DEVICE, A METHOD, AND A COMPUTER PROGRAM PRODUCT, FOR DETECTING AIRBORNE PARTICULATE MATTER IN AEROSOLS

Abstract

Provided is a device for detecting airborne particulate matter in aerosols, comprising: an air sampler to collect a sample of airborne particles suspended in air; an optical sensor; a controller; a fluidic apparatus to, under the control of the controller: capture, from the air sampler, and resuspend in a liquid medium, at least part of the airborne particles of the sample; and deliver the resuspended airborne particles to the optical sensor, which is configured to detect airborne particulate matter in the delivered airborne particles.

Also provided is a method adapted to use the device of the invention, and to a computer program product adapted to implement the method of the invention.

Claims

1. A device for detecting airborne particulate matter in aerosols, comprising: an air sampler configured to collect a sample of airborne particles suspended in air; an optical sensor configured to detect airborne particulate matter in at least part of said sample; a fluidic apparatus configured at least to deliver at least part of said sample to said optical sensor; and a controller configured to automatically control the operation of said air sampler, said optical sensor, and said fluidic apparatus; wherein said fluidic apparatus is configured and arranged to, under the control of said controller: capture, from said air sampler, and resuspend in a liquid medium, at least part of said airborne particles of said sample; and deliver the resuspended airborne particles to said optical sensor; and wherein the optical sensor is configured to detect said airborne particulate matter in the delivered airborne particles.

2. The device of claim 1, wherein said optical sensor is an optical biosensor configured to detect bioparticles, included in said airborne particulate matter, including one or more pathogens and/or one or more allergens and/or one or more other contaminants.

3. The device of claim 1, wherein said fluidic apparatus is configured and arranged to, under the control of said controller, label the resuspended airborne particles for said airborne particulate matter, and deliver the labelled resuspended airborne particles to the optical sensor, and wherein the optical sensor is configured to detect the labelled airborne particles.

4. The device of claim 3, wherein the fluidic apparatus comprises a reaction chamber to carry out said labelling of the resuspended airborne particles with a reagent; and wherein the fluidic apparatus further comprises at least one fluid dispenser fluidically connectable, under the control of said controller, to said reaction chamber to deliver the resuspended airborne particles, in the liquid medium, to said reaction chamber and to extract therefrom the labelled resuspended airborne particles, and also fluidically connectable to the optical sensor to deliver the same to the optical sensor.

5. The device of claim 4, wherein at least one of: the fluidic apparatus further comprises a reagent container containing said reagent, and wherein said at least one fluid dispenser is fluidically connectable, under the control of said controller, to said reagent container to withdraw said reagent therefrom, and to said reaction chamber to deliver the reagent thereinto; the air sampler comprises an air sampler container, and wherein said at least one fluid dispenser is configured for providing, under the control of said controller, said liquid medium to said air sampler container to capture and resuspend in the liquid medium at least part of the airborne particles of the sample contained in the air sampler container; and the fluidic apparatus further comprises a liquid medium container, and wherein the at least one fluid dispenser is fluidically connectable, under the control of said controller, to said liquid medium container to withdraw said liquid medium therefrom.

6. The device of claim 5, wherein the fluidic apparatus comprises a valvular arrangement automatically controlled by the controller to selectively and fluidically connect at least with part of said air sampler and with said reaction chamber.

7. The device of claim 6, wherein said valvular arrangement is configured to selectively and fluidically connect, under the control of said controller, said at least one fluid dispenser with any of said air sampler container, reaction chamber, reagent container, and liquid medium container.

8. The device of claim 7, wherein one of: said valvular arrangement is also configured to selectively and fluidically connect, under the control of said controller, said at least one fluid dispenser with said optical sensor; and said at least one fluid dispenser is configured to directly fluidically connect, under the control of said controller, with said optical sensor, to deliver the labelled airborne particles to the optical sensor without passing through the valvular arrangement.

9. The device of claim 7, wherein the fluidic apparatus further comprises at least one of: an air vent, and wherein the valvular arrangement is also configured to selectively and fluidically connect, under the control of said controller, said air vent to the air sampler container to provide a pulsation air flow thereto to aid in the elution and recovery, in the liquid medium, of the captured airborne particles; and a waste container fluidically connected or connectable, under the control of said controller, to the optical sensor to receive waste therefrom.

10. The device of claim 9, implemented as a compact device integrating at least said air sampler, said optical sensor, and said fluidic apparatus in a common housing, wherein said liquid medium container, reagent container, and waste container are respective removable cartridges removably attached to said common housing or to a support attached thereto.

11. The device of claim 10, wherein the controller is configured to automatically control the operation of the air sampler, fluidic apparatus, and optical sensor, continuously according to a sequence of consecutive detection tests, each starting by the air sampling with the air sampler and ending with the waste deliverance to the waste container, said sequence lasting at least until one of said removable cartridges is emptied and thus needs of replacement.

12. The device of claim 4, comprising at least a further reaction chamber to label the resuspended airborne particles with said reagent or with a further reagent, different to said reagent, to allow the detection of said airborne particulate matter, or of a further airborne particulate matter that is different to said airborne particulate matter, and wherein the optical sensor is configured to detect the airborne particles labelled with said further reagent, and wherein the controller is configured to automatically control the operation of the air sampler or of a further air sampler, fluidic apparatus, and optical sensor, continuously according to a further sequence of consecutive detection tests, each detection test starting by the air sampling with the air sampler, or with said further air sampler, and ending with the waste deliverance to the waste container, each sequence lasting at least until one of the removable cartridges is emptied and thus needs of replacement.

13. The device of claim 12, wherein the controller is configured to automatically control the operation of the air sampler, fluidic apparatus, and optical sensor, or the operation of the air sampler, further air sampler, fluidic apparatus, and optical sensor, to perform said sequence and said further sequence of consecutive detection tests at least in part in parallel.

14. A method for detecting airborne particulate matter in aerosols, comprising the following steps: collecting, with an air sampler, a sample of airborne particles suspended in air; at least delivering, with a fluidic apparatus, at least part of said sample to an optical sensor; optically detecting, with said optical sensor, airborne particulate matter in at least part of said sample wherein the operation of said air sampler, said fluidic apparatus, and said optical sensor to perform said steps is automatically controlled; wherein the method further comprises: automatically controlling said fluidic apparatus to: capture, from said air sampler, and resuspend in a liquid medium, at least part of said airborne particles of said sample; and deliver the resuspended airborne particles to said optical sensor; and detecting said airborne particulate matter in the delivered airborne particles with the optical sensor.

15. A computer program product, comprising a tangible medium and, stored therein, a computer program including code instructions that, when executed on at least one processor of the controller of a device for detecting airborne particulate matter in aerosols which comprises: an air sampler configured to collect a sample of airborne particles suspended in air; an optical sensor configured to detect airborne particulate matter in at least part of said sample; a fluidic apparatus configured at least to deliver at least part of said sample to said optical sensor; and a controller configured to automatically control the operation of said air sampler, said optical sensor, and said fluidic apparatus; wherein said fluidic apparatus is configured and arranged to, under the control of said controller: capture, from said air sampler, and resuspend in a liquid medium, at least part of said airborne particles of said sample; and deliver the resuspended airborne particles to said optical sensor; and wherein the optical sensor is configured to detect said airborne particulate matter in the delivered airborne particles, implement the automatic control of the air sampler, optical sensor, and fluidic apparatus of the device, to perform the steps of the method of claim 14, to detect at least said airborne particulate matter.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0088] In the following some preferred embodiments of the invention will be described with reference to the enclosed figures. They are provided only for illustration purposes without however limiting the scope of the invention. In accordance with common practice, the components in the figures are drawn to emphasize specific features and they are not drawn to the right scale.

[0089] FIG. 1 is a schematic representation of prior art methods for aerosol analysis consisting in sample preparation and detection: from top to bottom culture method and RT-qPCR method.

[0090] FIG. 2 is a schematic representation of the device of the first aspect of the present invention, for an embodiment for which the device is implemented in the form of an integrated automatic online air monitoring device.

[0091] FIG. 3 is a schematic representation of the collection module or air sampler container of the active air sampler of the device of the first aspect of the present invention, for an embodiment.

[0092] FIG. 4 is a schematic representation of the fluidic apparatus of the device of the first aspect of the present invention, for an embodiment.

[0093] FIG. 5 is a schematic representation of the device of the first aspect of the present invention, for an embodiment or configuration for which the fluid dispenser of the fluidic apparatus is connected to the air sampler through the valvular arrangement and directly to the optical sensor, such as an optical biosensor.

[0094] FIG. 6 is a schematic representation of the device of the first aspect of the present invention, for an embodiment or configuration which differs from that shown in FIG. 5 in that the fluid dispenser of the fluidic apparatus is connected to the optical sensor through the valvular arrangement.

[0095] FIG. 7 is a schematic representation of a possible operation of the device of the first aspect of the present invention, and of the method of the second aspect, for an embodiment, to show that the alarm time interval depends only by the collection and recovery time.

[0096] FIG. 8A) Schematic representation of the device of the first aspect of the present invention, for an embodiment or configuration which differs from that shown in FIG. 5 in that the fluidic apparatus further comprises an air vent, and in that there are n=4 reaction chambers. FIG. 8B) and FIG. 8C) schematically show different valve positions for the fluid dispenser and selection valve of the valvular arrangement, respectively.

[0097] FIGS. 9A and 9B shows proof of concept results obtained with an experimental set-up of the device of the first aspect of the present invention. FIG. 9A) Diagram showing normalized counts of negative control(blank), SARS-COV-2 captured from air, positive control, and air from cleansed environment (after cleaning); FIG. 9B) Diagram showing normalized counts of negative control(blank), E. coli OP50 captured from air, positive control, and air from cleansed environment (after cleaning).

[0098] FIG. 10 is a schematic representation of the device of the first aspect of the present invention, for an implementation for which the device is a compact device integrating the different components thereof, including hardware and consumable (liquid medium, reagents, and waste) cartridges.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0099] The current invention relates to a fully automated collection and detection device for monitoring indoor/outdoor air for detecting airborne particulate matter, such as pathogens, allergens, and other contaminants in a semi-continuous way.

[0100] FIGS. 2, 4, 5, 6, 8 and 10 show, with different level of detail, the device of the first aspect of the present invention, for different embodiments.

[0101] The device comprises at least: [0102] an active air sampler AS (such as a cyclonic air sampler) configured to collect a sample of airborne particles suspended in air; [0103] an optical sensor S configured to detect airborne particulate matter, such as pathogens and/or allergen and/or other contaminants in at least part of the sample; [0104] a fluidic apparatus F, preferably a microfluidic apparatus, configured at least to deliver at least part of the sample to the optical sensor S; and [0105] a controller C configured to automatically control the operation of the active air sampler AS, optical sensor S, and fluidic apparatus F.

[0106] The fluidic apparatus F is configured and arranged to, under the control of the controller C: [0107] capture, from the active air sampler AS, and resuspend in a liquid medium, at least part of said airborne particles of said sample; and [0108] deliver the resuspended airborne particles to said optical sensor S.

[0109] For a preferred embodiment, the optical sensor S is an optical biosensor configured to detect bioparticles, included in the delivered airborne particles, including one or more pathogens and/or one or more allergens and/or one or more other contaminants.

[0110] FIG. 2 depicts an example block diagram of the device fundamental components identified above, for an embodiment for which the controller C also include a, preferably portable, power source to electrically feed the components of the device, and the device also an antenna An to offer a compact, online air quality monitoring system and airborne particulate matter alarm detector. An alarm unit (not illustrated) is operatively connected to the controller or to the optical sensor S, so that the latter can activate the alarm unit upon the detection of the airborne particulate matter, such as a pathogen or allergen.

[0111] For the embodiment of FIG. 2, the device comprises, in the form of a set of consumable removable cartridges Ct, a liquid medium container L containing a liquid medium (such as a washing solution) to resuspend the airborne particles, a reagent container Ra containing a reagent to label the resuspended airborne particles, and a waste container W fluidically connected to the optical sensor S to receive waste therefrom (generally, after each detection cycle).

[0112] For an embodiment, the optical sensor S is an optical biosensor that is a flow virometry reader (FVR) and the air sampler AS works in active mode. The device of the first aspect of the present invention that integrates, e.g., combines an active air sampler AS, a fluidic apparatus F and a FVR (or another type of optical biosensor S), enables the user to monitor air quality and receive an alert through a communication network (via the antenna An shown in FIG. 2).

[0113] The active air sampler AS, such as a cyclone sampler for collecting airborne particles, is connected to the fluidic apparatus F via a collection module comprising, for example, a 2.5 mL cylinder-conical shaped flask ASc and a tube ASt attached to the bottom of the flask ASc, as shown in FIG. 3.

[0114] As shown in FIGS. 4, 5, 6, 8 and 10, the fluidic apparatus F comprises a valvular arrangement Fv, such as a selection valve, and connected thereto a fluid dispenser Fd, such as a syringe pump, one or more consumable reagent cartridges Ra, and one or more wash reagent cartridges L containing washing liquid such as PBS-Tween as the above mentioned liquid medium, and connected to nth reaction chambers R1-Rn (see, for example, FIG. 5).

[0115] A schematic representation of the fluidic apparatus F is illustrated in FIG. 4. This comprises n reaction chambers R1-Rn, the valvular arrangement Fv comprising, for example, an active rotatory one-position nth-port valve. The rotatory valve is connected to a fluid dispenser Fd such as a syringe pump or a peristaltic pump, reagent(s) Ra and a liquid medium or wash container/cartridge L.

[0116] FIG. 5 shows a possible configuration of the interconnection of the fluidic apparatus F with the air sampler AS, the sensor S and a waste container W. The air sampler AS is connected directly to the selection valve Fv in the schematic, while the sensor S is connected to the fluid dispenser Fd. In this arrangement, the fluid dispenser Fd is equipped with a 3-port, 2-way valve.

[0117] FIG. 6 depicts an alternative configuration of the device, in which the air sampler AS and optical sensor S are both directly connected to the selection valve Fv of the fluidic apparatus F.

[0118] The selection valve Fv enables the washing liquid to be drawn from the reagent cartridge L and delivered to the inside of the air sampler flask ASc. A pulsation step is performed (optionally) to better aid in the elution and recovery of the captured air particles from the flask's inner walls. After being recovered in the washing/liquid medium, the particles are transferred to a reaction chamber R1-Rn. Reagents such as fluorescently labelled antibodies are collected from the reagent cartridge Ra and delivered to the reaction chamber R1-Rn, where a pulsation flow (or another type of mixing mechanism) is used to mix the target particles with the tagging molecules. Through the selection valve Fv, all of these stages are carried out automatically, controlled by the controller C. Finally, using the fluid dispenser Fd (for the embodiments of FIGS. 5 and 8) or the valvular arrangement Fv (for the embodiment of FIG. 6), the labelled sample is transferred to the sensor S, which, generally optically interrogates the sample at an interrogation location of a microfluidic channel.

[0119] FIG. 10 a schematic representation of the device of the first aspect of the present invention, for the implementation for which the device is a compact device integrating the different components thereof, particularly an active air sampler AS, including the collection flask ASc and tube ASt, liquid medium cartridge L, reagent cartridges Ra (containing the same or, in case different airborne particulate matter are to be detected, different reagents), waste cartridge W. The cartridges L, Ra, W are removably attached to a support or pocket-like housing Hc attached to a common housing H housing the rest of components not illustrated in the Figure (controller C, fluid dispenser Fd, valvular arrangement Fv, and optical sensor S).

[0120] A device following the design of FIG. 10 was built for performing 144 measurements in a single day, so that the removable cartridges would have to be filled or interchanged by filled ones only at the end of each day. The built device had the following dimensions: D1=16 cm, D2=30 cm, D3=25 cm, D4=13.5 cm, and the cartridges had the following capacity: liquid medium (or wash liquid) cartridge L=approx. 2 litres, reagent cartridges Ra=approx. 250 mL each reagent cartridge (or 500 mL when only one reagent cartridge is used), and waste cartridge W=approx. 2 litres.

[0121] FIG. 7 depicts how the addition of multiple reaction chambers can be utilized for parallel labelling allowing to shorten τ.sub.a until reaching the minimum possible value equal to τ.sub.c+τ.sub.r. To shorten it further one would have to use two or more devices of the first aspect of the present invention working in parallel. Each box represents one of the automated device's operating steps, performed according to an embodiment of the method of the second aspect of the present invention, and which are explained as:

[0122] C=collection, which is the time it takes for the air sampler AS to collect aerosols and other particles in the air;

[0123] R=recovery, which is the time it takes to wash (with the liquid medium) and recover the trapped air particles in the collection flask ASc;

[0124] L=labelling, which is the time it takes to label the sample;

[0125] M=measuring, which is the time it takes for the sample to travel through the sensor S and the software to calculate the particle concentration.

[0126] Each cycle is made up of the following components: collection time τ.sub.c, recovery time τ.sub.r, labeling time τ.sub.l, and measuring time τ.sub.m. τ.sub.a denotes the time-to-alarm interval of subsequent measurements for the presence of airborne particulate matter in the air.

[0127] FIG. 8A shows an example of the device of the first aspect of the present invention, for an embodiment or configuration which differs from that shown in FIG. 5 in that the fluidic apparatus F further comprises an air vent V, and in that there are n=4 reaction chambers.

[0128] FIG. 8B lists the different positions of the 3 port 2-way valve of the fluid dispenser Fd. Position A fluidically connects the fluid dispenser Fd to the selection valve Fv and position B fluidically connects the fluid dispenser to the optical sensor S.

[0129] In FIG. 8C, the possible positions of the 9 port active rotary valve Fv are illustrated. Position 0 fluidically connects the selection valve Fv to the wash cartridge L; position 1 fluidically connects the selection valve Fv to the air sampler AS; position 2 fluidically connects the selection valve Fv to the reagent cartridge Ra, Position 3 fluidically connects the selection valve Fv to reaction chamber 1; position 4 fluidically connects the selection valve Fv to reaction chamber 2; position 5 fluidically connects the selection valve Fv to reaction chamber 3; position 6 fluidically connects the selection valve Fv to reaction chamber 4; position 7 fluidically connects the selection valve Fv to air vent V.

[0130] A proof of concept experimental set-up has been built by the present inventors to provide experimental evidence supporting the invention disclosure.

[0131] The experimental set-up consists of a custom-made hermetic box of 36 L (30 cm×30 cm×40×m) with the scope to create a controlled closed environment. The box is equipped with an input hole to which a commercially available nebulizer is connected, and a door to allow the placement of the air sampler and the cone trapping the sampled particles. The air sampler is a commercially available, active, portable, cyclonic air sampler that operates at a flow rate of 50 L/minutes. The biosensor employed for the detection of the collected particles is a custom-build small form factor flow virometer reader (FVR). The FVR combines sample flow in a straight microfluidic channel at a flow-rate of 1 mL/minutes using an automatic syringe pump (fluidic control), and a blue laser interrogation to detect the fluorescence light emitted by the targeted pathogen or allergen passing through the field of view.

[0132] FIGS. 9A and 9B show proof of concept results obtained with the experimental set-up described above. To determine the feasibility of capturing and detecting viruses, an environment containing heat-inactivated SARS-CoV-2 viral particles dispersed in aerosols was created. First, a 2 mL solution of 50,000 viral copies per milliliter in PBS was prepared by serial dilution from a commercially available SARS-CoV-2 sample from ATTC, with a starting concentration of 10.sup.8 copies/mL. The prepared mock sample was nebulized inside the hermetic box to generate a concentration of 2.7 viral copies/mL in air. The air is collected using the cyclonic air sampler for 2 minutes, and the trapped viral particles are recovered from the inner surface of the cone by washing it with 2 mL of PBS. Once the sample has been collected, it is labelled by adding 50 ng/mL fluorescent labelled antibodies against SARS-CoV-2 and incubated for 20 minutes.

[0133] The labelled sample is then pumped through the FVR at 1 mL/min and the fluorescent events are detected. A series of controls were performed. As negative control, air collected prior to virus nebulization has been labelled and measured. As positive control, a 1 mL mock sample containing 50,000 viral copies per milliliters in PBS has been labelled, and measured. As an additional control, once the air containing the nebulized virus was collected, the hermetic box, and instruments have been cleaned using UV light and Ethanol. Then, the air from the cleaned box was collected, recovered, labelled, and measured. FIG. 9A shows the experimental results of the detection of SARS-CoV-2 from air. On the y-axis, the normalized counts [A.U.] of the fluorescent events are reported. Normalized counts here represent the counted events of each measured sample divided by the average counts of the fluorescent antibodies used. On the x-axis, controls and captured SARS-CoV-2 are reported. As can be seen, there is a statistically significant increase of the normalized counts of the SARS-CoV-2 captured samples with respect to the blank, and the signal of the captured virus is not different from the positive control, suggesting that most of the nebulized virus has been captured. The normalized counts of the collected air after the device was cleaned dropped to the level of the blank. This suggests that the proposed device can detect viruses in air and check for the air quality with respect to pathogen presence.

[0134] To determine the feasibility of capturing and detecting bacteria, the same experiment described above has been performed using Escherichia coli (E. coli), as example. E. coli OP50 at a concentration of 1,000 CFU/mL was nebulized inside the hermetic box to create an environment containing 55 CFU/100 mL of bacteria in the air. Then the bacteria dispersed in air has been captured, labelled using fluorescent-labelled E. coli antibodies, and measured (FIG. 9B). The device proved to be effective in the detection of E. coli from air.

[0135] An example of operation of the device of the first aspect of the present invention, and also of the method of the second aspect, is described below. In the following example the device of the embodiment of FIGS. 8A, 8B and 8C is used, and different cycles performed in part in parallel, as shown in FIG. 7, are performed.

EXAMPLE

[0136] 1.sup.st cycle: [0137] 1. Air sampler AS starts collecting. [0138] 2. Fluid dispenser Fd position A. [0139] 3. Selection valve Fv position 0, for a specific time, such as 2 seconds. [0140] 4. Fluid dispenser Fd withdraws washing liquid from the wash cartridge L, for example during 6 seconds for 1 ml at 10 ml/min. [0141] 5. Fluid dispenser Fd filled with wash liquid, for example for 6 sec. [0142] 6. Selection valve Fv position 1, for example for 2 seconds. [0143] 7. Air sampler AS stops collection. [0144] 8. Fluid dispenser Fd delivers wash liquid to the collection tube ASt, and thus to the air sample flask ASc, for example for 6 seconds. [0145] 9. Selection valve Fv position 7, for example for 2 seconds. [0146] 10. Fluid dispenser Fd withdraws air, for example for 6 seconds. [0147] 11. Selection valve Fv position 1, for example for 2 seconds. [0148] 12. Fluid dispenser Fd delivers air to collection tube ASc, and thus to the air sample flask ASc, to create pulsation flow, for example for 6 seconds. [0149] 13. Fluid dispenser Fd withdraws recovered air particle in washing liquid, for example for 6 seconds. [0150] 14. Air sampler AS starts collecting. [0151] 15. Selection valve Fv position 3, for example for 2 seconds. [0152] 16. Fluid dispenser Fd delivers sample 1, i.e., recovered air particle in washing liquid, to the reaction chamber R1, for example for 6 seconds. [0153] 17. Selection valve Fv position 2, for example for 2 seconds. [0154] 18. Fluid dispenser Fd withdraws reagent from Ra, for example for 6 seconds. [0155] 19. Selection valve Fv position 3, for example for 2 seconds. [0156] 20. Fluid dispenser Fd delivers reagent to the filled reaction chamber R1, for example for 6 seconds.

2.SUP.nd .Cycle:

[0157] 21. Selection Valve Fv position 0. [0158] 22. Air sampler AS stops collection. [0159] 23. Fluid dispenser Fd withdraws washing liquid from wash cartridge L. [0160] 24. Fluid dispenser Fd filled with wash liquid. [0161] 25. Selection valve Fv position 1. [0162] 26. Fluid dispenser Fd delivers wash liquid to the collection tube ASc, and thus to the air sample flask ASc. [0163] 27. Selection valve Fv position 7. [0164] 28. Fluid dispenser Fd withdraws air. [0165] 29. Selection valve Fv position 1. [0166] 30. Fluid dispenser Fd delivers air to collection tube ASc, and thus to the air sample flask ASc, to create pulsation flow. [0167] 31. Fluid dispenser Fd withdraws recovered air particle in washing liquid. [0168] 32. Air sampler AS starts collecting. [0169] 33. Selection valve Fv position 4. [0170] 34. Fluid dispenser Fd delivers sample 2, i.e., recovered air particle in washing liquid, to the reaction chamber R2. [0171] 35. Selection valve Fv position 2. [0172] 36. Fluid dispenser Fd withdraws reagent from Ra. [0173] 37. Selection valve Fv position 4. [0174] 38. Air sampler AS stops collection. [0175] 39. Fluid dispenser Fd delivers reagent to fill reaction chamber R2. [0176] 40. Selection valve Fv position 3. [0177] 41. Fluid dispenser Fd withdraws labelled sample 1 from R1. [0178] 42. Fluid dispenser Fd position B. [0179] 43. Fluid dispenser Fd delivers labelled sample 1 for measuring to the sensor S.
3rd cycle: [0180] 44. Selection valve Fv position 0. [0181] 45. Air sampler AS stops collection. [0182] 46. Fluid dispenser Fd withdraws washing liquid from wash cartridge L. [0183] 47. Fluid dispenser Fd filled with wash liquid. [0184] 48. Selection valve Fv position 1. [0185] 49. Fluid dispenser Fd delivers liquid to the collection tube ASt, and thus to the air sample flask ASc. [0186] 50. Selection valve Fv position 7. [0187] 51. Fluid dispenser Fd withdraws air. [0188] 52. Selection valve Fv position 1. [0189] 53. Fluid dispenser Fd delivers air to collection tube ASt, and thus to the air sample flask ASc, to create pulsation flow. [0190] 54. Fluid dispenser Fd withdraws recovered air particle in washing liquid. [0191] 55. Air sampler AS starts collecting. [0192] 56. Selection valve Fv position 5. [0193] 57. Fluid dispenser Fd delivers sample 3, i.e., recovered air particle in washing liquid, to reaction chamber R3. [0194] 58. Selection valve Fv position 2. [0195] 59. Fluid dispenser Fd withdraws reagent from Ra. [0196] 60. Selection valve Fv position 5 [0197] 61. Air sampler AS stops collection. [0198] 62. Fluid dispenser Fd delivers reagent to fill reaction chamber R3. [0199] 63. Selection valve Fv position 4. [0200] 64. Fluid dispenser Fd withdraws labelled sample 2. [0201] 65. Fluid dispenser Fd position B. [0202] 66. Fluid dispenser delivers labelled sample 2 for measuring to the sensor S. [0203] . . . .

[0204] The times in seconds indicated in Cycle 1 above are provided just as exemplary, and can vary, for example, depending on the type of reaction and type of sample to be labelled in the reaction chamber. Similar times can be used for subsequent cycles.

[0205] Some example use cases of the device of the first aspect of the present invention are described below.

Case 1: Single Pathogen Detection:

[0206] Considering the case of detecting a single pathogen, for e.g., SARS-CoV-2, for which the collection time τ.sub.c is 10 minutes, the recovery time τ.sub.r is 1 minute, and the labelling time τ.sub.l is 20 minutes. For this particular case, the required number of reaction chambers N.sub.rc≥2 i.e., at least two reaction chambers. With respect to FIG. 7, Cycle 1 starts with sample collection, from c1=0 lasting for 10 minutes i.e., till c1=10. The recovery time of 1 minute (r1=11) includes changing valve positions, withdrawing wash liquid from the wash cartridge L, delivering to the collection tube ASt, and thus air sample flask ASc, to elute the particles and finally delivering sample 1 to reaction chamber R1. The next step is labelling sample 1 for 20 minutes (I1=31). This step also includes the time taken by the fluid dispenser Fd to withdraw the reagent from the reagent cartridge Ra and deliver it to reaction chamber R1. The measurement time is 2 minutes which also includes the time for cleaning the microfluidic apparatus F after each sample measurement. Thus, sample 1 measurement is completed after a total time of 33 minutes (m1=33). Cycle 2 starts immediately after the recovery time of sample 1 i.e., c2=11. In the same way as the previous cycle, sample 2 is then eluted after collection, labelled and delivered to reaction 5 chamber R2. It is then measured after a total time of 43 minutes (m2=44). Thus, using multiple reaction chambers time-to-alarm, τ.sub.a is effectively shortened to 11 minutes. A cleaning cycle has to be included to clean the selection valve tubes and the fluid dispenser Fd carrying the fluorescent reagents after they are used to deliver the reagent to a reaction chamber. The table shows the time for each cycle if three reaction chambers are used.

TABLE-US-00001 Cycle 1 Cycle 2 Cycle 3 (minutes) (minutes) (minutes) collection = 10 min c1 = 10 c2 = 11 c3 = 22 recovery = 1 min .sup. r1 = 11 .sup. r2 = 22 .sup. r3 = 33 labelling = 20 min .sup. l1 = 31 .sup. l2 = 42 .sup. l3 = 53 measuring = 2 min m1 = 33  m2 = 44  m3 = 55 
Case 2: Single Pathogen Detection with Specific Probe that Fluorescent Only when Binding Occurs:

[0207] Same as Case 1 with the exception that the reagent used to label the sample is fluorescent only when binding occurs between the antibodies and the pathogen of interest. Therefore, the cleaning procedure is carried out only when a signal is detected after the sample has been measured.

Case 3: Two Different Pathogens, Same Excitation Different Emission Wavelength:

[0208] In this example, consider two different pathogens to be detected with only one reagent cartridge Ra. The fluorescent antibodies/probes/dyes used in this case have the same excitation wavelength but different emission wavelengths. The labelling time is also the same for both. If we assume the same collection, recovery, labelling time as Case 1, then, with at least two reaction chambers (N.sub.rc≥2) per pathogen, the time-to-alarm τ.sub.a is the same as before i.e., 11 minutes.

Case 4: Two Different Pathogens, Different Labelling Time, Excitation and Emission Wavelength:

[0209] Same as in Case 3 with the exception that the excitation wavelength of the fluorescent antibodies/probes/dyes and the labelling time for each pathogen are different. If the same collection and recovery time as Case 1 is assumed, but different labelling time, then the minimum number of reaction chamber needed to shorten the time-to-alarm is the sum of the minimum number of reaction chambers to label pathogen 1 and pathogen 2.

TABLE-US-00002 Pathogen 1 Pathogen 2 .sup. τ.sub.c = 10 minutes, .sup. τ.sub.c = 10 minutes, τ.sub.r = 1 minute  τ.sub.r = 1 minute  τ.sub.l = 20 minutes τ.sub.l = 30 minutes N.sub.rc ≥ 2 N.sub.rc ≥ 3

[0210] In this case the minimum number of reaction chambers needed is 5, which will result on a time-to-alarm of 11 minutes.

[0211] A person skilled in the art could introduce changes and modifications in the embodiments described without departing from the scope of the invention as it is defined in the attached claims.