Air purification system

Abstract

There is provided an air purification system for purifying ambient air, the air purification system comprising: an air ionizer system configured to charge air molecules of ambient air, where the air ionizer system is configured to generate positively charged air molecules and negatively charged air molecules; a sensor system configured to sense one or more physical characteristics of ambient air; and a controller configured to control the air ionizer system to vary a ratio of positively charged air molecules to negatively charged air molecules generated by the air ionizer system according to one or more physical characteristics of the ambient air sensed by the sensor system.

Description

Technical Field

[0001] The present invention relates to an air purification system. Background Art

[0002] The problem of air pollution has become increasingly serious, and a variety of air pollutants are known or suspected to be harmful to human health. The negative impacts that air pollutants may cause depend on the type and concentration of the pollutants, as well as the length of time of exposure to the polluted air. For example, high levels of air pollution may immediately cause health problems, such as the exacerbation of cardiovascular and respiratory diseases, while long-term exposure to polluted air may have a permanent impact on health, such as loss of lung capacity and reduced lung function, as well as the development of diseases, such as asthma, bronchitis, emphysema, and possibly cancer.

[0003] Many people have recognized the benefits of reducing exposure to these pollutants and use air purifiers. An air purifier is a device for air treatment that removes airborne particles, including pollutants, from the air. Known examples of air purifiers use particulate filters that physically capture airborne particles by size exclusion, and high-efficiency particulate air (HEPA) filters remove at least 99.97% of particles sized 0.3 micrometers. Other known examples of air purifiers ionize the air to generate negative ions, thereby removing airborne particles from the air. Some more advanced air purifiers combine multiple technologies, such as a particulate filter that physically captures airborne particles and an air ionizer that generates negative ions, to further improve the performance of the purifier. The ultimate goal is to improve the performance of air purifiers and ensure the rapid and effective removal of suspended particles in the air.

[0004] In view of the above considerations, the present invention has been designed. Summary of the Invention

[0005] According to a first aspect of the present invention, there is provided an air purification system for purifying ambient air, the air purification system comprising: an air ionizer system configured to charge air molecules of the ambient air, wherein the air ionizer system is configured to generate positively charged air molecules and negatively charged air molecules; a sensor system configured to sense one or more physical properties of the ambient air; and a controller configured to control the ionizer system to change the ratio of positively charged air molecules to negatively charged air molecules generated by the air ionizer system according to one or more physical properties of the ambient air sensed by the sensor system.

[0006] As understood by those skilled in the art, this ratio is generally understood as:

[0007] · 0 if the air ionizer system generates substantially only negative ions

[0008] · If the air ionizer system produces substantially equal amounts of positively charged air molecules and negatively charged air molecules, it is 1 (which can also be expressed as 1:1).

[0009] · If the air ionization system produces substantially only positive ions, it is >>1

[0010] Those skilled in the art can also understand that it is not necessary to measure the exact ratio to understand whether the ratio has changed, because if, for example, the air ionizer system is controlled to switch between any of the following, the ratio can be understood to be changing:

[0011] · Produces substantially only negative ions

[0012] · Produces substantially equal amounts of positively charged air molecules and negatively charged air molecules

[0013] · Produces substantially only positive ions.

[0014] By changing the ratio of the produced positively charged and negatively charged air molecules according to one or more physical properties of the ambient air, purification by ionization can be improved. For example, this may increase particle agglomeration, causing the particles in the air to adhere to each other and fall off or be attracted to an electrostatic surface from the air.

[0015] In some examples, one or more physical properties may include at least one physical property indicating the total charge of the ambient air; and the controller is configured to control the ionizer system to change the ratio of positively charged air molecules to negatively charged air molecules according to the total charge of the ambient air.

[0016] Based on the total charge of the ambient air, purification can be further increased. For example, ambient air that is normally neutral and ambient air that is normally charged can be ionized differently to increase purification.

[0017] In some examples, the physical property indicating charge can be a direct measurement of the charge of the ambient air, while in other examples, the physical property may not be a direct measurement of charge but a physical property indicating the total charge. A suitable model for relating the relevant physical property to the expected total charge may be known. For example, there are suitable models for relating the number of particles in the ambient air to the expected total charge of the ambient air. Similarly, there are models for particle size, humidity, and temperature distribution.

[0018] In some examples, the controller can be configured to control the ionizer system to change the ratio of positively charged air molecules to negatively charged air molecules generated by the ionizer system, thereby increasing the total charge of the air molecules (e.g., if the total charge of the air molecules is positive, the ionizer system can be controlled to generate positive ions to increase the total positive charge; e.g., if the total charge of the air molecules is negative, the ionizer system can be controlled to generate negative ions to increase the total negative charge).

[0019] By increasing the total charge of the air molecules, particle aggregation and electrostatic attraction to surfaces can be increased. Especially in cases where the sensor system senses charged air molecules, it may be desirable to increase the charge of the air molecules to improve purification.

[0020] In some examples, the sensor system can include a charge sensor configured to sense the charge of air molecules in ambient air; and the charge of the air molecules detected by the charge sensor indicates the total charge of the ambient air. For example, the charge sensor can be configured to measure the average charge of the ambient air. The charge sensor can measure the total charge of an aerosol as a Faraday cup electrometer, where a single negative charge and a single positive charge cancel each other out. The device for measuring the total charge can also be constructed to compare the product of the measured current (particle charge) and concentration from an optical particle sensor.

[0021] In some examples, one or more physical characteristics can include a parameter indicating the particle concentration (particles per unit volume) in ambient air; and the sensor system can include a particle sensor to detect the parameter indicating the particle concentration in ambient air. Here, the parameter can be measured by measuring the absolute number of particles (from which the concentration can be inferred) or by directly measuring the concentration, such as the number per cubic centimeter.

[0022] The parameter indicating the particle concentration in ambient air can indicate the total charge of the ambient air. Suitable models for relating the particle number to the total charge of ambient air are known to those skilled in the art.

[0023] In some examples, the controller can be configured to control the ionizer system to generate both positively charged air molecules and negatively charged air molecules simultaneously if the parameter indicating the concentration exceeds a predetermined threshold.

[0024] Generating both positively charged and negatively charged molecules simultaneously can change the ratio of positively charged air molecules to negatively charged air molecules generated by the air ionizer system to 1 (or expressed as "1:1"). Preferably, the ratio becomes approximately 1 (or "1:1") such that substantially equal amounts of positively charged air molecules and negatively charged air molecules are generated.

[0025] When high concentrations of particles are detected in ambient air, this may indicate that the separation between the particles is small and that the particles may be considered electrically neutral, such that the production of positively and negatively charged air molecules may increase particle agglomeration until the particles in the air stop propagating in the air. More specifically, without wishing to be bound by theory, it is believed that agglomeration results in an increase in particle size, which is believed to increase the Stokes settling velocity of the particles. In some examples, separate airflows may be generated, such as into different directions or at different locations, to carry positively charged air molecules and negatively charged air molecules, respectively. Accordingly, the reaction with surrounding air molecules may be increased and the direct interaction, such as neutralization, between the produced positively and negatively charged air molecules may be reduced.

[0026] Here, it can be understood that the simultaneous production of positively and negatively charged molecules can be achieved by producing positively and negatively charged molecules simultaneously (e.g., at two different locations), or by alternately producing positively and negatively charged molecules (e.g., at the same location) within a short predetermined time period (which can be 60 seconds or less).

[0027] In some examples, one or more physical properties may include at least one physical property indicative of the particle size distribution in ambient air; and the sensor system includes one or more particle sensors to detect at least one physical property indicative of the particle size distribution in ambient air.

[0028] One or more particle sensors may include particle sensors configured to detect particles having a given size. For example, the particle sensors may include a PM1 sensor, a PM2.5 sensor, and / or a PM10 sensor.

[0029] One or more physical properties indicative of the particle size distribution in ambient air may also indicate the total charge of the ambient air. Suitable models for relating the particle distribution to the total charge of the ambient air are known to those skilled in the art.

[0030] In some examples, the controller may be configured to control the ionizer system to simultaneously produce positively charged air molecules and negatively charged air molecules if the amount (e.g., number or ratio) of particles having a size below a threshold size inferred from one or more physical properties indicative of the particle size distribution in ambient air exceeds a threshold (e.g., a threshold).

[0031] Preferably, the simultaneous production of positively and negatively charged molecules changes the ratio of the positively charged air molecules to the negatively charged air molecules produced by the air ionizer system to 1 (or expressed as "1:1"). More preferably, the ratio becomes approximately 1 (or "1:1") such that substantially equal amounts of positively charged air molecules and negatively charged air molecules are produced.

[0032] It can be expected that a large number of small particles usually have a neutral charge, such that it may be preferable to generate both positively charged air molecules and negatively charged air molecules simultaneously.

[0033] In some examples, at least one physical property may include ambient humidity; and the sensor system includes a humidity sensor that detects ambient humidity.

[0034] In some examples, the controller may be configured to control the ionizer system to reduce the ratio of positively charged air molecules to negatively charged air molecules if the detected ambient humidity exceeds a threshold humidity.

[0035] By reducing the ratio of positively charged air molecules to negatively charged air molecules (i.e., increasing the number of negatively charged ions generated relative to the number of positively charged ions generated), the total charge can be increased more effectively because high humidity may indicate the generation of a large number of neutral air molecules due to the neutralization / degradation of charged ions, and known examples of ionization systems can generate negatively charged ions more effectively. More specifically, high humidity contributes to an increased rate of neutralization of either positive or negative ions. To slow down this high degradation rate, more ions need to be generated. This can be achieved more effectively with a negative ion generator because it has been observed that negative ion generators typically generate more ions (e.g., O2 is more easily ionized than N2), and at high humidity, the generation of ionized water molecules may be effective, thereby further increasing the rate.

[0036] In some examples, the ratio of positively charged air molecules to negatively charged air molecules can be reduced by generating only negatively charged air molecules.

[0037] In some examples, at least one physical property may be ambient temperature; and the sensor system may include a temperature sensor that detects ambient temperature.

[0038] In some examples, the air purification device may be configured to change the ratio of positively charged air molecules to negatively charged air molecules generated by the air ionizer system by generating both positively charged air molecules and negatively charged air molecules simultaneously.

[0039] In some examples, the air ionizer system may be configured to change the ratio of positively charged air molecules to negatively charged air molecules generated by the air ionizer system by generating predominantly positively charged air molecules (preferably only positively charged air molecules) or predominantly negatively charged air molecules (preferably only negatively charged air molecules).

[0040] In some examples, the air purification system may further include a particulate filter and a fan assembly configured to generate an air flow through the particulate filter by inhaling ambient air.

[0041] By adding a particulate filter and a fan assembly, air purification can be further improved. In particular, due to the condensation of air molecules and electrostatic attraction, generating charged air molecules can improve the efficiency of the particulate filter.

[0042] In some examples, the particulate filter, the fan assembly, and the air ionization system may be included in the air purification device; and the sensor system includes at least one sensor located inside the air purification device, or the sensor system includes at least one sensor located outside the air purification device.

[0043] In some examples, the air purification system may include one or more additional air ionization systems (for example, they may be located at different positions in the same room, which may contribute to the overall condensation as described above). The / each additional air ionization system may be located in the same unit as the / each external sensor.

[0044] The present invention includes combinations of the described aspects and preferred features, unless such combinations are clearly impermissible or explicitly avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Embodiments and experiments illustrating the principles of the present invention will now be discussed with reference to the accompanying drawings, in which:

[0046] Figure 1 is a schematic diagram of an air purification system including an air purification device.

[0047] Figure 2 is Figure 1 Another schematic diagram of the air purification system, also showing the on-board components.

[0048] Figure 3 is another schematic diagram of the air purification system, further including a plurality of external sensors. DETAILED DESCRIPTION

[0049] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying drawings. Further aspects and embodiments will be apparent to those skilled in the art.

[0050] Figure 1 and 2An exemplary air purification system 10 is shown. The air purification system 10 includes an air purification device 100 configured to process ambient air by removing particles from the air. In this example, the device 100 is configured to remove particles from the air by ionization and filtration. More generally, a device 100 without a filtration device can also be contemplated, for example, as part of a system that includes a separate filtration device.

[0051] In use, the device 100 inhales ambient air and discharges purified air by generating an air flow 110 that passes through a particle filter 120 and an air ionization system 130. The particle filter 120 is configured to retain particles 1000 carried in the air flow 110, such as dust and other contaminants. The air ionization system 130 is configured to generate charged air molecules 1010, 1020 in the air flow 110 by generating negatively charged molecules 1010 and positively charged air molecules 1020. In use, the device 100 returns the air molecules that have been charged by the air ionization system 130 to the ambient air, and the device 100 retains the particles 1000 captured by the particle filter 120. In this example, the air ionization system 130 is located downstream of the particle filter 120.

[0052] The device 100 includes a fan assembly 140 that generates the air flow 110. The fan assembly 140 causes ambient air to be inhaled into the device 100 and the purified air to be returned to the ambient air. The fan assembly 140 may also be referred to as a compressor and includes a motor 142 and a rotor 144 driven by the motor 142 to generate the air flow 110. In this example, the particle filter 120 is located upstream of the fan assembly 140 and the air ionization system 130 is located downstream of the fan assembly 140.

[0053] The device 100 includes a sensor system 150 configured to sense one or more physical properties of the ambient air. The one or more physical properties describe or indicate environmental conditions or the physical state of the surrounding air, such as charge, particle concentration (e.g., the number of particles per unit volume, such as per cubic centimeter), particle size distribution, and humidity. In this example, the sensor system 150 is configured to sense multiple physical properties of the ambient air.

[0054] Device 100 includes a controller 160 configured to control an air ionizer system 130 to vary the ratio of positively charged air molecules 1020 to negatively charged air molecules 1010 generated by the air ionizer system 130 based on multiple physical characteristics of ambient air sensed by a sensor system 150. By varying the ratio of the generated positively and negatively charged air molecules 1010, 1020 based on one or more physical characteristics of the ambient air, purification by ionization can be improved. For example, this may increase particle agglomeration such that particles in the air adhere to each other and fall out of or are attracted to an electrostatic surface. Additionally, this can improve purification by filtration as more particles can be captured by a particle filter 120 when the device 100 re - inhales air due to particle agglomeration. Thus, the air purification system 10 provides variable - polarity ionization based on sensed data indicative of at least one physical characteristic (or “ambient parameter” or “ambient condition”) of the ambient air to improve purification.

[0055] In this example, the sensor system 150 includes a charge sensor 152, a particle sensor 154, a humidity sensor 156, and a temperature sensor 158.

[0056] The charge sensor 152 is configured to sense the charge of air molecules in the ambient air. The charge of the air molecules detected by the charge sensor 152 represents the total charge of the ambient air. That is, the controller 160 determines whether the ambient air is generally positively charged, negatively charged, or neutral based on the output from the charge sensor 152.

[0057] Based on the charge sensor 152, the controller 160 is configured to control the air ionizer system 130 to vary the ratio of positively charged air molecules 1020 to negatively charged air molecules 1010 generated by the air ionizer system 130, thereby increasing the total charge of the air molecules. In this example, when it is determined that the ambient air is generally positively charged, the controller 160 controls the air ionizer system 130 to generate mainly or exclusively positively charged air molecules 1020. Similarly, when it is determined that the ambient air is generally negatively charged, the controller 160 controls the air ionizer system 130 to generate mainly or exclusively negatively charged air molecules 1010. By increasing the total charge of the ambient air, particle agglomeration can be improved. Additionally, there is an incremental increase in the charge between the ambient air and an electrostatic filter or surface. That is, the electrostatic attraction to the surface can be enhanced because the difference in charge can increase, and correspondingly, the electrostatic attraction increases. Thus, in some examples, neutralization of the existing total charge of the ambient air is avoided and instead the existing total charge is increased.

[0058] In this example, the physical property indicating charge is by direct measurement of the charge of ambient air by the charge sensor 152. However, it is also possible that the physical property is not a direct measurement of charge, but a physical property indicating the total charge. There is a suitable model that relates the physical property of the ambient air to the expected charge of the ambient air. In this way, other sensors of the sensor system 150 can also be used to estimate the total charge of the ambient air and the ionizer system 130, depending on the estimated total charge.

[0059] The particle sensor 154 is configured to detect a parameter indicating the particle concentration in the ambient air, such as by directly measuring the concentration. Based on the particle sensor 154, the controller 160 is configured to control the air ionizer system 130 to simultaneously generate positively charged air molecules 1020 and negatively charged air molecules 1010 if the parameter indicating the particle concentration in the ambient air exceeds a predetermined threshold. For example, the controller 160 can adjust the ratio of the positively charged air molecules 1020 to the negatively charged air molecules 1010 to 1 (or expressed as "1:1"). In this example, the controller 160 can adjust the ratio to approximately 1 (or "1:1") such that when the number of particles detected in the ambient air exceeds the predetermined threshold, the air ionizer system 130 generates substantially equal amounts of positively charged air molecules 1020 and negatively charged air molecules 1010.

[0060] In the case where a high concentration of particles is detected in the ambient air, these particles can be expected to be electrically neutral, such that generating positively and negatively charged air molecules 1010, 1020 can increase particle agglomeration, which can cause the particles in the air to fall out of the ambient air.

[0061] In this example, the controller 160 is configured to determine the distribution of particle sizes in the ambient air based on the particle sensor 154 and the parameter indicating the particle concentration in the ambient air.

[0062] Based on the particulate sensor 154, the controller 160 is configured to control the air ionizer system 130 to simultaneously generate positively charged air molecules 1020 and negatively charged air molecules 1010 when the amount of particles having a size below a threshold size inferred from one or more physical properties indicating the particle size distribution in ambient air exceeds a threshold number. For example, the controller 160 may adjust the ratio of the positively charged air molecules 1020 to the negatively charged air molecules 1010 to 1 (or may be expressed as "1:1"). In this example, the controller 160 may adjust the ratio to approximately 1 (or "1:1") such that when the number of particles having a size below the threshold size inferred from one or more physical properties indicating the particle size distribution in ambient air exceeds the threshold number, the air ionizer system 130 generates substantially equal amounts of positively charged air molecules 1020 and negatively charged air molecules 1010.

[0063] In this example, the particulate sensor 154 is configured to detect particles having a diameter of 1 micron or less, particles having a diameter of 2.5 microns or less, and particles having a diameter of 10 microns or less. Based on the output of the particulate sensor 154, a parameter indicating the particle concentration in ambient air and the distribution of the particle sizes in ambient air are determined.

[0064] The humidity sensor 156 is configured to detect the ambient humidity.

[0065] Based on the humidity sensor 156, the controller 160 is configured to control the air ionizer system 130 to reduce the ratio of the positively charged molecules 1020 to the negatively charged molecules 1010 when the detected ambient humidity exceeds a threshold humidity. In this example, the ratio of the positively charged molecules 1020 to the negatively charged molecules 1010 is adjusted such that when the threshold humidity is exceeded, only negatively charged molecules 1020 are generated. By reducing the ratio of the positively charged air molecules to the negatively charged air molecules, the total charge can be increased more effectively because high humidity may indicate a large number of electrically neutral air molecules and generating negatively charged air molecules can be more effective.

[0066] The temperature sensor 158 is configured to detect the ambient temperature. Based on the temperature sensor 158, the controller 160 is configured to control the ionizer system 130 to change the ratio of the positively charged air molecules 1020 to the negatively charged air molecules 1010 generated by the air ionizer system 130 according to the detected ambient temperature.

[0067] In summary, the above-described air purification system 10 is configured to change the polarity of the ionization charging based on at least some of the following sensed data:

[0068] · Particulate matter composition, such as size, material, charge, concentration; and / or

[0069] · Environmental conditions such as humidity, pressure, temperature.

[0070] The air purification system 10 can provide an optimized reduction of particles in the ambient air in the following ways:

[0071] · Only negative ionization,

[0072] · Only positive ionization,

[0073] · A simultaneous mixture of positive and negative ionization, for example at different locations, and / or

[0074] · A mixture of positive and negative ionization, for example an alternation of the two ionizations.

[0075] Thus, the air purification system 10 can provide:

[0076] · Increased particle agglomeration, so that the particles adhere to each other, become larger and are easier to filter;

[0077] · An increased charge on the particles, meaning that they are electrostatically attracted to the fibers; and / or

[0078] · An increased charge on the particles, meaning that they are electrostatically attracted to the surface, so that they are no longer in the air.

[0079] The above air purification device 100 uses a particle filter 120 and an air ionization system 130 to purify the air. In other examples, the particle filter 120 and the air ionization system 130 can be provided in separate devices. In further examples, the air ionization system 130 can be without the particle filter 120.

[0080] The above air ionization system 130 is a single structure configured to generate positively charged air molecules 1020 and negatively charged air molecules 1010. In other examples, the air ionization system 130 includes at least two separate structures for generating positively charged air molecules 1020 and negatively charged air molecules 1010 respectively. In some examples, there is a single positive ionizer and a single negative ionizer at different locations. In some examples, there is a single positive ionizer and a single negative ionizer at the same location (e.g., adjacent to each other) with the same electronic controller. In some examples, there are multiple negative and positive ionizers on the air purification device 100. In some examples, the ionization system is configured to change the polarity based on an electronic controller.

[0081] The sensor system 150 includes multiple sensors 152, 154, 156 to sense multiple physical properties of the ambient air. In other examples, a different number of sensors can be provided. For example, a single sensor or different multiple sensors can be included in the device 100.

[0082] The described sensor system 150 is fully included within the air purification device 100. In other examples, some of the sensors 152, 154, 156 may be external to the device 100. That is, the sensors may be in various locations, such as at the air inlet of the device 100, at the air outlet of the device 100, at a remote sensing station, or on a wearable smart device.

[0083] As described above, the particulate sensor 154 is used to determine parameters indicative of the particulate concentration and the particulate size distribution in ambient air. In other examples, the particulate sensor 154 may be used to determine only the total number of particles, or only the distribution of particulate sizes in ambient air.

[0084] In the air purification device 100 described above, the air ionization system 130 is located downstream of the particulate filter 120. In other examples, the air ionization system 130 is located upstream of the particulate filter 120. In either configuration, positively and negatively charged air molecules are generated in the air stream 110 before the air stream 110 is blown into ambient air. Thus, the ionization system 130 is arranged to affect the environment in which the air purification system 10 is located, such as a room or other enclosed space.

[0085] Figure 3 An air purification system 10 is shown that also includes a plurality of external sensors 200, 300, 400. In this example, the plurality of external sensors includes a first external sensor 200 configured to measure ambient humidity and temperature. The plurality of external sensors also includes a second external sensor 300 to detect particles in the air. The plurality of external sensors also includes a smart device 400. The device 100 is configured to communicate appropriately with the plurality of external sensors 200, 300, 400, for example, using Bluetooth or Wi-Fi. In an example, some or all of the external sensors may be present.

[0086] Features disclosed in the foregoing description, or in the following claims, or in the drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed result, may, where appropriate, be used alone or in any combination of these features in their different forms to implement the invention.

[0087] Although the invention has been described in connection with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art when the present disclosure is given. Accordingly, the above exemplary embodiments of the invention are considered illustrative and not restrictive. Various changes may be made to the described embodiments without departing from the spirit and scope of the invention.

[0088] For the avoidance of any doubt, any theoretical explanations provided herein are for the purpose of enhancing the reader's understanding. The inventors do not wish to be bound by any such theoretical explanations.

[0089] Any chapter headings used in this document are for organizational purposes only and should not be construed as limiting the subject matter described.

[0090] Throughout the specification, including the claims that follow, unless the context requires otherwise, the words "comprise" and "include" and variations thereof will be understood to imply the inclusion of the stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0091] It must be noted that, as used in the specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" a particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from one particular value and / or to another particular value. Similarly, when values are expressed as approximations by use of the antecedent "about", it will be understood that the particular value forms another embodiment. The term "about" associated with a numerical value is optional and means, for example, + / - 10%.

Claims

1. An air purification system for purifying ambient air, the air purification system comprising: An air ionizer system configured to charge air molecules of ambient air, wherein the air ionizer system is configured to generate positively charged air molecules and negatively charged air molecules; A sensor system configured to sense one or more physical characteristics of ambient air; and A controller configured to control the air ionizer system to change a ratio of positively charged air molecules to negatively charged air molecules generated by the air ionizer system based on the one or more physical characteristics of ambient air sensed by the sensor system.

2. The air purification system according to any one of the preceding claims, wherein, The one or more physical characteristics include at least one physical characteristic indicating a total charge of ambient air; And wherein the controller is configured to control the air ionizer system to change the ratio of positively charged air molecules to negatively charged air molecules based on the total charge of ambient air.

3. The air purification system according to claim 2, wherein, The controller is configured to control the air ionizer system to change the ratio of positively charged air molecules to negatively charged air molecules generated by the air ionizer system so as to increase a total charge of air molecules.

4. The air purification system according to claim 2 or 3, wherein, The sensor system includes a charge sensor configured to sense a charge of air molecules in ambient air; and wherein the charge of air molecules detected by the charge sensor indicates the total charge of ambient air.

5. The air purification system according to any one of the preceding claims, wherein, The one or more physical characteristics include a parameter indicating a particle concentration in ambient air; and wherein the sensor system includes a particle sensor to detect the parameter indicating the particle concentration in ambient air.

6. The air purification system according to claim 5, wherein, The controller is configured to control the air ionizer system to simultaneously generate positively charged air molecules and negatively charged air molecules if the parameter indicating the particle concentration detected in ambient air exceeds a predetermined threshold.

7. The air purification system according to any one of the preceding claims, wherein, The one or more physical characteristics include at least one physical characteristic indicating a particle size distribution in ambient air; and wherein the sensor system includes one or more particle sensors to detect the at least one physical characteristic indicating the particle size distribution in ambient air.

8. The air purification system according to claim 7, wherein, The controller is configured to control the air ionizer system to simultaneously generate positively charged air molecules and negatively charged air molecules if an amount of particles having a size below a threshold size inferred from the one or more physical characteristics indicating the particle size distribution in ambient air exceeds a threshold.

9. The air purification system according to any one of the preceding claims, wherein, The at least one physical characteristic includes ambient humidity; and wherein the sensor system includes a humidity sensor to detect the ambient humidity.

10. The air purification system according to claim 9, wherein, The controller is configured to control the air ionizer system to reduce the ratio of positively charged air molecules to negatively charged air molecules if the detected ambient humidity exceeds a threshold humidity.

11. The air purification system according to any one of the preceding claims, wherein, The at least one physical characteristic includes ambient temperature; and wherein the sensor system includes a temperature sensor to detect the ambient temperature.

12. The air purification device according to any one of claims 1 to 11, wherein, The air purification device is configured to change the ratio of positively charged air molecules to negatively charged air molecules generated by the air ionizer system by simultaneously generating positively charged air molecules and negatively charged air molecules.

13. The air purification device according to any one of claims 1 to 11, wherein, The air ionizer system is configured to change the ratio of positively charged air molecules to negatively charged air molecules generated by the air ionizer system by generating only positively charged air molecules or only negatively charged air molecules.

14. The air purification system according to any one of the preceding claims, further comprising: Particle filter; And A fan assembly configured to generate an air flow through the particle filter by sucking in ambient air.

15. The air purification system according to claim 14, wherein, The particle filter, the fan assembly, and the air ionizer system are included in an air purification device; and wherein the sensor system includes at least one sensor located inside the air purification device, or the sensor system includes at least one sensor located outside the air purification device.

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