GB2563199A

GB2563199A - Smart city air cleaning system

Info

Publication number: GB2563199A
Application number: GB1707575.5A
Authority: GB
Inventors: Rizzo Claudio
Original assignee: Spraytecs Tech Ltd
Current assignee: Spraytecs Tech Ltd
Priority date: 2017-05-11
Filing date: 2017-05-11
Publication date: 2018-12-12
Also published as: GB201707575D0

Abstract

A system for reducing particulate matter from polluted air in urban areas e.g. cities, having a central control system(SC-ACS) that controls a plurality of air treatment units (ATU) that are positioned around an urban area, as a result of inputs from air quality monitoring systems (AQMS) and a computational fluid dynamics model (CFD). The control system, ATUs and AQMs are connected via the internet. The control system controls the operation performance of the ATU e.g. air flow, according to their position and the polluted air. The air treatment units have a mechanical filter for removing particles between 1-10 micrometers from large volumes of air, and preferably UV-C LEDs operating between 266 275 nm to inactivate microorganisms. The ATUs may be powered by solar panels, and may be positioned on buildings, city installations e.g. an advertising installations, or on vehicles. The ATUs may have sensors/instruments e.g. to record wind speed and direction.

Description

SMART CITY AIR CLEANING SYSTEM

TECHNICAL FIELD

This invention discloses a method and system to decrease the particulate matters concentration in the outdoor air of polluted urban areas when necessary, consisting in a cloud-based communication system interacting with a network of air treatment devices, correctly positioned as ruled by a method, where are performed physical treatments of polluted urban air in large quantities.

BACKGROUND OF THE INVENTION

Outdoor air pollution is a mayor environmental risk to health, as proven by World Health Organization’s (WHO) many researches. There is current scientific evidence that outdoor air pollution in both cities and rural areas was estimated to cause 3 million premature deaths worldwide per year in 2012; this mortality is due to exposure to small particulate matter of 10 microns or less in diameter (PMio), which cause cardiovascular and respiratory diseases, and cancers. The principals air pollutants, monitored in all WHO Regions, are particulate matter (PM), ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2). Moreover WHO declares that PM affects more people than any other pollutant. PM is considered the worst pollutant issue because may contains many elements, over as Fe, Na, Al, K, Ca, Mn, Zn, Pb, Sc, V, Co, Ni, Mo, Cd, Sn, Sb, Ti, Cr, Cu, Mg, some of them may react in atmosphere when combined with 02, H2O, other air contained elements, temperature and sunlight, originating as secondary effect sulfates, nitrates, ammonia, sodium chloride, black carbon, mineral dust and various corrosive and dangerous substances for humans, animals, monuments with heavy direct and indirect costs in deaths, healthcare, monuments maintenance for individuals and public authorities, also shown in various economic studies about PM pollution effects vs Individual Costs. Large quantity of scientific PM effects literature is widely available and known. The PM concentration in air is particularly high in most urban areas, related to transport emissions, buildings heating systems and building dimension shapes barrier to wind action, that help to stand PM particles in the same urban area in certain weather or geographic conditions. WHO’s Global Health Observatory [Ref. 2] maintains daily mean concentrations of fine particulate matter (PM2.5) in 2,972 cities, and reports that 90% of citizens are inhaling PM over the WHO air quality guidelines.

Moreover another human health threat, related to high PM concentration level in air, is due to the same dimension of smaller PM particles to spores, bacteria, allergens, viruses contained in urban air where PM particles may vehicle and/or help proliferation and vitality of these microorganisms. In fact [Ref. 1] a growing body of evidence shows that chemical air pollution may interact with airborne allergens enhancing the risk of atopic sensitization and exacerbation of symptoms in sensitized subjects.

To better understanding the dispersion of pollutants in city air, Computational Fluid Dynamics (CFD) technology is currently being used by many research groups [Ref. 3] and private companies. As general it is possible to model city air currents and consequently obtain some information on probability of major PM concentration in any positions of urban areas and/or the whole city [Ref. 4] during different wind intensity, direction, air temperature and local pressure conditions. Also geographical city characteristics and industries activities positioning are relevant about pollutants sources and behaviour in the urban living areas.

The term “cloud” has been used to refer to platforms for distributed computing since 1994, about features of distributed programming language Telescript [Ref. 6]. Therefore any suitable cloud-based software platform may be used as service to raise the reliability level of a software system against limited local hardware faults, as well known technology. US. Pat. No. 3,490,211 (Cartier) discloses an air particulate filter with high efficiency where a great air filtering surface per unit volume is obtained using a filtering material organized in series of pleats. This permits to design filter sets with lower pressure drops, where the filtering material’s pores maximum size assures the size class of particulate matter to be filtered. This solution and similar are today widely used in industry to pre-define the particulate matter sizes and relative percentages [Ref. 5] treated in air flow passed through an air filter device. US. Pat. No. 6,589,486 (Spanton) discloses an air purifying apparatus that generates ultraviolet radiations (UV-C) and ozone together in order to kill microorganisms, including both bacteria, viruses, allergens. The UV-C radiations are emitted through a UV mercury lamp generator in a standard forced air building heating, ventilating and/or air conditioning system. Also ozone is generated through an ozone generator mercury lamp and the disclosed action is the sum of both effects to destroy microorganisms which are not killed by the sole UV radiation. Spanton does not disclose how to remove dust and residual particulate matter from the air. Spanton does not control the local concentration of ozone. The products of ozonolysis, when already in the air is a high concentration of ozone, may be more irritating and toxic than the original compounds. US. Pat. No. 8,318,084 B2 (Johnson et al.) discloses a method and device for air cleaning performed by physical and chemical treatments in six zones, where a forced air stream is treated with ozone from a corona discharge ozone generator, with optionally water and ammonia aerosol generator, with UV-C from a UV lamp, with an electrostatic filter and electrostatic charges from a corona discharge, with a catalyst to remove the excess of ozone and ozone sensors needed for safety and efficiency with the scope to control the quantity of generated ozone. The removal of residual ozone is essential, since prolonged exposures to elevated ozone concentrations may irritate the respiratory system and harm the lungs. The invention can be applicable inside buildings, inside vehicles and any point sources of air pollution. Johnson does not disclose exactly the UV-C range wavelengths suitable for the invention but only a wide 100-330 nm, but is also known that UV-C irradiation destroys microorganisms and different exposure times to UV-C radiations are more important than exact range irradiation wavelengths. Johnson does not disclose what times are required and what the range of external temperatures suitable for the device full functionality, related to the characteristics of low-pressure mercury UV lamp and water ammonia aerosols when installed in outdoor applications and low temperatures occurs. Johnson does not disclose the target average quantity, or the target average percentage, about the particulate matter present in inlet air flow and collected by device, but mentions a wide range of collected pollutants between 60% to 99% by weight.

It has been known for the last 100 years that UV-C irradiation is highly germicidal, and it is possible to generate UV-C irradiation in many ways. The low-pressure mercury UV lamps (LP-UV) have long been used for bacterial inactivation, but due to certain disadvantages, such as a long time to warm-up, the low efficacy at low outdoors temperatures, the relatively short working life, the fragility and the possibility of breakage when subjected to any shock, with possibility of mercury leakage and exposure, were factors generating troubles in many applications. Deep-UV-C light-emitting diodes (DUV-LEDs) for disinfection have recently been of great interest as an alternative [Ref. 7] to LP-UV lamps. DUV-LEDs common named UV-LEDs do not contain mercury. Moreover LP-UV lamps only emit UV light rays at 254 nm, as opposite UV-LEDs can produce the desired wavelengths have been developed. Wavelengths generated by UV-LEDs at 266, 270, 275 and 279 nm were tested and wavelengths between 266 to 270 nm showed best inactivation effects than other UV wavelengths [Ref. 8].

SUMMARY OF THE INVENTION

The invention relates to a reliable intelligent air treatment system dimensioned to reduce the particulate matter (PM) pollutants concentration in the outdoor air of defined city areas, at convenient exercise costs, where the collected PM particles size is in the range between 10 micrometers (PMio) and 1 micrometers (PMi.o). Moreover also dangerous microorganisms concentration may be reduced through the invention, and the system has an energy save function mode to treat air at correctly dimensioned flow-rates only when necessary. The problem to reduce PMs in urban area air is not approached as a local operation to be performed locally by a sole device of certain characteristics, but the method and system considers the whole city area as a sole aeraulic complex system, where many information must be considered and correctly managed by the system to drive the air treatment devices, with different performances related to their positioning, and here below better described, in order to reach the desired results when installed.

The method and system consist in the synergic actions between three different system sections: a) The collection of all available information on the target urban area as geography, three-dimensional map, architectural constraints, micro-climate, position of sources and kinds of pollutants, wind intensity, wind direction, air temperature, local atmospheric pressure, historical and actual conditions during high PM urban air concentration levels. Data sources may be public or private air quality monitoring systems (AQMS), sensors installed on air treatment unit devices as better described here below or other reliable data sources to consent the modelling of the local PM air concentrations behaviour through a computational fluid dynamics (CFD) software of the target urban area, in order to plan positioning and characteristics of the best suitable volume air treatment unit devices in a planned number and inter-distance, among a range of available air treatment unit (ATU) devices as better described here below. b) The cloud-based smart city air cleaning software system (SC-ACS), tuned on the PM urban’s behaviour knowledge database with the target urban area information, receives constantly PM pollutants and micro-climate updated conditions signals from all the system planned sources and sensors, coming from air treatment units and from local external climate/pollutant stations and/or other useful sources. The cloud-based software air cleaning management system SC-ACS starts (or stop) the action of the networked air treatment units, to maintain at acceptable levels the PM pollutants concentration in the air of the target urban area. Moreover the SC-ACS system manages the alarms due to various possible status of air treatment units, as maintenance service self-requests, faults, damages, sending to an external maintenance operators city department the service request order about the single air treatment unit device in alarm condition. c) The air treatment units (ATU) consists of air filtering devices of different dimensions and shapes, designed for very different polluted air treatment flowrates and suitable to be positioned in various city contexts, with the same physical common working principles, an electronic microcontroller intelligent unit (MIU) and four internal process sections, three ever present and one optionally present. The principal scope of device is the removing from polluted air of major part (average >95%) of filterable air suspended contaminants constituted by particulate matter of mean particles dimension range between 10 micrometers (PMio) and 1 micrometers (PMio). The secondary optional scope of device is the inactivation or destruction of airborne microorganisms in urban air, as bacteria, viruses, spores, allergens, to be performed when the optional process section is present. The ATU device has an external body and an internal processes frame, in materials as smooth surfaced metals, without rubber parts, suitable for UV-C irradiation process and suitable to do not help microorganisms growth inside the ATU, in materials obtained if possible by recyclable sources, consisting of an air intake area, with a coarse grid to stop insects. The outlet air is sucked in the ATU through the negative pressure drop created by a fan positioned in the air outlet area. The first ATU optional air treatment process section is the microorganisms inactivation through the optional UV-C radiation section, consisting of ultraviolet UV-C irradiation obtained from UV-C light emitting diodes (LEDs) operating in the restricted light wavelength range between 266 and 275 nm. This UV-C wavelength range is retained the most effective by various microorganisms photo-inactivation independent studies. In ATU the design fluence (UV-C dose) as energy light irradiated in a unit area for a time of 1 s, expressed in mWs/cm2, has to be calculated in the suitable UV-C LEDs number and light emitted intensity, in relation to the vane UV-C process section dimension and UV-C exposing radiation time of the air stream in the UV-C process vane, that is designed in order to maintain for the longer time the air at the UV-C irradiation exposure. The list of expected inactivated microorganisms may be shown for every ATU version, when the optional UV-C process section is installed. UV-C LEDs have important advantages if compared with classics UV-C low-pressure mercury lamps. UV-C LEDs have no heating long or short times to reach the full UV-C irradiation level, but are immediately ready. They can work at low outdoor temperatures still giving their standard performance, they have very long working life and UV-C irradiation level is substantially constant in the entire LED’s life, are not sensible to mechanical shocks, cannot have mercury leakages in urban air, have small energy consumption, do not emit irradiation at the sole mercury characteristic-based mandatory UV-C lamp wavelength of 254 nm but they can emit irradiation in the wavelength range between 266 nm and 275 nm, the most effective germicidal wavelengths at which DNA absorbs UV-C at the most. The second process section is a mechanical air filtering, where the air stream polluted by PM particles must pass through a recyclable (or fully incinerable) high efficiency air particulate filter (or air filters) in quality level European standard EN 779 class F9 or ISO standard 16890-1 class ePMi or ASHRAE standard 52.1 average arrestance class 99 or ASHRAE standard 52.2 class E2 MERV 15 or equivalent. The third section consists of an insulated vane, where the air stream passes in the vane between air filter and air fan outlet, as to obtain the certainty that the whole air stream flow-rate has been filtered before enter in the fourth process section, the area where cleaned air flow is expelled outside the ATU, at the maximum distance from the air intake, to obtain the best result about the collected PM quantity in weight of treated urban air. Inside the vane is positioned a differential pressure drop sensor, to communicate to microcontroller MIU when the maximum particulate air filter capacity is reached and must be substituted. Fan and typical filter pressure drop are designed to obtain very low electrical consumption and long interval times between air filters maintenance operations, in the indicative range between 7 to 24 months, depending from ATU model and local airborne PM concentrations. In the ATU body is present a Wi-Fi transmitter-receiver (TX-RX) internet remote connection processor module, a particulate matter concentration sensor, a temperature sensor, an humidity sensor, all connected to the MIU unit to perform the communication services between ATUs and cloud-based SC-ACS. Optionally the ATU body may be equipped of anemometer and wind direction sensor, to give more information, through MIU unit, directly to SC-ACS on local weather condition. The MIU unit, fan and all other ATU components have datasheet characteristics suitable to work in outdoor conditions, as air with high humidity and low temperatures. ATU devices optionally may incorporate other additional devices as LED street lamps, antiintrusion sensors, telecommunications antennas. MIU has a local software that define the activation (or de-activation) of the ATU when certain PM air concentration conditions appear, through the information handshaking with the cloud-based SC-ACS. ATU’s electric power supply can be obtained by electric power grid or optionally by a set solar panels with inverter and batteries, dimensioned to keep ATU fully operational every day of the year.

In conclusion of this summary description, the invention consists in a PM’s polluted city air cleaning self-managing aeraulic system with a feedback loop, where the urban cloud-based SC-ACS system receives inputs from different atmospheric data and PM level data sources, and controls the networked ATUs air cleaning devices activity, receiving back data updates on local PM concentration, and other parameters in an infinite loop every day, all time in the year with long working times before need of maintenance service.

BRIEF DESCRIPTION OF THE DRAWING

The invention is explained in detail below with reference to the drawing, in which

Fig. 1 represents the concept of working method of this feedback system;

Fig.2 represents the basic components of this feedback system that will be better explained in detailed description and next drawing pages;

Fig.3 shows how city’s particulate matter situation must be modelled by the computational fluid dynamics (CFD) software to obtain information about the best positioning of ATUs, and are shown also AQMS devices to have the maximum information level on local micro-climate;

Fig.4 shows the complete system with all the interacting components as better explained in the below detailed description of the invention;

Fig.5 shows the schematic view of the air treatment unit (ATU) device.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method and system to control and decrease the unhealthy particulate matter pollutant concentration in the air of a city or a restricted urban area, or any other large zone where airborne concentration of particulate matter must remain in the range of common known current standard healthy levels.

The sources of particulate matter urban air concentrations are various, depending from local geographic, industrial and traffic characteristics of the urban area, therefore it is known that any public limitation to a sole particulate matter pollutant source should make only partial benefits, and multiple limiting measures on other local particulate matter sources may need very long times or may be inapplicable for any reasons; therefore the present invention has the mission to constitute a prompt urban defence against unhealthy living conditions due to high particulate matter concentrations in thousands of cities worldwide, with billions of dollars in healthcare expenses and premature deaths.

The general principle of the invention consists in a particulate matter (PM)’s polluted city air cleaning self-managing aeraulic system with a feedback loop concept, where the cloud-based smart city air cleaning software system (SC-ACS) receives inputs from different atmospheric data and PM level data sources, and controls the networked air treatment units (ATU) devices activity, receiving back data updates on local PM concentrations in different micro-climate urban zones, and other parameters in an infinite loop every day, all the year with long working times without the need of maintenance service intervals.

The here disclosed system may also decrease the urban concentration level of unhealthy airborne microorganisms as bacteria, viruses, allergens and spores through an ultraviolet-C irradiation process optionally performed in the air treated by the air treatment units (ATU) devices.

In the following description, numerous specific details are set forth in order to provide a clear understanding of the invention. It will, however, be apparent to a person skilled in the art that this invention may be practiced without all these details.

One application of the invention is to control the particulate matter’s level in the air of a urban zone, but a person skilled in the art would know that the method and system may equally well be used not only with a network of fixed air treatment devices, but also with air treatment devices ATU suitable to be installed on vehicles and operating in the same zone, as public vehicles (as bus, rails), or city temporary activity vehicles (as ice-cream vans, shop-vehicles) or city temporary standing structures, and also adapted to be installed in outdoor or indoor areas. Moreover also other, different air filtering unit devices based on different or similar technologies may be connected at the smart city air cleaning system SC-ACS if equipped of the ATU Wi-Fi internet communication protocol and ATU sensors.

Fig.l shows the basic approach of this invention that aims to solve a complex problem as decrease the concentration of particulate matter in the air of urban areas. It is disclosed a method where the urban target area is considered a complex intelligent system 1, and system receives information in input to expand its knowledge about the local area and the actual particulate matter concentrations, with the possibility to make any operations in output. The effects of such operations are send back as new information in order to obtain the fine tuning of the system and the best results as cleaner air, healthier air and an higher energy efficiency in system running with lower costs.

Fig.2 shows the basic components of this feedback system, introducing the involved system parts and their role: the cloud-based smart city air cleaning system 1 (SC-ACS) software has the role of system intelligent manager, receives information and make actions, receiving feedbacks on their real effects; the air quality monitoring systems 2 (AQMS) are devices to collect particulate matter air concentration with other wind and weather information, and are often already installed in most cities worldwide, and AQMS 2 send data to SC-ACS 1; the computational fluid dynamics model 3 (CFD) of the urban area where the SC-ACS 1 is working, in order to understand the circumstances and the paths of particulate matter higher concentrations in any precise urban microareas than others, and CFD 3 sends data to SC-ACS 1; the air treatment unit 4 (ATU) devices, clean urban air from particulate matters and may optionally destroy many microorganisms in a way as better disclosed here below in detailed description, and ATUs 4 receive action data from SC-ACS 1; the ATU’s data 5 are the feedback local data to be sent back to SC-ACS 1 through the Wi-Fi internet communication system 15, the main way used by the SC-ACS 1 system to interact with other system parts.

Fig.3 describes the function of the computational fluid dynamics 3 CFD technology in this disclosed method and system, when applied to an urban area. The particulate matter 6 (PM) coming from various pollutant sources is driven at certain weather conditions, as well measured and communicated by the Wi-Fi or cloud connected AQMS 2 devices, and reaches unhealthy levels in urban air. Paths and distribution of airborne PM particles 6 are not uniform in all streets, places and vertical level in a city, but are affected by many factors where building shapes and air motions are a part of. These factors are locally recurrent under certain weather conditions, thus all available micro-climate and PM information 6 are useful to be represented in a computational model of the urban context, with the scope to see where the highest probable PM concentrations 6 have tendency to appear. It may happen more frequently in several, precise urban sites, that correspond at exact position of poles of highest attention during the whole smart city air cleaning system design, in the particular section regarding the ATUs 4 positioning and their air treatment flow-rates dimensioning plan.

Fig.4 represents in detail all the parts involved in the here disclosed smart city air treatment system, where the cloud-based smart city air cleaning system 1 (SC-ACS) software receives and manages data received by many sources, as AQMS 2 devices, CFD 3 calculated and updated information, and feedback information 5 coming from ATUs 4 devices, that may receive commands from SC-ACS 1 through the Wi-Fi internet communication system module 15. CFD 3 model and any other three-dimensional map information on the targeted urban area give also the polluted air volume dimensions that must be treated. The living spaces free from buildings as streets, places, public gardens are to be calculated as air volumes to be cleaned, and CFD 3 suggests the heights and positions of higher probability of particulate matter concentration. The decrease of PM 6 concentration in urban air, through subtraction of PM 6 particles from urban air in large quantities creates, in few words, cleaned air big zones that will be mixed with other PM 6 polluted air through natural air motion events, decreasing the PM 6 air concentration average level in the targeted urban area.

As general SC-ACS 1 controls continuously the targeted urban particulate matter air concentration and weather conditions, considering either historical as actual situation. Depending from the local SC-ACS 1 system design defined rule, the air treatment action by ATUs 4 may be immediately activated, overpassing the ATU’s 4 status about the local PM concentration level (a configuration defined OR condition mode event), or only suggested to ATUs 4 and activated if ATUs 4 are reading a local high PM level situation (a configuration defined AND condition mode).

The number of ATUs 4 in the targeted urban area, the positioning, the suitable air treatment flow-rates in different point of targeted urban zone, the exterior ATU 4 shapes are fully part of the system design, when the CFD 3 model plan is already fully operating and should be performed by a person skilled in the art of environmental engineering accordingly with urban area responsible architects, in order to reach the planned results in terms of level of reduction of historical particulate matters air concentration at the same weather condition and air pollutant sources and intensity condition.

Fig.5 shows the schematic representation of the air treatment unit (ATU 4) device with details, accordingly to be a fundamental part of the method and system invention. The ATU 4 may be realised in very different shapes, classes of performances and number of executed processes as below described. About the air treatment flow rate performance, very important in the application field of this invention, ATUs 4 models are been designed with air treatment flow rate as per 150,000 cubic meters/ hour, but it is possible extend or reduce the single ATU 4 device flow rate depending from positioning and body dimension requirements. About the ATUs 4 shapes, they may be squared, cylindrical, pyramidal, coloured, fixed to ground or suspended, may give hospitality to advertising spaces, have very small and very large dimensions, because many different positioning are possible or required in urban contexts and only the creativity of architects may offer the best attractive and functional solution for different urban context and local history. ATUs 4 have the primary mission to capture from airborne urban air the particulate matter in the range between PMio to PMi.o (between 10 to 1 micrometers particle size) and optionally the mission to destroy/inactivate the airborne microorganism in the air treated by the unit ATU 4, at the most reliability, self-managed and connected to the cloud-based smart city air cleaning system SC-ACS 1, in all outdoor conditions and without use of ozone or chemical substances, with the minimum frequency of planned maintenance services. ATU 4 body may be equipped of external optional devices as wind velocity sensor 7, wind direction sensor 8, and other accessory devices 9 that means led street lamps, proximity sensors, air pressure sensors, telecommunication antennas, signal repeaters, advertising electronic panels, advertising fixed panels. ATU 4 device is here represented and subdivided in four sections where are performed different operations; sections are named a), b), c) and d) : a) The ATU 4 device is represented as a channel 4 where urban air flow with a certain particulate matter PM concentration 6 enters in ATU 4 to be cleaned, because air entering effect is obtained by the depression created by fan 19 installed in section c). The ATU 4 air intake area has a coarse grid to stop insects. The cleaned air exits in atmosphere by outlet 20 positioned in the d) section of ATU 4. ATU 4 must ever be manufactured with details design and assembling care to assure that all PM 6 contaminated air passes through the air treatment unit ATU 4, where air intake area a) section and air outlet 20 in d) section are adapted to fit any internal existing ducts using methods known in the art so that no air is allowed to bypass the ATU 4 device. When PM polluted air 6 enters in section a) may be irradiated by the optional set of ultraviolet -C light (UV-C) light emitting diodes (LEDs) 10 to perform the inactivation or destruction of microorganisms in urban airborne, as bacteria, viruses, spores, allergens. The ATU 4 device is manufactured, about internal body sections, in materials as smooth surface metals and without rubber parts, suitable for UV-C 10 irradiation process and suitable to do not help microorganisms growth inside the ATU 4, and obtained if possible by recyclable sources. The optional UV-C 10 radiation section consists of an ultra-violet UV-C irradiation set obtained from UV-C 10 light emitting diodes (LEDs) operating in the restricted light wavelength range between 266 and 275 nm, the typical wavelength range retained the most effective by various microorganisms photoinactivation independent studies. In ATU 4 the design fluence (UV-C dose) as energy light irradiated in a unit area for a time of 1 s, expressed in mWs/cm , has to be calculated in suitable number of UV-C LEDs 10 and light emitted intensity in relation to the vane UV-C 10 process section dimension and UV-C 10 exposing radiation time of the air stream in the process vane, that is designed in order to maintain for the longer time the air exposed at UV-C 10 irradiation effectiveness. A list of expected inactivated microorganisms may be shown for every ATU 4 version, when the optional UV-C 10 process section is installed. UV-C LEDs 10 have important advantages if compared with classics UV-C low-pressure mercury lamps. UV-C LEDs 10 have no heating long times to reach the full UV-C irradiation level, but are immediately ready. They can work at low outdoor temperatures maintaining their standard performance, they have very long working life and UV-C irradiation level is substantially constant in the entire LED’s life, they are not sensible to mechanical shocks, they cannot have mercury leakages in urban air, they have small energy consumption, they are not emitting at the sole mercury characteristic-based mandatory UV-C lamp wavelength of 254 nm but they can emitting in the wavelength range between 266 nm and 275 nm, the most effective germicidal wavelengths at which DNA absorbs UV-C at the most. In the a) section moreover may be installed an hygrometer sensor 11 to know the humidity percentage value in air and a barometric air pressure sensor 13. The air temperature sensor 12 is ever installed to evaluate the ATU 4 working conditions. b) In this section the PM 6 polluted air flow meets the air filter 16 to simply perform a mechanical air filtering, where the air stream polluted by PM particles 6 must pass through a recyclable (or fully incinerable) high efficiency air particulate filter 16 (or air filters) in a quality level as per European standard EN 779 class F9 or ISO standard 16890-1 class ePMi or ASHRAE standard 52.1 average arrestance class 99 or ASHRAE standard 52.2 class E2 MERV 15 or actual and future equivalent and suitable as per specific ATU 4 model design. An efficient management or recycle process of worn air filters 16 is not here disclosed, but it was considered and designed at actual patent filing request date. Thus the PM 6 is collected in the air filter 16, exactly in the laminated filtering material surfaces that may consists in layers of porous microfibers sheet, or any other available technology solution where air filter 16 supplier manufactures and certifies the air filter 16 product as compliant at the here above mentioned air filtering suitable standard classes. c) The section drawing to be considered is exactly where the air stream passes in the insulated volume vane consisting in the space between the air filter 16 and the air fan 19. In this section the whole air stream flow-rate has been filtered and air flows because sucked by air fan 19, through the air de-pressure (negative pressure) created by air fan 19 palettes. When the air filter 16 is still clean and has collected PM 6 for a short time, and the air fan 19 is rotating, the air pressure inside the vane section is near the same value of the air pressure in the next section d), after the air fan 19. Inside the section c) vane is positioned the differential air pressure sensor 17. After a certain number of months or years, when air filter 16 filtering capacity will be near to be completed in its planned weight amount planned substitution, due to the capture of all sizes of PM 6 collected particles from urban air, and its filtering capability strongly decreased, as consequence also the internal air pressure will decrease, and its value will be very different than air pressure value outside the vane, in section d). The different pressure values between section c) and section d) of ATU 4 are the conditions to activate the status change of the differential air pressure sensor 17, signalling the request of substitution service of the air filter 16 component. d) This section is the area where particulate matter cleaned air flow is expelled in the air outside 20 of the ATU 4, designed at the maximum distance from the air intake, to obtain the best result of urban air treated about the PM 6 quantity in weight. The air fan 19 has an hall-effect rotating sensor 18, in order to check if the air fan 19 is still rotating or for any reason is in a fault condition and thus is not running.

All the mentioned sensors are wired up to an electronic microcontroller intelligent unit (MIU) 14 that manages the activities of ATU 4. The microcontroller MIU 14 is equipped with the Wi-Fi internet communication system module 15 (TX-RX, transmitter-receiver), and thus is connected with the cloud-based SC-ACS 1 system. MIU 14 collects the different information by sensors, receives commands and status requests by SC-ACS 1, sends status answers and alarms to SC-ACS 1.

The ATUs 4 are designed to have long uninterrupted working times between air filters maintenance operations, in an indicative range between 7 to 24 months, depending from ATU model and local airborne PM concentrations but this range may have different values in local urban areas with special conditions. Optionally, when ATU 4 body is equipped of anemometer and wind direction sensors, the MIU 14 unit sends directly to SC-ACS 1 information on local weather condition. The MIU 14 unit, air fan 19 and all other ATU 4 components have datasheet characteristics suitable to work in outdoor conditions, as air with high humidity and low temperatures. MIU 14 has a local software that define the activation (or de-activation) of the ATU 4 under presence of certain PM 6 air concentration conditions and after information handshaking with cloud-based SC-ACS 1. ATU’s 4 electric power supply can be obtained by electric power grid or optionally by a set solar panels with inverter and batteries, dimensioned to keep ATU 4 fully operational every day of the year. EXAMPFE 1

In a city existing in a South-Europe country must be installed a smart city air cleaning system, as described in Fig.4 and in Fig.5. Before to extend the SC-ACS installation at the whole city, it has been decided to evaluate the effects of the SC-ACS system in an historical urban central zone, with famous monuments, very busy vehicular traffic and lot of pedestrians, in PMio‘s very polluted conditions. Bad situations occur in winter, when exhausts buildings heat systems and low temperatures are added to many other local PMio sources, giving to local people the worst air quality conditions. The targeted urban zone is flat with no hills, has average medium high buildings and large places, has a dimension of 9.6 square kilometres, with about 100,000 inhabitants involved. Two reliable public air quality monitoring systems AQMS are available to update the SC-ACS system in the same zone. The city air cleaning preliminary design step, through the help of the computational fluid dynamics model CFD has defined the installation of 24 air cleaning units ATU of different flow rates, dimensions, to be installed in certain exact positions, as per technical reasons and as per co-ordinated solutions suggested by local architects to minimize any aesthetic impacts. The total air treatment requirement planned to protect this city area, as per air treated quantity is 14.4 million cubic meters/day. This amount is performed by 24 ATUs of various models. When PMio levels are softly raising, the SC-ACS activates the ATU devices and the particulate matter air concentration levels are mechanically forced to remain well under the historical values, in percentages that are constantly measured, in order may be optimized and optionally improved if requested. A tangible advantage is the valuable money amount in healthcare expenses saved per square kilometre, comparable when in presence, or not, of the SC-ACS system air filtering service. EXAMPFE 2

The smart city air cleaning system as described in Fig.4 and in Fig.5 is installed in a big urban area, as protection against PM2.5 frequent concentrations in urban air by different local PM2.5 sources, as vehicular traffic, industries, building heaters. The SC-ACS is dimensioned for the 50% of the total city area, equivalent to 40 square kilometres and affects about 300.000 inhabitants. But due to an extraordinary pollutant source event, as the great fire accident occurred in a deposit of a waste management local industry not far from the city, a great toxic cloud mainly constituted by particulate matter was emitted in urban atmosphere. The fire accident involves combustion of various dangerous materials, containing asbestos, coal, active carbon, rubbers and plastics. The SC-ACS prompt activation may reduce unhealthy effects of the extraordinary peak in PMio air concentrations and the long term harmful effects due to the temporary but heavy presence of solid fibres and substances highly dangerous for organisms health of humans, animals, vegetables. EXAMPLE 3 A smart city air cleaning system, as described in Fig.4 and in Fig.5, when installed in the urban area as normal protection against PMio concentrations in urban air by any different usual PM sources, may be useful also in extraordinary event of vulcanic eruption exhausts emissions, if the city is built in a region with a potential risk of vulcanic phaenomena. EXAMPLE 4

The smart city air cleaning system, as described in Fig.4 and in Fig.5, giving urban air cleaned from PM in urban area, may be useful also when the city is affected by frequent fine sands pollution coming from natural sources as deserts and dunes, that in certain circumstances are added to standard PM’s urban sources as vehicular traffic, industries, power stations. EXAMPLE 5

The smart city air cleaning system, as described in Fig.4 and in Fig.5, installed to offer an acceptable PM’s concentration level in urban air, may be very useful in cities with intense particulate matter emissions sources, as steelworks plants or other kind of industries where the probability or frequency of abnormal particulate matter emissions may create, or are creating damages to public health, and when in the meantime local economy reasons stop or delay any different, further action.

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Resource of International Association for Urban Climate - The Urban Flux Network Hosted by the Department of Geography, University of British Columbia Available at: http://ibis.geog.ubc.ca/urbanflux/ 5. Definition of filtration performance - from EN 779 to ISO 16890 (S. Courtey, Head of Ventilation Department, Eurovent Certita Certification, document published by REHVA, Federation of European Heating, Ventilation and Air Conditioning Associations, Brussel, Belgium) Available at: http ://w w w .rehva.eu/fileadmin/REHV A_Journal/REHV A_Journal_2017/RJ l/p.16/16-19_RJ1701_WEB.pdf 6. Bill and Andy’s excellent adventure II (S.Levy, Wired Magazine, 1994)

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Claims

CLAIMS SMART CITY AIR CLEANING SYSTEM The description of the invention reveals that it is obvious that it may be varied in many ways and details. Such variations are not to be considered a deviation from the scope of this invention, and all such modifications which are obvious to persons skilled in the art are also to be considered comprised by the scope of the following claims. The invention claimed is:

1. A method and system to remove particulate matter airborne concentrations from large air quantities in urban areas or polluted areas, and optionally remove microorganisms, where the urban area is considered as a large aeraulic system and particulate matter air concentrations as pollutant to be removed, and a planned air filtering actions are to be performed through a. Urban area information, historical and actual, come from different instruments and data sources to obtain the computational fluid dynamics model CFD of the PM polluted urban area, to collect and update the PM’s local concentration knowledge positions at certain atmospheric conditions; b. A cloud-based smart city air cleaning system (SC-ACS), constituted by a software management system that receive inputs from CFD model, various sensors and air quality instruments, that send commands to activate the well dimensioned air treatment units and that receives their information feedbacks; c. A number of well dimensioned and positioned, in the urban area, air treatment units ATU that process PM polluted air in large quantities, through a mechanical air filtering principle and optionally may destroy airborne organisms as bacteria, viruses, spores, allergens through the optional ultraviolet-C light emitting diodes (UV-C LED) process unit of UV-C irradiation in the restricted UV-C wavelength range. ATUs are connected with SC-ACS system by a Wi-Fi internet protocol module and have a number of sensors to collect local information. ATUs electric power supply can be received by electric power grid or optionally by a set of solar panels with inverter and batteries or other renewable power system.

2. The method and system according to claim 1 where many information are collected, considered and correctly managed by the system to immediately manage actions performed by connected city air treatment devices, with optimized performances related to their positioning, in order to reach and continuously update the current result values in the cloud-based smart city air cleaning system.

3. The method and system according to claim 1 where a computation fluid dynamics model CFD is directly applied and updated, being part of an active system of treatment and filtration of urban air particulate matter, in order to obtain and use the finest data results in local knowledge about the PM concentration urban air behaviour, as dimensions, level in height, intensity, exact positions, with the result to plan the dimensioning, positioning and timely activation of the air treatment unit ATU with the best filtration efficiency at the lowest energy consumption.

4. The method and system according to claim 1 where air treatment unit ATU as optional air treatment process section is the microorganisms inactivation through the optional UV-C radiation section, consisting of ultra-violet UV-C irradiation obtained from UV-C light emitting diodes (LEDs) operating in the restricted light wavelength range between 266 and 275 nm, and this solution may be applied in large urban air treatment unit devices connected in a networked city air cleaning system or urban air cleaning system.

5. The use of the method and system according to claim 1 to remove particulate matter airborne concentrations from large air quantities, and optionally to remove microorganisms from the same air, in urban areas, in known polluted areas for any reason, in areas involved in atmospheric smokes generated by fire accidents sources, in case of vulcanic eruption exhausts emissions, in regions or counties with potential risk of vulcanic phaenomena particulate matter emissions, in areas affected by fine sands pollution coming from natural sources as deserts and dunes and similar, in areas with intense particulate matter emission recurrent sources as steelworks plants and any other kind of industry where are performed processes generating high quantities of particulate matter emissions.

6. The use of the method and system according to claim 1 to remove particulate matter airborne concentrations from large air quantities, and optionally to remove microorganisms from the same air, may equally well be used not only with a network of fixed air treatment devices, but also with dimensioned air treatment devices ATU suitable to be installed on vehicles and operating in the same zone, as public vehicles (as bus, rails for example), or city temporary activity vehicles (as ice-cream vans, shop-vehicles for example) or city temporary standing structures and installations (as cultural or advertising installation for example), and also adapted to be installed in outdoor or indoor areas.

7. The use of the method and system according to claim 1 to remove particulate matter airborne concentrations from large air quantities, and optionally to remove microorganisms from the same air, may also be applied to other, different air filtering unit devices based on different or similar technologies and may be connected at the according to claim 1 smart city air cleaning system SC-ACS, when and if properly equipped of the ATU Wi-Fi internet communication protocol and the ATU sensors as per the method and system according to claim 1.