Impinger and Air Quality Assessment Method

Abstract

This invention provides an impinger capable of efficiently capturing small amounts of fine particles in the air, and an air quality evaluation method capable of analyzing the air quality in a confined space containing small amounts of fine particles. [Solution] The impinger 1 comprises a stopper body 10 equipped with a gas inlet pipe 13 and a gas outlet pipe 14, and a container body 20 connected to the stopper body 10, having a tubular section 21 through which the gas inlet pipe 13 is inserted, allowing the exhaust gas to pass between the outer wall and the gas inlet pipe 13, and a liquid reservoir section 22 for storing a solution, and collecting fine particles contained in the inlet gas in the solution of the liquid reservoir section 22. The liquid reservoir section 22 has a lower part 221 from a bottom 221a facing the outlet of the gas inlet pipe 13, with a side section 221b having a larger outer diameter than the tubular section 21 and being formed as a curved surface, and an upper part 222 formed continuously with the lower part 221, with a top surface 222a having a curved surface from the side section 221a. The top surface 222a is connected to the tubular section 21 by a recess 222b formed around one end of the tubular section 21.

Description

[Technical Field]

[0001] The present invention relates to an impinger for collecting airborne particles and a method for evaluating air quality using the collected particles. [Background technology]

[0002] Conventionally, methods have been developed to collect particulate matter (PM: Particulate Matter) and other particles in the air (hereinafter simply referred to as fine particles) and evaluate air quality based on the collected particles. These particle collections and air quality evaluations are generally carried out outdoors or in large indoor spaces such as factories. However, in recent years, there has been growing concern about allergies and sick building syndrome caused by dust mites, mold, and pets in homes, as well as the effects of exhaust fumes entering car cabins on human health. This has led to a growing need to evaluate air quality in smaller indoor spaces.

[0003] To perform chemical analysis of airborne particulate matter for air quality assessment, a certain minimum amount of the substance to be analyzed is required. For example, the detection limit (lower limit) for analyzing inorganic ions using ion chromatography is approximately 0.2 μg / mL for sulfate and chloride ions. The detection limit (lower limit) for analyzing metals using ICP-MS (Inductively Coupled Plasma Mass Spectrometry) is several milligrams. Furthermore, gas chromatograph-mass spectrometers (GC-MS), used for the analysis of polycyclic aromatic hydrocarbons, require a sample of several milligrams.

[0004] However, when analyzing the air quality in individual rooms of a residence, a car interior, etc., the amount of target substances in the air in these spaces is considered to be small compared to the required amount, making chemical analysis difficult. For example, the volume of a typical 6-tatami room in a Japanese house is approximately 2 × 10⁻⁶ 7 mL, the volume of the interior of a minivan-type passenger car is approximately 5 x 10 6The concentration of PM2.5 in these rooms is below the environmental standard of 35 μg / m³. 3 (35×10 -6 Assuming a concentration of approximately μg / mL, the amount of PM2.5 in the air would be 0.7 mg in a 6-tatami room and 0.2 mg inside a car. Therefore, it is difficult to chemically analyze the air quality in indoor spaces such as individual rooms in a residence or inside a car.

[0005] Therefore, a method different from chemical analysis is needed to evaluate air quality using small amounts of analyte particles in a confined indoor space. One possible method for evaluating air quality based on small amounts of particles is a bioassay using cultured cells. Bioassays offer higher sensitivity than chemical analysis and can confirm reactions with small amounts of particles.

[0006] One method for collecting microparticles for bioassays using cultured cells is the impinger method. The impinger method involves passing gas, drawn in by a suction pump, through a solution in a container, and collecting impurities such as microparticles contained in the gas by bubbling them into water. By collecting microparticles in the solution using an impinger, the solution containing the microparticles can be used for cell culture, making it possible to efficiently use the collected microparticles for analysis.

[0007] Conventionally, impingers, which are containers used in the impinger method, have been developed (for example, Patent Document 1). Furthermore, in order to perform analysis by cell culture, it is necessary for the analyte to be contained in the solution at a certain concentration or higher, and if the amount of fine particles to be collected is small, the amount of solution in the impinger must also be small.

[0008] Patent Document 2 discloses an impinger equipped with a receiving protrusion and a baffle plate to enable the collection of fine particles with a small amount of solution. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Special Publication No. 2024-529219 [Patent Document 2] Japanese Utility Model Publication No. 58-154444 [Overview of the project] [Problems that the invention aims to solve]

[0010] When performing evaluations using bioassays, it is important to secure a certain minimum sample size to ensure evaluation accuracy. Therefore, a certain minimum volume of the solution containing microparticles used for evaluation is required. In addition, for evaluations using bioassays with cell culture, it is necessary to ensure a certain minimum concentration of microparticles in the solution. To perform air quality evaluations using bioassays targeting microparticles present in relatively small spaces such as a single room or vehicle interior, it is necessary to efficiently collect microparticles while securing a small volume of solution, such as a few milliliters to 10 ml.

[0011] A typical impinger, the midget impinger, has a flat bottom. Therefore, some of the solution is scattered upwards due to bubbling that occurs when gas is introduced. Consequently, it is difficult to collect fine particles while keeping a small amount of solution inside the container.

[0012] The impinger described in Patent Document 2 is equipped with a receiving protrusion, which makes it easier for the lower end of the gas inlet tube to remain in the solution even when the container is tilted, and is configured to easily capture fine particles even when there is little solution. However, the solution that is scattered by bubbling generated at the receiving protrusion is scattered upward along the gas inlet tube, making it difficult to retain a small amount of solution in the container.

[0013] Furthermore, the impinger described in Patent Document 2 is equipped with a baffle plate, which causes splashes of the scattered solution to collide with the baffle plate and fall. However, it is difficult for the solution that is scattered upwards and spreads above the baffle plate through the gap between the baffle plate and the gas inlet pipe to be returned to the solution in the container against the flow of the discharged gas. In particular, when the amount of solution is very small, such as a few milliliters, it is even more difficult for the solution scattered along the gas discharge path between the gas inlet pipe and the main body of the pipe to return downwards. Therefore, it is difficult to collect bubbling water with a small amount of solution while maintaining the amount of solution.

[0014] This invention has been made in view of the above circumstances, and aims to provide an impinger capable of efficiently collecting small amounts of fine particles from the air, and an air quality evaluation method capable of analyzing the air quality of a small space containing small amounts of fine particles. [Means for solving the problem]

[0015] To achieve the above objective, the impinger according to the first aspect of this invention is: A plug body equipped with a gas inlet pipe and a gas outlet pipe, The container body comprises a gas inlet pipe through which the gas inlet pipe is inserted, a tubular section between the outer wall and the gas inlet pipe through which exhaust gas passes, and a liquid reservoir section for storing a solution, and is connected to the stopper body to collect fine particles contained in the introduced gas introduced from the gas inlet pipe into the solution stored in the liquid reservoir section, The aforementioned liquid reservoir section is The lower part of the gas inlet pipe, which is facing the outlet, has a side portion with a larger outer diameter than the tubular portion and is composed of a curved surface, It has an upper part which is formed continuously with the lower part and whose side and top surfaces are curved, The top surface is connected to the tubular portion by a recess formed around one end of the tubular portion.

[0016] Furthermore, the internal volume of the liquid reservoir is 5 ml or more and 10 ml or less. It would be acceptable to do so.

[0017] Further, the gas introduction pipe includes a spray nozzle that mixes the solution and the introduced gas. This may also be the case.

[0018] Further, in the air quality evaluation method according to the second aspect of the present invention, Particles in the air are collected using an impinger according to the first aspect, Cells are cultured in a culture solution containing the solution in which the particles are collected, RNA is extracted from the cultured cells, the extracted RNA is synthesized, and gene expression analysis is performed by real-time PCR testing to evaluate the air quality.

Effect of the Invention

[0019] According to the impinger and the air quality evaluation method of the present invention, a small amount of particles in the air can be efficiently collected. Further, according to the air quality evaluation method of the present invention, since the air quality evaluation by bioassay is performed using the impinger of the present invention for collecting particles, it is possible to appropriately evaluate the air quality in a small space containing a small amount of particles.

Brief Description of the Drawings

[0020] [Figure 1] It is a front view of an impinger according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view of a spray nozzle according to an embodiment. [Figure 3] It is an enlarged view of a liquid reservoir according to an embodiment. [Figure 4] It is a conceptual diagram showing the flow of the solution in the liquid reservoir. [Figure 5] It is a diagram showing an example of the dimensions of a liquid reservoir according to an embodiment. [Figure 6] It is a flowchart showing the flow of air quality evaluation according to an embodiment. [Figure 7] It is a diagram showing a configuration example of a particle collection device including an impinger according to an embodiment. [Figure 8] It is a diagram showing an example of an air quality evaluation result. [Modes for carrying out the invention]

[0021] (Impinja) The impinger 1 according to an embodiment of the present invention will be described below with reference to the figures. As shown in Figure 1, the impinger 1 comprises a container body 20 that contains a solution for collecting fine particles, and a stopper 10 that closes the top of the container body 20.

[0022] As shown in Figure 1, the stopper 10, when connected to the container body 20 in use, constitutes the upper part of the impinger 1. The material of the stopper 10 is not particularly limited and may be glass, fluororesin, etc. The stopper 10 comprises a main body 11, an insertion part 12, a gas introduction pipe 13, and a gas discharge pipe 14.

[0023] The main body 11 is a cylindrical portion with one end, which is the upper part when in use, closed. The insertion portion 12 is a cylindrical portion that is continuously formed below the main body 11 and is open at the bottom. The outer diameter of the insertion portion 12 is configured to gradually decrease from the main body 11 side towards the tip side in order to connect with the container body 20.

[0024] The gas introduction pipe 13 is a tubular member integrally formed with the main body 11 so as to connect the outside and inside of the main body 11. The gas introduction pipe 13 passes through the central axis of the main body 11 and introduces outside air (hereinafter also simply referred to as gas) from the outside of the impinger 1 to the inside of the impinger 1. As shown in Figure 1, one end of the impinger 1, which is on the outside side, is an open intake port 13a so as to be able to draw in outside air from the stopper 10. The other end of the impinger 1, which is on the inside side, is formed to introduce outside air into the solution inside the container body 20 when in use.

[0025] A spray nozzle 13b is formed at the end of the gas inlet pipe 13 opposite to the inlet 13a, i.e., the end on the inside side of the impinger 1. The spray nozzle 13b may be formed integrally with the gas inlet pipe 13, or a separate spray nozzle 13b may be connected to the gas inlet pipe 13.

[0026] The spray nozzle 13b according to this embodiment is a two-fluid nozzle internal mixing type spray nozzle, as shown in the cross-sectional view of Figure 2. Specifically, the introduced gas flowing through the gas introduction pipe 13 and the solution inside the impinger 1 that flows in from the side of the spray nozzle 13b are mixed inside the nozzle and ejected from the nozzle outlet 13c at the tip of the spray nozzle 13b. This makes it possible to reduce the size of the gas bubbles introduced into the solution, thereby increasing the contact area between the introduced gas and the solution, and efficiently capturing fine particles in the introduced gas.

[0027] A splash prevention valve 13d may be attached to the gas inlet pipe 13. The material of the splash prevention valve 13d is, for example, a fluororesin such as Teflon (registered trademark), and it is attached to the outer surface of the gas inlet pipe 13 by press-fitting. The shape of the splash prevention valve 13d is not particularly limited, and it can be, for example, abacus bead shape, that is, a shape in which two cones are joined at their bases. Furthermore, the mounting position of the splash prevention valve 13d is not particularly limited, and it should be mounted at a position corresponding to the height at which the solution inside the impinger 1 splashes.

[0028] The gas discharge pipe 14 is a tubular member integrally formed on the main body 11 so as to connect the inside and outside of the main body 11, at a position that does not interfere with the gas inlet pipe 13 at the top of the main body 11. The outlet 14a, which is the end of the gas discharge pipe 14 opposite to the connection point with the main body 11, is connected to a suction pump 32 (not shown).

[0029] The container body 20 comprises a central portion of the container body 20, a tubular section 21 through which an introduction gas containing fine particles and an exhaust gas from the impinger 1 pass, a liquid reservoir section 22 in which a solution for collecting fine particles is stored, a fitting section 23 into which the insertion section 12 of the stopper 10 is inserted, and an intermediate section 24 connecting the liquid reservoir section 22 and the fitting section 23.

[0030] The tubular section 21 is a cylindrical part through which the gas inlet pipe 13 of the plug body 10 is inserted when in use. When in use, the gas inlet pipe 13 is positioned to pass through the central axis of the tubular section 21. The exhaust gas passes between the outer wall of the tubular section 21 and the gas inlet pipe 13 and is discharged to the outside from the outlet 14a of the plug body 10.

[0031] As shown in Figure 1, the liquid reservoir 22 is formed continuously at one end of the tubular portion 21 so as to become the lower end when in use, and is the portion where a solution for capturing fine particles in the gas is stored.

[0032] As shown in the enlarged view of Figure 3, the liquid reservoir 22 comprises a lower section 221, which is formed from a curved surface from the bottom 221a facing the outlet 13c of the gas introduction pipe 13 to the side section 221b, which has a larger outer diameter than the tubular section 21, and an upper section 222, which is formed continuously with the lower section 221 and whose top surface 222a from the side section 221b is formed of a curved surface. Furthermore, the top surface 222a of the upper section 222 and the tubular section 21 are connected via a recess 222b formed around one end (lower end) of the tubular section 21.

[0033] As a result, the cross-section of the liquid reservoir 22 has a heart shape, as shown in Figure 3, with the bottom 221a at the tip curved in a convex shape and the base end connected to the tubular section 21 curved in two concave shapes. As a result, as shown in Figure 4, the solution stored inside the liquid reservoir 22 rises along the curved surface inside the lower part 221 along with the bubbles ejected from the spray nozzle 13b. The rising solution then reaches the top surface 222a of the upper part 222 and flows downward through the concave part 222b, causing it to circulate within the liquid reservoir 22. As a result, the solution stored in the liquid reservoir 22 is discharged to the outside along with the exhaust gas, which is indicated by the white arrows in the figure, or its adhesion to the inside of the upper impinger 1 from the tubular section 21 is suppressed, making it possible to collect fine particles while maintaining a small amount of solution. In this embodiment, the range of the side portion 221b generally refers to the area from the midpoint between the upper and lower ends of the liquid reservoir portion 22 to the position where the outer diameter is maximum.

[0034] As described above, the impinger 1 according to this embodiment is intended to collect particulate matter present in the air of relatively small spaces, such as a room in a residence or the interior of a car. Furthermore, in collecting particulate matter, it is necessary to trap the small amount of particulate matter collected from a small amount of air in a solution to a predetermined concentration in order to measure its effect by bioassay. To satisfy these conditions, the internal volume of the liquid reservoir 22 of the impinger 1 is preferably 5 ml or more and 10 ml or less, and more preferably 5 ml or more and 8 ml or less. Here, the volume of the liquid reservoir 22 is the volume from the bottom 221a of the liquid reservoir 22 to the side 221b, excluding the top surface 222a, that is, the volume of the lower part 221. In other words, the volume of the liquid reservoir 22 is the volume of the area where the solution does not come into contact with the top surface 222a and the recess 222b, that is, the inner surface of the upper part 222, when a solution is stored in the liquid reservoir 22. In this way, by introducing gas while the solution in the liquid reservoir 22 does not fill the upper part 222, the rising solution is not discharged to the outside but can circulate and remain in the liquid reservoir 22.

[0035] The curvature of the curved surface of the lower part 221 is not particularly limited, but for example, a radius of curvature of about 38 mm is preferable (Figure 5). Similarly, the curvature of the convex upper surface 222a is not particularly limited, but for example, a radius of curvature of about 4 mm is preferable. Furthermore, the depth of the recess 222b, that is, the length from the top of the upper surface 222a to the bottom of the recess 222b, is preferably about 5 mm. This makes it easier for the solution that has risen on the inner surface of the liquid reservoir 22 to flow downward, thereby suppressing the discharge of the solution and enabling efficient collection of fine particles even with a small amount of solution.

[0036] The fitting portion 23 is a tubular section formed continuously above the tubular portion 21, with the top open. The inner surface shape of the fitting portion 23 is formed to conform to the outer surface shape of the insertion portion 12 for connection with the stopper body 10. Specifically, the inner diameter of the fitting portion 23 is formed to gradually increase from the tubular portion 21 side to the open end side. As a result, as shown in Figure 1, the insertion portion 12 is inserted into the fitting portion 23, connecting the stopper body 10 and the container body 20.

[0037] An intermediate section 24 is formed between the tubular section 21 and the fitting section 23. The intermediate section 24 is formed so that its diameter gradually increases from the tubular section 21 towards the fitting section 23. In this embodiment, when the stopper 10 and the container body 20 are connected, the splash prevention valve 13d attached to the gas introduction pipe 13 is adjusted to be located in the intermediate section 24. As a result, even if the solution splashes upward from the liquid reservoir section 22, the solution will hit the splash prevention valve 13d, reducing the amount of solution discharged to the outside, thus suppressing a decrease in the amount of solution in the liquid reservoir section 22.

[0038] (Collection of fine particles) By using a suction pump 32 connected to the outlet 14a of the gas discharge pipe 14 to draw air from inside the impinger 1, a negative pressure is created inside the impinger 1, and outside air is introduced into the impinger 1 from the intake port 13a. The gas introduced through the gas introduction pipe 13 is mixed with the solution stored in the liquid reservoir 22 by the spray nozzle 13b. As a result, the bubbles become smaller and are ejected into the liquid reservoir 22, more specifically to the bottom 221a, where the solution is stored.

[0039] If the gas inlet pipe 13 does not have a spray nozzle 13b, the bubbles of the gas introduced from the gas inlet pipe 13 become larger, reducing the contact area between the introduced gas and the solution, and resulting in insufficient capture of fine particles in the gas. In particular, when the amount of gas introduced is limited to a small amount, it becomes difficult to capture a sufficient amount of fine particles, making it difficult to perform an accurate air quality assessment. Also, when the amount of solution is small, the contact time between the bubbles and the solution is shortened, making it even more difficult to capture fine particles in the gas. The spray nozzle 13b enables more efficient capture of fine particles by increasing the contact area between the introduced gas and the solution.

[0040] As described above, with the impinger 1 according to this embodiment, the solution circulates within the liquid reservoir 22, suppressing evaporation of the solution and allowing for the collection of fine particles in the introduced gas while maintaining the amount of solution necessary for air quality evaluation, even when the amount of solution is small. Therefore, a relatively small amount of fine particles in the air can be collected at a predetermined concentration or higher. Furthermore, since the gas introduction tube 13 of the impinger 1 is equipped with a spray nozzle 13b, the size of the gas bubbles introduced into the solution can be reduced. Therefore, even when the amount of introduced gas is small, fine particles in the introduced gas can be efficiently collected into the solution.

[0041] (Air quality assessment) The following describes the method for collecting particulate matter using the impinger 1 described above, and the method for evaluating air quality based on the collected particulate matter, with reference to the flowchart in Figure 6.

[0042] First, particulate matter in the air within the space is collected using the impinger 1 (step S1). More specifically, 5 ml of distilled water is added as a solution and stored in the liquid reservoir 22 of the impinger 1. Next, the stopper 10 and the container body 20 are connected. The outlet 14a of the impinger 1 is connected to the suction pump 32 via a tube 31, as shown in Figure 7. A trap 33 may be placed between the gas discharge pipe 14 and the suction pump 32 to prevent the solution from flowing into the suction pump 32.

[0043] The assembled impinger 1 is placed in the space to be evaluated, and the suction pump 32 is started. This introduces air from the space to the impinger 1, and airborne particles are collected by bubbling into the solution inside the impinger 1. In this embodiment, outside air is passed through the distilled water solution at a flow rate of 10 L / min for 30 minutes.

[0044] As described above, the air drawn into the impinger 1 causes the solution to rise along the curved surface inside the liquid reservoir 22, and it is circulated from the top surface 222a back into the liquid reservoir 22. This suppresses the discharge of the solution to the outside, so even when the amount of solution in the liquid reservoir 22 is as small as 5 ml, fine particles can be collected while maintaining the amount of solution.

[0045] After the collection in step S1 is completed, air quality is evaluated by bioassay. Specifically, human monoblast-like cell line U937 is cultured using RPMI culture medium (step S2). The RPMI culture medium in this embodiment is RPMI1640 medium (Thermo Fisher Scientific) containing 10% FBS (fetal bovine serum, Thermo Fisher Scientific) and 1 / 100 volume of penicillin-streptomycin solution (Fujifilm Wako Pure Chemical Industries). In this embodiment, Thermo Fisher Scientific's FBS (Performance Plus) is used without inactivation in order to suppress the activation of U937 by FBS.

[0046] To culture U937 using the RPMI culture medium described above, we will use 2 × 10⁶ U937. 5 Seed the cells in a 12-well plate at a cell density of cells / mL media / well. More specifically, after counting the U937 cells, centrifuge and then divide into 2 × 10⁻⁶ wells. 5Add RPMI culture medium to achieve a cell / mL concentration. Then, add PMA (Phorbol 12-Myristate 13-Acetate, Fujifilm Wako Pure Chemical Industries) at a 1000-fold dilution to a final concentration of 4 nM, suspend the mixture, and seed it into a 12-well plate at a rate of 1 mL / well. Finally, culture U937 in an environment of 5% CO2 and 37°C.

[0047] After culturing U937 for 2 days under the above conditions, the culture medium is changed and the culture is continued for another 2 days.

[0048] Next, an RPMI culture medium containing the microparticles collected in step S1 (hereinafter referred to as the microparticle-containing RPMI culture medium) is prepared (step S3). The components of the microparticle-containing RPMI culture medium for one well of a 12-well plate are as shown in the table below. [Table 1]

[0049] Here, the 10×RPMI culture medium is prepared by dissolving 104 mg of RPMI1640 powder (Sigma-Aldrich) and 20 mg of sodium bicarbonate (NaHCO3) in 1 mL of distilled water and filtering it through a syringe filter with a pore size of 0.2 μm.

[0050] In step S2, remove the culture medium from the 12-well plate in which U937 was cultured, add the microparticle-containing RPMI culture medium prepared in step S3, and culture U937 in a 5% CO2, 37°C environment for 6 hours (step S4).

[0051] After culturing in step S4, the cells are harvested, RNA extraction and cDNA synthesis are performed, and gene expression analysis is conducted by real-time PCR (step S5). Based on these results, the impact of the collected particulate matter on the human body is estimated, and air quality is evaluated.

[0052] As described above, according to the air quality evaluation method according to the present embodiment, since air quality evaluation by bioassay is performed using the impinger according to the present invention for collection of fine particles, air quality evaluation of a small space containing a small amount of fine particles can be appropriately performed.

[0053] (Evaluation Example) FIG. 8 is a diagram showing an example of results when fine particles in indoor air are collected and air quality evaluation is performed by the method according to the above embodiment for each of a clean room, a children's room, and a vehicle interior. Each PM (Particle Matter) concentration is 0.1 μg / m 3 , 6.5 μg / m 3 , 4.8 μg / m 3 . In this example, evaluation is also performed for the case (untreated) where no fine particles are contained for comparison. Specifically, in the untreated case, the RPMI culture medium in step S3 is prepared using distilled water instead of the fine particle-containing water. As shown in FIG. 8, the mRNA expressions of IL-8, CCL3, CYP1A1, and HO-1 differ depending on the space, and it can be seen that fine particles can be efficiently collected from a limited amount of air in a narrow space and air quality evaluation by bioassay can be appropriately performed.

Industrial Applicability

[0054] The impinger and the air quality evaluation method according to the present invention are suitable for air quality evaluation of a relatively narrow space such as a single room in a residence or the interior space of an automobile. In particular, it is suitable for air quality evaluation in a space containing only fine particles of 1 mg or less for which it is difficult to measure the contained chemical substances.

Explanation of Signs

[0055] 1 Impinger, 10 Stopper, 11 Main body, 12 Insertion part, 13 Gas inlet pipe, 13a Inlet, 13b Spray nozzle, 13c Outlet, 13d Splash prevention valve, 14 Gas discharge pipe, 14a Outlet, 20 Container body, 21 Tubular part, 22 Liquid reservoir, 221 Lower part, 221a Bottom, 221b Side, 222 Upper part, 222a Top surface, 222b Recess, 23 Fitting part, 24 Middle part, 31 Tube, 32 Suction pump, 33 Trap

Claims

1. A plug body equipped with a gas inlet pipe and a gas outlet pipe, The container body comprises a gas inlet pipe through which the gas inlet pipe is inserted, a tubular section between the outer wall and the gas inlet pipe through which exhaust gas passes, and a liquid reservoir section for storing a solution, and is connected to the stopper body to collect fine particles contained in the introduced gas introduced from the gas inlet pipe into the solution stored in the liquid reservoir section, The aforementioned liquid reservoir section is The lower part of the gas inlet pipe, which is facing the outlet, has a side portion with a larger outer diameter than the tubular portion and is composed of a curved surface, It has an upper part which is formed continuously with the lower part and whose side and top surfaces are curved, The top surface portion is a recess formed around one end of the tubular portion, and is connected to the tubular portion. An impinger characterized by the following features.

2. The internal volume of the liquid reservoir is 5 ml or more and 10 ml or less. The impinger according to feature 1.

3. The gas introduction pipe is equipped with a spray nozzle for mixing the solution and the introduced gas. The impinger according to feature 1.

4. Collect airborne particulate matter using an impinger according to any one of claims 1 to 3, Cells are cultured in a culture medium containing the solution in which the fine particles have been collected. By extracting RNA from cultured cells, synthesizing the extracted RNA, and performing gene expression analysis using real-time PCR testing, air quality can be evaluated. A method for evaluating air quality characterized by the following features.

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