Field of the Invention

This disclosure relates to air purification, and particularly relates to smart control of air purifiers.

Background of the Invention

Air purifiers clean air by removing airborne injurants in the air, which typically comprise particles as well as bacteria and viruses. Therefore, air purifiers are very important for human health. For example, air purifiers help people that suffer from allergies, particularly hay fever by removing the pollens in the air.

Modern air purifiers may comprise a set of different filters which are designed to cope with different sizes and types of airborne injurants. An air purifier is shown in Figure 1, wherein reference signs L, M, N and O denote four separate filters. P is the front panel. A is an air quality indicator, G is an air inlet, B is an outlet for purified air, and H is the front panel. Control panel K acts as a user interface and includes buttons and indicators 1-10. The purifier also includes a handle F, a base I and a power cord J. C, D and E denote air quality sensors.

Performances of air purifiers can be evaluated by their effectiveness in reducing airborne injurant (pollutant such as toxic gas, allergic source such as pollen, atmospheric particulate matter and etc.). This effectiveness is measured by the clean air delivery rate, or CADR, developed by the

Association of Home Appliance Manufacturers, or AHAM. The CADR is a measure of a portable air purifier's delivery of contaminant-free air, expressed in cubic feet per hour (ftVh). This enables the cleaning rate of different air purifiers to be compared. Summary of the Invention

The characteristic of airborne injurants in the atmosphere is not constant, but varies in different seasons, different days, even different hours and varies over different geographic regions.

For example, the concentration of inhaling particulate matter, including respirable suspended particle (PM10 for short) and fine particles (PM2.5 for short), partially depends upon the industrial particulate discharge resulted by e.g., electricity generation or district heat supply from coal. In summer, there is no district heat supply thus the concentration of inhaling particulate matter is relatively lower.

A person suffering from hay fever can have an allergy to one or multiple types of pollens, but the relative importance of the kinds of pollen that can be the trigger for hay fever depend on different climatic and vegetation zones. Specific plants are known to pollinate at specific times of the year. For example, the season of tree pollen is from late March to mid-May. The season of grass pollen is from mid-May to July. The season of weed pollen is from end of June to September. A more detailed statistic for pollen for each of a plurality of plants is provided in a Pollen Calendar by University of Worcester at the website of http://www.worc.ac.uk/discover/pollen-calendar.html.

Environmental protection office and healthy office now make forecasts about the airborne injurants. For example, environmental protection office makes a daily forecast about the inhaling particulate matter. In another example, The UK MET (Meteorological) office makes pollen forecasts on a daily basis, which can be found at the website of http://www.metoffice.gov.uk/public/weather/forecast/?tab=map &map=Pollen. The website also describes a European wide survey of pollen by which hay fever sufferers can keep a pollen diary.

Symptoms last much longer than the actual exposure. Therefore, exposure has to be avoided or at least minimized. However, the current air purifiers despite the different characteristic of the coming airborne injurants. In an example, the injurant concentration is predicted to be high, but since the air purifier is unaware of that, it starts to operate too late, such that it does not have enough time to clean the injurants completely before the user arrives at home. In another example, the injurants concentration is predicted to be low, but the purifier is unaware of that and starts too early, causing energy to be wasted.

To better address this problem, a smart use of injurant forecast data is required to determine an operation scheme for the air purifier. Preferably, presence information of the user, for example the time when the user is presumed to arrive at home, may be used to determine the operation scheme.

Preferably, characteristic of airborne injurants may be detected and the detection result may be provided to the user, thereby allowing the user to have a cross reference with their personal symptoms caused by the injurants. Preferably, weather forecast and/or real-time weather report (e.g., including wind direction) may be used to refine the forecasted injurant data, in view that weather condition has influence on characteristic of injurants. Preferrably, location information may be used to refine the injurant forecast data, thereby the injurant forecast is made specific to a certain location. To this end, in an aspect of the invention, it is proposed a controller for controlling an air purifier, comprising: a first obtaining module adapted to obtain a forecast of airborne injurants; a determination module adapted to determine an operation scheme of the air purifier according to said forecast of airborne injurants; and a purifier interface adapted to communicate with the air purifier and to transmit said operation scheme to the air purifier.

In this aspect, the operation scheme is determined according to the airborne injurant forecast. Therefore this aspect can enable the air purifier to act intelligently: scheduling early starts on high injurant risk days to ensure the cleaning effect, and delaying starting on low injurant risk days to save energy and decrease noise.

Preferably, the controller further comprises a second obtaining module adapted to obtain schedule information, the schedule information related to a target time when the injurants have been substantially removed; wherein said determination module is further to determine said operation scheme according to said forecast of airborne injurants and said schedule information; and the operation scheme comprises at least any of the following: the time to start and/or to stop purifying; the intensity of purifying.

In this embodiment, a target time when the injurants have been substantially removed is used by the controller to determine the time to start and/or to stop purifying or the intensity of purifying, such that the injurants can be substantially removed when the target time comes. This embodiment brings extra convenience to the user by intelligently configuring the air purifier to conform to the user's arrangement. When the target time comes, the air has been cleaned thus is safe for the user.

Further preferably, the second obtaining module is further adapted to obtain presence information of a user as the schedule information, said presence information related to the target time when the user is at the air purifier; wherein the presence information comprises: the target time entered by the user; or a location of the user provided by a positioning system, the second obtaining module calculating the target time according to the location of the user.

In this embodiment, the target time is entered by the user, and air purifier configured at the user's discretion. Or an estimated target time that the user would arrive at home is calculated based on the location of the user that is provided by a positioning system. Preferably, said purifier interface is further adapted to receive, from this air purifier and/or other air purifiers throughout a geographic region or a country, a detection of the injurants; the controller further comprises: a user interface adapted to receive user symptoms from a user; a database adapted to store the user symptoms in relation to the detection of the injurants; wherein the user interface is further adapted to correlatively display the stored user symptoms and the detection of the injurants.

In this embodiment, these air purifiers can shares their detections to form a crowd sourced network. This would greatly increase the number of detection samples and improve the accuracy of detection. Additionally, the controller can generate correlations between the detection of injurant and the user's symptoms, for example from day to day. This enables users to check their symptoms by reference to the detection of injurants, to have a better understanding about how injurant influences them. This understanding is very important for the user to take appropriate countermeasures against the injurant in their daily life. The user can also share this information with external support organisations, such as medical institutions to have a better diagnosis on his/her condition.

Further preferably, the user interface can be adapted to receive sensitivity information about the user's symptoms for different levels of the injurants; and/or the database is further adapted to generate sensitivity information about the user's symptoms for different levels of the injurants according to the stored user symptoms and the detection of the injurants;

and said determination module is further configured to: obtain a target level of the injurants according to the sensitivity information, the user's symptoms for the target level being better than a threshold; and determine the operation scheme of the air purifier according to the obtained target level of the injurants and a level of the injurants indicated by said forecast.

User may have different symptoms under different levels of the injurants. In this embodiment, The embodiment obtains a target level is obtained under which the user may have no symptom. Given the forecasted level and the target level, the operation of the purifier can be determined to clean the air from the forecasted level to the target level, thereby ensuring a sufficient cleaning and preventing the user from any symptoms.

In an embodiment, the injurants comprises a plurality of types, and the sensitivity information comprises the user's symptoms for each type; said determination module is further to: for each type, identify the user's symptoms that corresponds to the level of the injurants indicated by said forecast; determine one or more types, with the identified user's symptoms worse than the threshold, as specific types; obtain the target level of the injurants of the specific types according to the sensitivity information; and determine the operation scheme of the air purifier according to the obtained target level of the injurants of the specific type and the level of the injurants of the specific type indicated by said forecast.

In the daily life, there may be a plurality of types of injurants, and the user suffers from each of them differently. Taking pollen for example, a person may have different allergic symptom under pollen of different plants. In this case, the present embodiment further analyzes each type of injurants to find the threatening types, and determines operation scheme to clean these types of injurants, thereby avoiding any symptoms.

Preferably, the controller further comprises a third obtaining module adapted to obtain forecasted/realtime weather; wherein, said determination module is further adapted to determine the operation scheme according to the forecast of airborne injurants and the forecasted/realtime weather, wherein the determination module is to: adjust the forecast of airborne injurants according to the forecasted/realtime weather; and determine the operation scheme according to the adjusted forecast of airborne injurants. Preferably, said forecasted/realtime weather comprises at least any one of: wind; temperature; humidity; and rain.

The characteristic of airborne injurant is influenced by the weather. For example, if it is a windy day, the concentration of airborne injurant is relatively higher than the usual forecasted concentration. In this embodiment, in order to have a more accurate characteristic of airborne injurant, the forecasted/realtime weather is considered to refine the forecast of airborne injurants. Therefore, a more accurate forecast can be obtained, and the purifier can operate more adaptively.

Preferably, the controller further comprises a fourth obtaining module adapted to obtain location information related to the air purifier; wherein said first obtaining module is further to localize the forecast of airborne injurants, according to the location information; said third obtaining module is further to localize the forecasted/realtime weather, according to the location information; and said determination module is further adapted to determine the operation scheme according to the localized forecast of airborne injurants and the localized forecasted/realtime weather.

In this embodiment, the location of the purifier is further considered to refine the injurant forecast and the forecasted/realtime weather, thus these forecasts are more specific to the purifier and therefore are more accurate. Thus, the purifier can operate more adaptively.

Preferably, the controller further comprises a fifth obtaining module adapted to obtain purification performance, the purification performance comprising any one of the following: purification capability of the air purifier; purification history of the air purifier; the size of indoor environment to be purified; the air ventilation condition of the indoor environment with outdoor atmosphere; and purification capability of other purifiers within the indoor environment, when there are other purifiers within the indoor environment; and the determination module determines the operation scheme according to the purification performance.

This embodiment proposes a more detailed solution about how to determine the operation scheme by taking the practical purification performance into consideration. This embodiment conforms to practical implementation.

Further preferably, the determination module is further to estimate the duration for purifying the air according to:

V Pi (1 - E)

R Pt

wherein J ¹ is said duration, J ⁷ is the volume size of the indoor environment, Pi is the level of the injurants indicated by said forecast, Pt is the obtained target level of the injurants, E is an efficiency of purification and R is a clean air delivery rate; and the determination module is further to determine the time to start purifying according to the target time and the duration for purifying the air.

This embodiment proposes a quantitative solution to calculate how long the purification would last to ensure that the injurant is cleaned to the target level. The desired purification effect can be obtained.

Preferably, the user interface is further adapted to receive the user's adjustment to the operation scheme; and the determination module is adapted to adjust the operation scheme according to the user's adjustment before the purifier interface transmits said operation scheme to the air purifier.

This embodiment provides the user with a manual override controlling capability, and gives the user a flexibility of adjusting the operation scheme according to his/her discretion.

Preferably, the purifier interface is further adapted to receive a detection of the injurants from the air purifier and/or other air purifiers; the controller further comprises: a collecting module adapted to collect detections of the injurants from the air purifier and/or the other air purifiers; and an external interface adapted to provide the collected detections of the injurants from the plurality of the air purifiers for external processing.

In this embodiment, these air purifiers can shares their detections to form a crowd sourced network, and the detection of the injurants are collected by the controller for external processing. In one embodiment, these detections can be used by an external application to analyse local changes to pollen conditions and compared with weather data and time of year to improve the understanding of pollen flare ups. In another embodiment, the pollen data can be used for a model updating processing, carried out by the forecasters to enable them to improve forecasting models by using the accurate and real-time detection. In this case, a feedback mechanism is formed, the forecasters can compare a given forecast with the real samples taken to improve their forecasting model, and more accurate forecast can be generated. In a further embodiment, the environmental office can use these detections to enable local personalized injurants alarms, ensuring that the user is warned earlier for specific injurants. The collected detection can also be used to create a detailed injurants map for the users, showing areas of higher risk due to local environmental conditions at specific times of the year. To sum up, in the present disclosure, the concept of constructing a crowd sourced network of a plurality of air purifiers would provide a statistically more accurate detection of injurants, to enable more accurate forecasting as well as alarming.

Preferably, the purifier interface comprises at least any one of: a wired or wireless network interface; and a near field communication interface.

This embodiment proposes different solutions of communicating the operation scheme to the purifier. Through a wired or wireless network interface, the controller can be located on any network entity, such as a server, a PC, and a mobile phone, thus it is very convenient to control the purifier. Alternatively, through a near field communication (NFC) interface, the controller can be implemented by a mobile phone. The user may simply run a mobile application installed on the mobile phone to communicate the operation scheme to the air purifier. Since many current mobile phones have already integrated the NFC interface, this implementation is low cost and convenient for domestic use of user.

Preferably, said forecast of airborne injurants comprises any one of: pollen forecast; and air pollution forecast.

Pollen is a big allergic source. How to better eliminate the pollen to prevent hay fever is a very important technical problem. The present embodiment can be used for purifying air and removing pollen intelligently according to the actual pollen counts, thereby alleviating pollen's threats to people, and thus the present embodiment is very promising.

Air pollution such as PM10 and PM2.5 is a significant environmental problem in some regions and countries. The present embodiment can be used for removing the particulate matter intelligently according to the air pollution forecast, and provides the user a clean indoor atmosphere.

Preferably, the controller is integrated in any one of: a server; a portable equipment; and the air purifier.

This embodiment proposes several ways to implement the controller. In case that the controller is in a server, a centralized controlling can be implemented wherein the controller can provide operation scheme for air purifiers across the country. In case that the controller is in a portable equipment of the user, the user can control the air purifier very conveniently. And in case that the controller is integrated in the air purifier, the air purifier alone can operate intelligently, without the involvement of other controlling entities.

In a preferred embodiment, the controller is further adapted to: predict the user's symptoms for each geographic region, by comparing the level of the injurants in each region in the forecast of airborne injurants with the sensitivity information about the user's symptoms for different levels of the injurants; make suggestions about whether or not the user can go to each region based on the predicted user's symptoms for each region; and provide the user with the suggestions about whether or not the user can go to each region.

In this embodiment, the controller can provide the user with going or not going suggestions so as to alert the user about potential regions that would probably be unhealthy. The user can arrange his journey according to this suggestion to avoid being influenced by the injurants.

In a preferred embodiment, the determination module is further adapted to: obtain occupancy information about the user in the room, from an occupancy sensor; and determine whether to or not to start the purifier according to occupancy information.

In this embodiment, occupancy information about the user can be used as a trigger to switch the air purifier on/off. In case that occupancy information indicates that the user is in the room, the air purifier can be switched on; otherwise it would be switched off. This intelligent configuration allows energy to be saved.

In another embodiment, the determination module is further adapted to: obtain injurant presence information in the room based on sensor detection; and determine to start or not to start the purifier according the injurant presence information. In this embodiment, other environmental condition, which would influence the presence of injurants, can be detected. Thus the presence of injurant can be determined according to this detection, and corresponding purification can be controlled. Preferably, the sensor detection comprises any one of: a detection of human activity that might re-introduce injurants settled in the room into the air, from an occupancy sensor; a detection of open doors/windows that allow outdoor airborne injurants into the room, from a door/window sensor.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Brief Description of the Drawings

Features, aspects and advantages of the present invention will become obvious by reading the following description of non-limiting embodiments with the aid of appended drawings.

Fig. 1 schematically illustrates a structure of an example air purifier;

Fig. 2 shows a communication network including the air purifier and a controller according to an embodiment of the invention,

Fig. 3 shows a block diagram of the controller according to an embodiment of the invention;

Fig. 4 shows the relationship between the symptom score and the pollen counts (concentration);

Fig. 5 shows the relationship between the percentage of people that suffers from symptoms and the pollen counts (concentration) with a threshold;

Fig. 6 shows an overview of an expert system to implement the controller according to the embodiments of the invention.

Detailed Description

The present application proposes a controller for controlling an air purifier, comprising:

- a first obtaining module adapted to obtain a forecast of airborne injurants;

- a determination module adapted to determine an operation scheme of the air purifier according to said forecast of airborne injurants;

- a purifier interface adapted to communicate with the air purifier and to transmit said operation scheme to the air purifier. The systematic architecture and functions of the controller will be elucidated with reference to fig. 2 and fig. 3, while the detailed way of determining the operation scheme will be discussed later.

Fig. 2 illustrates an example system network architecture including a controller according to an embodiment of the invention. The controller denoted by reference sign 20 is integrated into a server. Reference sign 22 denotes a server providing a forecast of airborne injurant, which may be pollen forecast or pollution forecast. Reference sign 24 denotes a network router connecting the controller 20 and an air purifier 10. Reference sign 26 denotes a portable device such as a mobile phone which can access the controller 20 via for example a radio network. The air purifier 10 can also be equipped with a network interface, such as Ethernet interface or via WiFi interface with the router, so as to exchange information with the server.

Fig. 3 shows an example block diagram of the controller 20. The controller 20 comprises the first obtaining module 200, the determination module 202 and the purifier interface 204. In the following elucidations, pollen will be taken as an example of the airborne injurants. Those skilled in the art would understand that the principle of the embodiment of the invention is also applicable for other injurants such as air pollutions.

In a most basic embodiment, as shown in fig. 2, the first obtaining module 200 of controller 20 retrieves the pollen forecast from server 22. The forecast may be the pollen concentration at each clock/half clock of a certain day. The first obtaining module 200 may be a network interface to retrieve the pollen forecast from the server 22 of a public or private pollen forecaster. Currently, there have been a lot of facilities providing such forecast.

The determination module 202 determines an operation scheme of the air purifier according to said forecast of airborne injurants, for example the time to start the air purifier. The operation scheme comprises at least any of the following: the time to start and/or to stop purifying; the intensity of purifying. And the purifier interface 204 sends this operation scheme to the air purifier over the network. The air purifier 10 receives this operation scheme, and configures this scheme by for example setting the start time. The operation scheme can be exchanged by using Java Messaging Service (JMS) to ensure delivery, and other necessary information as described in the following embodiments can be exchanged via JMS as well. Alternatively, other general or dedicated protocol can be used to exchange the operation scheme and other necessary information.

In an advanced embodiment, as shown in fig. 3, the controller 20 further comprises a second obtaining module 206 adapted to obtain schedule information, the schedule information related to a target time when the injurants have been substantially removed. And the determination module 202 is further to determine the operation scheme according to said forecast of airborne injurants and said schedule information.

To be more specific, the second obtaining module 206 obtains the presence information of a user as the schedule information. The presence information relates to the target time when the user is at the air purifier. For example, the presence information is the target time inputted by the user. As shown in fig. 2, the portable device 26 may prompt the user to input a desired time when he/she wishes the air is ready, and the portable device 26 transmit this time to the controller 20. Or the second obtaining module 206 retrieves the user's daily arrangement from the user's diary in his smart phone. And the second obtaining module 206 would estimate a target time according to the user's arrangement.

Alternatively, the presence information is a location of the user provided by a positioning system. The second obtaining module 206 calculates an arrival time, according to the location of the user and the route from the user to his home, as the target time. Traffic conditions which are widely available can be further considered by the second obtaining module 206 to more accurately estimate the arrival time. In a more detailed application scenario, a positioning system can detect that the user leaves his work location by locating the user's smart phone, and provide a distance from the user to his home. The second obtaining module 206 could estimate a target time when the user will arrive at home.

In a further embodiment, the second obtaining module 206 could obtain repeating pattern of behavior that the user arrives home at certain days of the week as the schedule information, and predict the target time. For example, a door sensor may provide the second obtaining module 206 with the time when the door is open in each evening, and the second obtaining module 206 may calculate an average time as the predicted arrival time of the user, and take this arrival time as the target time.

The determination module 202 also determines the operation duration for purifying. Given the target time and the duration, the start time can be calculated by subtracting the duration from the target time. The detailed way of determining the duration will be discussed later.

In a varied embodiment, the user's position can also be used as the schedule information to trigger the purifier to switch on. For example, the user's position indicates that the user leaves his/her work place.

In another advanced embodiment, as shown in fig. 3, the controller 20 further comprises a third obtaining module 208 adapted to obtain forecasted/realtime weather from a weather server 28, as shown in fig. 2. And the determination module 202 is further adapted to determine the operation scheme according to the forecast of airborne injurants and the forecasted/realtime weather. To be more specific, the determination module 202 adjusts the forecast of airborne injurants according to the forecasted/realtime weather; and determines the operation scheme according to the adjusted forecast of airborne injurants. Specifically, the determination module 202 may elevate the pollen concentration indicated in the forecast if it is a dry and windy day. In another example, if the humidity is high or just after a thunderstorm, the determination module 202 may also elevate the pollen concentration. In a further embodiment, the controller does not access a weather server to retrieve the weather, but communicates with external outdoor sensors for detecting temperature, humidity wind, rain etc.. These local sensors, as shown by reference sign 34 in fig. 2, are used to detect the realtime weather information and transmit it to the controller 20 via the router 30.

In another advanced embodiment, as shown in fig. 3, the controller 20 further comprises a fourth obtaining module 210 adapted to obtain location information related to the air purifier. The first obtaining module 200 is further to localize the forecast of airborne injurants, according to the location information. The third obtaining module 208 is further to localize the forecasted/realtime weather, according to the location information. The determination module 204 is further adapted to determine the operation scheme according to the localized forecast of airborne injurants and the localized forecasted/realtime weather. To be more specific, the user may use his smart phone to locate his home position, e.g. from GPS, WiFi or cellular triangulation methods to know exactly where the air purifier is located within a few meters. This location can be uploaded to the server 20. Alternatively, the user may input his home address to the server 20. Such accurate location can be cross-referenced with geographic database, so as to retrieve information about what crops are growing in local fields or the numbers of percentages of various trees and grasslands in the local area. This information can be used to refine the pollen forecast. Additionally, the forecasted/realtime weather can also be refined according to the location. Finally, a highly accurate pollen forecast can be obtained.

In another advanced embodiment, the controller 20 has a user interface 212 to provide the user with the determined operation scheme and to receive the user's adjustment to the scheme. And the determination module 202 is adapted to adjust the operation scheme according to the user's adjustment before the purifier interface 204 transmits the scheme to the air purifier. Specifically, this user interface can be a web page server to which the user may access via his web browser; alternatively, the user interface can be a back end for an application running on the user's smart phone, wherein the back end sends the scheme to the application to display and receives the user's adjustment collected by the application.

In another advanced embodiment, the air purifier can be further improved by the use of one or more sensors at the different filter stages to determine the levels of each kind of pollen. And the purifier interface 204 is further adapted to receive a detection of the injurants from the air purifier and/or other air purifiers. The controller further comprises: a collecting module 214 adapted to collect detections of the injurants from the air purifier and/or other air purifiers; and an external interface 216 adapted to provide the collected detections of the injurants from the plurality of the air purifiers for external processing. In an embodiment, the environmental office can use these detections to enable local personalized injurants alarms, ensuring that the user is warned earlier for specific injurants. More specifically, the collected detections of the injurants can be used to create a detailed pollen map to be displayed to the user, showing areas of higher risk due to local environmental conditions at specific times of the year. Additionally, the collected detections of the injurants can be fed back to the pollen forecasters to enable them to assess the accuracy of their forecasting in all areas of the country, so as to further improve forecasting models. The present disclosure constructs a crowd sourced network of a plurality of air purifiers to collect a statistically more accurate detection of injurant. It should also be noted that the user of the respective air purifier in the crowd sourced network could permit or forbid the involvement of his/her air purifier in this network. Other various uses of the collected detections of the injurants are also possible and the present disclosure will not give unnecessary elucidation.

It is important for the user to have a pollen diary, from which the user may realize what kind of pollen threatens him/her most, in order to take appropriate countermeasure. To address this, the user interface 212 is further adapted to receive user's symptoms from a user. The user interface 212 may provide the user with a simple multiple choice questionnaire, which can be done at any time, for example when they are outside to indicate the severity of symptoms suffered. The controller 20 also has a database 218 adapted to store the user symptoms in relation to the detection of the injurants provided by the air purifier. Alternatively or additionally, the controller may also obtain detection of the injurants from external networks where the known sources of pollen at that time and in that area are present. One example of external networks is the crowd sourced network formed by a plurality of air purifiers, wherein the each of air purifiers provides the controller its detection of injurant such as the type of sensed pollen and its count. Preferably, the plurality of air purifiers also provides its location and the controller could obtain the detections of injurant specific to each geographic regions. After the collection of user's symptoms as well as the detection of injurant, the user interface 212 is further adapted to correlatively display the stored user symptoms and the detection of the injurants. In some cases, the detection of the injurant reflects the level of pollen of different size, which can be correlated with pollen from different plants. Therefore, the user can compare his symptoms with the type of plant collected on that day to better understand what plant's pollen most affects the user. In this manner, a user may realize that it is a particular type of plant pollen (e.g. rapeseed) that causes the greatest allergic reaction, allowing him to take appropriate steps to mitigate the condition. In case that the controller is implemented in the server, the user may log in the server via his PC or smart phone to input his/her daily symptoms. Alternatively, in case that the controller is implemented in the smart phone, the user may input his/her symptoms directly into the smart phone.

In the above embodiment, the controller is integrated in the server. In an alternative embodiment, the controller is integrated in the smart phone of the user. The smart phone may access the pollen forecaster to obtain the pollen forecast, and it may access other sources to obtain other necessary information such as forecasted/realtime weather. In one case, the smart phone may determine the operation scheme and transmit it to the air purifier via radio network. Alternatively, it is also possible that the user uses his smart phone to determine the operation scheme for tomorrow when he is at home in the evening, and uses a near field communication (NFC) interfaces or Bluetooth interface with the smart phone to transmit the operation scheme to the air purifier.

In another alternative embodiment, the controller can be integrated in the air purifier itself. The air purifier may have a network interface to access the pollen forecaster; or, the air purifier may download the necessary information from the user's smart phone via NFC or Bluetooth interface, wherein the user's smart phone has previously accessed the pollen forecaster to retrieve the necessary information for the air purifier. Those skilled in the art may understand that there are various practical implementations for the controller, and as along as a controlling entity uses the injurant forecast to determine operation scheme for air purifiers, this controlling entity would fall in the scope of the claims, no matter in what equipment the controlling entity is actually embodied.

Besides the injurant forecast, the controller can determine to or not to start the purifier according the injurant presence information that is detected by sensors. In one embodiment, injurant sensors, such as particle sensors 30 as shown in fig. 2, can be placed inside the room or outside the window to detect the injurant, and notify the controller of the detection to start the purifier. Alternatively, the sensors do not detect the injurant directly, but detect other environment factors that would be correlated with the presence of injurant. In one such example, since human activities such as walking would re-introduce the injurant settled in the room into the air again, an occupancy sensor/presence sensor 32 that detects human activities would be used to notify the controller to start the purifier. In another such example, the user may open a window and outdoor airborne injurants would come into the room. Open doors/windows would be detected by door/window sensors (not shown) and provided to the controller to start the purifier. In the above embodiments, the functionality of the controller can be implemented in the purifier. The sensors 30 and 32 can access the controller 20 via the router 24.

In a further embodiment, the controller can determine to start or not to start the purifier according to a detection representing whether the user has arrived home, namely according to the occupancy information of the user. In one embodiment, the above occupancy/presence sensor can be used. In another embodiment, a user's mobile phone detected in the home network can be used to indicate his/her arrival. Or, the manipulation of home appliances can be sensed to indicates the arrival of the user, such as a schedule of a thermostat, lights being on, etc.. Those skilled in the art would envisage other detection indicating the occupancy information, and the present disclosure would not give other elucidations.

In a still further embodiment, the determination module is further adapted to: obtain behavior information of the user and determine the operation scheme further according to the behavior information. In one example, the behavior information comprises the location of the user with respect to injurant source. For example, the route that was taken by the user when coming home was monitored by GPS tracking in a mobile phone. The determination module obtains this route and compares this route with the geographic location of injurants source, such as fields with a lot of pollen. If the user was in or near the pollen source, the air purifier will adapt its program to a more intense program. This route with respect to the field can also be displayed to the user to check his/her pollen diary feature and self diagnose.

In another embodiment, the behavior information comprise sleep pattern of the user. When the user is in deep asleep cycles, it is okay for to have some noise, therefore the determination module could switch the air purifier on or increase its intensity. On the contrary, in light sleep cycles of the user, the determination module could switch the purifier off or set it on low intensity mode to avoid noise. Human beings share a general common sleep cycles, and these common cycles can be prestored in the determination module. In another example, since the user will breath more after wake up, the determination module could start the purifier a little before the user need to wake up, to ensure that the air the user will breath in is less polluted. The time when the user would wake up could be retrieved from the user's alarm clock.

It should be noted that other behavior information of the user can also be considered by the determination module to determine how to control the air purifier.

The controller could be configured with other functionality besides controlling the purifier according to injurant forecast. For example, the controller can be configured to provide the user with an allergy map indicating places the user can go to and can not go to. More specifically, the controller predicts the user's symptoms for each geographic region, by comparing the level of the injurants in each region in the forecast of airborne injurants with the sensitivity information about the user's symptoms for different levels of the injurants. Then the controller makes suggestions about whether or not the user can go to each region based on the predicted user's symptoms for each region, and provides the user with the suggestions about whether or not the user can go to each region. This suggestion could be alerted to the user in case that the user's location is near dangerous regions, which can be calculated by the positioning system. The above description discusses the system architecture and functions of the controller according to embodiments of the invention. The following description will introduce allergy symptoms due to pollen and how to determine the operation scheme to mitigate the user's symptoms.

A most popular system for translating pollen counts into allergic symptomology appears to have been derived from Burge's work. She analyzed pollen counts from 51 pollen measuring stations to calculate ranges in pollen abundance for three broad categories of pollen types. Although she did not assign clinical significance to these statistical categories, her system has been widely construed by others to have such meaning. The following table 1 presents Burge's ranges and their apparent clinical consequences. (Frenz, 2001).

Table 1

For specific pollen e.g. birch pollen it even seems to be possible to derive the mathematical correlation between symptom score and pollen count as can be seen in fig. 4, wherein the horizontal axis is symptom score and the vertical axis is pollen count (concentration). The symptom scores range from 0 to 3, wherein <0.5 stands for few symptoms; 0.6-10 stands for some symptoms; 1.1-1.5 stands for many symptoms; 1.6-2.0 stands for high symptoms; and >2 stands for very high symptoms. It becomes clear that the symptom score depends logarithmically on pollen count.

Another important fact is that symptoms decay exponentially with a characteristic half-life of 1 to 2 days. (Taudorf & Moseholm, 1988) This means sudden absence of pollen is noticeable quickly, but full recovery takes longer. It was discovered that for the outbreak of pollen allergies individuals show a threshold behavior. As shown in fig. 4, the horizontal axis is percentage of people with symptoms and the vertical axis is pollen count (concentration). For birch pollen, first seasonal symptoms in most people appear to start when the pollen levels rise above a certain threshold level of 20-50 pollen per m ³ , quoted by line 40 and can also be seen in this graph. After the threshold level, the percentage of people with symptoms increases exponentially, as shown by the curve 42. Similar thresholds have been found for other tree pollen such as olive pollen (~400/m ³ ) (Fernando Florida, et al., 1999) and for grass pollen (~50/m ³ ).

Based on the above research, in order to prevent the user from being influenced by the pollen or to mitigate the user's symptoms, the inventors adapt the air purifier to decrease the pollen count (concentration) in the air to a target level that results in no or little symptoms to the user. Given the pollen level (count) indicated by the forecast, and the target level, the operation scheme of the air purifier can be calculated.

More specifically, the controller 20 further comprises a fifth obtaining module 219 adapted to obtain purification performance, the purification performance comprising any one of the following:

- purification capability of the air purifier; and

- the volume size of indoor environment to be purified.

The determination module 204 is further to estimate a duration for purifying the air:

^ _ V Pi (l - E)

¹ R Pt (1) wherein T is said duration, J ⁷ is the volume size of the indoor environment, Pi is the level of the injurants indicated by said forecast, Pt is the obtained target level of the injurants, E is an efficiency of purification and R is a clean air delivery rate (CADR).

An example condition is a room of size 240m ³ , an initial pollen count of 10000 per m ³ , and a target pollen count of 10 per m ³ . A typical air purifier of Philips AC4072 is used, wherein its clean air delivery rate is 320m ³ /h and its efficiency (filters out dust pollen) is 99.9%. The operation duration of this air purifier can be calculated as 24-0 * 10000 * (i - ϋ,9 9)

T = = 0.75 hours

320 * 10

Thus, with any given system with a certain purification capability and in a specific space volume, the time duration taken to reduce pollen levels to a target level that will relieve the symptoms can be calculated. Given this time to clean a room to the required level, an air purifier can subtract the time duration from the above target time, to identify best time at which the purifier begins cleaning so that the room is always ready when the target time comes, and little energy would be wasted and noise will be decreased.

Besides the above listed purification capability and volume size of the room, the purification performance could further comprises:

- purification history of the air purifier. This information can be obtained by the purifier from its previous purification operations.

- the air ventilation condition of the indoor environment with outdoor atmosphere. This information can be input by the user, or be provided by a smart home system which could detect whether the windows/doors are open.

- purification capability of other purifiers within the indoor environment, when there are other purifiers within the indoor environment. This information can be input by the user, provided by a smart home system which manage all purifiers, or collected from those purifiers via a home appliance communication network.

Equation (1) can be updated to reflect these parameters. Those skilled in the art would understand how to modify the equation (1 ) to take these influences into consideration. For example, the purification history and the air ventilation condition can be modeled as a ratio factor to be multiplied with R. The present disclosure would not give further discussion. Additionally, the disclosure invention is not limited to the above equation (1), and other ways of determining the operation duration is also possible.

The above embodiment calculates the operation duration of the air purifier, and those skilled in the art would understand that other operation scheme, such as power (intensity of the purifier) can also be calculated similarly. The present disclosure would not give further discussion.

From the above embodiment, it can be seen that the target level of the pollen is an important factor to determine the operation scheme. In one embodiment, the target level can be fixed as a low pollen count, such as 10/m ³ . Alternatively, the target level can be further tuned according to the user's sensitivity input by the user, such as:

• Extremely sensitive

• Sensitive

• Partially sensitive

• Generally sensitive

The more sensitive the user is, the lower the concentration of the target level is.

Still alternatively, the target level can be determined from the stored user's symptoms with respect to levels, stored in the database 218 as described in the previous part of the description. For example, under a certain level of pollen, the user's input is no symptom, and this certain level can be considered as the target level.

In a more preferable embodiment, types of the pollen can be further considered. The threatening type would be identified. Taking pollen as an example, the pollen comprises a plurality of types, such as birch pollen, olive pollen and grass pollen. The controller may obtain the sensitivity information comprises the user's symptoms for each type. This information can be obtained from the above described database.

Specifically, for each type, the determination module 202 identifies the user's symptoms that correspond to the level of the injurants indicated by said forecast. The determined user's symptoms may be no symptom, medium symptom or severe symptom.

After that, the determination module 202 determines one or more types, with the identified user's symptoms worse than the threshold, as specific types. For example, any type that would result in at least medium symptom would be determined as specific type.

The determination module 202 also obtains the target level of the injurants of the specific types according to the sensitivity information, such as at what pollen count the user would suffer no symptoms.

Finally, the determination module 202 determines the operation scheme of the air purifier according to the obtained target level of the injurants of the specific type and the level of the injurants of the specific type indicated by the forecast. The detailed method has been elucidated above with reference to equation (1). In case that there are several specific types, durations can be determined for each of the specific types according to equation (1), and a maximum duration among them would be used as the operation duration to guarantee that all injurants would be sufficiently removed.

In the practical implementation of the controller, an expert system can be designed to realize the above functions. Intelligent computer systems which can emulate the decision-making ability of a human expert are called as expert systems. Fig. 6 shows an overview of a possible expert system for an indoor allergy management system that can be used to intelligently control the operation of air purifiers.

Reference sign 600 denotes the location of the air purifier. The user's home location can be used to create a localized pollen count forecast as well as forecasted/realtime weather which are specific to the situation faced by the air purifier.

Reference sign 601 denotes daily pollen count forecast. This pollen count can be based on a number of individual forecasts that specifies the count of pollen per m ³ for each specific pollen threat: grass or birch (or other pollen sources).

Reference sign 602 denotes daily forecasted/realtime weather. The weather may comprise wind, temperature, humidity and rain.

Reference sign 603 denotes pollen counts (concentration) adjusted according to the weather.

Reference sign 604 denotes the sensitivity of the user. Individuals will have different sensitization levels to different pollen sources. This can be derived from different sources. The users perceived sensitivity can be initially primed using a questionnaire and fined tuned using feedback from previous symptoms of using the system and allergy test results, if available. This will assign each user a category that is aligned with Burges ranges of clinical consequences (showing allergy symptoms): extremely sensitive; sensitive; partially sensitive; and generally sensitive.

Reference sign 605 denotes the target level and forecasted level of the pollen.

Reference sign 606 denotes the user's schedule information.

Reference sign 607 denotes the purification performance of the purifier.

Reference sign 608 denotes determining the operation scheme. With any given system and power setting in a specific space, the time taken to reduce pollen levels to a target level that will relieve the symptoms can be calculated. The determination module 202 can estimate at any given moment the time at which the purifier needs to switch on to reduce pollen in the space to the required target levels. Given this time to clean a room to the required target level, the determination module can use information to identify the best time at which to begin cleaning so that the room is always ready when the target time comes.

And reference sign 609 denotes user's manual set to the operation scheme 608, and user's input to the sensitivity 604.

The above description takes pollen as an example of airborne injurant to elucidate the embodiments of the invention. Potentially, the embodiments of the invention could also be applied for people with other respiratory conditions e.g. to aid people with inhalers to purify local threat levels. This can be used as information to provide advice for various conditions when atmospheric or seasonal variations affect their condition. It is intended that the term "airborne injurants" covers any substance that injures, threatens, or in other manner does harm to creatures including plants, animals and human being. The "airborne injurants" covers substance that either is gas itself, or is solid or liquid carried in the atmosphere.

For a system which provides symptom improvement it could also cover other types of injurant, such as air pollution for which the impact is more long term and less visible, like particles or gasses. The embodiments of the invention are able to cope with regional variations and can be adapted to the needs of individuals, thereby a wide range of different embodiments are feasible.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

Those ordinary skilled in the art could understand and realize modifications to the disclosed embodiments, through studying the description, drawings and appended claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Some features in one embodiment can be combined with some features in another embodiment to construct yet another embodiment. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.