Method and device for measuring moisture content of atmospheric environment aerosol

Abstract

The invention discloses a method and a device for measuring the moisture content of atmospheric environment aerosol. According to the invention, a drying tube, a first optical particle spectrometer and a second optical particle spectrometer are adopted to obtain dry and non-dry particle size distribution of the aerosol, a moisture absorption growth factor is obtained through inversion by using the measured particle size spectrum distribution of the whole aerosol, and then the particle size of the aerosol after moisture absorption growth under environmental humidity is calculated according to a Kappatrah theoretical formula. Further obtaining the water content of the environmental aerosol; a differential electromigration analyzer is not adopted, so that the instrument cost is remarkably reduced; a humidifying unit is not needed to control the humidity of the instrument equipment, so that the maintenance difficulty is obviously reduced; according to the inversion method, the moisture absorption growth factor is obtained through inversion by means of the measured particle size spectrum distribution of the whole aerosol, then the moisture content of the aerosol is obtained through calculation, and the error is smaller.

Description

Technical Field

[0001] This invention relates to aerosol measurement technology, specifically to a method and apparatus for measuring the water content of atmospheric aerosols. Background Technology

[0002] Atmospheric aerosols possess unique environmental, health, and climate effects. Water in aerosols significantly influences their optical properties, such as scattering and absorption, altering the macro- and microscopic characteristics of clouds and indirectly impacting the Earth's radiation balance. Simultaneously, it can significantly reduce atmospheric visibility, promoting pollutant transformation and secondary formation. Furthermore, increased aerosol water content may alter their chemical composition and surface properties, enhancing the toxicity of harmful substances. Hygroscopic aerosol particles are more likely to deposit in the respiratory tract, increasing the bioavailability of pollutants and raising human exposure levels, thereby exacerbating health risks. Accurately obtaining the water content of atmospheric aerosols helps improve air quality models, enabling them to more accurately simulate the physicochemical processes, transport, and transformation of aerosols, thus improving the ability to predict and assess air pollution. It also contributes to a better understanding of the interaction between aerosols and the climate system, improving the simulation accuracy and reliability of climate models, and providing a scientific basis for climate change prediction and response. However, most current methods for obtaining atmospheric aerosol water content are calculated by measuring its chemical composition and aerosol particle size distribution characteristics. These methods have high time resolution, complex procedures, and high costs, which limit their widespread application in obtaining atmospheric aerosol water content. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention proposes a method and device for measuring atmospheric aerosol water content. The method uses measurement data from two optical particle size spectrometers (OPS) to calculate atmospheric aerosol water content. It features high measurement time resolution, simple equipment, easy maintenance, and can meet the needs of aircraft observation and vertical observation.

[0004] One object of the present invention is to provide a method for measuring the water content of atmospheric aerosols.

[0005] The method for measuring the water content of atmospheric aerosols according to the present invention includes the following steps:

[0006] 1) Measuring device:

[0007] After sampling the environmental aerosols from the sampling port, they were divided into two paths. One path passed through a drying tube, and the particle size distribution PNSD1 of the dried aerosol was measured using the first optical particle spectrometer OPS1. The drying temperature T1 and relative humidity RH1 of the dried aerosol were measured using the first temperature and humidity probe. The other path was not dried, and the particle size distribution PNSD2 of the undried aerosol was directly measured using the second optical particle spectrometer OPS2. At the same time, before and after the second optical particle spectrometer OPS2, the undried inlet temperature T2 and relative humidity RH2 of the undried inlet, and the undried outlet temperature T3 and relative humidity RH3 of the undried outlet were measured using the second and third temperature and humidity probes, respectively.

[0008] 2) Calculate the equivalent relative humidity:

[0009] Using the undried inlet temperature T2 and the undried inlet relative humidity RH2, the water vapor content e2 at the inlet of the second optical particle spectrometer OPS2 is calculated as follows:

[0010]

[0011] Using the undried outlet temperature T3 and the undried outlet relative humidity RH3, the outlet water vapor content e3 of the second optical particle spectrometer OPS2 is calculated as follows:

[0012]

[0013] The equivalent water content e0 in the second optical particle spectrometer OPS2 is obtained as follows:

[0014]

[0015] The equivalent temperature T0 in the second optical particle spectrometer OPS2 is:

[0016]

[0017] Using the equivalent temperature T0 and equivalent water content e0 in the second optical particle spectrometer OPS2, calculate the equivalent relative humidity RH0 of the aerosol in the second optical particle spectrometer OPS2:

[0018]

[0019] 3) The hygroscopic growth factor was obtained through inversion:

[0020] Based on the dry particle size distribution PNSD1 and the undried particle size distribution PNSD2 of the aerosol, the equivalent relative humidity RH0 of the aerosol in the second optical particle spectrometer OPS2, and the commonly used complex refractive index RI0 of aerosols, the hygroscopic growth factor κ of the aerosol is calculated using the following method:

[0021] (1) The second total scattering intensity S2 is obtained by directly using the scattering intensity distribution spectrum calculated from wet particle size aerosol:

[0022] a. Particle size distribution of undried aerosols. PNSD2 represents different particle sizes Dp1, Dp2, ... Dp n The concentrations of the undried samples were N 21 N 22 …N 2n n represents the number of different particle sizes;

[0023] b. Using the Mie scattering model, the commonly used complex refractive index combinations for calculating particle size and aerosols are (Dp1,RI0), (Dp2,RI0)...(Dp... n The scattering intensities under RI0) are S 21 ,S 22 …S 2n The corresponding scattering intensity distribution spectrum obtained directly from wet particle size aerosol calculations is:

[0024] c. Based on the scattering intensity distribution spectrum obtained directly from wet particle size aerosols, the corresponding second total scattering intensity S2 is:

[0025]

[0026] (2) The first total scattering intensity S1 was obtained by calculating the characteristics of the aerosol after moisture absorption using a dry particle size aerosol combined with a moisture absorption growth model:

[0027] a. An initial value for the hygroscopic growth factor is arbitrarily set. The particle size distribution of the aerosol drying process, PNSD1, represents different particle sizes Dp1, Dp2, ... Dp. n The concentrations of N2 and N2 during drying were respectively 11 N 12 …N 1n ;

[0028] b. Using Capacola (κ- Theoretical formulas are used to calculate the aerosol particle sizes Dp1, Dp2, ... Dp under dry relative humidity RH1 to equivalent relative humidity RH0 and equivalent temperature T0 conditions. n Particle size Dp after hygroscopic growth at equivalent relative humidity 11 ,Dp 12 ,…Dp 1n ;

[0029] c. Calculate the particle size Dp of the corresponding aerosol after the i-th wet growth using the volume-weighted average method. 1i aerosol complex refractive index RI 1i :

[0030] Where i = 1, 2, ..., n

[0031] Among them, RI water is the complex refractive index of water;

[0032] d. Using the Mie scattering model, the combined complex refractive index of the wet-grown particle size and aerosol was calculated to be (Dp) 11 ,RI 11 ), (Dp 12 ,RI 12 ...(Dp) 1n ,RI 1n The scattering intensities calculated using the hygroscopic growth model are S... 11 ,S 12 …S 1n The corresponding scattering intensity distribution spectrum calculated using the hygroscopic growth model is as follows:

[0033] e. Obtain the corresponding first total scattering intensity based on the scattering intensity distribution spectrum calculated using the hygroscopic growth model.

[0034] Degree S1 is:

[0035]

[0036] (3) The first total scattering intensity S1 and the second total scattering intensity S2 are essentially the same, both being the total scattering intensity of wet particle size aerosols. The initial value of the hygroscopic growth factor is changed by using the gradient descent method until the first total scattering intensity S1 and the second total scattering intensity S2 are equal or the deviation between them is less than a set threshold. When this condition is met, the value of the hygroscopic growth factor κ0 is the aerosol hygroscopic growth factor obtained by the final inversion.

[0037] 4) Calculate the particle size after moisture absorption and growth under ambient humidity:

[0038] A temperature and humidity probe was used to measure the ambient humidity. The aerosol hygroscopic growth factor obtained in step 3) was then used, based on the Capacella (κ-)... Theoretical formulas calculate, under measured ambient humidity, the aerosols from different particle sizes Dp1, Dp2, ... Dp n The particle size D after hygroscopic growth under ambient humidity 31 D 32 ,…D 3n :

[0039]

[0040] Where RH4 represents ambient humidity, and D 3i Let σ be the particle size after hygroscopic growth under the i-th ambient humidity, κ be the hygroscopic growth factor of the aerosol, and σ be the particle size after hygroscopic growth.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, T0 be the equivalent temperature, and ρ be the molar mass of water. w The density of water;

[0041] 5) Calculate the water content of the aerosol:

[0042] Based on the particle size after hygroscopic growth under ambient humidity and the drying concentration N 11 N 12 …N 1n Calculate the water content of aerosols

[0043] Quantity W:

[0044]

[0045] Where, ρ w N is the density of water. 1i Let the i-th particle size Dp i The concentration of the dried product.

[0046] In step 3), (1) any initial value is 0.01 to 1. n is 32 or 64, which is the number of particle sizes measured in the aerosol particle size distribution. The n corresponding to different optical particle spectrometer OPS models is different.

[0047] In step 3) (2), Capacola The theoretical formula is:

[0048]

[0049] Among them, Dp 1i Let Dp be the particle size after hygroscopic growth at the i-th equivalent relative humidity. i Let σ represent the i-th particle size, κ be the hygroscopic growth factor of the aerosol, reflecting the hygroscopic growth capacity of the aerosol itself, and σ be the hygroscopic growth factor. 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 It is the molar mass of water, T0 is the equivalent temperature, and ρ is the molar mass of water. w It is the density of water.

[0050] In step 3), (3) the threshold is set to 10. -6 ~10 -5 .

[0051] Another object of the present invention is to provide a device for measuring the water content of atmospheric aerosols.

[0052] The atmospheric aerosol moisture content measuring device of the present invention includes: a drying tube, first and second optical particle spectrometers, and first and third temperature and humidity probes; wherein, the inlet of the atmospheric aerosol is connected via pipes to the inlet of the drying tube and the air inlet of the second optical particle spectrometer; the outlet of the drying tube is connected to the air inlet of the first optical particle spectrometer; a first temperature and humidity probe is installed at the inlet of the first optical particle spectrometer; a second and a third temperature and humidity probe are installed at the air inlet and outlet of the second optical particle spectrometer, respectively; after sampling, the atmospheric aerosol is divided into two paths, one of which passes through the drying tube and is measured by the first optical particle spectrometer. The particle size distribution of the dried aerosol was measured using a first temperature and humidity probe, which measured the drying temperature and relative humidity. In another path, no drying was performed; the particle size distribution of the undried aerosol was directly measured using a second optical particle spectrometer. Simultaneously, before and after the second optical particle spectrometer, the inlet temperature and relative humidity of the undried aerosol, as well as the outlet temperature and relative humidity, were measured using second and third temperature and humidity probes, respectively. The equivalent relative humidity was calculated based on the inlet and outlet temperatures and humidity readings from the second optical particle spectrometer. The particle size distribution was then measured using a Capacitor (κ-) sensor. The theoretical formula is used to calculate the particle size of aerosols after hygroscopic growth. The characteristics of the hygroscopic aerosol after hygroscopic growth are calculated by combining the dry particle size aerosol with the hygroscopic growth model to obtain the first total scattering intensity. The second total scattering intensity is directly calculated using the wet particle size aerosol. The initial value of the hygroscopic growth factor is changed using the gradient descent method until the first total scattering intensity and the second total scattering intensity are equal or the deviation between them is less than a set threshold. When this condition is met, the value of the hygroscopic growth factor is the hygroscopic growth factor of the aerosol obtained by inversion. Based on the hygroscopic growth factor of the aerosol obtained by inversion, the particle size of the aerosol after hygroscopic growth is calculated using the Kappacolla theoretical formula. The water content of the aerosol is calculated based on the particle size after hygroscopic growth and the dry concentration.

[0053] Advantages of this invention:

[0054] This invention employs a drying tube and first and second optical particle spectrometers to obtain the particle size distribution of dried and undried aerosols. The hygroscopic growth factor is then derived from the measured particle size distribution of the entire aerosol, and further analyzed according to the Capacitor (κ-) model. Theoretical formulas are used to calculate the particle size of aerosols after hygroscopic growth under ambient humidity, thereby obtaining the water content of the aerosols in the environment. This invention does not use a differential electromigration analyzer, which significantly reduces instrument costs. Furthermore, it does not require a humidification unit to control the humidity of the instrument, which significantly reduces maintenance difficulty. In the inversion method of this invention, the hygroscopic growth factor is obtained by measuring the entire aerosol particle size distribution, and then the water content of the aerosol is calculated, resulting in smaller errors. Attached Figure Description

[0055] Figure 1This is a schematic diagram of the atmospheric aerosol moisture content measuring device of the present invention;

[0056] Figure 2 This is a flowchart of the method for measuring the water content of atmospheric aerosols according to the present invention. Detailed Implementation

[0057] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0058] The method for measuring the water content of atmospheric aerosols in this embodiment is as follows: Figure 2 As shown, it includes the following steps:

[0059] 1) Measuring device:

[0060] like Figure 1 As shown, after sampling the environmental aerosol from the sampling port, it is divided into two paths. One path passes through a drying tube, and the particle size distribution PNSD1 of the dried aerosol is measured using the first optical particle spectrometer OPS1. The drying temperature T1 and the relative humidity RH1 of the dried aerosol are measured using the first temperature and humidity probe. The other path is not dried, and the particle size distribution PNSD2 of the undried aerosol is directly measured using the second optical particle spectrometer OPS2. At the same time, before and after the second optical particle spectrometer OPS2, the undried inlet temperature T2 and the undried inlet relative humidity RH2, as well as the undried outlet temperature T3 and the undried outlet relative humidity RH3 are measured using the second and third temperature and humidity probes, respectively.

[0061] 2) Calculate the equivalent relative humidity:

[0062] Using the undried inlet temperature T2 and the undried inlet relative humidity RH2, the water vapor content e2 at the inlet of the second optical particle spectrometer OPS2 is calculated as follows:

[0063]

[0064] Using the undried outlet temperature T3 and the undried outlet relative humidity RH3, the outlet water vapor content e3 of the second optical particle spectrometer OPS2 is calculated as follows:

[0065]

[0066] The equivalent water content e0 in the second optical particle spectrometer OPS2 is obtained as follows:

[0067]

[0068] The equivalent temperature T0 in the second optical particle spectrometer OPS2 is:

[0069]

[0070] Using the equivalent temperature T0 and equivalent water content e0 in the second optical particle spectrometer OPS2, calculate the equivalent relative humidity RH0 of the aerosol in the second optical particle spectrometer OPS2:

[0071]

[0072] 3) Hygroscopic growth factor κ:

[0073] (1) The second total scattering intensity S2 is obtained by directly using the scattering intensity distribution spectrum of wet particle size aerosol:

[0074] a. Particle size distribution of undried aerosols. PNSD2 represents different particle sizes Dp1, Dp2, ... Dp n The concentrations of the undried samples were N 21 N 22 …N 2n n represents the number of different particle sizes;

[0075] b. Using the Mie scattering model, the commonly used complex refractive index combinations for calculating particle size and aerosols are (Dp1,RI0), (Dp2,RI0)...(Dp... n The scattering intensities under RI0) are S 21 ,S 22 …S 2n RI0 = 1.46; the corresponding scattering intensity distribution spectrum S′ is obtained directly from wet particle size aerosol calculation. 2i for:

[0076] c. Based on the scattering intensity distribution spectrum obtained directly from wet particle size aerosols, the corresponding second total scattering intensity S2 is:

[0077]

[0078] (2) The first total scattering intensity S1 was obtained by calculating the characteristics of the aerosol after moisture absorption using a dry particle size aerosol combined with a moisture absorption growth model:

[0079] a. An initial value for the hygroscopic growth factor is arbitrarily set. The particle size distribution of the aerosol drying process, PNSD1, represents different particle sizes Dp1, Dp2, ... Dp. n The concentrations of N2 and N2 during drying were respectively 11 N 12 …N 1n ;

[0080] b. Using Capacola (κ- Theoretical formulas are used to calculate the aerosol particle sizes Dp1, Dp2, ... Dp under dry relative humidity RH1 to equivalent relative humidity RH0. n Particle size Dp after hygroscopic growth at equivalent relative humidity 11 ,Dp 12 ,…Dp 1n :

[0081]

[0082] Among them, Dp 1i Let Dp be the particle size after hygroscopic growth at the i-th equivalent relative humidity. i Let σ represent the i-th particle size, κ be the hygroscopic growth factor of the aerosol, reflecting the hygroscopic growth capacity of the aerosol itself, and σ be the hygroscopic growth factor. 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, T0 be the equivalent temperature, and ρ be the molar mass of water. w The density of water;

[0083] c. Calculate the particle size Dp of the corresponding aerosol after the i-th wet growth using the volume-weighted average method. 1i aerosol complex refractive index RI 1i :

[0084] Where i = 1, 2, ..., n

[0085] Among them, RI water is the complex refractive index of water;

[0086] d. Using the Mie scattering model, the combined complex refractive index of the wet-grown particle size and aerosol was calculated to be (Dp) 11 ,RI 11 ), (Dp 12 ,RI 12 ...(Dp) 1n ,RI 1n The scattering intensities calculated using the hygroscopic growth model are S... 11 ,S 12 …S 1n The corresponding scattering intensity distribution spectrum S′ calculated using the hygroscopic growth model is... 1i for:

[0087] e. Based on the scattering intensity distribution spectrum calculated using the hygroscopic growth model, the corresponding first total scattering intensity S1 is:

[0088]

[0089] (3) The first total scattering intensity S1 and the second total scattering intensity S2 are essentially the same, both being the total scattering intensity of wet particle aerosols. The initial value of the hygroscopic growth factor is changed using the gradient descent method until the first total scattering intensity S1 and the second total scattering intensity S2 are equal or their deviation is less than 10. -5 The value of the hygroscopic growth factor κ0 when this condition is met is the aerosol hygroscopic growth factor obtained by the final inversion.

[0090] 4) Calculate the particle size after moisture absorption and growth under ambient humidity:

[0091] Using the aerosol hygroscopic growth factor obtained from step 3), the Kappacolla (κ-) was used. Theoretical formulas were used to calculate aerosols from different particle sizes Dp1, Dp2, ... Dp n The particle size D after hygroscopic growth under ambient humidity 31 D 32 ,…D 3n :

[0092]

[0093] Where RH4 represents the ambient humidity, D 3i Let σ be the particle size after hygroscopic growth under the i-th ambient humidity, κ be the hygroscopic growth factor of the aerosol, and σ be the particle size after hygroscopic growth. 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, T0 be the equivalent temperature, and ρ be the molar mass of water. w The density of water;

[0094] 5) Calculate the water content of the aerosol:

[0095] Based on the particle size after hygroscopic growth and the drying concentration N 11 N 12 …N 1n Calculate the water content W of the aerosol:

[0096]

[0097] Where, ρ w It is the density of water, N 1i Let the i-th particle size Dp i The concentration of the dried product.

[0098] 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 method for measuring the water content of atmospheric aerosols, characterized in that, The measurement method includes the following steps: 1) Measuring device: After sampling the environmental aerosols at the inlet, they were divided into two paths. One path passed through a drying tube, and the particle size distribution PNSD1 of the dried aerosol was measured using a first optical particle spectrometer. The temperature T1 and relative humidity RH1 of the dried aerosol were also measured. The other path was not dried, and the particle size distribution PNSD2 of the undried aerosol was measured directly using a second optical particle spectrometer. At the same time, the temperature T2 and relative humidity RH2 of the undried inlet, as well as the temperature T3 and relative humidity RH3 of the undried outlet, were measured before and after the second optical particle spectrometer. 2) Calculate the equivalent relative humidity: Using the temperature and relative humidity of the undried inlet and outlet, the water vapor content of the inlet and outlet is calculated to obtain the equivalent water content and equivalent temperature in the second optical particle spectrometer, and then the equivalent relative humidity of the aerosol in the second optical particle spectrometer is calculated. 3) Hygroscopic growth factor κ: (1) The second total scattering intensity S2 is obtained by directly using the scattering intensity distribution spectrum calculated from wet particle size aerosol; (2) Obtain the particle size after hygroscopic growth under equivalent relative humidity, and obtain the first total scattering intensity S1 by calculating the scattering intensity distribution spectrum of dry particle size aerosol combined with hygroscopic growth model. (3) Use the gradient descent method to change the initial value of the hygroscopic growth factor until the first total scattering intensity S1 and the second total scattering intensity S2 are equal or the deviation between them is less than the set threshold. When this condition is met, the value of the hygroscopic growth factor is the aerosol hygroscopic growth factor obtained by the final inversion. 4) Calculate the particle size after moisture absorption and growth under ambient humidity: A temperature and humidity probe was used to measure the ambient humidity. Using the aerosol hygroscopic growth factor obtained in step 3), the growth rate of aerosols from different particle sizes Dp1, Dp2, ... Dp was calculated according to the Kappacolla theory formula under the measured ambient humidity. n The particle size D after hygroscopic growth under ambient humidity 31 D 32 ,…D 3n ; 5) Calculate the water content of the aerosol: Based on the particle size after hygroscopic growth under ambient humidity and the drying concentration N 11 N 12 …N 1n Calculate the water content W of the aerosol.

2. The measurement method as described in claim 1, characterized in that, In step 2), the equivalent relative humidity is calculated, including the following steps: a) Using the undried inlet temperature T2 and the undried inlet relative humidity RH2, calculate the water vapor content e2 at the inlet of the second optical particle spectrometer as follows: b) Using the undried outlet temperature T3 and the undried outlet relative humidity RH3, calculate the outlet water vapor content e3 of the second optical particle spectrometer as follows: c) The equivalent water content e0 in the second optical particle spectrometer is obtained as follows: d) The equivalent temperature T0 in the second optical particle spectrometer is: e) Using the equivalent temperature T0 and equivalent water content e0 in the second optical particle spectrometer, calculate the equivalent relative humidity RH0 of the aerosol in the second optical particle spectrometer:

3. The measurement method as described in claim 1, characterized in that, In step 3), (1) the second total scattering intensity S2 is obtained directly from the scattering intensity distribution spectrum calculated using wet particle size aerosol, including the following steps: a. Particle size distribution of undried aerosols. PNSD2 represents different particle sizes Dp1, Dp2, ... Dp n The undried concentrations of the aerosols were N 21 N 22 …N 2n n represents the number of different particle sizes; b. Using the Mie scattering model, the commonly used complex refractive index combinations for particle size and aerosols are (Dp1,RI0), (Dp2,RI0)...(Dp... n The scattering intensities under RI0) are S 21 ,S 22 …S 2n The corresponding scattering intensity distribution spectrum S′ is obtained directly from wet particle size aerosol calculations. 2i for: c. Based on the scattering intensity distribution spectrum obtained directly from wet particle size aerosols, the corresponding second total scattering intensity S2 is:

4. The measurement method as described in claim 1, characterized in that, In step 3), (2) the first total scattering intensity S1 is obtained by calculating the scattering intensity distribution spectrum of dry particle size aerosol combined with the hygroscopic growth model, including the following steps: a. An initial value for the hygroscopic growth factor is arbitrarily set. The particle size distribution of the aerosol drying process, PNSD1, represents different particle sizes Dp1, Dp2, ... Dp. n The concentrations of N2 and N2 during drying were respectively 11 N 12 …N 1n ; b. Using the Capacola theory, under dry relative humidity RH1 to equivalent relative humidity RH0 and equivalent temperature T0, calculate the aerosol particle sizes Dp1, Dp2, ... Dp. n Particle size Dp after hygroscopic growth at equivalent relative humidity 11 ,Dp 12 ,…Dp 1n ; c. Calculate the particle size Dp of the corresponding aerosol after the i-th wet growth using the volume-weighted average method. 1i aerosol complex refractive index RI 1i : Where i = 1, 2, ..., n Among them, RI water is the complex refractive index of water; d. Using the Mie scattering model, the combined complex refractive index of the wet-grown particle size and aerosol is calculated to be (Dp) 11 ,RI 11 (Dp) 12 ,RI 12 ...(Dp) 1n ,RI 1n The scattering intensities under the following conditions are S 11 ,S 12 …S 1n The corresponding scattering intensity distribution spectrum calculated using the dry particle size aerosol combined with the hygroscopic growth model is as follows: e. Based on the scattering intensity distribution spectrum calculated using the dry particle size aerosol combined with the hygroscopic growth model, the corresponding first total scattering intensity S1 is:

5. The measurement method as described in claim 1, characterized in that, In step 3), (2) the initial value of the hygroscopic growth factor is 0.01 to 1.

6. The measurement method as described in claim 1, characterized in that, In step 3), (3) the threshold is set to 10. -6 ~10 -5 .

7. The measurement method as described in claim 1, characterized in that, In step 4), the particle size after hygroscopic growth under ambient humidity satisfies: Where RH4 represents ambient humidity, and D 3i Let σ be the particle size after hygroscopic growth under the i-th ambient humidity, κ be the hygroscopic growth factor of the aerosol, and σ be the particle size after hygroscopic growth. 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, T0 be the equivalent temperature, and ρ be the molar mass of water. w The density of water.

8. The measurement method as described in claim 1, characterized in that, In step 5), the aerosol water content is calculated to satisfy: Where, ρ w N is the density of water. 1i Let be the dry concentration of the i-th particle size.

9. A device for measuring the water content of atmospheric aerosols, characterized in that, The measuring device includes: a drying tube, first and second optical particle spectrometers, and first to third temperature and humidity probes; wherein, the inlet of the environmental aerosol is connected via pipes to the inlet of the drying tube and the air inlet of the second optical particle spectrometer; the outlet of the drying tube is connected to the air inlet of the first optical particle spectrometer; a first temperature and humidity probe is installed at the inlet of the first optical particle spectrometer; a second and a third temperature and humidity probe are installed at the air inlet and outlet of the second optical particle spectrometer, respectively; after sampling, the environmental aerosol is divided into two paths, one path passes through the drying tube, and the particle size distribution of the dried aerosol is measured using the first optical particle spectrometer, while the drying temperature and relative humidity of the aerosol are measured using the first temperature and humidity probe; the other path is not dried, and the particle size distribution of the undried aerosol is directly measured using the second optical particle spectrometer, while the temperature and relative humidity of the undried air inlet of this path are measured using the second and third temperature and humidity probes before and after the second optical particle spectrometer, respectively. The process involves considering humidity, temperature at the undried outlet, and relative humidity at the undried outlet; calculating the equivalent relative humidity based on the temperature and humidity at the inlet and outlet of the second optical particle spectrometer; calculating the particle size of each aerosol particle size after hygroscopic growth using the Kappacolla theory formula; obtaining the first total scattering intensity by calculating the scattering intensity distribution spectrum of dry particle size aerosols combined with the hygroscopic growth model; and directly calculating the second total scattering intensity using wet particle size aerosols; changing the initial value of the hygroscopic growth factor using the gradient descent method until the first and second total scattering intensities are equal or their deviation is less than a set threshold, with the value of the hygroscopic growth factor being the final inverted aerosol hygroscopic growth factor; calculating the particle size of the aerosol after hygroscopic growth using the Kappacolla theory formula based on the hygroscopic growth factor; and calculating the water content of the aerosol based on the particle size after hygroscopic growth and the dry concentration.

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