occurs;

[0049] Step S24: After both the aerosol generator and the instrument under calibration have reached a stable state, read the aerosol humidity measured by the portable calibration device. When the aerosol humidity When the humidity level is not higher than the preset humidity threshold, connect the tubing to the sampling port of the instrument being calibrated and record the aerosol temperature measured by the portable calibration device. Output values ​​of particle sensors for various particle size ranges ~ Atmospheric pressure and ambient temperature When the aerosol humidity When the humidity exceeds the preset threshold, the control system stops subsequent calibration operations and outputs an error message.

[0050] Step S25: Calculate the degree of difference between the field-calibrated aerosol and the aerosol sensor particle size distribution in the standard parameter database. The degree of difference between the sensor and the particle size ratio ;

[0051] Step S26, when , When all values ​​are less than the corresponding preset threshold, ~ The instrument being calibrated is calibrated using the standard value; otherwise, the control system stops the calibration operation and outputs an error message.

[0052] Preferably, the degree of difference between the aerosol sensor particle size distribution values ​​calibrated on-site and those in the standard parameter database is considered. The calculation formula is as follows:

[0053] ;

[0054] ;

[0055] in, Indicates the first Sensor-particle size spectrum difference values ​​in a standard database of particle size ranges Indicates the first Sensor-particle size spectrum difference during on-site calibration for each particle size range Indicates the particle size in the standard particle size spectrum. Indicating the particle sensor number in the standard particle size spectrum The initial particle size within a particle size range, Indicating the particle sensor number in the standard particle size spectrum Termination particle size within a particle size range This represents the ratio between the particle size distribution measurement results and the particle sensor measurement results. This represents the measured value of the corresponding particle size in the particle size spectrum. This represents the sum of all measured values ​​in the particle size distribution. Indicates the particulate sensor during on-site calibration. i Measurement values ​​for a particle size range, This represents the sum of measurements taken across the entire particle size range during on-site calibration of the particle sensor. This represents the total number of all particle size ranges.

[0056] Preferably, the degree of difference between the on-site calibrated aerosol and the aerosol sensor-particle size distribution ratio in the standard parameter database. The calculation formula is as follows:

[0057] .

[0058] Therefore, the present invention employs the above-mentioned calibration system and method for atmospheric particulate matter water-soluble ion analysis instruments, and the beneficial technical effects are as follows:

[0059] Using a portable calibration device as the transfer standard, an atmospheric environment simulation measurement device is used to simulate all temperature and pressure conditions for on-site calibration. By permuting and combining environmental conditions and generation parameters, a standard parameter database of aerosols generated by the portable calibration device is obtained, serving as the source of standard values ​​for on-site calibration. This calibration system and method solve the problem that existing particulate matter water-soluble ion mass concentration standard devices cannot be transported to monitoring stations, and address the accuracy issue of particulate matter concentration values ​​generated on-site by comparing particulate matter size spectra, providing a feasible solution for on-site calibration of atmospheric particulate matter water-soluble analyzers. Attached Figure Description

[0060] Figure 1 This is a structural diagram of an atmospheric environment simulation and measurement device.

[0061] Figure 2 A structural diagram of the aerosol mixing chamber of an atmospheric environment simulation and measurement device;

[0062] Figure 3 This is a structural diagram of a portable calibration device;

[0063] Figure 4 This diagram illustrates the instrument connections used when building a standard parameter database.

[0064] Figure 5 This is a diagram showing the instrument connections during on-site calibration.

[0065] Figure 6 This is a schematic diagram illustrating the motion trajectory of the geometric center of the cross section solved using the infinitesimal element method. Figure 6 In the diagram, A represents the starting center point and the initial direction of motion. Figure 6 In the diagram, B represents the moving distance and cross-section. Figure 6 C in the diagram represents the geometric center of the cross section. Detailed Implementation

[0066] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0067] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0068] Example 1

[0069] The atmospheric particulate matter water-soluble ion analyzer calibration system includes an atmospheric environment simulation measurement device and a portable calibration device. The portable calibration device generates standard particulate matter aerosols as transfer standards for on-site calibration of the instrument under test. The atmospheric environment simulation measurement device simulates various temperature and pressure environments, comprehensively tests the performance of the portable calibration device, establishes a standard parameter database, and provides standard values ​​for on-site calibration.

[0070] The structure of the atmospheric environment simulation measurement device is as follows: Figure 1 As shown, it includes an aerosol mixing chamber set in a constant temperature chamber, as well as a pressure-stabilized vacuum pump, a switching valve, a standard aerosol particle size analyzer, and a standard particulate matter water-soluble ion analyzer connected to the aerosol mixing chamber.

[0071] Artificially generated aerosols enter the aerosol mixing chamber, which is placed in a constant-temperature chamber, through an inlet. The aerosol mixing chamber employs a two-stage design. The first stage chamber simulates different temperature and pressure environments in the field and initially mixes the particulate matter. Since portable calibration devices may be used in different temperature and pressure environments in the field, the flow rate, density, and velocity of the aerosols generated by the portable calibration device may change, thus affecting the formation state of particulate matter in the aerosol. Therefore, by simulating changes in temperature and pressure, a reference standard can be established for aerosol particulate matter generated under different environmental conditions. The second stage chamber ensures thorough mixing of the particulate matter and provides it to the measuring instruments, while simultaneously regulating the pressure in the first stage chamber.

[0072] To achieve the above objectives, the side wall of the first chamber is equipped with a first barometer and a first thermometer. The first barometer transmits the pressure signal to a pressure-stabilized vacuum pump outside the thermostatic chamber. The first and second chambers are connected using a double-flare-mouth design. The second chamber contains a sampling tube, a vacuum tube, a first hygrometer, and a second barometer. The sampling tube extends from the sampling port on the surface of the thermostatic chamber and is connected to a standard aerosol particle size analyzer and a standard particulate water-soluble ion analyzer via a switching valve. The vacuum tube extends from the vacuum port on the surface of the thermostatic chamber and is connected to the pressure-stabilized vacuum pump. The pressure-stabilized vacuum pump adjusts the pumping rate based on the barometer measurements to maintain the pressure in the first chamber at a set value. The first hygrometer and the second barometer measure the aerosol temperature, humidity, and pressure in the second chamber for sampling volume correction.

[0073] A switching valve connected to the sampling tube outlet controls the on / off state of the gas path, allowing the aerosol sample output from the sampling port to be sent to a standard aerosol particle size analyzer or a standard particulate matter water-soluble ion analyzer. The standard aerosol particle size analyzer measures the particle size distribution in the aerosol sample, comparing the results with those obtained from multiple particle size ranges by the particle sensor in the portable calibration device. This comparison determines whether the aerosol generator's operating status during on-site calibration is consistent with the established standard parameter database. Its particle size and particle number concentration measurements are metrologically calibrated and traceable to the corresponding national standards. The standard particulate matter water-soluble ion analyzer measures the water-soluble ion content in the aerosol sample, and its measurement results are traceable to the corresponding standard substances and national standards.

[0074] The detailed structure of the aerosol mixing chamber of the atmospheric environment simulation measurement device is as follows: Figure 2 As shown.

[0075] When the flared opening at the end of the first compartment is designed in a conical shape, the angle between the generatrix of the cone and the height... The following conditions must be met:

[0076] .

[0077] When the flare opening is designed without a conical shape, the geometric center of the gas outlet section is used as the starting point, and the opposite direction of the gas flow is taken as the initial direction of motion. The trajectory of the geometric center of the section is obtained using the infinitesimal element method. For any point on the trajectory, a plane perpendicular to the direction of motion at that point is constructed. The radius of a circle of equal area is calculated by using the area of ​​the cross-section obtained from the intersection of this plane and the flare opening. ,radius The length of the trajectory from the geometric center of the gas outlet section to the current geometric center of the section. The following conditions must be met:

[0078] ;

[0079] in, The radius of the circle whose area is equal to the cross-sectional area obtained by the intersection of the plane perpendicular to the direction of motion and the flared end. This represents the length of the trajectory from the geometric center of the gas outlet section to the current geometric center of the section.

[0080] The structural features of the flared opening at the beginning of the second compartment are the same as those at the end of the first compartment. When the flared opening adopts a conical design, the angle between the generatrix of the cone and the height... The following conditions must be met:

[0081] .

[0082] When the flare is designed as a non-conical shape, the starting point for calculating the motion trajectory is the geometric center of the gas inlet section, and the initial motion direction is the same as the gas motion direction.

[0083] Inner diameter of the pipe between the two bell mouths The following conditions must be met:

[0084] ;

[0085] in, This represents the lowest achievable air pressure in the first cabin during the simulation measurement process, expressed in kPa. This indicates the highest temperature that can be reached during the simulation measurement process, expressed in Kelvin (K). This represents the lowest aerosol input flow rate during the simulation measurement, expressed in L / min. The calculated inner diameter... The unit is cm.

[0086] The second compartment adopts a cylindrical design with an inner diameter of [missing information]. The following conditions must be met:

[0087] ;

[0088] In the second compartment, the distance from the end of the horn-shaped opening to the top of the sampling port... The following conditions must be met:

[0089] ;

[0090] Distance from the top of the sampling port to the top of the air extraction port The following conditions must be met:

[0091] ;

[0092] The sampling port adopts a constant velocity sampling design, that is, the gas flow rate entering the sampling port is the same as the gas flow rate not entering the sampling port.

[0093] In this embodiment, the double horn opening adopts a non-conical design. Taking the horn opening at the beginning of the second compartment as an example, an example of a method for obtaining the motion trajectory of the geometric center of the cross-section using the infinitesimal element method is given:

[0094] Step 1: Take the geometric center of the gas inlet section as the starting center point. The starting direction of motion is the direction perpendicular to the cross section at the starting point. Figure 6 (A in the middle)

[0095] Step 2, from the first x Each center point Move a small distance along the direction of motion Get points ( Figure 6 (B in the middle)

[0096] Step 3, done a little And perpendicular to the line segment The plane is used to obtain the cross section that intersects with the boundary of the bell mouth. Figure 6 (B) Calculate the geometric center of the cross section. ( Figure 6 (C in the middle)

[0097] Step 4, if line segment The length exceeds the limit Then use points As a point in step 3 Then continue with step 3;

[0098] Step 5, if line segment The length does not exceed the limit. Then For the first x +1 center point and with to The direction is the center point The direction of movement at that location;

[0099] Step 6: Repeat steps 2 to 5 until the end position of the horn opening is reached. Use straight line segments to connect all the center points as the center point movement path.

[0100] In the above steps, all tiny distances The value of should ensure that the total number of center points obtained is not less than 20; limit value No more than 1 / 20 of.

[0101] The structure of the portable calibration device is as follows Figure 3As shown. Compressed air enters the aerosol generator through the inlet. The generated aerosol passes through an isokinetic splitter, flowing into the particle sensor inside the device and exiting through the aerosol outlet. The particle sensor measures particle concentration within various particle size ranges. During on-site calibration, this is compared with particle size distribution data in a standard parameter database to determine if the aerosol generator's operating status matches the established database. The particle sensor outputs measurement results either as a differential result within a given particle size range or as an integral result from 0 to the upper limit of that range; it can be either quantity concentration or mass concentration. A second thermometer and hygrometer are installed on the pipeline before the isokinetic splitter to measure the aerosol's temperature and humidity. A third barometer is installed inside the device to measure ambient atmospheric pressure (the enclosure is not sealed). A second thermometer is installed outside the device to measure ambient temperature. The aerosol generator, particle sensor, second thermometer and hygrometer, and third barometer are all connected to the control system. An isokinetic sampling head can be installed at the end of the aerosol outlet pipeline of the device for connection to the instrument being calibrated. Aerosol samples exceeding the instrument's sampling flow rate can be discharged through the vent of the isokinetic sampling head.

[0102] Example 2

[0103] The calibration method for atmospheric particulate matter water-soluble ion analyzers adopts the atmospheric particulate matter water-soluble ion analyzer calibration system of Example 1, including the construction of a standard parameter database for portable calibration devices and the on-site calibration method using portable calibration devices.

[0104] The standard parameter database includes the following values, among which the following are used as query conditions:

[0105] Components of the dust source solution used to generate aerosols ~ and its concentration ~ Aerosol generation parameters ~ Simulated ambient atmospheric pressure Simulated ambient temperature .

[0106] Among them, aerosol generation parameters refer to all parameters that affect the working state of the aerosol generator, such as the generation gas flow rate, dilution gas flow rate, and heating temperature.

[0107] The query results include:

[0108] Aerosol Standard Particle Size Spectrum Sensor-particle size spectrum difference for various particle size ranges ~ Sensor-particle size ratio Standard mass concentration of each component ~ .

[0109] A standard parameter database for portable calibration devices shall be constructed using the following method:

[0110] Step S11, Press Figure 4 Connect the portable calibration device and the atmospheric environment simulation measurement device by directly connecting the aerosol outlet of the portable calibration device to the aerosol inlet on the constant temperature chamber, without installing the isokinetic sampling head.

[0111] Step S12: Prepare the dust source solution and record the composition of each component. ~ and its concentration ~ The components are water-soluble ions, such as Na+. + K + Ca 2+ Mg 2+ Cl - NO3 - SO4 2- It should be noted that the combination of cations and anions should not produce species with volatile or semi-volatile properties, such as NH4NO3, NH4Cl, HCl, HNO3, etc.

[0112] Step S13: Add the dust source solution to the aerosol generator of the portable calibration device and set the aerosol generation parameters. ~ Aerosol generation occurs.

[0113] Step S14: Set the constant temperature of the constant temperature chamber and adjust the pressure-stabilizing vacuum pump.

[0114] Step S15: After the aerosol temperature, aerosol humidity, and output values ​​of the particle sensor for each particle size range measured by the portable calibration device have stabilized, and the measured values ​​of the first barometer and the first thermometer in the atmospheric environment simulation measurement device have stabilized, record the aerosol temperature measured by the portable calibration device. aerosol humidity Output values ​​of particle sensors for various particle size ranges ~ The measured value of the first barometer in the atmospheric environment simulation measurement device simulates the atmospheric pressure of the environment. The first thermometer's measurement simulates the ambient temperature. The second barometer measures atmospheric pressure. The first temperature and humidity meter measured the sampling temperature. and sampling humidity Among them, aerosol humidity The aerosol humidity should not exceed the preset humidity threshold. If the aerosol humidity exceeds the preset humidity threshold, it indicates that the particulate matter may not be sufficiently dry, and the aerosol generation parameters should be adjusted until the aerosol humidity is below the preset humidity threshold. In this embodiment, the preset humidity threshold ranges from 25%RH to 40%RH. This humidity threshold is used to ensure that the generated particulate matter is sufficiently dry.

[0115] Step S16: Adjust the switching valve and measure the aerosol standard particle size distribution using a standard aerosol particle size analyzer and a standard particulate matter water-soluble ion analyzer, respectively. and the mass concentration of each component of the aerosol under sampling conditions ~ .

[0116] Step S17: Calculate the mass concentration of each component of the sampled aerosol using the following formula. ~ After correction, the standard mass concentrations of each component are obtained. ~ :

[0117] ;

[0118] in, Indicates the first Standard mass concentration of each component Indicates the total number of components;

[0119] Calculate the sensor-particle size spectrum difference for each particle size range using the following formula. ~ :

[0120] ;

[0121] in, Indicates the first Sensor-particle size spectrum difference for a particle size range Indicates the particle size in the standard particle size spectrum. Indicating the particle sensor number in the standard particle size spectrum The initial particle size within a particle size range, Indicating the particle sensor number in the standard particle size spectrum Termination particle size within a particle size range This represents the ratio between the particle size distribution measurement results and the particle sensor measurement results. This represents the measured value of the corresponding particle size in the particle size spectrum. This represents the sum of all measured values ​​in the particle size distribution. Indicates the particulate sensor during on-site calibration. Measurement values ​​for a particle size range, This represents the sum of measurements taken by the particle sensor across the entire particle size range. This represents the total number of all particle size ranges.

[0122] Since particle size distribution measurements can be expressed in various forms, such as number distribution and mass distribution, and particle sensor measurements can be expressed in various forms, such as number concentration or mass concentration, the proportionality coefficient... This is used to adjust for differences introduced by statistical methods such as quantity and quality. For example, if the particle size distribution is a quantity distribution and the particle sensor measurement result is a quantity concentration, then... The value is 1; the particle size distribution is the number distribution, and the particle sensor measurement result is the mass concentration. for , The particle size is denoted as .

[0123] For example, the particle size range of the particle sensor is: PM 2.5 PM 10 All dust, then PM 2.5 The initial particle size was 0 μm, and the final particle size was 2.5 μm; PM 10 The initial particle size is 0 μm, and the final particle size is 10 μm; the initial particle size of all dust particles is 0 μm, and the final particle size is 100 μm; the sum of the measured values ​​for the entire particle size range. This is the measured value for total dust.

[0124] Calculate the sensor-particle size ratio using the following formula. :

[0125] ;

[0126] Step S18, if sampling humidity Data is considered valid if the humidity does not exceed the preset sampling threshold. This involves analyzing the components of the dust source solution used to generate the aerosol. ~ and its concentration ~ Aerosol generation parameters ~ Simulated ambient atmospheric pressure Simulated ambient temperature Aerosol standard particle size distribution Sensor-particle size spectrum difference for various particle size ranges ~ Sensor-particle size ratio and the standard mass concentration of each component ~ Enter into the database. When sampling humidity If the humidity exceeds the preset sampling threshold, all data is invalidated and not entered into the database; in this embodiment, the preset sampling humidity threshold is (55%RH~65%RH). This humidity threshold is used to ensure that particulate matter does not deliquesce.

[0127] Step S19: Change the dust source solution ratio, air inlet flow rate, generation parameters, constant temperature chamber temperature, and air pressure stabilization device target pressure respectively to make the above parameters cover all conditions of the expected calibration work, and measure and record according to steps S12 to S18 to build a standard parameter database for the portable calibration device.

[0128] Perform on-site calibration of the instrument using a portable calibration device as follows:

[0129] Step S21, press Figure 5 Place the portable calibration device and the instrument to be calibrated. Place the thermometer of the portable calibration device next to the sampling port of the instrument to be calibrated. Connect the aerosol outlet of the portable calibration device to the sampling port of the instrument to be calibrated using a tubing and extend it to the sampling port of the instrument to be calibrated. Start the instrument to be calibrated and put it into working condition.

[0130] Step S22: Prepare the dust source solution and record its components. ~ and its concentration ~ To facilitate subsequent database queries, the components and their concentrations should ideally match the corresponding data combinations in the standard parameter database.

[0131] Step S23: Add the dust source solution to the aerosol generator and set the aerosol generation parameters. ~ Aerosol generation is then carried out. To facilitate subsequent database queries, the generation parameters should ideally match the corresponding data combination in the standard database.

[0132] Step S24: After both the aerosol generator and the instrument under calibration have reached a stable state, read the aerosol humidity measured by the portable calibration device. If the aerosol humidity Connect the tubing to the sampling port of the instrument being calibrated, ensuring the humidity level does not exceed the preset humidity threshold, and record the aerosol temperature measured by the portable calibration device. Output values ​​of particle sensors for various particle size ranges ~ Atmospheric pressure and ambient temperature When the aerosol humidity When the humidity exceeds the preset threshold, the control system stops subsequent calibration operations and outputs an error message.

[0133] Step S25, according to the components ~ and its concentration ~ Occurrence parameters ~ Atmospheric pressure and ambient temperature The corresponding aerosol standard particle size distribution can be calculated by querying the database or using a bilinear interpolation algorithm. Sensor-particle size spectrum difference for various particle size ranges ~ Sensor-particle size ratio and the standard mass concentration of each component ~ Among them, the components, concentrations, and generation parameters can be precisely matched because they use the same data combination as those in the database; atmospheric pressure and ambient temperature Because the actual environment and the data combination in the database may not match exactly, the closest match can be found by querying. , The four sets of results were used to calculate the aerosol standard particle size distribution using bilinear interpolation. Sensor-particle size spectrum difference for various particle size ranges ~ Sensor-particle size ratio and the standard mass concentration of each component ~ .

[0134] Step S26: Compare the aerosols generated during on-site calibration with those generated when establishing the standard parameter database using the following formula to determine if there is a significant difference:

[0135] ;

[0136] ;

[0137] .

[0138] in, Indicates the first Sensor-particle size spectrum difference during on-site calibration for each particle size range Indicates the particulate sensor during on-site calibration. Measurement values ​​for a particle size range, This indicates the degree of difference between the on-site calibrated aerosol sensor and the aerosol sensor-particle size ratio value in the standard parameter database;

[0139] like or If any result exceeds the corresponding preset threshold, it is considered that the aerosol generated during on-site calibration is significantly different from the aerosol generated when establishing the standard parameter database, and the aerosol generated during on-site calibration cannot be used for the calibration of the instrument being calibrated.

[0140] Step S27: If there is no significant difference between the aerosols generated during on-site calibration and those generated during the establishment of the standard parameter database, then... ~ To calibrate the concentration of each component of the aerosol generated on-site, the instrument being calibrated is continuously measured multiple times, and the indication error is calculated.

[0141] Step S28: Change the dust source solution ratio, air inlet flow rate, generation parameters, etc., and repeat steps S21 to S27 to calibrate the instrument being calibrated.

[0142] It is worth noting that all contents not described in detail in this invention are existing technologies and are well known to those skilled in the art.

[0143] Therefore, the present invention adopts the above-mentioned calibration system and calibration method for atmospheric particulate matter water-soluble ion analyzers, which solves the problems of traditional calibration equipment being large in size and unable to be calibrated on-site, and provides reliable technical support for on-site calibration of atmospheric particulate matter water-soluble ion analyzers.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A calibration system for an atmospheric particulate matter water-soluble ion analyzer, characterized in that, Used for calibration of instruments for analyzing water-soluble ions in atmospheric particulate matter, including atmospheric environment simulation measurement devices and portable calibration devices; The atmospheric environment simulation and measurement device includes: The constant temperature chamber has an aerosol mixing chamber inside, which includes a first compartment and a second compartment. The first barometer and the first thermometer are installed on the side wall of the first compartment, and their outlets are connected to the second compartment through a double-flare structure. The second cabin is equipped with a first thermometer and hygrometer and a second barometer, and the top is equipped with a sampling tube and an exhaust tube. The portable calibration device includes a housing, inside which are: The aerosol generator has its input end connected to the compressed air inlet and its output end connected to the input end of the constant velocity splitter. The constant velocity splitter has a first output end connected to a particle sensor and a second output end connected to an aerosol outlet pipeline. The second temperature and humidity meter is installed on the pipeline before the constant velocity shunt. The third barometer is installed inside the chamber and is used to measure the ambient air pressure inside the chamber. An ambient temperature gauge interface is provided on the outside of the enclosure for installing a second thermometer; The control system is connected to the interfaces of the aerosol generator, particle sensor, second temperature and humidity meter, third barometer and ambient temperature meter respectively; An isokinetic sampling head can be detachably installed at the end of the aerosol outlet pipeline, and the isokinetic sampling head is equipped with an air vent. The sampling tube adopts a constant velocity sampling design, that is, the gas flow rate entering the sampling port is the same as the gas flow rate not entering the sampling port. The sampling tube extends to the sampling port outside the constant temperature chamber and is connected to a standard aerosol particle size analyzer and a standard particulate matter water-soluble ion analyzer respectively through a switching valve. The gas extraction tube extends to the gas extraction port outside the constant temperature chamber and is connected to the input terminal of the pressure-stabilized gas extraction pump. The control terminal of the pressure-stabilized gas extraction pump receives the measurement signal from the first barometer. In the double-flare structure, either flare is a conical flare, and the angle between the generatrix of the conical flare and its height is... satisfy: ； In a double-flare structure, any one of the flares is a non-conical flare. The normal cross-sectional radius of the non-conical flare at any point on the gas trajectory is... With trajectory length satisfy: ； Inner diameter of the double-flare pipe satisfy: ； in, This indicates the lowest achievable air pressure inside the first compartment during the simulation measurement process. This indicates the highest temperature that can be reached during the simulation measurement process. This represents the lowest aerosol input flow rate during the simulation measurement process; The second compartment is a cylinder of constant diameter, with an inner diameter of... satisfy: ； In the second compartment, the distance from the end of the horn-shaped opening to the top of the sampling port... satisfy: ； Distance from the top of the sampling port to the top of the air extraction port satisfy: 。 2. A calibration method for an instrument for analyzing water-soluble ions in atmospheric particulate matter, characterized in that, The calibration system for atmospheric particulate matter water-soluble ion analyzers as described in claim 1 includes the following steps: Step S1: Construct a standard parameter database for portable calibration devices; Step S2: Perform on-site calibration using a portable calibration device.

3. The calibration method for an atmospheric particulate matter water-soluble ion analyzer according to claim 2, characterized in that, Step S1 specifically includes: Step S11: Connect the aerosol outlet of the portable calibration device to the aerosol inlet on the constant temperature chamber. The portable calibration device is not equipped with an isokinetic sampling head. Step S12, prepare the mixture containing The dust source solution contains each component, and the composition of each component is recorded. ~ and its concentration ~ Add the dust source solution to the aerosol generator of the portable calibration device and set the aerosol generation parameters. ~ Aerosol generation occurs; Step S13: Adjust the temperature and air pressure stabilization device of the constant temperature chamber; Step S14: After the aerosol temperature, aerosol humidity, and output values ​​of the particle sensor for each particle size range measured by the portable calibration device have stabilized, and the measured values ​​of the first barometer and the first thermometer in the atmospheric environment simulation measurement device have stabilized, record the aerosol temperature measured by the portable calibration device. aerosol humidity Output values ​​of particle sensors for various particle size ranges ~ The measured value of the first barometer in the atmospheric environment simulation measurement device simulates the atmospheric pressure of the environment. The thermometer readings simulate ambient temperature. The second barometer measures atmospheric pressure. The first temperature and humidity meter measured the sampling temperature. and sampling humidity ; Step S15: Obtain the aerosol standard particle size distribution by adjusting the switching valve. and the mass concentration of each component of the aerosol under sampling conditions ~ ; Step S16: Calculate the standard mass concentration of each component. ~ Sensor-particle size spectrum difference for various particle size ranges ~ Sensor-particle size ratio ; Step S17: When sampling humidity When the humidity does not exceed the preset sampling threshold, the dust source solution used for aerosols will be affected by various components. ~ and its concentration ~ Aerosol generation parameters ~ Simulated ambient atmospheric pressure Simulated ambient temperature Aerosol standard particle size distribution Particle sensor-particle size spectrum difference for various particle size ranges ~ Sensor-particle size ratio and the standard mass concentration of each component ~ Enter into the database; when sampling humidity When the preset sampling humidity threshold is exceeded, all data is invalidated and not entered into the database; Step S18: Change the dust source solution ratio, air inlet flow rate, generation parameters, constant temperature chamber temperature, and air pressure stabilization device target pressure respectively to make the above parameters cover all conditions of the expected calibration work, and measure and record according to steps S12 to S17 to build a standard parameter database for the portable calibration device.

4. The calibration method for an atmospheric particulate matter water-soluble ion analyzer according to claim 3, characterized in that, Step S2 specifically includes: Step S21: Place the second thermometer of the portable calibration device next to the sampling port of the instrument being calibrated, connect the instrument connection port of the isokinetic sampling head to the sampling port of the instrument being calibrated, connect the isokinetic sampling head to the aerosol outlet of the portable calibration device using a pipeline, and start the instrument being calibrated to enter the working state. Step S22, prepare the mixture containing The dust source solution contains each component, and the composition of each component is recorded. ~ and its concentration ~ ; Step S23: Add the dust source solution to the aerosol generator and set the aerosol generation parameters. ~ Aerosol generation occurs; Step S24: After both the aerosol generator and the instrument under calibration have reached a stable state, read the aerosol humidity measured by the portable calibration device. When the aerosol humidity When the humidity level is not higher than the preset humidity threshold, connect the tubing to the sampling port of the instrument being calibrated and record the aerosol temperature measured by the portable calibration device. Output values ​​of particle sensors for various particle size ranges ~ Atmospheric pressure and ambient temperature When the aerosol humidity When the humidity exceeds the preset threshold, the control system stops subsequent calibration operations and outputs an error message. Step S25: Calculate the degree of difference between the field-calibrated aerosol and the aerosol sensor particle size distribution in the standard parameter database. The degree of difference between the sensor and the particle size ratio ; Step S26, when , When all values ​​are less than the corresponding preset threshold, ~ The instrument being calibrated is calibrated using the standard value; otherwise, the control system stops the calibration operation and outputs an error message.

5. The calibration method for an atmospheric particulate matter water-soluble ion analyzer according to claim 4, characterized in that, On-site calibration of the difference between aerosol and standard parameter database aerosol sensor particle size distribution values The calculation formula is as follows: ； ； in, Indicates the first Sensor-particle size spectrum difference values ​​in a standard database of particle size ranges Indicates the first Sensor-particle size spectrum difference during on-site calibration for each particle size range Indicates the particle size in the standard particle size spectrum. Indicating the particle sensor number in the standard particle size spectrum The initial particle size within a particle size range, Indicating the particle sensor number in the standard particle size spectrum Termination particle size within a particle size range This represents the ratio between the particle size distribution measurement results and the particle sensor measurement results. This represents the measured value of the corresponding particle size in the particle size spectrum. This represents the sum of all measured values ​​in the particle size distribution. Indicates the particulate sensor during on-site calibration. Measurement values ​​for a particle size range, This represents the sum of measurements taken across the entire particle size range during on-site calibration of the particle sensor. This represents the total number of all particle size ranges.

6. The calibration method for an atmospheric particulate matter water-soluble ion analyzer according to claim 5, characterized in that, The degree of difference between the aerosol sensor particle size distribution ratio and the standard parameter database aerosol sensor in on-site calibration The calculation formula is as follows: 。

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