High time resolution aerosol hygroscopic growth parameter measurement method and apparatus

Abstract

The application discloses a kind of high time resolution aerosol hygroscopic growth parameter measurement method and equipment.The present application uses two aerosol optical quantity counters, respectively get the scattering signal intensity measurement value of the dry aerosol of set particle size and the scattering signal intensity measurement value after aerosol humidification, according to the inversion of Mie scattering theory, the complex refractive index of aerosol particle, based on the scattering signal intensity measurement value after aerosol humidification and the relative humidity of aerosol, using gradient descent method, the hygroscopic growth parameter of aerosol is calculated;The present application can greatly reduce the time resolution of measurement, the time required for measuring the hygroscopic growth of one particle size aerosol is about 5 seconds, while greatly improving the particle size range of measurement, reaches 160-1000nm.

Description

Technical Field

[0001] This invention relates to aerosol measurement technology, specifically to a method and equipment for measuring the moisture absorption growth parameter of aerosols with high time resolution. Background Technology

[0002] Atmospheric aerosols can directly affect the radiation balance of the Earth-atmosphere system by scattering and absorbing solar radiation. They can also act as cloud condensation nuclei or ice nuclei, influencing the macroscopic and microscopic characteristics of clouds, and thus indirectly affecting weather and climate. However, the direct and indirect effects of aerosols on climate are often closely related to factors such as aerosol particle size distribution, hygroscopicity, and morphology. Among the many factors affecting the direct or indirect radiation effects of aerosols, hygroscopicity plays a crucial role, significantly impacting weather, climate, and the environment. Hygroscopicity describes the ability of aerosol particles to interact with water vapor. On the one hand, hygroscopic growth of aerosols under high relative humidity alters their particle size distribution and complex refractive index, directly affecting radiation. On the other hand, the strength of aerosol hygroscopicity determines its ability to activate as cloud condensation nuclei, thus indirectly affecting radiation. These direct or indirect effects on radiation are highly dependent on aerosol hygroscopicity.

[0003] The current method for quantifying the hygroscopic growth capacity of aerosols under different relative humidity conditions uses Capacitor. Theoretically, relative humidity (RH) is expressed as:

[0004]

[0005] Where Dp is the particle size of the aerosol after hygroscopic growth at a given RH, D d σ represents the particle size of the aerosol during drying, κ is the aerosol hygroscopic growth parameter, reflecting the aerosol's own hygroscopic growth capacity, and σ... s / a R is the surface tension of the aerosol. Under high relative humidity, this value is usually taken to be equal to the surface tension of water. R is Avogadro's constant, and M is... water Let ρ be the molar mass of water, T be the ambient temperature, and ρ be the temperature at room temperature. wLet κ be the density of water. Traditional methods for measuring the hygroscopic growth parameter κ of aerosols utilize a Humidified Mobility Migration Differential Analyzer (HTDMA). Specifically, this involves a separator, a first differential electromigration analyzer, a humidification unit, a second differential electromigration analyzer, and a particle counter. The first differential electromigration analyzer selects a set particle size, the humidification unit humidifies the aerosol, and the second differential electromigration analyzer measures the particle size after hygroscopic growth. Finally, the particle counter obtains the number of aerosol particles, and the particle size at which the largest number of particles is obtained represents the particle size of the humidified aerosol. This method is time-consuming; when measuring the hygroscopic growth parameter κ of a single-size aerosol in online measurements, at least 5 minutes are required, and it cannot measure the hygroscopic growth parameter of aerosols with a particle size greater than 400 nm. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention proposes a method and device for measuring the moisture absorption and growth parameters of aerosols with high temporal resolution. This invention can significantly reduce the temporal resolution of the measurement, requiring approximately 5 seconds to measure the moisture absorption and growth of an aerosol of one particle size, while also greatly increasing the measurement particle size range to 160–1000 nm.

[0007] One object of the present invention is to provide a device for measuring aerosol moisture absorption growth parameters with high time resolution.

[0008] The high temporal resolution aerosol moisture absorption growth parameter measurement device of the present invention includes: a neutralizer, a differential electromigration analyzer, a first aerosol optical quantity counter, a humidification unit, a second aerosol optical quantity counter, and first and second temperature and humidity probes; wherein, the neutralizer is connected to the differential electromigration analyzer via a conductive tube; the differential electromigration analyzer is connected to the first aerosol optical quantity counter and the humidification unit respectively via a three-way pipe; the humidification unit is connected to the second aerosol optical quantity counter via a pipe; and the first and second temperature and humidity probes are respectively installed at the air inlet and air outlet of the second aerosol optical quantity counter.

[0009] The dried aerosol is charged by passing it through a neutralizer. The charged aerosol is then passed through a differential electromigration analyzer with a pre-set particle size, allowing only the pre-set particle size to pass through the device to obtain the particle size at the time of drying. The aerosol is divided into two parts by a three-way tube. The first part of the aerosol is directly passed through a first aerosol optical quantity counter, which measures the scattering signal intensity during drying. Furthermore, the complex refractive index of the aerosol during drying is uniquely determined using Mie scattering theory. The second part of the aerosol... The aerosol is first humidified to a set relative humidity by a humidification unit. Then, a second aerosol optical quantity counter is used to measure the intensity of the scattering signal after humidification. The intensity of the scattering signal after humidification is a function of the aerosol particle size and complex refractive index, corresponding to a unique aerosol moisture absorption growth parameter. Using the gradient descent method, the intensity of the scattering signal after humidification is compared with the calculated intensity until it is less than the threshold after moisture absorption, thus obtaining the aerosol moisture absorption growth parameter.

[0010] The preset particle size for the differential electromigration analyzer is 160–1000 nm.

[0011] The relative humidity is humidified to the set level of 80%–95% using aerosol from the humidification unit.

[0012] Another objective of this invention is to provide a method for measuring aerosol moisture absorption growth parameters with high time resolution.

[0013] The method for measuring the high temporal resolution aerosol moisture absorption growth parameter of the present invention includes the following steps:

[0014] 1) The dry aerosol is passed through a neutralizer to make the aerosol charge.

[0015] 2) Pass the charged aerosol through a differential electromigration analyzer with a pre-set particle size. Only aerosols of the pre-set particle size are allowed to pass through the equipment. The particle size of the aerosol passing through the differential electromigration analyzer is the same as the particle size D of the dried aerosol. d Then these aerosols were divided into two parts;

[0016] 3) The first part of the aerosol is directly passed through the first aerosol optical quantity counter, and the scattering signal intensity value S1 during the drying of the aerosol is measured using the first aerosol optical quantity counter;

[0017] 4) Determine the complex refractive index RI during aerosol drying:

[0018] a) The calculated value of the scattered signal intensity S1′ during aerosol drying is:

[0019] S1′=C1·I1·σ1·PF 90o,1(1)

[0020] Where C1 is the first temperature-dependent constant, which is related to the temperature of the first aerosol optical quantity counter; I1 is the laser intensity of the first aerosol optical quantity counter, the value of C1·I1 is obtained by calibrating the first aerosol optical quantity counter; σ1 is the scattering phase function of the aerosol during drying; and PF 90o,1 Let be the scattering phase function in the 90-degree direction during aerosol drying. According to Mie scattering theory, both the aerosol scattering coefficient and the scattering phase function in the 90-degree direction are functions of the aerosol particle size and complex refractive index.

[0021] In formula (1), the scattered signal intensity S1′ is a factor related to the particle size D during aerosol drying. d The nonlinear function of the complex refractive index RI increases monotonically;

[0022] Given an initial value of the complex refractive index during aerosol drying, the calculated value of the scattering signal intensity S1′ during aerosol drying is obtained according to Mie scattering theory and formula (1);

[0023] b) Compare the measured value of the scattered signal intensity S1 during aerosol drying with the calculated value of the scattered signal intensity S1′ during aerosol drying;

[0024] c) Using the gradient descent method, change the initial value of the complex refractive index during aerosol drying, and repeat steps a) and b) until the difference between the measured value S1 of the aerosol scattering signal intensity during drying and the calculated value S1′ of the aerosol scattering signal intensity during drying is less than the threshold during drying. Use this initial value as the complex refractive index RI during aerosol drying; 5) The second part of the aerosol first passes through the humidification unit to humidify the aerosol to the set relative humidity, and then passes through the...

[0025] Two aerosol optical quantity counters were used to measure the intensity of the scattered signal after aerosol humidification, S2. The intensity of the scattered signal after aerosol humidification, S2, is a function of the particle size and complex refractive index of the aerosol, and corresponds to a unique aerosol hygroscopic growth parameter κ.

[0026] By installing first and second temperature and humidity probes at the inlet and outlet of the second aerosol optical quantity counter, respectively, the temperature T1 and humidity RH1 at the inlet of the second aerosol optical quantity counter are obtained, and the temperature T2 and humidity RH2 at the outlet are obtained, thus obtaining the temperature in the second aerosol optical quantity counter. Using the temperature T1 and humidity RH1 at the air inlet of the second aerosol optical quantity counter, the air water vapor pressure e1 is calculated; using the temperature T0 in the second aerosol optical quantity counter and the calculated air water vapor pressure e1, the humidity RH0 of the aerosol in the second aerosol optical quantity counter is calculated.

[0027] 6) Based on the measured value of the scattered signal intensity S2 after aerosol humidification and the relative humidity RH0 of the aerosol in the second aerosol optical quantity counter, calculate the aerosol moisture absorption growth parameter κ:

[0028] a) The relationship between the particle size Dp of aerosols after hygroscopic growth and relative humidity RH is:

[0029]

[0030] Where Dp is the particle size of the aerosol after hygroscopic growth, D d σ is the particle size of the aerosol during drying, κ is the aerosol hygroscopic growth parameter, and σ is the particle size of the aerosol during drying. s / a Let M be the surface tension of the aerosol, R be Avogadro's constant, and M be the surface tension of the aerosol. water Let ρ be the molar mass of water, T be the ambient temperature, and ρ be the temperature at room temperature. w The density of water;

[0031] Given an initial value of an aerosol hygroscopic growth parameter κ, the particle size Dp of the aerosol after hygroscopic growth is calculated using formula (2), with the relative humidity RH0 of the aerosol in the second aerosol optical quantity counter as the relative humidity and the temperature T0 in the second aerosol optical quantity counter as the ambient temperature.

[0032] b) Calculate the complex refractive index RI2 after hygroscopic growth of the aerosol using the volume-weighted average method:

[0033]

[0034] Among them, RI water is the complex refractive index of water;

[0035] c) The calculated value of the scattered signal intensity S2′ after the aerosol absorbs moisture and grows is:

[0036] S2′=C2·I2·σ2·PF 90o,2 (4)

[0037] Where C2 is the second temperature-dependent constant, which is related to the temperature of the second aerosol optical quantity counter; I2 is the laser intensity of the second aerosol optical quantity counter, the value of C2·I2 is obtained by calibrating the second aerosol optical quantity counter; σ2 is the scattering phase function after aerosol hygroscopic growth; and PF 90o,2 The scattering phase function in the 90-degree direction after the aerosol absorbs moisture and grows;

[0038] Based on the particle size Dp and complex refractive index RI2 after aerosol hygroscopic growth, σ2·PF is calculated using Mie scattering theory. 90o,2The value of , combined with the value of C·I0 obtained by calibrating the first aerosol optical quantity counter, is substituted into formula (4) to calculate the calculated value S2′ of the scattering signal intensity after aerosol humidification. The measured value S2 of the scattering signal intensity after aerosol humidification is compared with the calculated value S2′ of the scattering signal intensity after aerosol humidification.

[0039] d) Use the gradient descent method to change the initial value of the aerosol hygroscopic growth parameter κ until the difference between the measured value S2 of the scattering signal intensity after aerosol humidification and the calculated value S2′ of the scattering signal intensity after aerosol humidification is less than the threshold after humidification. Use the initial value at this time as the aerosol hygroscopic growth parameter κ.

[0040] In step 2), the preset particle size of the differential electromigration analyzer is 160–1000 nm.

[0041] In step 4)a), the initial value of the complex refractive index RH during aerosol drying is arbitrary.

[0042] In step 4)b), the threshold value during drying is ≤10. -3 .

[0043] In step 5), the second part of the aerosol passes through the humidification unit, so that the aerosol is humidified to a set relative humidity of 80% to 95%.

[0044] Using the temperature T1 and humidity RH1 at the inlet of the second aerosol optical quantity counter, the air vapor pressure e1 is calculated:

[0045]

[0046] Using the temperature T0 in the second aerosol optical quantity counter and the calculated air vapor pressure e1, the relative humidity RH0 of the aerosol is calculated:

[0047]

[0048] In step 6)a), the initial value of the aerosol hygroscopic growth parameter κ is arbitrary.

[0049] In step 6), d), the threshold value after moisture absorption is ≤10. -3 .

[0050] Advantages of this invention:

[0051] This invention can significantly reduce the time resolution of measurements, requiring approximately 5 seconds to measure the moisture absorption and growth of an aerosol of one particle size, while also greatly increasing the range of particle sizes that can be measured, reaching 160–1000 nm. Attached Figure Description

[0052] Figure 1This is a structural block diagram of the high temporal resolution aerosol moisture absorption growth parameter measurement device of the present invention;

[0053] Figure 2 This is a flowchart of the method for measuring the high temporal resolution aerosol moisture absorption growth parameter of the present invention. Detailed Implementation

[0054] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0055] like Figure 1 As shown, the high time resolution aerosol moisture absorption growth parameter measurement device of this embodiment includes: a neutralizer, a differential electromigration analyzer, a first aerosol optical quantity counter, a humidification unit, a second aerosol optical quantity counter, and first and second temperature and humidity probes; wherein, the neutralizer is connected to the differential electromigration analyzer through a conductive tube; the differential electromigration analyzer is connected to the first aerosol optical quantity counter and the humidification unit respectively through a three-way pipe; the humidification unit is connected to the second aerosol optical quantity counter through a pipe; and the first and second temperature and humidity probes are respectively installed at the air inlet and air outlet of the second aerosol optical quantity counter.

[0056] The method for measuring high temporal resolution aerosol moisture absorption growth parameters in this embodiment, such as... Figure 2 As shown, it includes the following steps:

[0057] 1) The dry aerosol is passed through a neutralizer so that the aerosol becomes charged with a set probability;

[0058] 2) Pass the charged aerosol through a differential electromigration analyzer (DMA) with a pre-set particle size. Only aerosols with a pre-set particle size of 200 nm are allowed to pass through the device. The particle size of the aerosol passing through the DMA analyzer is the same as the particle size D of the dried aerosol. d Then these aerosols were divided into two parts;

[0059] 3) The first part of the aerosol is directly passed through the first aerosol optical quantity counter (OPC1), and the scattering signal intensity value S1 during the drying of the aerosol is measured using the first aerosol optical quantity counter;

[0060] 4) Determine the complex refractive index RI during aerosol drying:

[0061] a) The calculated value of the scattered signal intensity S1′ during aerosol drying is:

[0062] S1′=C1·I1·σ1·PF 90o,1 (1)

[0063] Where C1 is the first temperature-dependent constant, which is related to the temperature of the first aerosol optical quantity counter; I1 is the laser intensity of the first aerosol optical quantity counter, the value of C1·I1 is obtained by calibrating the first aerosol optical quantity counter; σ1 is the scattering phase function of the aerosol during drying; and PF 90o,1 Let σ be the scattering phase function in the 90-degree direction during aerosol drying. According to Mie scattering theory, both the scattering phase function σ and the scattering phase function in the 90-degree direction are functions of the aerosol particle size and complex refractive index.

[0064] In formula (1), the scattered signal intensity S is a factor related to the particle size D during aerosol drying. d The nonlinear function of the complex refractive index RI increases monotonically;

[0065] Given an initial value of the complex refractive index during aerosol drying, based on Mie scattering theory and formula (1),

[0066] The calculated value of the scattered signal intensity S1′ during aerosol drying is obtained;

[0067] b) Compare the measured value of the scattered signal intensity S1 during aerosol drying with the calculated value of the scattered signal intensity S1′ during aerosol drying;

[0068] c) Using the gradient descent method, change the initial value of the complex refractive index during aerosol drying, and repeat steps a) and b) until the difference between the measured value S1 of the scattered signal intensity during aerosol drying and the calculated value S1′ of the scattered signal intensity during aerosol drying is less than 10. -5 The initial value at this time is used as the complex refractive index RI during aerosol drying; 5) The second part of the aerosol first passes through the humidification unit to humidify the aerosol to the set relative humidity of 90%, and then passes through...

[0069] The scattering signal intensity S2 of the aerosol after humidification was measured using the second aerosol optical quantity counter (OPC2). The scattering signal intensity S2 of the aerosol after humidification is a function of the aerosol particle size and complex refractive index, and corresponds to a unique aerosol hygroscopic growth parameter κ.

[0070] By installing first and second temperature and humidity probes at the inlet and outlet of the second aerosol optical quantity counter, respectively, the temperature T1 and humidity RH1 at the inlet of the second aerosol optical quantity counter are obtained, and the temperature T2 and humidity RH2 at the outlet are obtained, thus obtaining the temperature in the second aerosol optical quantity counter.

[0071] Using the temperature T1 and humidity RH1 at the air inlet of the second aerosol optical quantity counter, the air water vapor content is calculated.

[0072] Press e1:

[0073]

[0074] Using the temperature T0 in the second aerosol optical quantity counter and the calculated air vapor pressure e1, the relative humidity RH0 of the aerosol is calculated:

[0075]

[0076] 6) Based on the measured value of the scattered signal intensity S2 after aerosol humidification and the relative humidity RH0 of the aerosol, calculate the aerosol moisture absorption growth parameter κ:

[0077] a) The relationship between the particle size Dp of aerosols after hygroscopic growth and relative humidity RH is:

[0078]

[0079] Where Dp is the particle size of the aerosol after hygroscopic growth, D d σ is the particle size of the aerosol during drying, κ is the aerosol hygroscopic growth parameter, and σ is the particle size of the aerosol during drying. s / a Let M be the surface tension of the aerosol, R be Avogadro's constant, and M be the surface tension of the aerosol. water Let ρ be the molar mass of water, T be the ambient temperature, and ρ be the temperature at room temperature. w The density of water;

[0080] Given an initial value for the aerosol hygroscopic growth parameter κ, the particle size Dp of the aerosol after hygroscopic growth is calculated using formula (2) under the conditions that the relative humidity RH0 of the aerosol in the second aerosol optical quantity counter is the relative humidity and the temperature T0 in the second aerosol optical quantity counter is the ambient temperature.

[0081] b) Calculate the complex refractive index RI2 after hygroscopic growth of the aerosol using the volume-weighted average method:

[0082]

[0083] Among them, RI water is the complex refractive index of water;

[0084] c) The calculated value of the scattered signal intensity S2′ after the aerosol absorbs moisture and grows is:

[0085] S2′=C2·I2·σ2·PF 90o,2 (4)

[0086] Where C2 is the second temperature-dependent constant, which is related to the temperature of the second aerosol optical quantity counter; I2 is the laser intensity of the second aerosol optical quantity counter, the value of C2·I2 is obtained by calibrating the second aerosol optical quantity counter; σ2 is the scattering phase function after aerosol hygroscopic growth; and PF 90o,2 The scattering phase function in the 90-degree direction after the aerosol absorbs moisture and grows;

[0087] Based on the particle size Dp and complex refractive index RI2 after aerosol hygroscopic growth, σ2·PF is calculated using Mie scattering theory. 90o,2 The value of , combined with the value of C·I0 obtained by calibrating the first aerosol optical quantity counter, is substituted into formula (4) to calculate the calculated value S2′ of the scattering signal intensity after aerosol humidification. The measured value S2 of the scattering signal intensity after aerosol humidification is compared with the calculated value S2′ of the scattering signal intensity after aerosol humidification.

[0088] d) Use the gradient descent method to change the initial value of the aerosol hygroscopic growth parameter κ until the difference between the measured value S2 of the scattering signal intensity after aerosol humidification and the calculated value S2′ of the scattering signal intensity after aerosol humidification is less than 10. -5 The initial value at this time is used as the aerosol moisture absorption growth parameter κ.

[0089] Finally, it should be noted that the purpose of disclosing the embodiments is to help further understand the present invention. However, those skilled in the art will understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the scope of protection of the present invention is defined by the claims.

Claims

1. A device for measuring the moisture absorption and growth parameters of aerosols with high temporal resolution, characterized in that, The measuring device includes: a neutralizer, a differential electromigration analyzer, a first aerosol optical quantity counter, a humidification unit, a second aerosol optical quantity counter, and first and second temperature and humidity probes; wherein, the neutralizer is connected to the differential electromigration analyzer via a conductive tube; the differential electromigration analyzer is connected to the first aerosol optical quantity counter and the humidification unit via a three-way pipe; the humidification unit is connected to the second aerosol optical quantity counter via a pipe; and the first and second temperature and humidity probes are respectively installed at the air inlet and air outlet of the second aerosol optical quantity counter. The dried aerosol is charged by passing it through a neutralizer. The charged aerosol is then passed through a differential electromigration analyzer with a pre-set particle size, allowing only the pre-set particle size to pass through the device to obtain the particle size at the time of drying. The aerosol is divided into two parts by a three-way tube. The first part of the aerosol is directly passed through a first aerosol optical quantity counter, which measures the scattering signal intensity during drying. Furthermore, the complex refractive index of the aerosol during drying is uniquely determined using Mie scattering theory. The second part of the aerosol... The aerosol is first humidified to a set relative humidity by a humidification unit. Then, a second aerosol optical quantity counter is used to measure the intensity of the scattering signal after humidification. The intensity of the scattering signal after humidification is a function of the aerosol particle size and complex refractive index, corresponding to a unique aerosol moisture absorption growth parameter. Using the gradient descent method, the intensity of the scattering signal after humidification is compared with the calculated intensity until it is less than the threshold after moisture absorption, thus obtaining the aerosol moisture absorption growth parameter.

2. The measuring device as described in claim 1, characterized in that, The preset particle size of the differential electromigration analyzer is 160–1000 nm.

3. The measuring device as described in claim 1, characterized in that, The relative humidity is humidified to the set level of 80%–95% using aerosol from the humidification unit.

4. A method for measuring the high temporal resolution aerosol moisture absorption growth parameter as described in claim 1, characterized in that, The measurement method includes the following steps: 1) The dry aerosol is passed through a neutralizer to make the aerosol charge. 2) Pass the charged aerosol through a differential electromigration analyzer with a pre-set particle size. Only aerosols of the pre-set particle size are allowed to pass through the equipment. The particle size of the aerosol passing through the differential electromigration analyzer is the same as the particle size D of the dried aerosol. d Then these aerosols were divided into two parts; 3) The first part of the aerosol is directly passed through the first aerosol optical quantity counter, and the scattering signal intensity value S1 during the drying of the aerosol is measured using the first aerosol optical quantity counter; 4) Determine the complex refractive index RI during aerosol drying: a) The calculated value of the scattered signal intensity S1′ during aerosol drying is: S1′=C1·I1·σ1·PF 90°,1 (1) Where C1 is the first temperature-dependent constant, which is related to the temperature of the first aerosol optical quantity counter; I1 is the laser intensity of the first aerosol optical quantity counter, the value of C1·I1 is obtained by calibrating the first aerosol optical quantity counter; σ1 is the scattering phase function of the aerosol during drying; and PF 90°,1 Let be the scattering phase function in the 90-degree direction during aerosol drying. According to Mie scattering theory, both the aerosol scattering coefficient and the scattering phase function in the 90-degree direction are functions of the aerosol particle size and complex refractive index. In formula (1), the scattered signal intensity S1′ is a factor related to the particle size D during aerosol drying. d The nonlinear function of the complex refractive index RI increases monotonically; Given an initial value of the complex refractive index during aerosol drying, the calculated value of the scattering signal intensity S1′ during aerosol drying is obtained according to Mie scattering theory and formula (1); b) Compare the measured value of the scattered signal intensity S1 during aerosol drying with the calculated value of the scattered signal intensity S1′ during aerosol drying; c) Using the gradient descent method, change the initial value of the complex refractive index during aerosol drying, and repeat steps a) and b) until the difference between the measured value S1 of the aerosol drying scattering signal intensity and the calculated value S1′ of the aerosol drying scattering signal intensity is less than the threshold during drying. Use the initial value at this time as the complex refractive index RI during aerosol drying. 5) The second part of the aerosol first passes through the humidification unit to humidify the aerosol to the set relative humidity. Then, the second aerosol optical quantity counter measures the scattering signal intensity value S2 after humidification. The scattering signal intensity value S2 after humidification is a function of the aerosol particle size and complex refractive index, corresponding to a unique aerosol moisture absorption growth parameter κ. By installing first and second temperature and humidity probes at the inlet and outlet of the second aerosol optical quantity counter, respectively, the temperature T1 and humidity RH1 at the inlet of the second aerosol optical quantity counter are obtained, and the temperature T2 and humidity RH2 at the outlet are obtained, thus obtaining the temperature in the second aerosol optical quantity counter. Using the temperature T1 and humidity RH1 at the air inlet of the second aerosol optical quantity counter, the air water vapor pressure e1 is calculated; using the temperature T0 in the second aerosol optical quantity counter and the calculated air water vapor pressure e1, the humidity RH0 of the aerosol in the second aerosol optical quantity counter is calculated. 6) Based on the measured value of the scattered signal intensity S2 after aerosol humidification and the relative humidity RH0 of the aerosol in the second aerosol optical quantity counter, calculate the aerosol moisture absorption growth parameter κ: a) The relationship between the particle size Dp of aerosols after hygroscopic growth and relative humidity RH is: Where Dp is the particle size of the aerosol after hygroscopic growth, D d σ is the particle size of the aerosol during drying, κ is the aerosol hygroscopic growth parameter, and σ is the particle size of the aerosol during drying. s / a Let M be the surface tension of the aerosol, R be Avogadro's constant, and M be the surface tension of the aerosol. water Let ρ be the molar mass of water, T be the ambient temperature, and ρ be the temperature at room temperature. w The density of water; Given an initial value of an aerosol hygroscopic growth parameter κ, the particle size Dp of the aerosol after hygroscopic growth is calculated using formula (2), with the relative humidity RH0 of the aerosol in the second aerosol optical quantity counter as the relative humidity and the temperature T0 in the second aerosol optical quantity counter as the ambient temperature. b) Calculate the complex refractive index RI2 after hygroscopic growth of the aerosol using the volume-weighted average method: Among them, RI water is the complex refractive index of water; c) The calculated value of the scattered signal intensity S2′ after the aerosol absorbs moisture and grows is: S2′=C2·I2·σ2·PF 90°,2 (4) Where C2 is the second temperature-dependent constant, which is related to the temperature of the second aerosol optical quantity counter; I2 is the laser intensity of the second aerosol optical quantity counter, the value of C2·I2 is obtained by calibrating the second aerosol optical quantity counter; σ2 is the scattering phase function after aerosol hygroscopic growth; and PF 90°,2 The scattering phase function in the 90-degree direction after the aerosol absorbs moisture and grows; Based on the particle size Dp and complex refractive index RI2 after aerosol hygroscopic growth, σ2·PF is calculated using Mie scattering theory. 90°,2 The value of , combined with the value of C·I0 obtained by calibrating the first aerosol optical quantity counter, is substituted into formula (4) to calculate the calculated value S2′ of the scattering signal intensity after aerosol humidification. The measured value S2 of the scattering signal intensity after aerosol humidification is compared with the calculated value S2′ of the scattering signal intensity after aerosol humidification. d) Use the gradient descent method to change the initial value of the aerosol hygroscopic growth parameter κ until the difference between the measured value S2 of the scattering signal intensity after aerosol humidification and the calculated value S2′ of the scattering signal intensity after aerosol humidification is less than the threshold after humidification. Use the initial value at this time as the aerosol hygroscopic growth parameter κ.

5. The measurement method as described in claim 4, characterized in that, In step 4)a), the initial value of the complex refractive index RH during aerosol drying is arbitrary.

6. The measurement method as described in claim 4, characterized in that, In step 4b), the threshold value during drying is ≤10. -3 .

7. The measurement method as described in claim 4, characterized in that, In step 5), the air vapor pressure e1 is calculated using the temperature T1 and humidity RH1 at the air inlet of the second aerosol optical quantity counter.

8. The measurement method as described in claim 4, characterized in that, Using the temperature T0 in the second aerosol optical quantity counter and the calculated air vapor pressure e1, the relative humidity RH0 of the aerosol is calculated:

9. The measurement method as described in claim 4, characterized in that, In step 6)a), the initial value of the hygroscopic growth parameter κ of the aerosol is arbitrary.

10. The measurement method as described in claim 4, characterized in that, In step 6), d), the threshold value after moisture absorption is ≤10. -3 .

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