Bioaerosol and volatile organic compound generation, balance and co-exposure system and use method thereof

Abstract

The invention discloses a bioaerosol and volatile organic compound generation, equilibrium and co-exposure system and a use method thereof. The system comprises a co-exposure balance box, a volatile organic compound gas balance box, a biological aerosol balance box, a biological aerosol collection device and the like, wherein the volatile organic compound gas balance box and the biological aerosol balance box are connected with the co-exposure balance box through a pipeline system. By utilizing the system, the generation balance of multi-component multi-gradient VOCs and multi-type multi-concentration biological aerosols can be quickly controlled in real time by regulating and controlling the gas path ratio of the VOCs gas to the biological aerosols and changing the types and concentrations of microorganisms and VOCs in the biological aerosols, so that the real-time regulation and control of the VOCs exposed biological aerosols are realized; the release of different concentrations, different types and various VOCs and the generation of different types of biological aerosols in different natural scenes are simulated, so that the interaction between the VOCs and the biological aerosols is evaluated, and the subsequent treatment of the VOCs and the biological aerosols is facilitated.

Description

Technical Field

[0001] The present invention belongs to the field of ecological environment technology, and more specifically, relates to a system for generating, balancing and co-exposure of bioaerosols and volatile organic compounds and a method for using the system. Background Art

[0002] Bioaerosol refers to aerosol containing biological ions such as bacteria and viruses. In addition to the characteristics of general aerosols, it is also prone to cause a variety of respiratory diseases. Volatile organic compounds (VOCs) include industrially produced halogenated hydrocarbons, unsaturated hydrocarbons caused by incomplete combustion, and benzene series, which can damage the nervous system and organs such as the liver and kidneys.

[0003] Bioaerosol and VOCs pollution are the focus of researchers in the field of atmospheric environmental science. However, this field currently usually only evaluates the emission characteristics of bioaerosols or VOCs, and evaluates their health risks through the emission content and type of single bioaerosols and VOCs. The interaction mechanism between bioaerosols and VOCs is unknown, and there are few reports on the interaction between VOCs and bioaerosols. However, in the fields of urban domestic waste disposal, sewage treatment and industrial production, bioaerosols and VOCs are usually released simultaneously. For example, in the process of aeration treatment in sewage treatment plants and garbage decomposition in landfills, not only a large amount of VOCs with pungent odors will be produced, but also a large amount of bioaerosols containing pathogens such as Staphylococcus aureus, Escherichia coli, Legionella, Salmonella, Mycobacterium tuberculosis, etc. will be released. Such mixed pollutants will spread to the surrounding environment with the diffusion of the atmosphere and the influence of meteorological conditions, bringing adverse effects on human health.

[0004] When bioaerosols and VOCs coexist, on the one hand, microorganisms and VOCs will affect each other, and exploring the mutual influence between the two is conducive to the subsequent treatment of their mixed pollutants; on the other hand, VOCs will select and cause microbial evolution as an environmental stressor, leading to more serious health risks. In addition to short-term observations of the mutual influence between the two, their long-term effects need to be evaluated to avoid greater safety hazards. Although there are reports of equipment that can capture aerosols and VOCs at the same time, it is only for collection and cannot be used to observe the mutual influence of bioaerosols and VOCs. That is, there is a lack of available equilibrium exposure systems for the co-occurrence of bioaerosols and volatile organic compounds. Summary of the invention

[0005] In view of the technical problems existing in the above-mentioned prior art, the present invention provides a bioaerosol and volatile organic compound co-generation, balance and exposure system and a use method thereof.

[0006] The first object of the present invention is to provide a generation, balance and co-exposure system for bioaerosols and volatile organic compounds.

[0007] A second object of the present invention is to provide applications of the system.

[0008] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0009] The present invention provides a system for the generation, balance and co-exposure of bioaerosols and volatile organic compounds (VOCs). The system of the present invention can simulate the co-generation and dynamic balance of bioaerosols and VOCs of different types and concentrations, and can flexibly adjust the types, exposure concentrations and exposure time of VOCs to construct a VOCs exposure bioaerosol interaction system, and realize the physiological state activity evaluation research of bioaerosols under VOCs exposure, so as to facilitate the treatment of mixed pollutants of bioaerosols and VOCs.

[0010] Specifically, the bioaerosol and volatile organic compound generation, balance and co-exposure system of the present invention comprises a co-exposure balance box, a volatile organic compound gas balance box and a bioaerosol balance box respectively connected to the co-exposure balance box through a pipeline system, and a control device for controlling the operation of the system;

[0011] The pipeline system includes input paths connected to the volatile organic compound gas balance box and the bioaerosol balance box respectively, and output paths connecting the volatile organic compound gas balance box and the bioaerosol balance box to the co-exposure balance box respectively; the input paths are sequentially provided with an air compressor, a flow controller and an air filter, the input path connected to the volatile organic compound gas balance box is also provided with a volatile organic compound generator, and the input path connected to the bioaerosol balance box 3 is also provided with a bioaerosol generator;

[0012] The co-exposure balance box is also connected to a bioaerosol collection device; the volatile organic compound gas balance box is also connected to a volatile organic compound detector; the bioaerosol balance box 3 is also connected to a bioaerosol particle real-time monitor.

[0013] Specifically, in the pipeline system, the input path and / or the output path contains at least one branch. That is, in the most basic pipeline system of the present invention, the input path and the output path only contain one passage, but for the purpose of increasing flow, technicians can add branches.

[0014] For example, in a specific embodiment of the present invention, the input path in the pipeline system includes at least one branch. Specifically, the branch of the input path is separated from the air compressor, and a flow controller and an air filter are sequentially arranged on the branch. The branch is used to input clean air into the balance box connected thereto, so as to dilute or adjust the concentration of bioaerosol or VOCs gas.

[0015] Optionally, the addition of branches in the pipeline system is achieved by using a multi-way pipe and a connector connected to the multi-way pipe, which can flexibly adjust the number of channels of the input or output path to construct a branch pipeline system.

[0016] Specifically, the pipeline system is also provided with an air valve for controlling the inflow and outflow of aerosol or gas.

[0017] Optionally, the air valve is a ball gate air valve.

[0018] Specifically, each pipeline in the pipeline system is connected to the box through a fluid inlet and outlet.

[0019] Specifically, the co-exposure balance box, the volatile organic compound gas balance box and the bioaerosol balance box are all provided with a turbulent device.

[0020] Specifically, the co-exposure balance box, the volatile organic compound gas balance box and the bioaerosol balance box are all provided with exhaust pressure relief devices.

[0021] Optionally, the disturbance device is a fan, which is arranged inside the balance box, and disturbs the gas inside the balance box so that VOCs and bioaerosols are quickly and evenly distributed in the balance box.

[0022] Optionally, the fan is a magnetic fan.

[0023] Preferably, the fan blades are covered with an anti-stick coating, which can reduce the adhesion / adsorption of microorganisms and VOCs, reduce the loss of bioaerosols and VOCs, and maintain the activity of bioaerosols.

[0024] Similarly, the inner wall of each balancing box is covered with an anti-stick coating.

[0025] Optionally, the coating is a polytetrafluoroethylene coating or a silicone coating.

[0026] Optionally, the exhaust pressure relief device is an exhaust pressure relief valve; a portion of the gas is discharged through the exhaust pressure relief valve to control the air pressure in the balance box, and the exhausted VOCs and bioaerosols are discharged after being harmlessly treated.

[0027] Specifically, the bioaerosol generator is a liquid microbial aerosol generator.

[0028] Optionally, the liquid microbial aerosol generator is a three-hole bioaerosol generator, a six-hole bioaerosol generator or a twenty-four-hole bioaerosol generator.

[0029] Specifically, the VOCs detector is connected to the box body through the fluid inlet and outlet (used as a sampling port, hereinafter referred to as the sampling port for easy distinction) provided on the box body and is used to monitor the concentration of VOCs in the VOCs balance box in real time, and monitor whether the balance box is in a balanced state; similarly, the bioaerosol particle real-time monitor is also connected to the box body through the fluid inlet and outlet provided on the box body and is used to monitor the particle concentration of bioaerosol in real time, and is used to monitor whether the balance box is in a balanced state.

[0030] Specifically, when the detection readings of the VOCs detector at multiple sampling ports equidistantly distributed on the vertical side of the box remain stable and consistent, it indicates that the balance box is in a balanced state. Similarly, when the detection readings of the bioaerosol particle real-time monitor at multiple sampling ports equidistantly distributed on the vertical side of the box remain stable and consistent, it indicates that the balance box is in a balanced state.

[0031] Specifically, the number of the sampling ports is at least 3.

[0032] Specifically, the control device is a circuit control switch.

[0033] The present invention also provides a method for using the system, or a method for testing the interaction between microbial aerosol and volatile organic compounds using the system of the present invention, comprising the following steps:

[0034] S1. Add the solution of the volatile organic compound to be tested into the injection needle of the volatile organic compound generator, use the pipeline system to make the volatile organic compound generator generate volatile organic compounds and enter the volatile organic compound gas balance box, turn off the volatile organic compound generator after the box is full of volatile organic compounds, and wait for the volatile organic compounds in the box to enter dynamic equilibrium;

[0035] S2. Place the suspension of the microorganism to be tested in the liquid bottle of the bioaerosol generator, use the pipeline system to make the bioaerosol generator generate microbial aerosol and enter the bioaerosol balance box, turn off the bioaerosol generator after the box is filled with microbial aerosol, and wait for the aerosol in the box to be dynamically balanced;

[0036] S3. The dynamically balanced volatile organic compounds and microbial aerosols are simultaneously introduced into the co-exposure balance box through the output of the pipeline system for dynamic balance, and the microbial aerosol samples are collected and enriched by the bioaerosol collection device. The enriched microorganisms are gradiently diluted and plated for culture, and the culturable number of microorganisms in the sample is calculated based on the dilution multiple, and the changes in the culturable number of microorganisms are observed to observe the effect of volatile organic compounds on microbial aerosols;

[0037] The calculation formula for the culturable number is:

[0038]

[0039] Among them, C 液体浓度 The culturable number of microorganisms counted on a dilution plate.

[0040] Specifically, the preparation method of the microbial suspension is: inoculating the preserved microbial strain into the culture medium and culturing until the microorganism enters the logarithmic growth phase, centrifuging and discarding the supernatant, washing the precipitate with a buffer solution, and then re-vortexing with the buffer solution to obtain a microbial suspension, wherein the concentration of the microbial suspension is 0 to 10 10 CFU / mL.

[0041] Specifically, the buffer solution is a phosphate solution.

[0042] Specifically, in S3, the collected microbial aerosol sample is enriched by an ultrafiltration tube, and the enriched sample is eluted from the ultrafiltration membrane with physiological saline.

[0043] More specifically, the collected bioaerosol samples are enriched in a centrifugal ultrafiltration tube, centrifuged at 3000-6000× for 1-30 min, and the samples are eluted from the ultrafiltration membrane with a 0.9% saline solution.

[0044] Specifically, the microorganisms include bacteria, fungi and viruses.

[0045] Specifically, the bacteria are one or more of Escherichia coli, Bacillus, Bacillus aeruginosa, and Staphylococcus aureus.

[0046] Specifically, the constant flow rate described in S2 is 0 to 50 L / min, and the flushing time is 0 to 30 min.

[0047] Specifically, the VOCs are one or more of aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, oxygen-containing hydrocarbons, and organic sulfur hydrocarbons.

[0048] Specifically, the temperature of the generator in S2 is 0-300° C., the injection flow rate is 0-500 μL / min, and the constant flow rate is 0-100 L / min.

[0049] Specifically, the common equilibrium time in S3 is 0 to 120 minutes, and the collection time is 0 to 200 minutes.

[0050] Specifically, the sampler in S3 may be a liquid impact sampler. After the liquid impact sampler collects the sample, the bioaerosol sample is diluted with a 0.9% saline solution in a continuous gradient and incubated on a nutrient agar plate at 37° C. for 1 to 24 hours.

[0051] Specifically, the gradient dilution is performed at a volume ratio of 1:10.

[0052] The present invention has the following beneficial effects:

[0053] 1. The present invention provides a bioaerosol and volatile organic compound co-existence equilibrium exposure system including a co-exposure equilibrium box, a volatile organic compound gas equilibrium box and a bioaerosol equilibrium box connected to the co-exposure equilibrium box through a pipeline system, and a bioaerosol collection device. The system can be used to evaluate the interaction between VOCs and bioaerosols, so as to facilitate the subsequent treatment of VOCs and bioaerosols.

[0054] 2. Based on the system described in the present invention, by adjusting the gas path ratio of VOCs and bioaerosols, changing the type and concentration of VOCs and the release and atomization parameters of bioaerosols, the occurrence balance of multi-component and multi-gradient VOCs and multi-type and multi-concentration bioaerosols can be quickly controlled in real time, and real-time regulation of VOCs exposure to bioaerosols can be achieved. The release of different concentrations, types and multiple VOCs and the occurrence of different types of bioaerosols in natural scenes can be simulated, and real-time dynamic balance of bioaerosols and VOCs can be achieved. The effect of VOCs on bioaerosols in the natural environment can be systematically and completely evaluated.

[0055] 3. The system of the present invention is easy to operate, and the results obtained are accurate and intuitive, which is convenient for simulating the interaction between VOCs and bioaerosols in natural scenes (such as landfills, industrial emissions, sewage treatment plants, and nature). BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 Schematic diagram of the system described in Example 1 of the present invention; in the figure, 1 is a co-exposure balance box, 2 is a VOCs gas balance box, 3 is a bioaerosol balance box, 4 is a VOCs generator, 5 is a bioaerosol generator, 6 is a bioaerosol collection device, 7 is a VOCs detector, 8 is a bioaerosol particle real-time monitor, 9 is an air compressor, 10 is a turbulence device, 11 is a flow controller, 12 is an air filter, 13 is a fluid inlet and outlet, and 14 is an exhaust pressure relief valve.

[0057] Figure 2 Schematic diagram of the system described in Example 2 of the present invention; in the figure, 1 is a co-exposure balance box, 2 is a VOCs gas balance box, 3 is a bioaerosol balance box, 4 is a VOCs generator, 5 is a bioaerosol generator, 6 is a bioaerosol collection device, 7 is a VOCs detector, 8 is a bioaerosol particle real-time monitor, 9 is an air compressor, 10 is a turbulence device, 11 is a flow controller, 12 is an air filter, 13 is a fluid inlet and outlet, and 14 is an exhaust pressure relief valve.

[0058] Figure 3 Statistical chart of the culturable number of Escherichia coli bioaerosols exposed to different types of VOCs.

[0059] Figure 4 Figure 2 is a graph of the culturable number of Escherichia coli bioaerosols exposed to different concentrations of dimethyl trisulfide. DETAILED DESCRIPTION

[0060] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0061] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0062] Example 1

[0063] This embodiment provides a system for the generation, balance and co-exposure of bioaerosols and VOCs, the schematic diagram of which is as follows: Figure 1 As shown. Figure 1 It can be seen that the bioaerosol and volatile organic compound generation, balancing and co-exposure system of the present invention includes a co-exposure balance box 1, a volatile organic compound gas balance box 2 and a bioaerosol balance box 3 respectively connected to the co-exposure balance box 1 through a pipeline system, and a control device for controlling the operation of the system;

[0064] The pipeline system includes an input path connected to the volatile organic compound gas balance box 2 and the bioaerosol balance box 3 respectively, and an output path connecting the volatile organic compound gas balance box 2 and the bioaerosol balance box 3 to the co-exposure balance box 1 respectively; the input path is provided with an air compressor 9, a flow controller 11 and an air filter 12 in sequence, the input path connected to the volatile organic compound gas balance box 2 is also provided with a volatile organic compound generator 4, and the input path connected to the bioaerosol balance box 3 is also provided with a bioaerosol generator 5;

[0065] The co-exposure balance box 1 is connected to a bioaerosol collection device 6 and an exhaust pressure relief valve 14, and is provided with a flow disturbance device 10 therein; the volatile organic compound gas balance box 2 is connected to a volatile organic compound detector 7 and an exhaust pressure relief valve 14, and is provided with a flow disturbance device 10 therein; the bioaerosol balance box 3 is connected to a bioaerosol particle real-time monitor 8 and an exhaust pressure relief valve 14, and is provided with a flow disturbance device 10 therein.

[0066] In this embodiment, the flow disturbance device is a magnetic fan. At the same time, in order to reduce the adhesion / adsorption of microorganisms and VOCs, reduce the loss of bioaerosols and VOCs and maintain the activity of bioaerosols, this embodiment also coats the fan blades and the inner wall of each balance box with a polytetrafluoroethylene coating.

[0067] According to the functional division, the system of the present invention can be divided into a bioaerosol generation balance system, a VOCs gas generation balance system, a co-exposure balance system, a pipeline system for distributing air, and a control system. Through the bioaerosol generation balance system, the VOCs gas generation balance system obtains controllable and stable bioaerosols and VOCs gases, and through the co-exposure balance system, the environmental behavior, exposure, and prevention and control of bioaerosols under different concentrations and types and multiple VOCs exposure can be studied.

[0068] The bioaerosol generation balance system includes a bioaerosol generator 5, a pipeline system input line for conveying pure air to the bioaerosol generator 5, a bioaerosol balance box 3 connected to the bioaerosol generator 5, a bioaerosol particle real-time monitor 8 connected to the bioaerosol balance box 3, a turbulence device 10 arranged in the bioaerosol balance box 3, and a control device connected to the bioaerosol generator 5, the pipeline system, and the bioaerosol balance box 3. The input line of the pipeline system transports the filtered and disinfected clean air stably and evenly to the bioaerosol generator 5. The bioaerosol generator 5 evenly disperses the microbial suspension that maintains biological activity into the clean air to form an active bioaerosol. The generated bioaerosol is introduced into the bioaerosol balance box 3. The bioaerosol generator 5 can adjust the particle size distribution, concentration and population of the active bioaerosol in the system; the turbulence device 10 can make the aerosol in the bioaerosol balance box 3 flow to form a uniform and stable bioaerosol gas; the bioaerosol particle real-time monitor 8 connected to the bioaerosol balance box 3 can monitor the stable balance of the particle concentration of the bioaerosol in the bioaerosol balance box 3 in real time; the operation of the entire device is controlled and adjusted by the control device system. The vertical side of the bioaerosol balance box 3 is provided with at least three equidistantly distributed fluid inlets and outlets 13, which are used as sampling ports. The bioaerosol particle real-time monitor 8 is connected to the bioaerosol balance box 3 through the fluid inlets and outlets 13. When the detection readings of the bioaerosol particle real-time monitor 8 at each fluid inlet and outlet 13 are consistent, it indicates that the bioaerosol balance box 3 is in a balanced state.

[0069] The VOCs generation balance system includes a VOCs generator 4, a pipeline system input line for delivering clean air to the VOCs generator, a VOCs balance box 2 connected to the VOCs generator 4, a VOCs detector 7 connected to the VOCs balance box 2, a spoiler 10 provided on the VOCs balance box 2, and a control device connected to the VOCs generator 4, the pipeline system, and the VOCs balance box 2. The input line of the pipeline system delivers the filtered and disinfected clean air to the VOCs generator 4 in a stable and uniform manner. The VOCs generator 4 can heat up and gasify liquid organic matter to form VOCs gas. The generated VOCs are introduced into the VOCs balance box 2. The VOCs generator 4 can adjust the concentration and type of VOCs in the system by changing the amount, type and injection volume of liquid organic matter; the turbulence device 10 allows the aerosol in the VOCs balance box 2 to flow and form a uniform and stable VOCs gas; the VOCs detector 7 connected to the VOCs balance box 2 can monitor the stability of the VOCs concentration in the VOCs balance box in real time; and the operation of the entire device is controlled and adjusted by the control device system. Among them, the vertical side of the VOCs balance box 2 is provided with at least 3 equidistantly distributed fluid inlets and outlets 13, which are used as sampling ports. The VOCs detector 7 is connected to the VOCs balance box 2 through the fluid inlets and outlets 13. When the detection readings of the VOCs detector at each fluid inlet and outlet 13 are consistent, it indicates that the VOCs balance box 2 is in a balanced state.

[0070] The co-exposure balance system includes a co-exposure balance box 1 connected to a bioaerosol balance box 3 and a VOCs balance box 2, a turbulence device 10 arranged on the co-exposure balance box 1 for evenly distributing the aerosol and VOCs in the balance box, a fluid inlet and outlet 13 is arranged on a vertical side of the co-exposure balance box 1, and a bioaerosol collection device 6 connected to the fluid inlet and outlet 13 of the co-exposure balance box 1 is used to collect the bioaerosol after co-exposure for subsequent analysis.

[0071] The pipeline system includes an air compressor 9, a flow controller 11 connected to the air compressor 9 in sequence, and a high-efficiency air filter 12, and the high-efficiency air filter 12 is connected to the bioaerosol generator 5 and the VOCs generator 4 through an air quick connector. The air compressor 9 pumps in air, and the air pressure of the gas provided by the air compressor 9 is adjusted to be stable through the exhaust pressure relief valve 14. The flow rate of the incoming air entering the bioaerosol generator 5 or the VOCs generator 4 is changed through the flow controller 11, thereby adjusting the concentration of the bioaerosol generator 5 and the VOCs generator 4. The air filter 12 filters out pollutants such as dust, microorganisms and VOCs in the air to avoid contaminating the bioaerosols and VOCs in the bioaerosol balance box 3 and the VOCs balance box 2.

[0072] Example 2

[0073] Based on the system described in Example 1, this embodiment further improves it. Specifically, a branch with a flow controller 11 and a high-efficiency air filter 12 is added to the input of the pipeline system connected to the VOCs balance box 2 and the bioaerosol balance box 3 respectively. The branch is used to input clean air into the balance box connected to it, so as to adjust the concentration of bioaerosol or VOCs gas. The schematic diagram of the generation, balance and co-exposure system of bioaerosol and VOCs described in this embodiment is shown in FIG. Figure 2 shown.

[0074] Example 3

[0075] This example uses the system described in Example 2 to test the interaction between Escherichia coli and different types of VOCs, and also illustrates the method of using the system of the present invention, including the following steps:

[0076] S1. Pick the E. coli strain stored in the -80℃ ultra-low temperature refrigerator with an inoculation loop and inoculate it into the prepared 50mL nutrient broth medium, and culture it in a shaker at 37℃ and 140rpm until the E. coli is in the logarithmic growth phase; centrifuge the bacterial culture at 8000rpm for 2min, discard the supernatant, wash the bacterial precipitate twice with 0.9% NaCl solution, resuspend the bacterial precipitate, and adjust the bacterial concentration using an ELISA reader to make its OD600 1.0, indicating that the E. coli concentration at this time is 10 9 CFU / mL.

[0077] S2. Transfer the E. coli suspension prepared in S1 to the bioaerosol generator (six-nozzle Collison) in a clean workbench, adjust the relative height between the internal device of the generator and the liquid surface, and use clean air to aerosolize the bacterial suspension into the balance box at a flow rate of 12.5L / min. Connect the exhaust gas to an air microbial sampling pump, and pump the exhaust gas into the fume hood at the same flow rate of 12.5L / min to maintain a stable equilibrium in the balance box. Suspend the generated bioaerosol in the balance box, and continuously flush the entire system with bioaerosol for 5 minutes until the box is filled with bioaerosol.

[0078] S3. Take out 99% pure dimethyl trisulfide, dimethyl disulfide, formic acid and ethyl mercaptan liquid from a 4°C refrigerator, draw 5 mL of each with the injection needle of the VOCs generator, fix the injection needle horizontally on the base, set the injection needle aperture to 10 mm, set the VOC gas concentration to 140 ppm, connect the VOCs generator to the air pipeline of the air distribution system and check the air tightness and pipeline flow, then set the reactor temperature to the boiling point of VOCs, use clean air at a constant flow rate of 5 L / min to atomize and generate each VOCs gas, suspend the VOCs gas in the VOCs balance box, and continuously flush with VOCs until the box is filled with VOCs gas and enters dynamic equilibrium;

[0079] S4. The stably generated (after equilibrium) bioaerosol and the stably generated VOCs gas are introduced into a sterile co-exposure equilibrium box for dynamic equilibrium. After 10 minutes of equilibrium, the bioaerosol samples are collected using a liquid impact sampler for 20 minutes. The collected bioaerosol samples are enriched using a centrifugal ultrafiltration tube, centrifuged at 4000× for 30 minutes, and the samples are eluted from the ultrafiltration membrane with 0.9% saline solution.

[0080] S5. Continuously dilute the bioaerosol sample enriched in S4 with 0.9% NaCl solution at a volume ratio of 1:10, record the dilution multiple, take an equal amount of the dilution solution and inoculate it on a nutrient agar plate, incubate at 37°C for 24 hours, and calculate the culturable number of microorganisms in the sample based on the dilution multiple.

[0081] The calculation method of the culturable number is as follows:

[0082]

[0083] Among them, C 液体浓度 It is the culturable number of microorganisms counted on the diluted plate, and 10,000 is a fixed value in unit conversion.

[0084] The statistical diagram of the culturable number of Escherichia coli bioaerosols exposed to different types of VOCs is shown in the figure below. Figure 3 As shown in the figure, during the experiment, except for the different types of VOCs used, the conditions were the same. Figure 3 The results show that compared with the blank control, the culturable concentration of E. coli bioaerosols exposed to dimethyl disulfide changes little, indicating that it has little effect on E. coli bioaerosols, while dimethyl trisulfide, ethanethiol and formic acid have a great impact on E. coli bioaerosols, and the culturable number decreases by 2 to 3 times; among them, formic acid has the greatest impact on E. coli bioaerosols. It can be seen from this embodiment that the system of the present invention can realize the autonomous adjustment of VOCs exposure, and can meet the evaluation of the co-exposure of different types of VOCs and bioaerosols in different environmental places.

[0085] Example 4

[0086] The difference between this embodiment and embodiment 3 is that, in this embodiment, the injection flow rate of VOCs in S3 is set to 0.8, 8.9 and 17.7 μL / min, and the VOCs concentration is calculated to be 5 ppm, 50 ppm and 100 ppm, Escherichia coli is selected as the test bacteria, dimethyl trisulfide is selected as VOCs, and the reactor temperature is set to 60°C. Clean air is used to atomize at a constant flow rate of 5 L / min to generate dimethyl trisulfide gas and Escherichia coli bioaerosol to be balanced together in a co-exposure balance box for 10 minutes.

[0087] The collection of samples and calculation of the culturable number include the following steps:

[0088] S1. Use a bioaerosol sampler to collect bioaerosol samples into 10 mL of 0.9% saline solution for 20 min.

[0089] S2. Dilute the bioaerosol sample by a factor of 10 using 0.9% saline solution and record the dilution factor.

[0090] S3. Spread 100 μL of the sample on a nutrient agar plate and place it in a 37°C constant temperature incubator for 24 hours.

[0091] S4. Calculate the culturable number of E. coli in the sample based on the dilution factor, expressed as CFU / m 3 count.

[0092]

[0093] Among them, C 液体浓度 It is the culturable number of microorganisms counted on the diluted plate, and 10,000 is a fixed value in unit conversion.

[0094] The culturable number of Escherichia coli bioaerosols exposed to different concentrations of dimethyl trisulfide is shown in Figure 2. Figure 4 The test results are similar to those in Example 3. As the concentration of VOCs increases, the number of culturable bioaerosols decreases. This also shows that the system of the present invention can truly simulate the interaction between bioaerosols and malodorous waste gas in landfills, and can autonomously adjust the exposure concentration of VOCs, which is convenient for analyzing the environmental behavior of different concentrations of VOCs exposed to bioaerosols in different areas.

[0095] Example 5

[0096] The difference between this embodiment and embodiment 3 is that in this embodiment S1, the bacterial solution is diluted 10 times by 0.9% saline solution to obtain 10 5CFU / mL of bacterial suspension, Bacillus was selected as the test strain, a three-nozzle Collison bioaerosol generator was selected, methanol was selected as VOC, the injection flow rate was set to 0.2μL / min, and the VOC gas concentration was 0.5ppm for interactive exposure experiments. A liquid impact bioaerosol sampler was used to collect for 20 minutes, and an ultrafiltration tube was used to concentrate the bioaerosol sample.

[0097] The collection of samples and calculation of the culturable number include the following steps:

[0098] S1. Collect the bioaerosol sample into 10 mL of 0.9% saline solution using an impact liquid bioaerosol sampler for 20 min.

[0099] S2. Add the collected bioaerosol samples into a centrifugal ultrafiltration tube for enrichment and concentration, centrifuge at 4000× for 30 min, and elute the samples from the ultrafiltration membrane with 0.9% saline solution.

[0100] S3. Dilute the bioaerosol sample by a factor of 10 using 0.9% saline solution and record the dilution factor.

[0101] S4. Spread 100 μL of the sample on a nutrient agar plate and place it in a 37°C constant temperature incubator for 24 hours.

[0102] S5. Calculate the culturable number of E. coli in the sample based on the dilution factor, expressed as CFU / m 3 count.

[0103]

[0104] Among them, C 液体浓度 It is the culturable number of microorganisms counted on the diluted plate, and 10,000 is a fixed value in unit conversion.

[0105] The test results showed that methanol had an impact on the physiological state of Bacillus bioaerosols, and the culturable number decreased slightly, indicating that the experimental simulation of co-equilibrium exposure of Bacillus bioaerosols to low-concentration methanol was feasible.

[0106] Example 6

[0107] The difference between this embodiment and embodiment 4 is that, in this embodiment, the VOC in S3 is set to an injection flow rate of 10.8, 21.7 and 37.4 μL / min, the calculated VOCs concentration is 40 ppm, 120 ppm and 200 ppm, Pseudomonas aeruginosa is selected as the test strain, dimethyl disulfide and dimethyl trisulfide are selected as VOCs, and the reactor temperature is set to 85°C, and clean air is used to atomize at a constant flow rate of 5 L / min to generate dimethyl disulfide and dimethyl trisulfide gases and bioaerosols to be balanced together in a VOCs co-exposure balance box for 30 minutes.

[0108] The collection of samples and calculation of the culturable number include the following steps:

[0109] S1. Use a bioaerosol sampler to collect bioaerosol samples into 10 mL of 0.9% saline solution for 20 min.

[0110] S2. Dilute the bioaerosol sample by a factor of 10 using 0.9% saline solution and record the dilution factor.

[0111] S3. Spread 100 μL of the sample on a nutrient agar plate and place it in a 37°C constant temperature incubator for 22 hours.

[0112] S4. Calculate the culturable number of E. coli in the sample based on the dilution factor, expressed as CFU / m 3 count.

[0113]

[0114] Among them, C 液体浓度 It is the culturable number of microorganisms counted on the diluted plate, and 10,000 is a fixed value in unit conversion.

[0115] The test results show that the mixed sulfide gases dimethyl disulfide and dimethyl trisulfide have an impact on the physiological state of Pseudomonas aeruginosa bioaerosols, and the culturable number decreases by 2 to 3 powers, indicating that the experimental simulation of the co-equilibrium exposure of mixed sulfide gases dimethyl disulfide and dimethyl trisulfide to Pseudomonas aeruginosa bioaerosols is feasible, which can be used to evaluate the effects of VOCs on bioaerosols in real landfills and evaluate the risks of VOCs and bioaerosols in landfills.

[0116] Example 7

[0117] The difference between this embodiment and embodiment 6 is that in this embodiment, Staphylococcus aureus is selected as the test strain, and clean air is used to atomize at a constant flow rate of 8L / min to generate xylene gas and bioaerosol to be balanced together in a VOCs co-exposure balance box for 30 minutes, and the VOC gas concentration is 20ppm.

[0118] The collection of samples and calculation of the culturable number include the following steps:

[0119] S1. Use a bioaerosol sampler to collect bioaerosol samples into 10 mL of 0.9% saline solution for 30 minutes.

[0120] S2. Dilute the bioaerosol sample by a factor of 10 using 0.9% saline solution and record the dilution factor.

[0121] S3. Spread 100 μL of the sample on a nutrient agar plate and place it in a 37°C constant temperature incubator for 22 hours.

[0122] S4. Calculate the culturable number of E. coli in the sample based on the dilution factor, expressed as CFU / m 3 count.

[0123]

[0124] Among them, C 液体浓度 It is the culturable number of microorganisms counted on the diluted plate, and 10,000 is a fixed value in unit conversion.

[0125] The test results show that xylene gas has an impact on the physiological state of Staphylococcus aureus bioaerosols, and the culturable number decreases by 1 to 2 powers, indicating that the experimental simulation of co-equilibrium exposure of xylene gas to Staphylococcus aureus bioaerosols is feasible, and can be used to evaluate the effect of VOCs in real printing and dyeing wastewater on bioaerosols, and evaluate the risks of VOCs and bioaerosols in real scenarios.

[0126] Example 8

[0127] The difference between this embodiment and embodiment 7 is that, in this embodiment, Staphylococcus aureus and Escherichia coli are selected as test bacteria, and dimethyl disulfide gas is atomized with clean air at a constant flow rate of 5L / min to be balanced with bioaerosol in a VOCs co-exposure balance box for 60 minutes, and the VOC gas concentration is 20ppm.

[0128] The collection of samples and calculation of the culturable number include the following steps:

[0129] S1. Collect the bioaerosol sample into 10 mL of 0.9% saline solution using an impact liquid bioaerosol sampler for 30 min.

[0130] S2. Dilute the bioaerosol sample by a factor of 10 using 0.9% saline solution and record the dilution factor.

[0131] S3. Spread 100 μL of the sample on a nutrient agar plate and place it in a 37°C constant temperature incubator for 22 hours.

[0132] S4. Calculate the culturable number of E. coli in the sample based on the dilution factor, expressed as CFU / m 3 count.

[0133]

[0134] Among them, C 液体浓度 It is the culturable number of microorganisms counted on the diluted plate, and 10,000 is a fixed value in unit conversion.

[0135] The test results show that dimethyl disulfide has a weak effect on the physiological state of Staphylococcus aureus and Escherichia coli bioaerosols, and the culturable number decreases by 0 to 1 power, indicating that the experimental simulation of the co-equilibrium exposure of dimethyl disulfide to Staphylococcus aureus and Escherichia coli bioaerosols is feasible, and can be used to evaluate the effect of VOCs on bioaerosols in real sewage treatment plants and evaluate the risks of VOCs and bioaerosols in sewage treatment plants.

[0136] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A system for the generation, balance and co-exposure of bioaerosols and volatile organic compounds, characterized in that: It comprises a co-exposure balance box (1), a volatile organic compound gas balance box (2) and a bioaerosol balance box (3) respectively connected to the co-exposure balance box (1) through a pipeline system, and a control device for controlling the operation of the system; The pipeline system comprises input paths respectively connected to a volatile organic compound gas balance box (2) and a bioaerosol balance box (3), and output paths respectively connecting the volatile organic compound gas balance box (2) and the bioaerosol balance box (3) to a co-exposure balance box (1); an air compressor (9), a flow controller (11) and an air filter (12) are sequentially arranged on the input paths, a volatile organic compound generator (4) is also arranged in the input path connected to the volatile organic compound gas balance box (2), and a bioaerosol generator (5) is also arranged in the input path connected to the bioaerosol balance box (3); The co-exposure balance box (1) is also connected to a bioaerosol collection device (6); the volatile organic compound gas balance box (2) is also connected to a volatile organic compound detector (7); and the bioaerosol balance box (3) is also connected to a bioaerosol particle real-time monitor (8).

2. The system according to claim 1, characterized in that: The input path and / or the output path contains at least one branch.

3. The system according to claim 2, characterized in that: A branch of the input path is separated from the air compressor (9), and a flow controller (11) and an air filter (12) are sequentially arranged on the branch.

4. The system according to any one of claims 1 to 3, characterized in that: The pipeline system is also provided with an air valve for controlling the inflow and outflow of aerosol or gas.

5. The system according to claim 4, characterized in that: The co-exposure balance box (1), the volatile organic compound gas balance box (2) and the bioaerosol balance box (3) are all provided with a turbulent device (10).

6. The system according to claim 5, characterized in that: The co-exposure balance box (1), the volatile organic compound gas balance box (2) and the bioaerosol balance box (3) are all provided with an exhaust pressure relief device (14).

7. The system according to claim 6, characterized in that: The flow-disturbing device (10) is a fan.

8. The system according to claim 6, characterized in that: The exhaust pressure relief device (14) is an exhaust pressure relief valve.

9. The system according to claim 6, characterized in that: The fan blades and the inner wall of each balancing box are covered with an anti-stick coating.

10. The method for using the system according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Add the solution of the volatile organic compound to be tested into the injection needle of the volatile organic compound generator (4), use the pipeline system to make the volatile organic compound generator (4) generate volatile organic compounds and enter the volatile organic compound gas balance box (2), and turn off the volatile organic compound generator (4) after the box is filled with volatile organic compounds, and wait for the volatile organic compounds in the box to enter dynamic equilibrium; S2. Place the suspension of the microorganism to be tested in the liquid bottle of the bioaerosol generator (5), use the pipeline system to make the bioaerosol generator (5) generate microbial aerosol and enter the bioaerosol balance box (3), and turn off the bioaerosol generator (5) after the box is filled with microbial aerosol, and wait for the aerosol in the box to be dynamically balanced; S3. The dynamically balanced volatile organic compounds and microbial aerosols are simultaneously introduced into the co-exposure balance box (1) through the output path of the pipeline system for dynamic balance, and the microbial aerosol samples are collected and enriched using the bioaerosol collection device (6). The enriched microorganisms are gradient diluted and plated for culture, and the culturable number of microorganisms in the sample is calculated based on the dilution multiple, and the change in the culturable number of microorganisms is observed, so as to observe the influence of volatile organic compounds on microbial aerosols; The calculation formula for the culturable number is: Among them, C 液体浓度 The culturable number of microorganisms counted on a dilution plate.

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