JP2008022764A - Environment evaluation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environment evaluation method for evaluating microorganisms suspending in air in improved accuracy. <P>SOLUTION: Microorganisms are supplied to an evaluation chamber 1 separated from outer space with a separation wall 2, elimination particles for sterilizing and eliminating the microorganisms are supplied to the chamber, microorganisms are collected and the collected microorganisms are measured. In the above environment evaluation method, spore-forming bacteria of sporular state such as Bacillus subtilis are used as the microorganisms for preventing the spontaneous death of the microorganisms. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an environment evaluation method for evaluating microorganisms in a space.

  In recent years, interest in improving the air environment has increased day by day due to air pollution problems, the occurrence of various pathogens and viruses, and the increase in allergic patients. In order to meet the demand for a comfortable indoor environment, technologies and evaluation methods have been proposed to remove minute substances present in the atmosphere, such as microorganisms such as bacteria, fungi, viruses, and harmful chemical substances. Yes.

  Conventionally, as a method for improving the air environment, various methods for removing particles in the air using a filter have been generally used. Air purification is performed by physically collecting and removing minute substances in the air.

  In recent years, various air purification techniques represented by radicals and ions have attracted attention. This method eliminates the harmful effects of minute substances floating in the air, such as by denaturation and decomposition. For example, as a method for sterilizing treatment by irradiating microorganisms with particles such as ionized ions, Patent Document 1 discloses a technique for generating positive and negative ions for air purification and a method for sterilizing airborne bacteria by applying the technique. Has been.

  In the development of home appliances using such technology, it is possible to achieve a design that achieves both the required air purification function and lower energy by accurately evaluating the performance of the product. Environmental measurement technology has become very important in product development.

  For example, as a method for detecting and quantifying how much harmful substances are present in the environment, Patent Document 2 discloses a technique relating to a measurement device and a measurement system for airborne minute substances.

Patent Document 3 proposes that quantitative evaluation of a removal effect test by applying some action to suspended solids can be effectively performed in a closed space using a microorganism removal evaluation method and apparatus. is doing.
JP 2002-095731 A Japanese Patent Application Laid-Open No. 11-14511 JP 2004-159508 A

  However, the technique described in Patent Document 1 shows a sterilization method using ionized particles such as ions, and does not specifically show an effective test method for changes in the amount of minute substances.

  The evaluation apparatus described in Patent Document 2 has a feature of collecting and detecting minute substances floating in the space, but does not consider the kind of minute substances that can be stably suspended in the space.

  The technique described in Patent Document 3 is intended to evaluate the removal of suspended solids, but does not consider the types of microorganisms that can stably float in space, and an evaluation apparatus that can perform more accurate evaluation. Is required.

  Therefore, in view of the above, the present invention is to provide an environment evaluation method capable of performing removal evaluation of minute substances floating in a space with higher accuracy.

  In order to achieve the above object, the present invention is an environmental evaluation method for collecting microorganisms after supplying microorganisms into an evaluation chamber separated from the external space by an isolation wall, and measuring the collected microorganisms, In order to prevent the natural disappearance of microorganisms, the present invention is an environmental evaluation method characterized by using spore-forming bacteria in the spore state as microorganisms. As a result of the study by the inventors, the general activity state (nutrient state) of spore-forming bacteria and other microorganisms such as Escherichia coli greatly change the number of viable bacteria floating due to the influence of humidity.

  Therefore, by applying a special treatment to the spore-forming bacteria to form a spore state, the floating number of viable bacteria when sprayed in the air is not easily affected by humidity, and floats alive for a long time at a wide range of humidity. Can do. Therefore, since the influence by the natural annihilation (attenuation) of microorganisms can be reduced, more accurate evaluation can be performed.

  In addition, in an environmental evaluation method in which microorganisms are collected in an evaluation chamber separated from an external space by an isolation wall, and after removing particles for removing microorganisms are collected, the microorganisms are collected and the collected microorganisms are measured. In order to prevent the natural disappearance of the microorganism, a spore-forming spore-forming bacterium can be used as the microorganism. According to this method, microorganisms are collected and measured after irradiating the removed particles in the internal space of the evaluation room, so the ability to remove microorganisms by irradiating the removed particles can be evaluated, and the removed particles are irradiated. It is possible to quantitatively evaluate various conditions to be performed.

  In addition, although it does not specifically limit as a spore formation microbe, Bacillus subtilis is preferable. Bacillus subtilis is characterized by little harm to the human body and safe testing. For this reason, for example, even when the airborne microbe removal test using an air cleaner is performed in a large space of 6 tatami or more, the tester can safely perform the test without risk of being exposed to microorganisms. Furthermore, since it is not easily affected by humidity, a test with excellent reproducibility can be easily performed without performing humidity control.

  As another means for preventing the natural disappearance of microorganisms, there is a method for controlling the humidity in the evaluation chamber. Specifically, it is an environmental evaluation method in which microorganisms are collected in an evaluation room separated from the external space by an isolation wall, then the microorganisms are collected, and the collected microorganisms are measured. This is an environment evaluation method characterized by controlling the humidity in the evaluation chamber. The amount of microorganisms in the air is easily affected by humidity. By controlling the humidity to a humidity suitable for microorganisms, it can be floated in a living state for a long time. Therefore, since the influence by the natural annihilation (attenuation) of microorganisms can be reduced, more accurate evaluation can be performed.

  Furthermore, an environmental evaluation method for collecting microorganisms in an evaluation chamber separated from an external space by an isolation wall, collecting removed particles for removing the microorganisms, and then measuring the collected microorganisms. The environmental evaluation method can be characterized in that the humidity in the evaluation chamber is controlled in order to prevent the natural disappearance of microorganisms. According to this method, microorganisms are collected and measured after irradiating the removed particles in the internal space of the evaluation room, so the ability to remove microorganisms by irradiating the removed particles can be evaluated, and the removed particles are irradiated. It is possible to quantitatively evaluate various conditions to be performed.

  Although it does not specifically limit as microorganisms used under humidity control, Escherichia coli can be used. Escherichia coli is suitable as a microorganism for evaluating changes in planktonic bacteria because it has relatively little harm to the human body. However, variations during testing were large, and ensuring reproducibility was a major issue. As a result of intensive studies by the inventors, it has been clarified that the viable cell count greatly changes due to the influence of humidity in the test environment. Escherichia coli has a problem that floating microbes are rapidly reduced in an environment with low humidity. For example, when examining the ability to remove airborne bacteria with an air purifier, there is a problem that the air suspension time for evaluating the removal ability cannot be secured. By controlling the humidity to be high, the air floating time can be extended, and there is an advantage that it takes a long time to check the removal capability. Further, by controlling the humidity, it is possible to perform a test with small variations and excellent reproducibility.

  Further, the relative humidity in the test environment is preferably 45% or more. FIG. 8 shows the results of the investigation of the correlation between the relative humidity and the floating amount of E. coli by the inventors, and the number of viable bacteria after 0 to 60 minutes after changing the humidity. As is clear from this figure, the floating amount of E. coli can be kept large by setting the relative humidity to 45% or more.

  The humidity in the test environment can be adjusted using an ultrasonic humidifier. There are two types of humidifiers: one is generally evaporated by heating water, the other is a method in which energy is given to water by ultrasonic waves and scattered in the air, or a hybrid method in which both are combined. Among these, in the method of heating water, as a result of investigations by the inventors, it has been found that there is a disadvantage that the floating time of the bacteria cannot be kept long.

  In this method of heating water, it is estimated that the decay of the amount of microorganisms is accelerated because the steam at a high temperature has the effect of sterilizing microorganisms in the air. On the other hand, the humidification method using ultrasonic waves is suitable for the floating test of microorganisms because the reduction of floating bacteria is delayed. In the humidification method using ultrasonic waves, since high-temperature steam is not generated, it is estimated that the floating state can be maintained without sterilizing microorganisms.

  In the present invention, the term “microorganism” is used in a concept including bacteria, fungi (including molds), viruses, allergen substances (including mites), and the like. In addition, microorganisms are not limited to those harmful to humans but include useful ones. Moreover, the microorganisms to be removed can be one or a combination of two or more selected from the above group. Thereby, various microorganisms can be targeted for removal evaluation according to the present invention.

  In addition, when supplying microorganisms to the internal space of the evaluation chamber, the solution in which the microorganisms are dispersed can be sprayed in the form of a mist. Thereby, it is easy to supply microorganisms into the evaluation chamber, and it is easy to perform the removal process of microorganisms. And about the case where this microorganism is sprayed in mist form, it can be made into the object of evaluation by the present invention.

  In addition, when the microorganisms are supplied to the space inside the evaluation chamber, the space inside the evaluation chamber can be stirred from below with respect to the microorganisms supplied to the evaluation chamber. Thereby, when supplying microorganisms into an evaluation room, the natural sedimentation by the dead weight of microorganisms can be prevented and the removal process by irradiating a removal particle can be performed effectively.

  Moreover, as the removal particles for removing microorganisms, a gas generated by any one of discharge in air, radiation irradiation in air, and the Leonard effect can be used. Furthermore, synchrotron radiation, X-rays, gamma rays, or electromagnetic waves can be used as the removal particles. Furthermore, positive and / or negative ions can also be used as removal particles.

  In particular, the reason why microorganisms can be sterilized when positive and negative ions are used as specific removal particles for sterilizing microorganisms will be described below.

That is, when an ionization phenomenon such as discharge is caused in the atmosphere to generate positive ions and negative ions, H ⁺ (H ₂ O) n is used as positive ions and O ₂ ⁻ (H ₂ O) n is used as negative ions. Produces the most stable.

When these ions are generated, hydrogen peroxide H ₂ O ₂ or radicals OH which are active species are generated by a chemical reaction. Since this H ₂ O ₂ or radical • OH exhibits extremely strong activity, it is possible to sterilize and remove suspended microorganisms in the air.

  Further, a gas mainly composed of either positive or negative ions can be used as particles for sterilizing microorganisms. In that case, for example, the electrical action on the microorganisms due to the charge of the ions may have the effect of causing a bactericidal action by destroying the cells of the microorganisms or destroying the surface proteins.

  In addition, ozone or radicals can be used as particles for sterilizing microorganisms. Ozone or radicals are excellent in sterilizing ability for microorganisms and can effectively remove microorganisms. After these sterilization capabilities are demonstrated, ozone becomes harmless oxygen and does not remain, and radicals combine with airborne microorganisms or various molecules in the air and change into inactive substances. , It will be rendered harmless over time and will not remain. And it becomes possible to evaluate the ability to sterilize microorganisms by such ozone or radical.

  Further, a drug can be used for sterilizing microorganisms, and sterilization can be performed by irradiating the particles of the drug. When sterilization is performed using a chemical, the particles can be supplied with a simple device as compared with the case of using ions or ozone. And it becomes possible to evaluate the microbe removal ability by such a chemical | medical agent.

  In particular, it can be suitably used in a test method using charged particles, radicals, or particles having sterilizing ability as the removed particles. In a test to release charged particles, radicals or sterilizing particles into the air and verify their effects, the test is conducted by releasing these particles into the air without harming the human body, assuming general household use. Tests that perform are common. Therefore, in order to examine the effect of removing these microorganisms in the air, it is necessary to examine the effect of removing the floating bacteria in a relatively long time. At this time, since it is necessary to suspend microorganisms stably for a long time, the above method is particularly effective, and is suitable for evaluation of charged particles in the air, radicals or particles having sterilizing ability.

  Examples of the measurement of microorganisms include measurement of the concentration of microorganisms. Microorganism measurement is microbial concentration measurement, cell infection rate measurement, or allergic reaction measurement, whereby microbial removal evaluation can be performed.

  Moreover, when measuring the collected microorganisms, it is also possible to measure the change with time of the irradiation time of the particles. Thereby, the quantitative evaluation with respect to the passage of time of the ability to sterilize microorganisms can be performed.

  In measuring the collected microorganisms, the concentration dependency of the removed particles can also be measured. Thereby, quantitative evaluation with respect to particle concentration dependence of the ability to sterilize microorganisms can be performed.

  In the evaluation method, cell culture by microorganisms, hemagglutination reaction by microorganisms, or allergic reaction by microorganisms can be used. Thereby, the activity or concentration of microorganisms can be evaluated.

  According to the present invention, it is possible to prevent the natural disappearance of microorganisms and to float them stably, and it is possible to stably perform environmental evaluation tests such as sterilization and deodorization.

  Hereinafter, embodiments of the present invention will be described.

<First Embodiment>
This environmental evaluation system uses negative pressure in the evaluation chamber, sprays and stirs the microorganisms to be evaluated in the evaluation chamber, floats them uniformly, processes the suspended microorganisms with the removed particles, and then samples them. It has a series of mechanisms for analysis and evaluation.

  In addition, this environmental evaluation method is characterized in that spore-forming spore-forming bacteria (Bacillus subtilis) are used as microorganisms in order to prevent the natural disappearance of microorganisms.

  Hereinafter, the present invention will be described in more detail with reference to more specific embodiments, but the present invention is not limited thereto. In the following description of the embodiments, the description is made with reference to the drawings. In the drawings of the present application, the same reference numerals denote the same or corresponding parts. The arrows indicate the air flow.

  FIG. 1 is a schematic configuration diagram of an environment evaluation apparatus according to the first embodiment, and FIG. 2 is a diagram illustrating an air flow of the environment evaluation apparatus according to the first embodiment. As shown in FIGS. 1 and 2, the environment evaluation apparatus includes an evaluation chamber 1 that is isolated from an external space by an isolation wall 2, a minute substance supply means 3 that supplies microorganisms into the evaluation chamber 1, and an evaluation chamber 1. It has an air cleaning device 4 as a fine substance removing means for supplying removal particles for sterilizing and removing microorganisms, and a fine substance collecting means 5 for collecting microorganisms in the evaluation chamber 1, and a fine substance collecting means In addition, the microorganisms collected from 5 are measured and evaluated. In addition, it has a loading / unloading mechanism 6 for loading / unloading the minute substance collecting means 5 into / from the evaluation chamber 1.

The four sides of the evaluation chamber 1 are separated from the external space by the isolation wall 2, and the portion other than the air supply hole 21 described later is a highly airtight clean room. The space size of the evaluation chamber 1 is about 20 m ³ (the dimensions of the drawing are the 10 inner walls), but the size is not limited. Moreover, the double door 1a for a user's exit / entry is provided in part. A stirring fan 7 is provided below the evaluation chamber 1. The agitating fan 7 can form an air flow around the agitating space to agitate the space, prevent natural sedimentation downward due to the dead weight of microorganisms, and effectively remove the particles generated from the air cleaning device 4. More microorganisms can be suspended. Therefore, the sterilization process by the removal particles can be performed effectively. Further, an ultrasonic humidifier 8 is installed in the evaluation chamber 1 as a first air conditioner for adjusting the humidity. In addition, it is equipped with a germicidal lamp 9 and can be sterilized indoors. This sterilization lamp 9 is mainly used for sterilization in the evaluation chamber 1 before the start of the evaluation test.

  The isolation wall 2 includes an inner wall 10, an outer wall 11, and an air flow passage 12 formed between the inner wall 10 and the outer wall 11. For the inner wall 10 and the outer wall 11, a baked steel plate, which is a standard wall material of the evaluation chamber 1, is employed. A vinyl chloride floor material is used for the floor of the inner wall 10. The interior is designed to prevent leakage of bacteria to the outside by a weak negative pressure design.

  The outer wall 11 is provided with an air intake 13 for taking air into the air flow passage 12 from the external space. Further, an air intake vent 14 and an air exhaust vent 15 are provided as vents for ventilating before and after the evaluation test. The air intake vent 14 and the air exhaust vent 15 can be closed and are closed during the evaluation test.

  The air intake port 13 and the air intake vent port 14 are provided with HEPA / activated carbon filters so that purified air can be introduced. Further, the air exhaust vent 15 is also provided with a HEPA / activated carbon filter, which can be exhausted to the external space after the air is purified. The filters provided at the air inlet 13 and the air outlet 22 are not limited to the HEPA / activated carbon filter, and other types of filters may be used.

  An air supply pipe 16 is connected to the air intake 13. The air supply pipe 16 is provided with a valve 17 that opens and closes the inside of the pipe, an inflow amount measurement unit 18, and a heater 19 as a second air conditioning unit that adjusts the temperature. The inflow amount measuring unit 18 is a flow meter and detects the amount of air passing through the air supply pipe 16, that is, the inflow amount to the control unit 20.

  The heater 19 adjusts the air passing through the air supply pipe 16 to an appropriate temperature. The adjusted air is introduced into the evaluation chamber 1 from each air supply hole 21 described later through the air flow passage 12. Generally, when the substance to be suspended is a liquid such as solution particles containing bacteria as in this embodiment, the solution particles adhere to the wall surface due to condensation as the temperature of the air introduced from the air supply hole 21 is increased. Can be prevented. In the present embodiment, the inner wall 10 itself may be heated.

  As shown in FIGS. 3A and 3B, the inner wall 10 is provided with a large number of air supply holes 21 on almost the entire surface except the floor surface. Air in the external space from the air inlet 13 through the air flow passage 12 can flow into the evaluation chamber 1 from these air supply holes 21. The air supply hole 21 is a pore having a diameter of approximately 0.1 to 2 cm, and the interval W between adjacent holes is set to be approximately 1 to 3 times the diameter of the hole. With such a configuration, the entire wall surface is covered with the air ventilated into the evaluation chamber 1, and part of the air vented from each air supply hole 21 It intersects with part of the air vented from the air supply hole 21. In this embodiment, the hole diameter is set to approximately 0.2 mm, and the hole interval is set to 0.4 mm.

  The inner wall 10 is provided with an air discharge port 22 for discharging the air in the evaluation chamber 1. An exhaust pipe 23 is connected to the air discharge port 22, and the exhaust pipe 23 passes through the air flow passage 12 and the outer wall 11 and opens to the external space. The exhaust pipe 23 includes a valve 24 for opening and closing the inside of the pipe, an exhaust amount measuring unit 25, a pump device 26 as a suction means for sucking the air in the evaluation chamber 1 and keeping the inside at a negative pressure, An impinger 27 as a minute substance collecting means is provided.

  Exhaust gas discharged from the air discharge port 17 is configured to be discharged to the external space after being purified by a filter or the like via the impinger 27. Since the total amount of air introduced per unit time from each air supply hole 21 is designed to be sufficiently small with respect to the capacity of the evaluation chamber 1, the amount of exhaust air from the exhaust port 17 is also small, and the inside of the evaluation chamber 1 The influence of the stirring on the airflow is extremely small. However, when a more accurate test condition is required, correction is performed based on the exhaust amount from the exhaust port 17 and the number of bacteria collected in the impinger 27. The impinger 27 may be omitted.

  The exhaust amount measurement unit 25 is a flow meter, and grasps the amount of air passing through the exhaust pipe 23, that is, the exhaust amount discharged from the evaluation chamber 1, and detects this to the control unit 20. The control unit 20 controls the pump device 26 so that the exhaust amount becomes constant based on the detected exhaust amount.

  Here, the displacement is an important factor in the microorganism evaluation test. This is because the greater the amount of air exhausted from the evaluation chamber 1, the greater the amount of microorganisms discharged with it. If the amount of the base microorganism is different between the comparative tests due to fluctuations in the displacement, accurate evaluation cannot be performed. Therefore, if the displacement is constant, the evaluation can be performed under the same conditions, so that the evaluation accuracy can be further improved. According to this method, since the attenuation of microorganisms is subtracted, the performance of the air cleaning device 4 itself can be measured.

  In the above-described embodiment, the control unit 20 is configured to control the exhaust amount to be constant at all times. However, when the microorganism removal is not performed, the change in the exhaust amount with time and the microorganism removal are performed. You may make it control so that the time-dependent change of exhaust_gas | exhaustion amount becomes the same. Both evaluation tests can be performed under the same conditions.

  In addition, the control unit 20 determines whether or not the air circulation in the evaluation chamber 1 is normal based on the difference between the exhaust amount from the exhaust amount measuring unit 25 and the inflow amount from the inflow amount measuring unit 18. . For example, when the exhaust amount is smaller than the inflow amount and the difference is larger than a predetermined value, the occurrence of air leakage from the evaluation chamber 1 is estimated. In such a case, the notification unit 28 gives a warning. The notification unit 28 includes display on a display unit such as a monitor, and notification by sound or light.

  As a fine substance supply means, nebulizer 3 (NE-C16 manufactured by OMRON Corporation) capable of spraying a microbial solution is used. The nebulizer 3 has an air pump 3a, and the aqueous solution is converted into particles of about 1 to 10 μm from the nozzle by compressed air by the air pump 3a and is discharged into the space. In addition, the density | concentration of the microbe which can be filled, and its solution amount can be adjusted arbitrarily, A microbe can be discharge | released to space as a liquid fine particle by filling the solution containing microorganisms into the filling solution reservoir.

  The microorganism used here will be described.

  The microorganism used was Bacillus subtilis belonging to the genus Bacillus in the spore state. Bacillus subtilis is a bacterium that exists in the natural world and is an aerobic Gram-positive rod and forms spores depending on conditions.

   A spore is a cell structure that exhibits high resistance to heat, chemicals, and the like. In a normal proliferating state, the spore-forming bacterium does not form a spore as a nutritional state, but when placed in a poorly nutritional state, it forms a spore and changes to a state that is extremely suitable for storage.

  Bacillus subtilis is generally not pathogenic to humans.

  Next, a method for producing the Bacillus subtilis (spore) used will be described. This time, Bacillus subtilis, which is the original strain, is applied on an SCD agar medium and cultured at 37 ° C. for about one week. In this way, nutrients on the agar medium are depleted by culturing for a long time, and Bacillus subtilis is transformed into a spore and becomes a gel-like membrane.

  The membrane is peeled off with a spatula, stirred and centrifuged in a test tube containing a phosphate buffer solution, and further subjected to heat treatment at a temperature of 95 ° C. for 5 minutes to prepare a solution containing only Bacillus subtilis spores.

  The air purifying device 4 as a fine substance removing means is a method using ions utilizing discharge in the air, which releases positive and negative ions and is sterilized or deodorized by the oxidizing ability by the energy of the ions. Is realized.

In the discharge electrode in the present embodiment, ions containing H ⁺ (H ₂ O) m as positive ions and O ²⁻ (H ₂ O) n (m and n are natural numbers) as negative ions are generated as main components. . However, since ions discharged from the discharge electrode generally can be discharged by adjusting discharge voltage and electrode structure as discharge conditions, for example, H ⁺ (H ₂ O) In addition to m, for example, H ₂ O ⁺ , H ₃ O ⁺ , N ₂ ⁺ , O ₂ ⁺ , CO ₂ ^{+ and the} like may be included. Similarly, not only the ion O ²⁻ (H ₂ O) n but also OH ⁻ , H ₂ O ⁻ , O ₃ ⁻ , O ₂ ⁻ , N ₂ ⁻ , NO ₂ ⁻ , NO ₃ ⁻ , CO ₂ ^−. , CO _3- ^{and the} like can also be used in this test technique.

  An air sampler 5 (MAS-100 manufactured by Merck & Co., Inc.) is used as a minute substance collecting means for collecting floating bacteria. This air sampler 5 is a method called the Andersen method. As shown in the principle diagram of FIG. 4, by passing bacteria (or particles) in the sucked air through the holes 5a and hitting them on the medium 5b, the air sampler 5 is 1 μm or more. The particles can be recovered almost 100%. In addition, the microbe adhering on the culture medium 5b grows by storing it in a moderate temperature environment (for example, 30 ° C.), and can be observed as a colony in about one day.

The observed coefficient value is corrected by a conversion table prepared in advance because a plurality of bacteria may pass through one hole and may be counted as one colony.
Further, as shown in FIG. 5, a mechanism 6 for taking in and out the air sampler 5 into the evaluation chamber 1 is provided. The loading / unloading mechanism 6 includes a rectangular parallelepiped path box 29 and moving means 30 that can move the air sampler 5 between the path box 29 and a predetermined position in the evaluation chamber 1.

  The pass box 29 is a container body that is fixed through the isolation wall 2, one of which opens into the evaluation chamber and the other of which opens into the external space. The evaluation chamber side opening 31 and the external space side opening 32 are provided with doors 31a and 32a that can be freely opened and closed. Of the door 32a on the external space side and the door 31a on the evaluation room side, at least the door 31a on the evaluation room side can be automatically opened and closed by controlling the fluid pressure with a cylinder or the like (not shown). This is done remotely.

  The moving means 30 has a rail 33 as a guide path provided between the pass box 29 and a predetermined position in the evaluation chamber 1, and a moving body 34 on which the air sampler 5 is placed and moves along the rail 33. It consists of.

  The rail 33 is provided so as to reach a predetermined position of the evaluation chamber 1 from the bottom surface of the pass box 29, and is fixed to the floor surface of the evaluation chamber 1 by a plurality of legs 33a.

  The moving body 34 includes a mounting table 35 that serves as a mounting surface for the air sampler 5 and wheels 36 that are provided on the bottom surface of the mounting table 35. The wheel 36 is fitted to the rail 33 and is movable along the rail 33. The mounting table 35 has a drive unit (not shown) for driving the wheel 36 and a receiving unit (not shown) that can be remotely operated, and the drive of the wheel 36 is remotely controlled. The moving body 34 on which the air sampler 5 is placed can be freely moved back and forth along the rail 33 by remote control.

  In the above description, the guide path is the rail 33, but a belt conveyor may be used instead of the rail. In the case of the belt conveyor, the moving body 34 does not need to be provided with the wheels 36 and the receiving unit, and the moving body 34 can be moved by controlling the rotation driving of the belt conveyor.

  The test procedure using the environment evaluation apparatus configured as described above will be described below.

(1) Test preparation Before starting the test, the air intake vent 14 and the air exhaust vent 15 are operated so that the room is filled with clean air with little dust.

  In addition, the inner wall of the evaluation chamber 1 is irradiated with a sterilizing lamp 9 that generates ultraviolet rays for a predetermined period of time in advance, and further, an ultrasonic humidifier 8 provided in the evaluation chamber 1 is used to evaluate the evaluation chamber. It is desirable to adjust the humidity of the air in 1.

  After the disinfection in the evaluation chamber 1 is completed, the operation of the air intake vent 14 and the air exhaust vent 15 and the operation of the germicidal lamp 9 are stopped.

(2) Spraying of bacteria Next, the bacteria solution is sprayed from the nebulizer 3 into the evaluation chamber 1. At this time, it is assumed that air is blown by the stirring fan 7 so that the sprayed bacteria diffuse into the space. Moreover, the spraying time can select the method of performing about 10 minutes, for example.

  At this time, the valve 24 of the exhaust pipe 23 and the valve 17 of the air supply pipe 16 are opened, and a constant amount of air in the evaluation chamber 1 is always sucked and exhausted by the pump device 26, so that the temperature of the heater 19 is increased. Conditioned air is taken from the air intake 13. The air taken in from the air inlet 13 flows into the evaluation chamber 1 from the air supply hole 21 of the inner wall 10 through the air flow passage 12, and an air flow is formed in the vicinity of the surface of the inner wall 10. This air flow can prevent sprayed bacteria from adhering to the inner wall 10 surface of the evaluation chamber 1.

At this time, the inflow and discharge of air into the evaluation chamber 1 are set to a very small amount. Specifically, the air discharge amount is set to 10 m ³ / hour, and this is continued during the evaluation test. This control is performed by the control unit 20 controlling the pump device 26 based on the displacement signal detected from the displacement measurement unit 25. Further, the control unit 20 controls the valve 17 provided in the air supply pipe 16 so that the inside of the evaluation chamber 1 is slightly depressurized by about 1/10000 atm than the outside based on the atmospheric pressure data from the barometer 40. To control. By this method, since the inside of the evaluation chamber 1 is maintained at a weak negative pressure, leakage of airborne bacteria to the external space can be prevented.

  Further, the control unit 20 determines whether or not the air flow in the evaluation chamber 1 is normal from the difference between the exhaust amount from the exhaust amount measuring unit 25 and the inflow amount from the inflow amount measuring unit 18. If it is abnormal, a warning is given from the notification unit 28. Specifically, when the exhaust amount is smaller than the inflow amount and the difference is larger than a predetermined value, since the occurrence of air leakage from the evaluation chamber 1 is estimated, the notification unit 28 warns.

(3) Recovery of bacteria The air sampler 5 is moved into the evaluation room 1 to collect the floating bacteria in the room. The floating bacteria are collected once every 10 minutes and 7 times in total for 60 minutes. Thereby, the change with time of the floating bacteria concentration is measured.

  Specifically, the door 32a on the external space side of the pass box 29 is opened, the air sampler 5 equipped with the agar medium 5b is placed on the moving body 34, and the door 32a on the external space side is closed.

  Then, the door 31a on the evaluation room side is opened by remote operation, and the moving body 34 is moved to a predetermined position in the evaluation room 1. The door 31a on the evaluation room side is closed. Next, the air sampler 5 is operated by a timer function or remote control operation, and airborne bacteria in the evaluation chamber 1 are collected.

  Further, in order to take out the air sampler 5, the door 31 a on the evaluation room side is opened by remote control, the moving body 34 is moved into the pass box 29, and then the door 31 a on the evaluation room side is closed. And if the door 32a by the side of external space is opened, the air sampler 5 which collect | recovered airborne bacteria can be taken out.

(4) Driving of the air cleaning device 4 The air cleaning device 4 is operated. For example, a method of starting the operation of the air cleaning device 4 at the time when the bacteria are first recovered can be selected. Ions released from the air cleaning device 4 collide with and react with bacteria to sterilize them, thereby reducing floating bacteria in the room.

(5) End When the collection of airborne bacteria is finished, the air purification device 4 is stopped, clean air is introduced into the room, and air containing airborne bacteria is discharged to the outside.

  According to the above configuration, the bacteria or solution particles suspended in the evaluation chamber 1 are greatly prevented from colliding with the walls of the evaluation chamber 1 and collected by multiple tests regardless of the concentration of the suspension. It is possible to perform a stable test with a small statistical variation in the results.

  In addition, since the displacement is kept constant, there is no variation in the amount of attenuation of airborne bacteria due to exhaust, and stable test data can be acquired. Moreover, by setting the inside of the evaluation chamber 1 to a negative pressure, leakage of airborne bacteria to the outside can be prevented. Furthermore, by detecting the amount of air inflow, air leakage from the evaluation chamber 1 can be determined, and a safer environment evaluation apparatus can be obtained.

  Furthermore, with regard to the collection of airborne bacteria, the provision of the take-in / out mechanism 6 eliminates the need for a person to enter and exit the air sampler 5, thereby increasing safety and invasion of airborne bacteria from the external space. Therefore, the accuracy of evaluation can be further improved.

  Next, an example of test results obtained by this test facility is shown below.

[Removal effect test]
FIG. 6 shows the change with time by selecting the concentration of airborne bacteria in the 20 m ³ evaluation chamber 1 in which Bacillus subtilis is suspended on the vertical axis. In this test result, about 83% of the floating bacteria are removed after 60 minutes when ions are released compared to the case where ions (removed particles) are not released. As a result, it has been confirmed that a stable test in which the slope of the approximate curve of the plot is controlled to a variation level of 10% or less can be performed.

[Stability test of Bacillus subtilis]
Bacillus subtilis spores and nutrients were used, the relative humidity was set to 32%, and the change in the number of bacteria in a state where ions (removed particles) were not released was evaluated. The evaluation results are shown in FIG.

  In FIG. 7, Bacillus subtilis (nutrient state) is attenuated by about 1/100 or less after 60 minutes, and large attenuation is observed. On the other hand, in Bacillus subtilis (spore state), the decay after 60 minutes is 1/10, and no significant decrease is observed. Since the Bacillus subtilis spores are resistant to drying, it is presumed that the bacteria are not easily killed even in a low humidity environment with a relative humidity of about 30%, and can be suspended in a living state for a long time.

  Thus, in the environment evaluation apparatus according to the present invention, by using Bacillus subtilis spores, the bacteria can be suspended in a live state for a long time. Therefore, a highly accurate test can be performed without being affected by variations in humidity.

  In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of the present invention. For example, in the above embodiment, ions are used as a sterilization method, but various chemical substances such as ozone, plasma, radicals, and the like can be selected as test objects. Moreover, although Bacillus subtilis is used as a minute substance, it is possible to evaluate using other spore-forming bacteria.

  Moreover, in the said embodiment, although the isolation wall 2 of the evaluation chamber 1 was comprised from the inner wall 7, the outer wall 8, and the air flow path 9, and it was set as the structure which provided the several air supply hole 10 in the inner wall 7, air supply A configuration in which the hole 10 is not provided, that is, a configuration in which the inner wall 7 and the air flow passage 9 are omitted and only the outer wall 8 is provided.

<Second Embodiment>
In the first embodiment, spore-forming bacteria in the spore state are used as microorganisms in order to prevent the natural disappearance of microorganisms, but in this embodiment, in order to prevent the natural disappearance of microorganisms, the humidity in the evaluation chamber 1 is adjusted. It is characterized in that it is controlled to 45% or more, and the other basic configuration is the same as that in the first embodiment. Note that E. coli is used as a microorganism.

  Specifically, the relative humidity in the evaluation chamber 1 is controlled to be 45% or more by using an ultrasonic humidifier 8 provided in the evaluation chamber 1.

  FIG. 8 shows the result of examining the correlation between the relative humidity and the floating amount of E. coli, and the result of examining the number of floating bacteria after 0, 10, 30 and 60 minutes by changing the relative humidity in the evaluation chamber 1. It is. Note that CFU is an abbreviation of colony forming unit.

  As is clear from FIG. 8, the floating amount of E. coli can be kept higher by setting the relative humidity to 45% or more.

  Thus, in the suspended microorganism test method according to the present invention, since E. coli is sprayed and tested under humidity control, the bacteria can be suspended in a live state for a long time.

  In the above embodiment, Escherichia coli is used as the microorganism, but it is possible to evaluate using other microorganisms.

It is a schematic block diagram of the environment evaluation apparatus of 1st Embodiment. It is a figure which shows the flow of the air of the environment evaluation apparatus of 1st Embodiment. It is the front view seen from the (a) sectional view and the (b) inner wall side which showed the structure of the isolation wall of the evaluation room of the environment evaluation apparatus of 1st Embodiment. Principle diagram of air sampler (MAS-100 by Merck) It is a schematic block diagram of the taking-in / out mechanism 6 of the air sampler of the environment evaluation apparatus of 1st Embodiment. It is the figure which showed the removal effect test result. It is the figure which showed the stability test result of Bacillus subtilis. It is the figure which showed the humidity test result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Evaluation room 1a Double door 2 Separation wall 3 Nebulizer 4 Air purifier 5 Air sampler 6 Taking in / out mechanism 8 Humidifier 10 Inner wall 11 Outer wall 12 Air flow passage 13 Air intake 16 Air supply pipe 18 Inflow amount measurement part 19 Heater 20 Control Unit 21 Air supply hole 22 Air exhaust port 23 Exhaust pipe 25 Exhaust amount measuring unit 26 Pump device 27 Impinger 28 Notifying unit 29 Pass box 30 Moving means 33 Rail 34 Moving body

Claims (9)

An environmental evaluation method for collecting microorganisms after feeding the microorganisms into an evaluation chamber separated from the external space by an isolation wall, and measuring the collected microorganisms, in order to prevent natural disappearance of the microorganisms And an spore-forming spore-forming bacterium. An environmental evaluation method for collecting microorganisms into an evaluation chamber separated from an external space by an isolation wall, collecting removed particles for removing the microorganisms, collecting the microorganisms, and measuring the collected microorganisms. In order to prevent the natural disappearance of the microorganism, an environmental evaluation method using a spore-forming bacterium in a spore state as the microorganism. 3. The method for testing the amount of planktonic bacteria according to claim 1, wherein the spore-forming bacterium is Bacillus subtilis. An environmental evaluation method for collecting microorganisms after supplying microorganisms into an evaluation chamber isolated from an external space by an isolation wall, and measuring the collected microorganisms, in order to prevent the natural disappearance of the microorganisms An environmental evaluation method characterized by controlling indoor humidity. In the environmental evaluation method for collecting microorganisms in the evaluation chamber separated from the external space by the isolation wall and supplying the removed particles for removing the microorganisms, and measuring the collected microorganisms, An environmental evaluation method characterized by controlling humidity in an evaluation chamber in order to prevent the natural disappearance of microorganisms. 6. The environmental evaluation method according to claim 4, wherein Escherichia coli is used as the microorganism. The environmental evaluation method according to claim 4, wherein the relative humidity in the evaluation chamber is 45% or more. The environmental evaluation method according to claim 4, wherein the humidity of the evaluation chamber is adjusted using an ultrasonic humidifier. The environmental evaluation method according to claim 1, wherein charged particles, radicals, or particles having sterilizing ability are used as the removed particles.

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