Soil steam vertical upward migration flux monitoring device and method

Abstract

The invention discloses a device and method for monitoring the vertical upward migration flux of soil steam. The device comprises a main body supporting shell with a downward opening, and a static monitoring box with a downward opening and a dynamic monitoring box with a downward opening are fixed in the main body supporting shell; a static sampling output pipe communicated with the interior of the static monitoring box is arranged on the outer side of the static monitoring box, extends out of the main body supporting shell and is provided with a first flow meter; a dynamic box input pipe communicated with the interior of the dynamic monitoring box is arranged on the outer side of the dynamic monitoring box, a dynamic sampling output pipe communicated with the interior of the dynamic monitoring box is arranged on the outer side of the dynamic monitoring box, the dynamic sampling output pipe extends out of the main body supporting shell, and a second flow meter is arranged on the dynamic sampling output pipe; the monitoring device can simulate various scenes, for example, the maximum volatilization flux of soil gas under the open air condition is measured, the real flux of an actual house is simulated, and the upward migration potential of volatile organic compounds in soil and underground water is accurately evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of migration risk assessment of contaminated sites, and specifically to a device and method for monitoring the vertical upward migration flux of soil vapor. Background Art

[0002] According to the Technical Guidelines for Risk Assessment of Soil Pollution in Construction Land (HJ25.3-2019), there are mainly 9 exposure pathways for pollutants in soil or groundwater to cause carcinogenic risks or harm levels to human health, namely oral ingestion of soil, skin contact with soil, inhalation of soil particles, inhalation of gaseous pollutants from the surface soil in outdoor air, inhalation of gaseous pollutants from the underlying soil in outdoor air, inhalation of gaseous pollutants from the underlying soil in indoor air, inhalation of gaseous pollutants from groundwater in outdoor air, inhalation of gaseous pollutants from groundwater in indoor air, and drinking groundwater. For volatile organic compounds, the main exposure pathway causing human health risks is that the pollution sources in soil and groundwater are released through volatilization and transported in the form of gas through the pores of the vadose zone soil into indoor and outdoor environments.

[0003] At present, the environmental media concerned in the soil pollution investigation of construction land in China are mainly soil and groundwater, and the main monitoring is the concentration of pollutants in the soil and groundwater at the source. However, abroad, it is generally not recommended to use the concentration of VOCs in soil as the core basis for risk assessment because: ① there is a large uncertainty in the distribution relationship between VOCs in soil and soil gas; ② it is easy to lose during the sampling of soil VOCs, and there is a large uncertainty in the soil concentration results; ③ there may be a very large spatial heterogeneity in soil VOCs. In addition, due to the accuracy of the attenuation factor or mathematical model, there is a large uncertainty in deducing the concentration in indoor and outdoor air through the concentration at the soil or groundwater pollution source. Therefore, at present, the sampling representativeness is poor, and it is difficult to truly and directly reflect the potential and risk of the upward migration of volatile organic compounds.

[0004] By monitoring the amount of volatile organic compounds released from soil and groundwater per unit area and time, i.e., the volatilization flux, it can effectively reflect various migration and transformation matrices of VOCs in the formation, which is a novel sampling technique for evaluating the vertical upward migration risk of volatile organic compounds. Currently, flux chambers can generally be divided into static flux chambers, dynamic flux chambers, or flux chambers combined with passive sampling. The static flux chamber collects a gas sample from the chamber at regular intervals. Its disadvantage is that when the pollutant concentration in the flux chamber accumulates to a relatively high level, it will significantly hinder the mass transfer of pollutants upward, which may lead to an underestimation of the true mass transfer flux. The dynamic flux chamber introduces an inert purge gas into the flux chamber at a preset flow rate and samples after reaching a steady state. The introduction and discharge of the purge gas will result in a lower sensitivity of the flux chamber, and its structure, operation, and maintenance are relatively complex. For the flux chamber combined with passive sampling, the actual absorption rate of the passive sampler will be affected by various factors at the site. If the absorption rate is too fast, it will significantly promote the mass transfer of pollutants upward, so there will also be a deviation in the concentration measured using the passive sampler. Summary of the Invention

[0005] The purpose of the present invention is to provide a device and method for monitoring the vertical upward migration flux of soil vapor, which can more accurately evaluate the upward migration potential of volatile organic compounds in soil and groundwater by combining the static method and the dynamic method.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A device for monitoring the vertical upward migration flux of soil vapor includes a main support housing (10) with an opening facing downwards. A static monitoring box (20) with an opening facing downwards and a dynamic monitoring box (30) with an opening facing downwards are fixed inside the main support housing (10);

[0008] A static sampling output pipe (201) communicating with the inside is provided outside the static monitoring box (20). The static sampling output pipe (201) extends outside the main support housing (10), and a first flowmeter (2010) is provided on the static sampling output pipe (201);

[0009] A dynamic box input pipe (301) communicating with the inside is provided outside the dynamic monitoring box (30). A dynamic sampling output pipe (302) communicating with the inside is provided outside the dynamic monitoring box (30). The dynamic sampling output pipe (302) extends outside the main support housing (10), and a second flowmeter (3020) is provided on the dynamic sampling output pipe (302);

[0010] A gas supply containment box (11) is fixedly provided on the outside of the main body support housing (10). A dynamic gas cylinder (303) is provided inside the gas supply containment box (11). The dynamic box input pipe (301) is communicated with the output end of the dynamic gas cylinder (303). A third flowmeter (304) and a gas supply regulating valve (305) are provided on the dynamic box input pipe (301).

[0011] A plurality of internal environment monitoring sensors (121) are provided inside both the static monitoring box (20) and the dynamic monitoring box (30).

[0012] A plurality of external environment monitoring sensors (122) are provided on the outside of the main body support housing (10).

[0013] Preferably, the static monitoring box (20) is composed of a static box ring housing (21) with a vertical through hole and a static box end housing (22) slidably connected to the outside of the static box ring housing (21) and opening downward.

[0014] A static box outer support plate (211) is fixedly provided on the outside of the static box ring housing (21). A static box lifting and fixing cylinder (231) with an upward opening is fixedly provided on the top of the static box outer support plate (211). A static box lifting and sliding cylinder (232) is slidably connected inside the static box lifting and fixing cylinder (231). The top end of the static box lifting and sliding cylinder (232) is fixedly connected to the static box end housing (22).

[0015] A static box lifting drive rod (233) for driving the lifting movement of the static box lifting and sliding cylinder (232) is provided inside the static box lifting and fixing cylinder (231).

[0016] Note: The static monitoring box (20) adopts a variable volume design to flexibly adjust the actual volume of the static monitoring box (20) according to actual needs, which is beneficial to improving the accuracy of monitoring.

[0017] Preferably, a static ground insertion structure (24) is provided on the outside of the static box ring housing (21). The static ground insertion structure (24) includes a static ground insertion mating ring (241) slidably connected coaxially to the outside of the static box ring housing (21).

[0018] A static ground insertion fixing cylinder (242) with a downward opening is fixedly provided at the bottom of the static box outer support plate (211). A static ground insertion sliding cylinder (243) with an upward opening is slidably connected inside the static ground insertion fixing cylinder (242). The lower end of the static ground insertion sliding cylinder (243) is fixedly connected to the static ground insertion mating ring (241).

[0019] A static ground insertion drive rod (244) for driving the lifting movement of the static ground insertion sliding cylinder (243) is provided inside the static ground insertion fixing cylinder (242).

[0020] Description: The static ground insertion structure (24) can keep a good airtightness between the lower end of the static monitoring box (20) and the ground, ensuring the accuracy of the monitoring data.

[0021] Preferably, the dynamic monitoring box (30) is composed of a vertically penetrating dynamic box ring shell (31) and a dynamic box end shell (32) slidably connected to the outside of the dynamic box ring shell (31) and opening downward;

[0022] A dynamic box outer support plate (311) is fixed to the outside of the dynamic box ring shell (31). A dynamic box lifting and fixing cylinder (331) with an upward opening is fixed to the top of the dynamic box outer support plate (311). A dynamic box lifting and sliding cylinder (332) is slidably connected in the dynamic box lifting and fixing cylinder (331). The top end of the dynamic box lifting and sliding cylinder (332) is fixedly connected to the dynamic box end shell (32);

[0023] A dynamic box lifting driving rod (333) for driving the dynamic box lifting and sliding cylinder (332) to lift and move is provided in the dynamic box lifting and fixing cylinder (331).

[0024] Description: The dynamic monitoring box (30) adopts a variable volume design to flexibly adjust the actual volume of the dynamic monitoring box (30) according to actual needs, which is beneficial to improving the accuracy of monitoring.

[0025] Preferably, a dynamic ground insertion structure (34) is provided on the outside of the dynamic box ring shell (31). The dynamic ground insertion structure (34) includes a dynamic ground insertion mating ring (341) slidably connected coaxially to the outside of the dynamic box ring shell (31);

[0026] A dynamic ground insertion fixing cylinder (342) with a downward opening is fixed to the bottom of the dynamic box outer support plate (311). A dynamic ground insertion sliding cylinder (343) with an upward opening is slidably connected in the dynamic ground insertion fixing cylinder (342). The lower end of the dynamic ground insertion sliding cylinder (343) is fixedly connected to the dynamic ground insertion mating ring (341);

[0027] A dynamic ground insertion driving rod (344) for driving the dynamic ground insertion sliding cylinder (343) to lift and move is provided in the dynamic ground insertion fixing cylinder (342).

[0028] Description: The dynamic ground insertion structure (34) can keep a good airtightness between the lower end of the dynamic monitoring box (30) and the ground, ensuring the accuracy of the monitoring data.

[0029] Preferably, an air supply balancing mechanism (35) is provided inside the dynamic monitoring box (30). The air supply balancing mechanism (35) includes an air supply balancing input ring shell (351) that is fixed on the inner side wall of the dynamic box ring shell (31) and is annular and hollow. A plurality of air supply balancing delivery pipes (352) that are connected to its interior are fixed to the top of the air supply balancing input ring shell (351). A plurality of air supply discharge holes (353) that communicate inside and outside are provided on the side wall of the air supply balancing delivery pipe (352).

[0030] An air flow outer discharge collecting pipe (354) that extends vertically coaxially with it is provided inside the dynamic box ring shell (31). A plurality of outer discharge collecting through holes (355) that communicate inside and outside are provided on the side wall of the air flow outer discharge collecting pipe (354). The interior of the air flow outer discharge collecting pipe (354) is connected to the dynamic sampling output pipe (32).

[0031] Note: The air supply balancing mechanism (35) can promote gas circulation more stably and efficiently, ensure that the gas in the box can be updated quickly and evenly, reduce gas retention and local concentration differences, and improve the accuracy and stability of measurement.

[0032] Preferably, a static pressure balancing mechanism (25) is provided on the top of the static monitoring box (20). The static pressure balancing mechanism (25) includes a pressure balancing communication pipe (251) that is fixed on the top of the static box end shell (22) and is connected to its interior. A pressure balancing fixed cylinder (252) with one end open is fixed to the outer end of the pressure balancing communication pipe (251). A pressure balancing sliding cylinder (253) that faces the opening is slidably connected inside the pressure balancing fixed cylinder (252).

[0033] A pressure balancing film (254) is fixed inside the pressure balancing sliding cylinder (253). A pressure balancing leveling pipe (255) that is connected to its interior is fixed to the outer end of the pressure balancing sliding cylinder (253). A leveling control valve (256) is provided on the pressure balancing leveling pipe (255).

[0034] An equilibrium air pressure sensor (250) is fixed inside the pressure balancing sliding cylinder (253).

[0035] A laser distance measuring sensor (257) is fixed to the inner end of the pressure balancing sliding cylinder (253).

[0036] An equilibrium driving fixed cylinder (258) that is arranged in parallel with it and has the same opening direction is fixed to the outside of the pressure balancing fixed cylinder (252). An equilibrium driving sliding cylinder (259) is slidably connected inside the equilibrium driving fixed cylinder (258). The outer end of the equilibrium driving sliding cylinder (259) is fixedly connected to the pressure balancing sliding cylinder (253).

[0037] The equalization driving fixed cylinder (258) is provided with an equalization driving telescopic rod (2580) for driving the equalization driving sliding cylinder (259) to move.

[0038] Explanation: By using the static pressure equalization mechanism (25), the air pressure inside the static monitoring box (20) can be accurately balanced with the outside world, and it can also play a certain compensating role in the hindrance phenomenon caused by this concentration difference, reducing the measurement error.

[0039] Preferably, a plurality of electric heating sheets (40) are fixed on the inner side walls of the ring shells of the static box ring shell (21) and the dynamic box ring shell (31).

[0040] Explanation: By using the electric heating sheets (40), the temperature inside the static monitoring box (20) and the dynamic monitoring box (30) can be adjusted to make the temperature inside the static monitoring box (20) and the dynamic monitoring box (30) consistent with the outside world.

[0041] Preferably, humidification connecting pipes (50) that communicate inside and outside are fixed on the tops of the static box end shell (22) and the dynamic box end shell (32). A humidifier (51) is provided in the air supply accommodating box (11). The output end of the humidifier (51) is connected to the humidification connecting pipe (50), and the humidification connecting pipe (50) is provided with a humidification control valve (501).

[0042] Explanation: By using the humidifier (51), the humidity inside the static monitoring box (20) and the dynamic monitoring box (30) can be supplemented and adjusted to make the humidity inside the static monitoring box (20) and the dynamic monitoring box (30) consistent with the outside world.

[0043] Preferably, a method for monitoring the vertical upward migration flux of soil vapor, based on the above-mentioned device for monitoring the vertical upward migration flux of soil vapor, includes the following steps:

[0044] S1. Clean the monitoring point:

[0045] Clean the land at the monitoring point, remove stones and sundries to make the land surface flat.

[0046] S2. Fix the monitoring equipment:

[0047] Place the monitoring device on the cleaned land, insert the static ground insertion mating ring (241) and the dynamic ground insertion mating ring (341) into the soil,

[0048] A static monitoring chamber and a dynamic monitoring chamber are formed between the static monitoring box (20) and the ground surface respectively;

[0049] Test the air tightness of the static monitoring chamber and the dynamic monitoring chamber by the flue gas detection method;

[0050] S3. Environmental parameter adjustment:

[0051] The external environmental monitoring sensors (122) outside the main body support housing (10) can obtain the temperature, humidity, and air pressure parameters of the outside world. The internal environmental monitoring sensors (121) inside the static monitoring box (20) and the dynamic monitoring box (30) can obtain the temperature, humidity, and air pressure parameters inside them respectively, and adjust the temperature, humidity, and air pressure parameters inside the static monitoring box (20) and the dynamic monitoring box (30) to make the temperature, humidity, and air pressure inside the static monitoring box (20) and the dynamic monitoring box (30) consistent with the outside world;

[0052] S4. Dynamic measurement:

[0053] The dynamic gas supply cylinder (303) contains nitrogen, and the nitrogen is continuously input into the dynamic monitoring box (30) through the dynamic box input pipe (301). The constantly input nitrogen is discharged from the dynamic sampling output pipe (302) together with the soil vapor;

[0054] Sampling is carried out from the output end of the dynamic sampling output pipe (302) to measure the initial concentration of the soil vapor;

[0055] The dynamic monitoring box (30) determines the sampling time by controlling the inlet and outlet flow rates, then samples from the dynamic sampling output pipe (302) and sends the sample for inspection. During sampling, the temperature and pressure changes inside and outside the dynamic monitoring box (30) are monitored in real time and adjusted to keep the temperature and pressure inside and outside the dynamic monitoring box (30) consistent;

[0056] The dynamic measurement uses the following formula to calculate the flux;

[0057]

[0058] Where: Flux a is the soil gas volatilization flux, with the unit of μg / m 2 min; C o is the pollutant concentration at the dynamic monitoring outlet, with the unit of μg / m 3 ; Q is the purge flow rate of the dynamic monitoring chamber, with the unit of m 3 / min; A chamber is the floor area of the dynamic monitoring chamber, with the unit of m 2 ;

[0059] S5. Static measurement:

[0060] According to actual needs, the static monitoring box (20) samples and sends the sample for inspection through the static sampling output pipe (201) by adjusting the sampling time, sampling interval, and sampling volume;

[0061] The static measurement uses the following formula to calculate the flux;

[0062]

[0063] Where: Flux s is the soil gas volatilization flux, with the unit of μg / m 2 h; C chamber is the pollutant concentration in the static monitoring chamber, with the unit of μg / m 3 ; V chamber is the volume of the static monitoring chamber, with the unit of m 3 ; A chamber is the floor area of the static monitoring chamber, with the unit of m 2 ; T is the installation time of the monitoring equipment, with the unit of min;

[0064] Considering that the flux difference varies greatly due to different degrees of soil and groundwater pollution, when the static chamber is larger than the dynamic chamber, static data is used; otherwise, dynamic data is used, and the maximum flux is selected.

[0065] Compared with the prior art, the beneficial effects of the present invention are reflected in the following aspects:

[0066] 1. The structure of the present invention is reasonably designed and can simulate various scenarios, such as measuring the maximum flux of soil gas volatilization under open-air conditions and simulating the real flux of an actual residence, accurately evaluating the potential of upward migration of volatile organic compounds in soil and groundwater;

[0067] 2. The measurement of the present invention is accurate. The static method can measure the maximum flux of upward migration of soil vapor when the volatilization flux is low, and the dynamic method can accurately measure the flux of upward migration of soil vapor when the volatilization flux is high. The combination of the two can achieve high-precision measurement of the vertical upward migration flux of soil vapor and reduce measurement errors;

[0068] 3. For the monitoring device of the present invention, the two methods verify and complement each other. When one method shows abnormalities or errors, the other method can play a calibration role to ensure that the obtained data is more reliable and comprehensive, providing a solid data basis for subsequent research and decision-making. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 is the front view of the present invention;

[0070] Figure 2 is Figure 1 the top view of;

[0071] Figure 3 is the structural schematic diagram of the static monitoring box of the present invention;

[0072] Figure 4 is the structural schematic diagram of the static ground insertion structure of the present invention;

[0073] Figure 5 is a schematic structural diagram of the static pressure equalization mechanism of the present invention;

[0074] Figure 6 is a schematic structural diagram of the dynamic monitoring box of the present invention;

[0075] Figure 7 is a schematic structural diagram of the dynamic ground insertion structure of the present invention;

[0076] Figure 8 is a schematic structural diagram of the air supply equalization mechanism of the present invention.

[0077] In the figure, 10 - main body support housing, 101 - thermal insulation layer, 11 - air supply accommodation box, 121 - internal environment monitoring sensor, 122 - external environment monitoring sensor, 20 - static monitoring box, 201 - static sampling output pipe, 2010 - first flowmeter, 202 - static overflow pipe, 21 - static box ring housing, 211 - static box outer support plate, 22 - static box end housing, 231 - static box lifting and fixing cylinder, 232 - static box lifting and sliding cylinder, 233 - static box lifting drive rod, 24 - static ground insertion structure, 241 - static ground insertion mating ring, 242 - static ground insertion fixing cylinder, 243 - static ground insertion sliding cylinder, 244 - static ground insertion drive rod, 25 - static pressure equalization mechanism, 250 - equalization air pressure sensor, 251 - pressure equalization communication pipe, 252 - pressure equalization fixing cylinder, 253 - pressure equalization sliding cylinder, 254 - pressure equalization film, 255 - pressure equalization balancing pipe, 256 - balancing control valve, 257 - laser ranging sensor, 258 - equalization drive fixing cylinder, 2580 - equalization drive telescopic rod, 259 - equalization drive sliding cylinder, 30 - dynamic monitoring box, 301 - dynamic box input pipe, 302 - dynamic sampling output pipe, 3020 - second flowmeter, 303 - dynamic gas cylinder, 304 - third flowmeter, 305 - air supply control valve, 31 - dynamic box ring housing, 311 - dynamic box outer support plate, 32 - dynamic box end housing, 331 - dynamic box lifting and fixing cylinder, 332 - dynamic box lifting and sliding cylinder, 333 - dynamic box lifting drive rod, 34 - dynamic ground insertion structure, 341 - dynamic ground insertion mating ring, 342 - dynamic ground insertion fixing cylinder, 343 - dynamic ground insertion sliding cylinder, 344 - dynamic ground insertion drive rod, 35 - air supply equalization mechanism, 351 - air supply equalization input ring housing, 352 - air supply equalization delivery pipe, 353 - air supply discharge hole, 354 - air flow external discharge collecting pipe, 355 - external discharge collecting through hole, 40 - electric heating sheet, 50 - humidification communication pipe, 501 - humidification control valve, 51 - humidifier. Detailed implementation manners

[0078] The following is combined with Figures 1 to 8A detailed description of the present invention is given. For the convenience of description, the orientations mentioned below are defined as follows: the up-down, left-right, front-back directions mentioned below are consistent with the up-down, left-right, front-back directions of the projection relationship of each main view or structural schematic diagram itself.

[0079] Embodiment 1:

[0080] A device for monitoring the vertical upward migration flux of soil vapor, as Figure 1 shown, includes a main body support housing (10) with an opening facing downwards. A static monitoring box (20) with an opening facing downwards and a dynamic monitoring box (30) with an opening facing downwards are fixed inside the main body support housing (10);

[0081] A layer of heat-insulating layer (101) is provided on the inner side wall of the main body support housing (10);

[0082] The outer side surface of the main body support housing (10) has a reflective layer, which can shield solar radiation and prevent the temperature inside the device from rising;

[0083] The inner walls of the static monitoring box (20) and the dynamic monitoring box (30) are coated with a layer of silanized inert coating by vapor deposition, which can effectively shield the contact between active iron and VOCs, and eliminate the degradation reaction and adsorption loss of VOCs;

[0084] As Figure 3 shown, a static sampling output pipe (201) connected to its interior is provided outside the static monitoring box (20). The static sampling output pipe (201) extends to the outside of the main body support housing (10), and a first flow meter (2010) is provided on the static sampling output pipe (201);

[0085] As Figure 4 shown, a static overflow pipe (202) connected to its interior is provided at the top of the static monitoring box (20);

[0086] As Figure 6 shown, a dynamic box input pipe (301) connected to its interior is provided outside the dynamic monitoring box (30), a dynamic sampling output pipe (302) connected to its interior is provided outside the dynamic monitoring box (30). The dynamic sampling output pipe (302) extends to the outside of the main body support housing (10), and a second flow meter (3020) is provided on the dynamic sampling output pipe (302);

[0087] As Figure 2As shown, an air supply accommodating box (11) is fixed to the outside of the main body support housing (10). A dynamic gas cylinder (303) is provided inside the air supply accommodating box (11). The dynamic box input pipe (301) is communicated with the output end of the dynamic gas cylinder (303). A third flowmeter (304) and an air supply regulating valve (305) are provided on the dynamic box input pipe (301).

[0088] As Figure 3 , Figure 6 shown, a plurality of internal environment monitoring sensors (121) are provided inside both the static monitoring box (20) and the dynamic monitoring box (30).

[0089] A plurality of external environment monitoring sensors (122) are provided on the outside of the main body support housing (10).

[0090] The internal environment monitoring sensors (121) include a temperature sensor, a humidity sensor, and a pressure sensor.

[0091] The external environment monitoring sensors (122) include a temperature sensor, a humidity sensor, and a pressure sensor.

[0092] As Figure 4 shown, the static monitoring box (20) is composed of a static box ring shell (21) that penetrates vertically and a static box end shell (22) that is slidably connected to the outside of the static box ring shell (21) and has an opening facing downwards.

[0093] A static box outer support plate (211) is fixed to the outside of the static box ring shell (21). A static box lifting fixed cylinder (231) with an upward opening is fixed to the top of the static box outer support plate (211). A static box lifting sliding cylinder (232) is slidably connected inside the static box lifting fixed cylinder (231). The top end of the static box lifting sliding cylinder (232) is fixedly connected to the static box end shell (22).

[0094] A static box lifting drive rod (233) for driving the lifting movement of the static box lifting sliding cylinder (232) is provided inside the static box lifting fixed cylinder (231). The static box lifting drive rod (233) is an electric control telescopic rod driven by a servo motor in the prior art. The outer rod end of the static box lifting drive rod (233) is fixedly connected to the inner bottom of the static box lifting fixed cylinder (231). The inner rod end of the static box lifting drive rod (233) is fixedly connected to the inner top of the static box lifting sliding cylinder (232).

[0095] As Figure 4 shown, a static ground insertion structure (24) is provided on the outside of the static box ring shell (21). The static ground insertion structure (24) includes a static ground insertion mating ring (241) that is coaxially and slidably connected to the outside of the static box ring shell (21).

[0096] A static ground insertion fixing cylinder (242) with a downward opening is fixed to the bottom of the static outer support plate (211). A static ground insertion sliding cylinder (243) with an upward opening is slidably connected inside the static ground insertion fixing cylinder (242). The lower end of the static ground insertion sliding cylinder (243) is fixedly connected to the static ground insertion mating ring (241).

[0097] A static ground insertion driving rod (244) for driving the lifting movement of the static ground insertion sliding cylinder (243) is provided inside the static ground insertion fixing cylinder (242). The static ground insertion driving rod (244) is an electric control telescopic rod of the prior art. The outer rod end of the static ground insertion driving rod (244) is fixedly connected to the inner top of the static ground insertion fixing cylinder (242), and the inner rod end of the static ground insertion driving rod (244) is fixedly connected to the inner bottom of the static ground insertion sliding cylinder (243).

[0098] As Figure 7 shown, the dynamic monitoring box (30) is composed of a vertically penetrating dynamic box ring shell (31) and a dynamic box end shell (32) slidably connected to the outside of the dynamic box ring shell (31) and having a downward opening;

[0099] A dynamic box outer support plate (311) is fixed to the outside of the dynamic box ring shell (31). A dynamic box lifting fixing cylinder (331) with an upward opening is fixed to the top of the dynamic box outer support plate (311). A dynamic box lifting sliding cylinder (332) is slidably connected inside the dynamic box lifting fixing cylinder (331). The top end of the dynamic box lifting sliding cylinder (332) is fixedly connected to the dynamic box end shell (32);

[0100] A dynamic box lifting driving rod (333) for driving the lifting movement of the dynamic box lifting sliding cylinder (332) is provided inside the dynamic box lifting fixing cylinder (331). The dynamic box lifting driving rod (333) is an electric control telescopic rod driven by a servo motor in the prior art. The outer rod end of the dynamic box lifting driving rod (333) is fixedly connected to the inner bottom of the dynamic box lifting fixing cylinder (331), and the inner rod end of the dynamic box lifting driving rod (333) is fixedly connected to the inner top of the dynamic box lifting sliding cylinder (332).

[0101] As Figure 7 shown, a dynamic ground insertion structure (34) is provided on the outside of the dynamic box ring shell (31). The dynamic ground insertion structure (34) includes a dynamic ground insertion mating ring (341) slidably connected coaxially to the outside of the dynamic box ring shell (31);

[0102] The bottom of the dynamic outer support plate (311) is fixed with a dynamic ground-inserting fixing cylinder (342) with a downward opening. A dynamic ground-inserting sliding cylinder (343) with an upward opening is slidably connected inside the dynamic ground-inserting fixing cylinder (342). The lower end of the dynamic ground-inserting sliding cylinder (343) is fixedly connected to the dynamic ground-inserting mating ring (341).

[0103] Inside the dynamic ground-inserting fixing cylinder (342), there is a dynamic ground-inserting driving rod (344) for driving the lifting movement of the dynamic ground-inserting sliding cylinder (343). The dynamic ground-inserting driving rod (344) is an electric control telescopic rod of the prior art. The outer rod end of the dynamic ground-inserting driving rod (344) is fixedly connected to the inner top of the dynamic ground-inserting fixing cylinder (342), and the inner rod end of the dynamic ground-inserting driving rod (344) is fixedly connected to the inner bottom of the dynamic ground-inserting sliding cylinder (343).

[0104] As Figure 8 shown, inside the dynamic monitoring box (30), there is an air supply balancing mechanism (35). The air supply balancing mechanism (35) includes an air supply balancing input ring shell (351) that is fixed on the inner side wall of the dynamic box ring shell (31) and is annular and hollow. The top of the air supply balancing input ring shell (351) is fixed with a plurality of air supply balancing delivery pipes (352) that are connected to its interior. The side wall of the air supply balancing delivery pipe (352) has a plurality of air supply discharge holes (353) that communicate inside and outside.

[0105] Inside the dynamic box ring shell (31), there is an air flow outer discharge collecting pipe (354) that extends vertically coaxially with it. The side wall of the air flow outer discharge collecting pipe (354) has a plurality of outer discharge collecting through holes (355) that communicate inside and outside. The interior of the air flow outer discharge collecting pipe (354) is connected to the dynamic sampling output pipe (32).

[0106] As Figure 4 shown, on the top of the static monitoring box (20), there is a static pressure balancing mechanism (25). As Figure 5 shown, the static pressure balancing mechanism (25) includes a pressure balancing connecting pipe (251) that is fixed on the top of the static box end shell (22) and is connected to its interior. The outer end of the pressure balancing connecting pipe (251) is fixed with a pressure balancing fixing cylinder (252) with one end open. Inside the pressure balancing fixing cylinder (252), there is a pressure balancing sliding cylinder (253) that slides in a direction facing its opening.

[0107] Inside the pressure balancing sliding cylinder (253), there is a pressure balancing film (254). The outer end of the pressure balancing sliding cylinder (253) is fixed with a pressure balancing balancing pipe (255) that is connected to its interior. The pressure balancing balancing pipe (255) is provided with a balancing control valve (256).

[0108] An equilibrium air pressure sensor (250) is fixedly installed inside the pressure equilibrium sliding cylinder (253);

[0109] A laser distance measuring sensor (257) is fixedly installed at the inner end of the pressure equilibrium sliding cylinder (253);

[0110] Outside the pressure equilibrium fixed cylinder (252), an equilibrium driving fixed cylinder (258) which is arranged in parallel with it and has the same opening direction is fixedly installed. An equilibrium driving sliding cylinder (259) is slidably connected inside the equilibrium driving fixed cylinder (258). The outer end of the equilibrium driving sliding cylinder (259) is fixedly connected to the pressure equilibrium sliding cylinder (253);

[0111] An equilibrium driving telescopic rod (2580) for driving the equilibrium driving sliding cylinder (259) to move is arranged inside the equilibrium driving fixed cylinder (258). The equilibrium driving telescopic rod (2580) is an electric control telescopic rod driven by a servo motor in the prior art. The outer rod end of the equilibrium driving telescopic rod (2580) is fixedly connected to the inner end of the equilibrium driving fixed cylinder (258), and the inner rod end of the equilibrium driving telescopic rod (2580) is fixedly connected to the inner end of the equilibrium driving sliding cylinder (259).

[0112] As Figure 3 、 Figure 6 shown, a plurality of electric heating sheets (40) are fixedly installed on the inner side walls of the ring shells of the static box ring shell (21) and the dynamic box ring shell (31).

[0113] As Figure 3 、 Figure 6 shown, humidification communication pipes (50) that are internally and externally connected are fixedly installed on the tops of the static box end shell (22) and the dynamic box end shell (32). As Figure 2 shown, a humidifier (51) is arranged inside the air supply accommodating box (11). The output end of the humidifier (51) is connected to the humidification communication pipe (50). A humidification control valve (501) is provided on the humidification communication pipe (50);

[0114] The humidifier (51) is an ultrasonic humidifier in the prior art.

[0115] Electric control valves for independently controlling the on-off of each pipeline are provided on the static sampling output pipe (201), the dynamic box input pipe (301), the dynamic sampling output pipe (302), and the pressure equilibrium communication pipe (251).

[0116] Embodiment 2:

[0117] This embodiment describes a method for monitoring the vertical upward migration flux of soil vapor. Based on the soil vapor vertical upward migration flux monitoring device in Embodiment 1 above, it includes the following steps:

[0118] S1. Clean the monitoring point:

[0119] Clean the land at the monitoring point, remove stones and sundries, and make the land surface flat;

[0120] S2. Fix the monitoring equipment:

[0121] Place the monitoring device on the cleaned land, and insert the static ground insertion mating ring (241) and the dynamic ground insertion mating ring (341) into the soil,

[0122] A static monitoring chamber and a dynamic monitoring chamber are respectively formed between the static monitoring box (20) and the dynamic monitoring box (30) and the ground surface;

[0123] Test the airtightness of the static monitoring chamber and the dynamic monitoring chamber by the flue gas detection method;

[0124] S3. Adjust environmental parameters:

[0125] The external environmental monitoring sensor (122) outside the main body support housing (10) can obtain the external temperature, humidity and air pressure parameters, and the internal environmental monitoring sensors (121) inside the static monitoring box (20) and the dynamic monitoring box (30) can obtain the temperature, humidity and air pressure parameters inside them respectively. Adjust the temperature, humidity and air pressure parameters inside the static monitoring box (20) and the dynamic monitoring box (30) to make the temperature, humidity and air pressure inside the static monitoring box (20) and the dynamic monitoring box (30) consistent with the outside;

[0126] S4. Dynamic measurement:

[0127] The dynamic gas cylinder (303) contains nitrogen, and the nitrogen is continuously input into the dynamic monitoring box (30) through the dynamic box input pipe (301). The constantly input nitrogen is discharged from the dynamic sampling output pipe (302) together with the soil vapor;

[0128] Sample from the output end of the dynamic sampling output pipe (302) to measure the initial concentration of the soil vapor;

[0129] The dynamic monitoring box (30) determines the sampling time by controlling the inlet and outlet flow rates, then samples from the dynamic sampling output pipe (302) and sends the sample for inspection. During sampling, the temperature and pressure changes inside and outside the dynamic monitoring box (30) are monitored in real time and adjusted to keep the temperature and pressure inside and outside the dynamic monitoring box (30) consistent;

[0130] The dynamic measurement uses the following formula to calculate the flux;

[0131]

[0132] Where: Fluxa is the soil gas volatilization flux, with the unit of μg / m 2 min; C o is the pollutant concentration at the dynamic monitoring outlet, with the unit of μg / m 3 ; Q is the purge flow rate of the dynamic monitoring chamber, with the unit of m 3 / min; A chamber is the floor area of the dynamic monitoring chamber, with the unit of m 2 ;

[0133] S5. Static determination:

[0134] According to actual requirements, the static monitoring box (20) samples and sends the samples for inspection through the static sampling output pipe (201) by adjusting the sampling time, sampling interval, and sampling volume;

[0135] The static determination uses the following formula to calculate the flux;

[0136]

[0137] In the formula: Flux s is the soil gas volatilization flux, with the unit of μg / m 2 h; C chamber is the pollutant concentration in the static monitoring chamber, with the unit of μg / m 3 ; V chamber is the volume of the static monitoring chamber, with the unit of m 3 ; A chamber is the floor area of the static monitoring chamber, with the unit of m 2 ; T is the installation time of the monitoring equipment, with the unit of min;

[0138] Considering that the flux difference varies greatly due to different degrees of soil and groundwater pollution, when the static chamber is larger than the dynamic chamber, static data is used; otherwise, dynamic data is used, and the maximum flux is selected.

[0139] In the actual application process of the present invention, in step S4, the nitrogen in the dynamic gas cylinder (303) first enters the gas supply equalization input ring shell (351) through the dynamic box input pipe (301). The nitrogen in the gas supply equalization input ring shell (351) then enters each gas supply equalization delivery pipe (352). The nitrogen in each gas supply equalization delivery pipe (352) is then discharged through a plurality of gas supply discharge holes (353). The discharged nitrogen flows from the outer edge to the center in the dynamic monitoring box (30). The constantly input nitrogen, mixed with soil vapor, enters the gas flow outer discharge collection pipe (354) through a plurality of outer discharge collection through holes (355). The mixture of nitrogen and soil vapor concentrated in the gas flow outer discharge collection pipe (354) is finally discharged through the dynamic sampling output pipe (32).

[0140] The air supply balancing mechanism (35) can promote gas circulation more stably and efficiently, ensure that the gas in the box can be updated quickly and evenly, reduce gas retention and local concentration differences, and improve the accuracy and stability of measurement;

[0141] In the actual application process of the present invention, in step S5, due to the continuous output of soil vapor, the air pressure inside the static monitoring box (20) will be slightly higher than the external air pressure. And due to the continuous output of soil vapor, when the pollutant concentration in the static monitoring box (20) accumulates to a relatively high concentration, it will have a significant hindering effect on the upward mass transfer of pollutants, thus leading to an underestimation of the true mass transfer flux;

[0142] By using the static pressure balancing mechanism (25), it can accurately balance the air pressure inside and outside the static monitoring box (20), and can play a certain compensating role in the hindering phenomenon caused by this concentration difference, reducing the measurement error;

[0143] During the process of balancing the air pressure, the trimming control valve (256) is in an open state. An external communication chamber is formed between the pressure balancing film (254) and the pressure balancing sliding cylinder (253), and a static communication chamber is formed between the pressure balancing film (254) and the pressure balancing fixed cylinder (252). The external communication chamber is connected to the outside through the pressure balancing trimming pipe (255), and the static communication chamber is connected to the inside of the static monitoring box (20) through the pressure balancing connecting pipe (251);

[0144] The laser distance measuring sensor (257) is used to monitor the undulating changes of the pressure balancing film (254), so as to achieve the purpose of monitoring the air pressure on both sides of the pressure balancing film (254). Set the value monitored by the laser distance measuring sensor (257) when the air pressure on both sides of the pressure balancing film (254) is balanced as D. When D decreases, it indicates that the air pressure in the static communication chamber is higher than that in the external communication chamber. When D increases, it indicates that the air pressure in the external communication chamber is higher than that in the static communication chamber;

[0145] When D decreases, the inner rod of the balancing driving telescopic rod (2580) extends and drives the pressure balancing sliding cylinder (253) to move outward in the pressure balancing fixed cylinder (252) through the balancing driving sliding cylinder (259), increasing the volume of the static communication chamber, so as to achieve the purpose of balancing the air pressure on both sides of the pressure balancing film (254);

[0146] When D increases, the inner rod of the balancing driving telescopic rod (2580) retracts and drives the pressure balancing sliding cylinder (253) to move inward in the pressure balancing fixed cylinder (252) through the balancing driving sliding cylinder (259), reducing the volume of the static communication chamber, so as to achieve the purpose of balancing the air pressure on both sides of the pressure balancing film (254);

[0147] In the actual application process of the present invention, it can simulate the true flux of an actual residence. First, the ventilation rate of the house to be simulated is obtained, and the dynamic measurement in step S4 of Embodiment 2 is adopted. The dynamic monitoring chamber (30) obtains the number of air changes in the simulated room by controlling the flow rate discharged from the dynamic sampling output pipe (302), and then calculates the actual flux using the dynamic measurement formula in step S4.

[0148] Test Example 1:

[0149] In the actual application process, conditions such as the type, concentration, vertical distribution depth of pollutants, soil porosity, temperature, and wind speed will all affect the vertical upward migration rate of soil vapor. Therefore, the parameters provided in this test example only represent one actual situation, and for the selection of actual monitored parameters, those skilled in the art need to make flexible adjustments according to on-site conditions and actual requirements;

[0150] (1) In the dynamic measurement, the dynamic monitoring chamber is set to be 0.03 m 3 ;

[0151] The floor area of the dynamic monitoring chamber is 0.13 m 2 ;

[0152] The purge flow rate of the dynamic monitoring chamber is 5 L / min;

[0153] The theoretical residence time is the ratio of the chamber volume to the flow rate. Assuming that equilibrium is reached after mixing 5 times, it takes 30 min;

[0154] The result is: the total non-methane concentration is 486.603 μg / m 3 ;

[0155] Using the dynamic measurement formula, the total non-methane flux is calculated to be 18.715 μg / m 2 min.

[0156] (2) In the static measurement, the volume of the static monitoring chamber is set to be 0.03 m 3 ;

[0157] The floor area of the static monitoring chamber is 0.13 m 2 ;

[0158] The sampling interval is 2,880 min;

[0159] The sampling volume is 1 L;

[0160] The total non-methane concentration is 145,304 μg / m 3 ;

[0161] Using the static measurement formula, the total non-methane flux is calculated to be 11.643 μg / m 2 min.

Claims

1. A device for monitoring the vertical upward migration flux of soil vapor, characterized in that, It includes a main body support housing (10) with an opening facing downwards, and a static monitoring box (20) with an opening facing downwards and a dynamic monitoring box (30) with an opening facing downwards are fixed inside the main body support housing (10); A static sampling output pipe (201) communicating with the inside is provided outside the static monitoring box (20), the static sampling output pipe (201) extends outside the main body support housing (10), and a first flowmeter (2010) is provided on the static sampling output pipe (201); A dynamic box input pipe (301) communicating with the inside is provided outside the dynamic monitoring box (30), a dynamic sampling output pipe (302) communicating with the inside is provided outside the dynamic monitoring box (30), the dynamic sampling output pipe (302) extends outside the main body support housing (10), and a second flowmeter (3020) is provided on the dynamic sampling output pipe (302); A gas supply accommodation box (11) is fixed outside the main body support housing (10), a dynamic gas cylinder (303) is provided inside the gas supply accommodation box (11), the dynamic box input pipe (301) is communicated with the output end of the dynamic gas cylinder (303), and a third flowmeter (304) and a gas supply regulating valve (305) are provided on the dynamic box input pipe (301); A plurality of internal environment monitoring sensors (121) are provided inside both the static monitoring box (20) and the dynamic monitoring box (30); A plurality of external environment monitoring sensors (122) are provided outside the main body support housing (10).

2. The soil vapor vertical upward migration flux monitoring device according to claim 1, characterized in that, The static monitoring box (20) is composed of a vertically penetrating static box ring shell (21) and a static box end shell (22) which is slidably connected to the outside of the static box ring shell (21) and has an opening facing downwards; A static box outer support plate (211) is fixed outside the static box ring shell (21), a static box lifting and fixing cylinder (231) with an opening facing upwards is fixed on the top of the static box outer support plate (211), a static box lifting and sliding cylinder (232) is slidably connected inside the static box lifting and fixing cylinder (231), and the top end of the static box lifting and sliding cylinder (232) is fixedly connected to the static box end shell (22); A static box lifting driving rod (233) for driving the lifting movement of the static box lifting and sliding cylinder (232) is provided inside the static box lifting and fixing cylinder (231).

3. The soil vapor vertical upward migration flux monitoring device according to claim 2, wherein A static ground insertion structure (24) is provided outside the static box ring shell (21), and the static ground insertion structure (24) includes a static ground insertion mating ring (241) slidably connected coaxially outside the static box ring shell (21); A static ground insertion fixing cylinder (242) with an opening facing downwards is fixed at the bottom of the static box outer support plate (211), a static ground insertion sliding cylinder (243) with an opening facing upwards is slidably connected inside the static ground insertion fixing cylinder (242), and the lower end of the static ground insertion sliding cylinder (243) is fixedly connected to the static ground insertion mating ring (241); A static ground insertion driving rod (244) for driving the lifting movement of the static ground insertion sliding cylinder (243) is provided inside the static ground insertion fixing cylinder (242).

4. The soil vapor vertical upward migration flux monitoring device according to claim 1, characterized in that The dynamic monitoring box (30) is composed of a vertically penetrating dynamic box ring shell (31) and a dynamic box end shell (32) which is slidably connected to the outside of the dynamic box ring shell (31) and has an opening facing downwards; A dynamic box outer support plate (311) is fixed to the outside of the dynamic box ring shell (31). A dynamic box lifting fixed cylinder (331) with an opening facing upwards is fixed to the top of the dynamic box outer support plate (311). A dynamic box lifting sliding cylinder (332) is slidably connected inside the dynamic box lifting fixed cylinder (331). The top end of the dynamic box lifting sliding cylinder (332) is fixedly connected to the dynamic box end shell (32); A dynamic box lifting driving rod (333) for driving the dynamic box lifting sliding cylinder (332) to lift and move is provided inside the dynamic box lifting fixed cylinder (331).

5. The soil vapor vertical upward migration flux monitoring device according to claim 4, characterized in that, A dynamic ground insertion structure (34) is provided on the outside of the dynamic box ring shell (31). The dynamic ground insertion structure (34) includes a dynamic ground insertion mating ring (341) that is coaxially and slidably connected to the outside of the dynamic box ring shell (31); A dynamic ground insertion fixed cylinder (342) with an opening facing downwards is fixed to the bottom of the dynamic box outer support plate (311). A dynamic ground insertion sliding cylinder (343) with an opening facing upwards is slidably connected inside the dynamic ground insertion fixed cylinder (342). The lower end of the dynamic ground insertion sliding cylinder (343) is fixedly connected to the dynamic ground insertion mating ring (341); A dynamic ground insertion driving rod (344) for driving the dynamic ground insertion sliding cylinder (343) to lift and move is provided inside the dynamic ground insertion fixed cylinder (342).

6. The vertical upward migration flux monitoring device for soil vapor according to claim 1, characterized in that An air supply balancing mechanism (35) is provided inside the dynamic monitoring box (30). The air supply balancing mechanism (35) includes an air supply balancing input ring shell (351) which is fixed to the inner side wall of the dynamic box ring shell (31) and is annular and hollow. A plurality of air supply balancing delivery pipes (352) which are connected to its interior are fixed to the top of the air supply balancing input ring shell (351). A plurality of air supply discharge holes (353) that communicate inside and outside are provided on the side wall of the air supply balancing delivery pipe (352); An air flow outer discharge collecting pipe (354) which extends vertically and coaxially with the dynamic box ring shell (31) is provided inside the dynamic box ring shell (31). A plurality of outer discharge collecting through holes (355) that communicate inside and outside are provided on the side wall of the air flow outer discharge collecting pipe (354). The interior of the air flow outer discharge collecting pipe (354) is connected to the dynamic sampling output pipe (32).

7. A soil vapor vertical upward migration flux monitoring device according to claim 1, characterized in that, A static pressure balancing mechanism (25) is provided on the top of the static monitoring box (20). The static pressure balancing mechanism (25) includes a pressure balancing connecting pipe (251) which is fixed to the top of the static box end shell (22) and is connected to its interior. The outer end of the pressure balancing connecting pipe (251) is fixed with a pressure balancing fixed cylinder (252) with one end open. A pressure balancing sliding cylinder (253) facing the opening is slidably connected inside the pressure balancing fixed cylinder (252); A pressure equalizing film (254) is fixed inside the pressure equalizing sliding cylinder (253). A pressure equalizing balancing pipe (255) connected to its interior is fixed to the outer end of the pressure equalizing sliding cylinder (253). A balancing control valve (256) is provided on the pressure equalizing balancing pipe (255); An equalizing air pressure sensor (250) is fixed inside the pressure equalizing sliding cylinder (253); A laser ranging sensor (257) is fixed to the inner end of the pressure equalizing sliding cylinder (253); An equalizing driving fixed cylinder (258) arranged in parallel with and having the same opening direction as the pressure equalizing fixed cylinder (252) is fixed to the outside of the pressure equalizing fixed cylinder (252). An equalizing driving sliding cylinder (259) is slidably connected inside the equalizing driving fixed cylinder (258). The outer end of the equalizing driving sliding cylinder (259) is fixedly connected to the pressure equalizing sliding cylinder (253); An equalizing driving telescopic rod (2580) for driving the equalizing driving sliding cylinder (259) to move is provided inside the equalizing driving fixed cylinder (258).

8. The soil vapor vertical upward migration flux monitoring device according to claim 1, characterized in that Multiple electric heating sheets (40) are fixed to the inner side walls of the ring shells of the static box ring shell (21) and the dynamic box ring shell (31).

9. The soil vapor vertical upward migration flux monitoring device according to claim 1, characterized in that Humidifying communication pipes (50) communicating inside and outside are fixed to the tops of the static box end shell (22) and the dynamic box end shell (32). A humidifier (51) is provided inside the air supply accommodating box (11). The output end of the humidifier (51) is connected to the humidifying communication pipe (50). A humidifying control valve (501) is provided on the humidifying communication pipe (50).

10. A method for monitoring the vertical upward migration flux of soil vapor, based on the device for monitoring the vertical upward migration flux of soil vapor according to any one of claims 1 to 9 above, characterized in that, It includes the following steps: S1. Clean the monitoring point: Clean the land at the monitoring point, remove stones and sundries to make the land surface flat; S2. Fix the monitoring equipment: Place the monitoring device on the cleaned land, insert the static ground insertion matching ring (241) and the dynamic ground insertion matching ring (341) into the soil, A static monitoring chamber and a dynamic monitoring chamber are formed between the static monitoring box (20) and the ground surface and between the dynamic monitoring box (30) and the ground surface respectively; Test the airtightness of the static monitoring chamber and the dynamic monitoring chamber by the flue gas detection method; S3. Adjust the environmental parameters: The external environmental monitoring sensor (122) outside the main body support housing (10) can obtain the external temperature, humidity and air pressure parameters. The internal environmental monitoring sensors (121) inside the static monitoring box (20) and the dynamic monitoring box (30) can obtain the temperature, humidity and air pressure parameters inside them respectively. Adjust the temperature, humidity and air pressure parameters inside the static monitoring box (20) and the dynamic monitoring box (30) to make the temperature, humidity and air pressure inside the static monitoring box (20) and the dynamic monitoring box (30) the same as the outside; S4. Dynamic measurement: Nitrogen is contained in the dynamic gas cylinder (303). The nitrogen is continuously input into the dynamic monitoring box (30) through the dynamic box input pipe (301). The constantly input nitrogen is discharged from the dynamic sampling output pipe (302) together with the soil vapor; Sample from the output end of the dynamic sampling output pipe (302) and measure the initial concentration of the soil vapor; The dynamic monitoring box (30) determines the sampling time by controlling the flow rates of the inlet and outlet, then samples from the dynamic sampling output pipe (302) and sends the sample for inspection. During sampling, the temperature and pressure changes inside and outside the dynamic monitoring box (30) are monitored in real time and adjustments are made to keep the temperature and pressure inside and outside the dynamic monitoring box (30) consistent; For dynamic determination, the flux is calculated using the following formula; Where: Flux a is the soil gas volatilization flux, with the unit of μg / m 2 min; C o is the pollutant concentration at the dynamic monitoring outlet, with the unit of μg / m 3 ; Q is the purge flow rate of the dynamic monitoring chamber, with the unit of m 3 / min; A chamber is the floor area of the dynamic monitoring chamber, with the unit of m 2 ; S5. Static determination: According to actual requirements, the static monitoring box (20) samples and sends the sample for inspection through the static sampling output pipe (201) by adjusting the sampling time, sampling interval, and sampling volume; For static determination, the flux is calculated using the following formula; Where: Flux s is the soil gas volatilization flux, with the unit of μg / m 2 min; C chamber is the pollutant concentration in the static monitoring chamber, with the unit of μg / m 3 ; V chamber is the volume of the static monitoring chamber, with the unit of m 3 ; A chamber is the floor area of the static monitoring chamber, with the unit of m 2 ; T is the installation time of the monitoring device, in minutes; Considering that the flux differences vary greatly due to different degrees of soil and groundwater pollution, when the static chamber is larger than the dynamic chamber, static data is used, and vice versa, and the maximum flux is selected.

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