Device for sampling and separating particulate and gaseous fractions of semi-volatile organic compounds present in the air

Abstract

A sampling device, portable or not, for separately quantifying the particulate and gaseous fractions of semi-volatile organic compounds present in the air, comprising an air flow inlet (4), an acceleration nozzle (5) connected to the air flow inlet (4), and a collection nozzle (6), the acceleration nozzle (5) and the collection nozzle (6) extending opposite each other around a common axis (X) and being spaced apart by a separation zone (7) of the air flow, said separation zone (7) being connected to a plenum (8), a main outlet (11) intended for sampling the particulate fraction and a first portion of the gaseous fraction being connected to the collection nozzle (6) and a secondary outlet (12) intended for sampling a second portion of the gaseous fraction being connected to the plenum (8).Furthermore, the plenum (8) comprises a homogenization disc (13) for the air flow speed and the collection nozzle (6) opening into said separation zone (7) at the center of said homogenization disc (13). Figure for abstract: Fig 2.

Description

Title of the invention: Device for sampling and separating the particulate and gaseous fractions of semi-volatile organic compounds present in the air

[0001] The present invention relates, in general, to the control of air quality in workplaces and relates, more specifically, to the evaluation of the occupational exposure of employees to semi-volatile organic compounds present in the air and harmful to health.

[0002] In particular, the invention relates to a sampling device for the separation of particulate and gaseous fractions of semi-volatile organic compounds present in the air, with a view to monitoring air quality and assessing employee exposure.

[0003] A semi-volatile organic compound (SVOC) or semi-volatile aerosol consists of a substance present in the form of vapors and particles. The NF EN 13936 standard defines a SVOC according to its saturated vapor pressure, between 0.001 and 100 Pa. These low saturated vapor pressures result in the simultaneous presence of a condensed phase (liquid or solid) and gaseous phase (vapors) under ambient pressure and temperature conditions.

[0004] Some semi-volatile organic compounds are known to be hazardous to health, and human exposure to these harmful compounds is very common. Many airborne SVOCs are sampled and analyzed to monitor environmental air quality, indoor air quality, and workplace air quality. Examples of these organic compounds include cutting oils, bitumen fumes, pesticides, and acrylamide.

[0005] Studies have shown that particles and vapors can theoretically have completely different deposition rates in the airways depending on the size of the inhaled particles and the polarity of the gas molecules, which are capable of solubilizing to a greater or lesser extent in body fluids. Thus, different health effects are expected for the particulate and vapor fractions of the same compound.

[0006] Particles suspended in the air, whether anthropogenic or natural, are conventionally called PM for "Particulate Matter", and are classified according to their size. The particles present, such as PM10 (particles with an aerodynamic diameter of less than 10 pm) can penetrate into the thoracic region of the respiratory tract, and are even likely to reach the alveolar space for particles of a sufficiently small size.

[0007] Known devices, called virtual impactors, make it possible to separate the particles of an aerosol present in a sampled air flow according to their size.

[0008] The principle of virtual impaction consists firstly in strongly accelerating the flow of air taken by a converging acceleration nozzle which opens into a separation zone where the majority of the air flow is sucked laterally while a minor part of the flow continues straight towards a diverging collection nozzle.

[0009] The inertia of the coarse particles does not allow them to accompany the fraction of air sucked laterally, which means that this lateral air (90% of the total air flow) contains only fine particles. The share of coarse particles and the share of fine particles in an aerosol can then be quantified separately.

[0010] However, existing virtual impactors are not suitable for sampling and assessing employee exposure to semi-volatile organic compounds. Indeed, virtual impactors operate with high air flow rates that are not compatible with available SVOC particle and vapor collection devices and are not compatible with individual pumps commonly used for assessing employee exposure in their workplace.

[0011] Many current sampling methods focus only on one of the phases of the SVOC aerosol. However, given that the particulate and vapor phases present in the air are absorbed by the human body using different mechanisms, sampling only one of these two phases would result in an erroneous estimate of human exposure to semi-volatile organic compounds. The particulate and vapor phases need to be measured separately.

[0012] Existing sampling techniques use supports (filter or metal plate) to trap particles contained in the air flow. These techniques generate significant measurement biases.

[0013] According to several studies, a phenomenon of evaporation of the particulate phase of the collected SVOCs has been highlighted and leads to a significant loss of mass during sampling, which distorts the quantification of this particulate phase as well as of the vapor phase when it is collected following the passage of the aerosol through a filter.

[0014] Consequently, current sampling techniques do not allow differentiation between the proportion of vapors originating from the semi-volatile aerosol before sampling and the proportion of vapors originating from the evaporation of particles collected during sampling. Similarly, it is not possible to model or calculate the fraction of the sampled particulate phase that evaporates during sampling.

[0015] For these reasons, to date, it is not possible to differentiate the particulate fraction from the vapor fraction of a semi-volatile aerosol. Currently, only a result expressing the sum of the two fractions can be given whereas it would be necessary to know precisely and without bias the quantities of particles and vapors present in the air inhaled by employees.

[0016] The invention therefore aims to remedy these drawbacks and to propose a device for the simultaneous sampling of the particulate and gaseous phases of semi-volatile organic compounds, limiting the phenomenon of evaporation during sampling, and leading to reliable quantification of each of these two phases.

[0017] There is therefore proposed a device for sampling and separating the particulate and gaseous fractions of semi-volatile organic compounds present in the air, comprising an air flow inlet, an acceleration nozzle connected to the air flow inlet, and a collection nozzle, the acceleration nozzle and the collection nozzle extending opposite each other around a common axis and being spaced apart by an air flow separation zone, said separation zone being connected to a plenum, a main outlet intended for sampling the particulate fraction and a first portion of the gaseous fraction being connected to the collection nozzle and a secondary outlet intended for sampling a second portion of the gaseous fraction being connected to the plenum.

[0018] Furthermore, the plenum comprises a disc for homogenizing the air flow speed and the collection nozzle opening into said separation zone at the center of said homogenizing disc.

[0019] Advantageously, the main and secondary outputs can extend along parallel axes.

[0020] Preferably, the section of the plenum passing through a plane perpendicular to the axis along which the main outlet extends is oval in shape.

[0021] In addition, the sampling device may comprise the assembly of first and second removable parts respectively incorporating the acceleration nozzle and the collection nozzle, and the respective internal surfaces of which delimit the plenum.

[0022] Advantageously, the sampling device may comprise at least one means for aligning the acceleration and collection nozzles.

[0023] According to an exemplary embodiment, one of the first and second parts comprises one or more alignment rods of the acceleration nozzle and the collection nozzle, the other of the first and second parts comprising a housing for receiving said alignment rods.

[0024] Preferably, the collection nozzle comprises a collection orifice opening onto the separation zone, the diameter of the collection orifice of the collection nozzle being between 0.5D and 1.5D, where D is the diameter of the acceleration orifice.

[0025] Preferably, the acceleration nozzle comprises an acceleration orifice opening onto the separation zone and a conical portion, the diameter of the base of the conical portion being between 4D and 5D, where D is the diameter of the acceleration orifice.

[0026] Preferably, the acceleration nozzle comprises an acceleration orifice opening onto the separation zone and the collection nozzle comprises a conical portion, the diameter of the base of the conical portion of the collection nozzle being between 1.5D and 2.5D.

[0027] Other aims, advantages and characteristics will emerge from the description which follows, given purely for illustrative purposes and with reference to the appended drawings in which:

[0028] [Fig-1] is a perspective view of a portable device for collecting and separating the particulate and gaseous fractions of semi-volatile organic compounds present in the air according to a first embodiment of the invention.

[0029] [Fig.2] illustrates a portion of the device for collecting and separating fractions particulate and gaseous semi-volatile organic compounds present in the air illustrated in [Fig.l] truncated according to the plane of symmetry of the sampling device.

[0030] [Fig.3] is a sectional view of the device for collecting and separating the particulate and gaseous fractions of the semi-volatile organic compounds present in the air illustrated in [Fig.l] passing through the plane of symmetry of the sampling device.

[0031] [Fig.4] is a perspective view of the lower part of the device for collecting and separating the particulate and gaseous fractions of semi-volatile organic compounds present in the air illustrated in [Fig.l].

[0032] [Fig.5] is an exploded view of a portable sampling and separation device particulate and gaseous fractions of semi-volatile organic compounds present in the air according to a second embodiment of the invention.

[0033] [Fig.6] is a sectional view of the device for collecting and separating the particulate and gaseous fractions of organic compounds or semi-volatile aerosols present in the air illustrated in [Fig.5] passing through the plane of symmetry of the sampling device.

[0034] [Fig.l] illustrates a first embodiment of a portable sampling device 1 intended, in this example, for the evaluation of air quality, in particular in the context of evaluating occupational exposures, and based on the principle of virtual impaction for the separation of the particulate and gaseous fractions of the semi-volatile organic compounds present in the sampled air.

[0035] It is not outside the scope of the invention if the sampling device is not a portable device.

[0036] The sampling device 1 may be formed by a plurality of independent, removable parts assembled together, for example first and second parts 2 and 3. The sampling device 1 may thus be disassembled to be cleaned for reuse.

[0037] In the illustrated example, the first part 2 is an upper part 2 and the second part 3 is a lower part 3.

[0038] As can be seen in Figures 2 and 3, the sampling device 1 comprises an air flow inlet 4. An acceleration nozzle 5 is connected to the air flow inlet 4.

[0039] The sampling device 1 further comprises a collection nozzle 6. The acceleration nozzle 5 and the collection nozzle 6 extend opposite each other around a common axis X.

[0040] The acceleration 5 and collection 6 nozzles are spaced apart by a separation zone 7 connected to a plenum 8. The separation zone 7 illustrated passes through the plenum 8, between the acceleration 5 and collection 6 nozzles.

[0041] By plenum, we mean a space of sufficient size to ensure the homogeneity of the static pressure at its outlets.

[0042] In the example illustrated, the plenum 8 is delimited by the internal surface, respectively 9 and 10 of the upper 2 and lower 3 parts which are removable when they are assembled. The upper part 2 incorporates the acceleration nozzle 5 and the lower part 3 incorporates the collection nozzle 6.

[0043] A main outlet 11 intended for sampling the particulate fraction and a first portion of the gaseous fraction is connected to the collection nozzle 6, and a secondary outlet 12 intended for sampling a second portion of the gaseous fraction is connected to the plenum 8.

[0044] In addition, the plenum 8 comprises a homogenization disc 13 for the speed of the air flow. The collection nozzle 6 opens into the separation zone 7, in the center of the homogenization disc 13.

[0045] The homogenizing disc 13 ensures a homogeneous distribution of the speed of the air flow around the separation zone.

[0046] The homogenizing disc 13 is preferably incorporated into the internal surface 10 of the lower part of the sampling device 1.

[0047] Advantageously, the collection nozzle 6 opens onto the surface of the homogenization disk 13 and the surface of the homogenization disk 13 extends along an axis perpendicular to the axis X along which the collection nozzle 6 extends.

[0048] In the illustrated example, the main 11 and secondary 12 outlets extend along parallel axes, respectively X and Y. Such an arrangement makes it possible to reduce the size of the sampling device 1 and to increase the compactness of the sampling device 1 and thus to improve its portability. The sampling device 1 can, for example, be carried by a user whose work environment air quality is to be analyzed.

[0049] The flow of the air stream through the sampling device 1 is generated by at least one pump arranged downstream of the main and secondary outlets 11 and 12.

[0050] Provision may be made for the sampling device 1 to comprise a flow regulator connected to each of the main and secondary outlets 11 and 12 in order to apply a specific flow rate thereto. Preferably, and unlike a conventional virtual impactor, the flow regulator is configured to apply a major flow rate to the main outlet 11 and a minor flow rate applied to the secondary outlet 12.

[0051] The air flow admitted into the sampling device 1 comprises a particulate fraction and a gaseous fraction. The air flow admitted into the sampling device 1 via the air flow inlet 4 is then accelerated by the acceleration nozzle 5 in order to give the particles a speed and thus an inertia dependent on the mass of each of the particles. The air flow then opens into the separation zone 7.

[0052] In the separation zone 7, a first part of the air flow continues its rectilinear trajectory and, driven by the suction force, heads towards the collection nozzle 6. Given the inertia of the particles present in the particulate phase of the semi-volatile organic compounds present in the air flow admitted into the sampling device 1, these particles are not affected by the lateral suction force and a first part of the sampled air flow comprising these particles continues in a straight line, crossing the separation zone 7 and entering the collection nozzle 6. This first part of the sampled air flow thus includes the particulate fraction as well as a first portion of the gaseous fraction of the semi-volatile organic compounds.

[0053] A second part of the sampled air flow branches off laterally, drawn into the plenum 8. This second part of the air flow constitutes a second portion of the gaseous fraction of the semi-volatile organic compounds present in the sampled air flow.

[0054] The circumference of the homogenizing disc 13 extending into the plenum allows for a uniform distribution of the air pressure. The homogenizing disc 13 thus makes it possible to obtain axisymmetric speeds around the separation zone 7 and makes it possible to keep the projection of the particles in alignment with the acceleration and collection nozzles 5, 6 of the laterally sucked air flow is controlled. The speed is uniform all around the separation zone 7, which reduces the deposition of particles on the internal surfaces 9 and 19 of the plenum 8 and limits the phenomenon of evaporation of the semi-volatile organic compounds.

[0055] Preferably, the flow rate of the air flow is regulated so that the particulate fraction entrained towards the main outlet 11 is greater than or equal to 86% of the air flow admitted into the sampling device 1, and that the gaseous fraction entrained towards the secondary outlet 12 represents 14% or less of the air flow admitted into the sampling device 1.

[0056] The first part of the air flow including the particles of the particulate phase and a first portion of the gaseous fraction enter the collection nozzle 6 then join the main outlet 11, and the second part including the second portion of the gaseous fraction enter the plenum 8 and then join the secondary outlet 12.

[0057] In the example illustrated, the first part of the air flow and the second part of the air flow are each collected first on a filter placed in a cassette and then on a clean activated carbon tube connected in series and connected, respectively, to the main and secondary outlets 11 and 12, in order to be analyzed separately and to determine the mass concentration of organic compounds that they contain.

[0058] Advantageously, the main and secondary outlets 11 and 12 can be formed by a tubular section conduit whose external walls form a cone complying with the manufacturing standard for “Luer” connectors. 25 mm diameter cassettes of the Milipore® type can thus be connected to them in a sealed manner to collect the particulate and gaseous fractions, respectively at the main and secondary outlets 11 and 12.

[0059] Preferably, the section of the plenum 8 passing through a plane perpendicular to the axis X along which the main outlet 11 extends is of oval shape.

[0060] By oval, we mean a curve which has only one axis of symmetry and whose revolution around this axis of symmetry leads to obtaining an ovoid or egg shape.

[0061] The oval shape makes it possible to reduce the residence time of the gas fraction in the plenum.

[0062] In the example illustrated, the general shape of the sampling device 1 is oval, extending along the plenum 8 so as to make the sampling device 1 more compact.

[0063] Advantageously, the secondary outlet 12 is arranged so as to open into the narrowest portion of the plenum 8 so that the air flow sucked laterally from the separation zone 7 located in the widest portion of the plenum 8 is quickly and easily guided towards the secondary outlet 12. The time of presence of the gaseous fraction in the plenum 8 is then reduced, which makes it possible to limit the phenomenon of condensation during the sampling of the semi-volatile organic compounds present in the air flow admitted into the sampling device 1.

[0064] In order to limit the risks of air leakage through the sampling device 1, a seal 14, for example an O-ring, may be arranged at the interface of the upper and lower parts, on the outer periphery of the plenum 8.

[0065] As illustrated in [Fig.4], the illustrated sampling device 1 comprises a groove 15 on the outer periphery of the plenum 8 configured to receive the seal 14 at the interface of the upper and lower parts 2 and 3 when they are assembled.

[0066] Furthermore, the first and second parts, in this example the upper and lower parts 2 and 3 are preferably assembled by a set of at least three fixing means 16. In the example illustrated, the fixing means 16 are five in number and are screws, distributed uniformly around the periphery of the sampling device 1 so that the position of the fixing means 16 makes it possible to apply uniform pressure along the entire length of the sealing joint 14.

[0067] As can be seen in [Fig. 3], the illustrated acceleration nozzle 5 advantageously comprises a convergent conical portion 17 which extends between an inlet orifice 18 of the air flow inlet 4 and a cylindrical acceleration orifice 19 opening into the separation zone 7.

[0068] The illustrated collection nozzle 6 comprises a diverging conical portion 20 extending between a collection orifice 21, opening onto the separation zone 7, and a main outlet orifice 22 connected to the main outlet 11.

[0069] The diameter of the acceleration orifice 19 of the acceleration nozzle 5 is slightly smaller than the diameter of the collection orifice 21 of the collection nozzle 6.

[0070] The secondary outlet 12 comprises a secondary outlet orifice 23 opening into the plenum 8.

[0071] Preferably, the dimensions of the device can be established by rule of proportionality so that the dimensions of the diameters of acceleration nozzle 5, collection nozzle 6 and the section of the plenum 8 can be defined and modified if they maintain the same proportionality between them.

[0072] The diameter of the acceleration orifice 19 of the acceleration nozzle 5 is denoted D. Hereinafter the dimensions are expressed by a multiple of D.

[0073] Preferably, the diameter of the base of the conical portion 17 of the acceleration nozzle 5 is between 4D and 5D.

[0074] Preferably, the diameter of the collection orifice 21 of the collection nozzle 6 is between 0.5D and 1.5D.

[0075] Preferably, the diameter of the base of the conical portion 20 of the collection nozzle 6 is between 1.5D and 2.5D.

[0076] According to one example, the diameter of the base of the conical portion 17 of the acceleration nozzle 5 may be between 2 and 11 mm, and the diameter of the acceleration orifice 19 of the acceleration nozzle 5 may be between 0.5 and 2.5 mm.

[0077] The diameter of the acceleration orifice advantageously makes it possible to improve the separation performance of the particulate and gaseous fractions of the semi-volatile organic compounds present in the sampled air flow.

[0078] The dimensions of the acceleration nozzle 5 and of the acceleration orifice are particularly advantageous for, on the one hand, ensuring optimal separation of the particulate fraction and the gaseous fraction while minimizing the pressure losses of the device, which allows its use with individual sampling pumps, and on the other hand, for minimizing the deposition of particles on the walls thereof, in particular particles with an aerodynamic diameter of less than 20 pm present in the sampled air flow, and thus preserve all of the semi-volatile organic compounds in the air flow passing through the sampling device 1.

[0079] According to one example, the diameter of the collection orifice 21 of the collection nozzle 6 may be between 0.6 and 3 mm, and the diameter of the base of the conical portion 20 of the collection orifice 21 may be between 1.1 and 5.6 mm.

[0080] The dimensions of the collection nozzle 6 and the collection orifice 21 also make it possible to improve the separation performance of the particulate and gaseous fractions of the semi-volatile organic compounds present in the sampled air flow. The dimensions of the collection nozzle 6 and the collection orifice 6 also make it possible to limit the deposition of particles on the walls thereof.

[0081] Furthermore, the dimensions of the acceleration nozzle 5, the acceleration orifice, the collection nozzle 6 and the collection orifice 21 are optimized and lead to easier machining and manufacturing of the sampling device.

[0082] According to an exemplary embodiment of the invention, the diameter of the base of the conical portion 17 of the acceleration nozzle 5 may be 8 mm and the diameter of the acceleration orifice 19 of the acceleration nozzle 5 may be 1.8 mm. The wall of the conical portion 17 of the acceleration nozzle 5 may extend at an angle of 16.9° relative to the axis X along which the acceleration nozzle 5 extends. The diameter of the collection orifice 21 of the collection nozzle 6 may be 2.1 mm and the diameter of the base of the conical portion 20 of the collection nozzle 6 may be 4 mm. The wall of the conical portion 20 can extend at an angle of 5.5° relative to the axis X along which the collection nozzle 6 extends. In addition, the flow rate of the air flow at the main outlet 11 of the sampling device 1 according to this exemplary embodiment can be 1.8 L.min 1 and the flow rate of the air flow at the secondary outlet 12 0.3 L.min *.

[0083] The air flow admitted into the sampling device 1 can, advantageously, be defined as the square of this coefficient of proportionality applied to the dimensions of the diameters of the acceleration nozzle 5, of the collection nozzle 6 and of the section of the plenum 8, to maintain the air speed in the sampling device 1.

[0084] A second embodiment is illustrated in Figures 5 and 6. The elements common to the first embodiment have similar references.

[0085] In addition, the sampling device 1 preferably comprises one or more means for aligning the acceleration and collection nozzles 5 and 6 around the common X axis along which they extend.

[0086] The means for aligning the acceleration and collection nozzles 5 and 6 lead to improved repeatability and reliability of the mass concentration measurements obtained from the particulate and gaseous fractions of the semi-volatile organic compounds sampled by the sampling device 24.

[0087] The means for aligning the acceleration and collection nozzles 5 and 6 also lead to minimizing the deposition of particles on the internal walls of the sampling device 24, in particular in the plenum 8.

[0088] For example, one of the upper and lower parts 2 and 3 comprises at least one alignment means for aligning the acceleration and collection nozzles 5 and 6, and the other of the upper and lower parts 2 and 3 comprises at least one housing for receiving the alignment means.

[0089] In the example illustrated, the upper part 2 comprises two alignment rods 25 and 26, and the lower part 3 comprises two receiving housings 27 for the alignment rods 25 and 26. The free end of the alignment rods 25 and 26 form a stop determining the spacing and position of the acceleration and collection nozzles 5 and 6 which are therefore independent of the mounting step and in particular of the tightening force applied to the fixing means 16, in this example screws. The means for aligning the acceleration and collection nozzles 5 and 6 allow better repeatability of the measurements obtained by the sampling device 24.

[0090] According to an alternative, the alignment rods 25 and 26 can also be rods independent of the upper and lower parts 2 and 3 of the sampling device 1. The alignment rods 25 and 26 can then be incorporated in a receiving housing on the upper part 2 and in a receiving housing 27 on the lower part 3. Only one of the receiving housings 27 is visible in the figures.

[0091] In this example, the main and secondary outlets 11 and 12 of the sampling device 24 are respectively formed by first and second parts 28 and 29 which are removable and independent of the upper and lower parts. This makes it possible in particular to adapt the configuration of the main and secondary outlets 11 and 12.

[0092] The air flow inlet 4 can also be formed by a third removable part 30.

[0093] The first, second and third parts 28, 29 and 30 can be connected to the first and second parts 2 and 3 by means of screws 31.

[0094] Preferably, a seal 32, 33 and 34 extends respectively between the main and secondary outlets 11 and 12 and the second part 3, and between the air flow inlet 4 and the first part 2.

[0095] The sampling device 24 according to the second embodiment further comprises a set of means 16 for fixing the first and second parts 2 and 3 with six screws.

[0096] The illustrated sampling device makes it possible to optimize the flow of air inside the device, without impaction and deposition on the walls, so as to minimize the phenomenon of evaporation of semi-volatile organic compounds present in the sampled air flow.

[0097] The configuration of the sampling device 1, 24 makes it possible to control the speed of the flow of the sampled air flow along its entire path, limiting pressure losses, the deposition of particles on the internal walls and thus minimizing the evaporation phenomenon.

[0098] The sampling device 1, 24 results in a more reliable quantification of the mass concentrations of each of the particulate and gaseous fractions of the semi-volatile organic compounds sampled in the air flow.

[0099] The separation performance of the device cannot be defined according to a cut-off diameter D50 as carried out for the evaluation of the performance of the impactors and virtual impactors. The D50 is the diameter for which 50% of the particles whose diameter is greater are directed by the collection nozzle 6 and 50% of the particles whose diameter is smaller are directed towards the plenum 8 then the secondary outlet 12. Indeed, even if the present sampling device 1, 24 uses the same physical principle of separation, it advantageously implements a distribution of the flow rates inverse to the virtual impactor which makes it possible to achieve a minimum performance equal to the ratio of the flow rates, i.e. greater than or equal to 86% regardless of the diameter of the particles.Thus, it is appropriate to evaluate the performance of the sampling device in terms of “transfer efficiency” of the particles between the inlet of the device 4 and the secondary outlet 12, rather than using the D50 which cannot be determined here because it is exceeded in all cases.

[0100] The sampling and separation performance of the sampling device 1, 24 illustrated with respect to COSV aerosols amounts to more than 94%.

[0101] The value of the pressure losses generated by the sampling device 1, 24 illustrated is less than 300 Pa and the value of the particle deposition on the walls is less than 6%. This deposition is advantageously located so as not to be able to bias by evaporation the vapor content of the portion of the sampled gas fraction which is directed towards the secondary outlet 12.

[0102] The sampling device 1, 24 illustrated is a portable, reliable device with optimized performance, simple to design and use, low manufacturing cost, which does not require maintenance and which is reusable.

Claims

Claims

1. Device for sampling and separating the particulate and gaseous fractions of semi-volatile organic compounds present in the air, comprising an air flow inlet (4), an acceleration nozzle (5) connected to the air flow inlet (4), and a collection nozzle (6), the acceleration nozzle (5) and the collection nozzle (6) extending opposite each other around a common axis (X) and being spaced apart by a separation zone (7) of the air flow, said separation zone (7) being connected to a plenum (8), a main outlet (11) intended for sampling the particulate fraction and a first portion of the gaseous fraction being connected to the collection nozzle (6) and a secondary outlet (12) intended for sampling a second portion of the gaseous fraction being connected to the plenum (8),characterized in that the plenum (8) comprises a homogenization disc (13) for the speed of the air flow and the collection nozzle (6) opening into said separation zone (7) at the center of said homogenization disc (13), the surface of the homogenization disc (13) extending along an axis perpendicular to the axis (X) along which the collection nozzle (6) extends, and the collection nozzle (6) opening onto the surface of the homogenization disc (13).,

2. Device according to claim 1, in which the main and secondary outlets (11, 12) extend along parallel axes (X, Y).

3. Device according to claim 1 or 2, in which the section of the plenum (8) passing through a plane perpendicular to the axis (X) along which the main outlet (11) extends is oval in shape.

4. Device according to any one of the preceding claims, comprising the assembly of first and second removable parts (2, 3) respectively incorporating the acceleration nozzle (5) and the collection nozzle (6), and the respective internal surfaces (9, 10) of which delimit the plenum (8).

5. Device according to claim 4, comprising at least one alignment means (25, 26) of the acceleration and collection nozzles (5, 6).

6. Device according to claim 4 or 5, wherein one (2) of the first and second parts (2, 3) comprises one or more alignment rods (25, 26) of the acceleration nozzle (5) and of the collection nozzle (6), the other (2) of the first and second parts (2, 3) comprising a receiving housing (27) of said alignment rods (25, 26).

7. Device according to any one of the preceding claims, wherein the acceleration nozzle (5) comprises an acceleration orifice (19) opening onto the separation zone (7) and the collection nozzle (6) comprises a collection orifice (21) opening onto the separation zone (7), the diameter of the collection orifice (21) of the collection nozzle (6) being between 0.5D and 1.5D, where D is the diameter of the acceleration orifice (19).

8. Device according to any one of the preceding claims, in which the acceleration nozzle (5) comprises an acceleration orifice (19) opening onto the separation zone (7) and a conical portion (17), the diameter of the base of the conical portion (17) being between 4D and 5D, where D is the diameter of the acceleration orifice (19).

9. Device according to any one of the preceding claims, in which the acceleration nozzle (5) comprises an acceleration orifice (19) opening onto the separation zone (7) and the collection nozzle (6) comprises a conical portion (20), the diameter of the base of the conical portion (20) of the collection nozzle being between 1.5D and 2.5D.