Aerosol particle measuring device for the determination of materials in real time using fluorescence lifetime measurement in the frequency domain

Description

[0001] The present invention relates to an aerosol particle measuring device and a method for the qualitative and / or quantitative determination of fluorescent materials in real time by means of fluorescence lifetime measurement, as well as the use of the aerosol particle measuring device and the method.

[0002] In our society, the prevalence of allergic rhinitis, also known as pollen allergy or hay fever, is steadily increasing, and the number of sufferers is rising worldwide. In Switzerland, 15-20% of the population is currently considered allergic to pollen. This not only represents a significant portion of healthcare costs, but the economic costs are also considerable.

[0003] To provide pollen allergy sufferers in Europe with the appropriate information about pollen levels, 10 to 20 different types of pollen must be distinguished. An older, but still very common, method for measuring pollen is based on Hirst pollen traps. Adhesive strips are mounted in these traps, to which the pollen in the air adheres. The pollen collected in this way is then periodically examined in the laboratory by a trained specialist, for example, manually using light microscopy, and subsequently identified. The results of the qualitative and quantitative pollen analysis are therefore usually only available after a delay of several days. Moreover, the process is considerable and expensive, even though a measurement uncertainty of up to 25% is assumed.

[0004] Therefore, in Switzerland, for example, pollen data is only available with a delay of approximately one week, despite a not insignificant inaccuracy, due to the currently available measurement methods. Furthermore, the geographical resolution is very low, as there are currently only 14 measuring stations in Switzerland.

[0005] In recent times, various measurement systems have been proposed for faster pollen identification. The measurement of the fluorescence of the materials under investigation is often suggested as a suitable method.

[0006] Fluorescence is the spontaneous emission of light, i.e., photons, directly after a material is excited. The light emitted by the material is generally lower in energy than the light used to excite it. Materials with this property are called fluorescent materials. If the materials exhibit this property naturally, it is called autofluorescence. If the excitable material is part of an organism, it is called biofluorescence. Materials without autofluorescence can be treated—that is, stained or labeled—with a fluorescent dye, i.e., a fluorochrome, allowing them to be analyzed by measuring their fluorescence.

[0007] When a fluorescent material is irradiated with light of a suitable wavelength, the light is absorbed by the material; that is, the irradiated atoms and molecules take up the light energy. This excites electrons from their ground state to a higher energy level. During the subsequent transition back to the ground state, a photon is emitted. In fluorescent materials, the emitted photon has lower energy than that of the excitation light. In other words, the photon emitted by the excited material has a longer wavelength than the photon of the excitation light. This phenomenon is also called fluorescence emission.

[0008] Fluorescence emission depends on the excitation wavelength, the excitation intensity, and the specific material. Therefore, the emitted light changes depending on the chemical composition of the excited material and is also dependent on the excitation light. Analyzing the emitted light allows conclusions to be drawn about the material under investigation. Suitable wavelengths for excitation—for example, in the case of biofluorescence—lie in the UV and near-UV wavelength range, such as the UV-A range with wavelengths of 315–380 nm, the UV-B range with wavelengths of 280–315 nm, the UV-C range with wavelengths of 100–280 nm, and the near-UV range with wavelengths of 380 nm to 410 nm.

[0009] Suitable measures of fluorescence emission are the intensity and lifetime at one or more emission wavelengths.

[0010] To measure the intensity of fluorescence emission, the material under investigation is typically excited with a specific wavelength and intensity of light, and the emission strength is measured at one or more wavelengths. Photomultiplier tubes (PMTs) and miniaturized photomultiplier tubes, known as multichannel plates (MCPs), are used to detect the emission. The measured intensity of the emitted photons depends not only on the excitation wavelength but also on the material being examined. It is particularly useful for investigating stationary materials and is especially suitable for fluorescence microscopy. However, measuring the intensity of fluorescence emission is not suitable for the unambiguous identification of different aerosol particles such as pollen.

[0011] Fluorescence lifetime, also known as fluorescence period, is the characteristic duration for which photons are emitted after a brief excitation. Fluorescence lifetime is defined as the average time a molecule remains in an excited state before emitting a photon and thus returning to its ground state. The fluorescence lifetime typically ranges from 10⁻¹² to 10⁻⁸ seconds and is specific to individual chemical groups and / or molecules, i.e., the excited material. It depends on the excitation wavelength but is largely independent of the excitation intensity and the concentration of fluorescent atoms and molecules in the material.

[0012] The fluorescence lifetime of fluorescent materials can be measured in the time domain or in the frequency domain (or phase modulation).

[0013] In fluorescence lifetime measurements—both in the time domain and the frequency domain—photomultiplier tubes (PMTs) and miniaturized photomultiplier tubes (MCPs) are used to detect the received photons. PMTs and MCPs exhibit an optimal signal-to-noise ratio and a gain of approximately 10⁷ and are particularly suitable for single-photon detection, thus making them ideal for time-domain fluorescence lifetime measurements. However, photomultiplier tubes are also used today for frequency-domain fluorescence lifetime measurements. It is crucial, however, to ensure that the number of photons received per unit of time does not exceed a relatively low value to prevent overloading and damage to the photomultiplier tubes. Furthermore, PMTs and MCPs are expensive, large, and require an operating voltage of up to 1000 volts or more, which makes them unsuitable for miniaturization.

[0014] In time-domain fluorescence lifetime measurement, the material under investigation is excited with light pulses. Individual fluorescence photons are then measured. Time-correlated single photon counting (TCSPC) has become an important standard method for time-domain fluorescence lifetime measurement. It is used, for example, to investigate biological macromolecules such as proteins and to image cells. This method uses light pulses of defined intensity and short duration in the picosecond range, with the required short and intense light pulses typically generated by lasers. Time-domain fluorescence lifetime measurement, and thus time-correlated single photon counting, requires very fast measurement systems for detecting the received photons as well as a highly sensitive detector.This makes such measurement setups complex, expensive, and sensitive to external influences. Therefore, the TCSPC method is suitable for investigating stationary materials where longer measurement times are possible, but not for rapidly moving objects such as aerosols. Thus, time-domain fluorescence lifetime measurement, such as the TCSPC method, is not suitable for determining pollen in flight.

[0015] In frequency-domain fluorescence lifetime measurement (FD FLM), fluorescence is periodically excited by light with modulated intensity. The measured fluorescence emission therefore also varies periodically, but with a phase shift relative to the excitation modulation. This phase shift and the strength of the fluorescence modulation depend on the fluorescence lifetime of the excited material, allowing conclusions to be drawn about the object under investigation. In contrast to time-domain fluorescence lifetime measurement, frequency-domain fluorescence lifetime measurement enables the detection of a large number of photons, allowing more photons to be captured per unit of time. This makes the method particularly suitable for measuring dynamic systems, such as in the imaging of cells, including cancer cells.However, due to the extremely short possible measurement duration, it is currently not possible to perform a qualitative and / or quantitative determination of aerosol particles such as pollen in flight using fluorescence lifetime measurement in the frequency domain.

[0016] Therefore, to this day there is no reliable method for determining pollen levels in real time. Consequently, pollen allergy sufferers cannot take appropriate precautions in time due to the delayed information on current pollen levels. This leads to a reduction in their quality of life and, as a rule, also to greater economic costs.

[0017] The object of the present invention is therefore to provide a measuring device with which a large number of diverse aerosol particles, such as pollen, can be qualitatively and, if necessary, quantitatively determined quickly and with a high degree of accuracy, in order, for example, to correctly inform pollen allergy sufferers shortly after the first pollen season. Furthermore, the measuring device should be compact, robust, and cost-effective, so that it can be used in a variety of ways and ideally flexibly, i.e., at different locations.

[0018] This problem was surprisingly solved with an aerosol particle measuring device according to claim 1.

[0019] A method for the qualitative and / or quantitative determination of fluorescent materials (2) in real time by means of fluorescence lifetime measurement with the aerosol particle measuring device (20) according to the invention is also claimed, wherein i) the fluorescence lifetime measurement is performed in the frequency domain and the light (31) emitted by the light source (3) is intensity-modulated, ii) a diode laser, an LED and / or a diode-pumped solid-state laser is used as the light source (3), iii) the materials (2) are measured in the form of aerosol particles of an aerosol in the measuring chamber (8) of the measuring device (1), iv) in the measuring chamber (8) the aerosol particles are exposed to the light (31) of the light source (3), wherein the aerosol particles absorb and partially re-emit the light, v) the emitted light is detected with the detector (4), wherein the detector (4) is a semiconductor-based electronic photon detector for light detection, in particular a silicon photomultiplier (SiPM), and vi) the obtained data are processed with a data processing program.

[0020] Furthermore, the use of the inventive aerosol particle measuring device (20) and / or the inventive method for the qualitative and / or quantitative determination by means of fluorescence lifetime measurement in the frequency domain, in particular in real time, of fluorescent materials (2) in the form of aerosol particles of an aerosol, in particular of pollen and / or spores suspended in the air, as well as for process and / or quality control of materials (2) such as in process engineering, is also claimed.

[0021] Surprisingly, it was found that the inventive aerosol particle measuring device (20), the inventive method, and the inventive use with the semiconductor-based electronic photon detector for light detection, i.e., the detector (4), such as a silicon photomultiplier (SiPM), can fulfill the demanding task. This is because, due to the fluorescence lifetime measurement in the frequency domain, the samples under investigation, such as aerosol particles and pollen, can be irradiated with higher light intensities, resulting in a significantly larger number of emitted and detected photons—and thus shorter measurement times. Therefore, even extremely small samples with sometimes very weak fluorescence emissions, such as aerosol particles like pollen, can be quantitatively and qualitatively analyzed in flight—and thus in real time.This means that, for example, relevant information about pollen can be made available to allergy sufferers within minutes or a few hours.

[0022] The detector (4) used in the aerosol particle measuring device (20) and in the method according to the invention allows even a very large number of photons to be measured and processed. Although the detector (4), like SiPM, has a significantly higher dark pulse rate than the photomultiplier tubes used in the prior art, a sufficient signal-to-noise ratio is nevertheless achieved – unexpectedly for those skilled in the art – enabling fast and accurate measurements.

[0023] Since the aerosol particle measuring device (20) and the method can measure a very large number of photons simultaneously, the aerosol particle measuring device (20) and the method are ideally suited for the qualitative and / or quantitative determination of fluorescent materials (2) in real time by means of fluorescence lifetime measurement.

[0024] Furthermore, the aerosol particle measuring device (20) is robust, fast, efficient, and can be used with standard operating voltages, making it suitable for outdoor use and / or as a mobile measuring device. It can also be built more cost-effectively and with smaller dimensions. For example, the measuring device (1) can be built with external dimensions of approximately 10 × 5 × 5 cm³, and the aerosol particle measuring device (20) with external dimensions of approximately 30 × 30 × 30 cm³, which makes them even more attractive. This allows for the installation of significantly more pollen measuring stations without considerable effort and at reasonable costs, and the level of automation in pollen determination can be considerably increased, leading to a denser pollen data network and thus to better spatial resolution.This means that pollen allergy sufferers will receive much more accurate information about the current daily pollen count much faster, which in turn improves the quality of life for pollen allergy sufferers and reduces economic costs.

[0025] Thus, the aerosol particle measuring device (20) according to the invention can surprisingly be used in a wide variety of applications. Furthermore, very fast-moving particles, such as aerosol particles of aerosols, in particular a large number – for example, 20 or more – of different pollens and spores, can be quantitatively and qualitatively examined and distinguished from one another in real time and even in flight, which was not possible until now.

[0026] EP-A-1109005 describes a pollen grain counting method and a pollen counting apparatus comprising the separation of particles contained in a specific atmospheric quantity, excluding particles significantly smaller than pollen grains, and the inducing the separation of the particles to flow through a flow cell in such a state that the intrinsic fluorescence of each particle can be measured. The fluorescence measurement only measures the intensity of the fluorescence emission, which severely limits the information obtained about the measured particles. This, in turn, significantly restricts the application range of the method and the apparatus. Photomultiplier tubes (PMTs) are used as detectors, making the measurement technology considerably more complex, larger, more expensive, and more susceptible to malfunctions. While the proposed counting method and apparatus can distinguish between several different pollen types, this limitation is limited.However, the necessary differentiation between 10 to 20 different types of pollen in Europe is not possible.

[0027] US patent A-2016 / 0266087 discloses devices and methods for differentiating tissue proteins, i.e., static samples, using frequency-domain fluorescence lifetime spectroscopy. The devices comprise a modulated light source, an optical focusing fiber, an optical detection fiber, and a detector. These focusing and detection fibers guide the light to the external detector. As a result, the overall transmission changes with each insertion and removal, necessitating recalibration of the device. Such devices are suitable for laboratory use but not for field applications. The proposed devices and methods are not suitable for an aerosol particle analyzer for the real-time determination of fluorescent materials such as aerosol particles within an aerosol. Measuring device (1)

[0028] The measuring device (1) of the aerosol particle measuring device (20) according to the invention is suitable for the qualitative and / or quantitative determination of fluorescent materials (2) in real time by means of fluorescence lifetime measurement in the frequency domain. In particular, measurements of rapidly moving samples such as aerosols – and thus of particles in the gas phase – can be carried out.

[0029] The measuring device (1) comprises at least one light source (3), at least one detector (4), and a measuring chamber (8). Preferably, the measuring device (1) also comprises at least one excitation optic (6), at least one detector optic (7), a data processing program, and / or electronics for device control, signal measurement, signal conditioning, signal evaluation, and data storage.

[0030] According to the present invention, real-time means that the measurement can be performed instantly, i.e., within a fraction of a second, for example, within a few nanoseconds, microseconds, or milliseconds. The subsequent evaluation of the obtained data typically takes from seconds to a few hours, depending on the amount of data and computing power. Thus, materials (2) that are exposed to the emitted light (31) and can emit fluorescence for only an extremely short time, as well as static materials (2) that can be examined over a longer period, can be determined. Materials (2)

[0031] The materials (2) to be examined with the aerosol particle measuring device (20) – and thus with the measuring device (1) – are, according to the invention, aerosol particles of an aerosol. Suitable materials (2) are known to those skilled in the art. They may exhibit autofluorescence and / or be treated with a fluorophore, i.e., a fluorochrome, before measurement.

[0032] According to the invention, the term "aerosol particles of an aerosol" means that the aerosol particles are dispersed in the gas phase. Accordingly, the aerosol particle measuring device (20) determines the aerosol particles in the gas phase and thus in flight.

[0033] According to the invention, an aerosol is understood to be a mixture of aerosol particles, also called suspended particles, in a gas or gas mixture, wherein the suspended particles are present in solid and / or liquid form at ambient temperature and typically have a mean diameter of about 20 nm to about 100 µm or more. Air is a typical gas mixture containing aerosols, which are important in everyday life and can often pose a health risk or even a burden.

[0034] Non-limiting examples of aerosols that can be measured with the aerosol particle measuring device (20) according to the invention include pollen, in particular flower, grass, plant and tree pollen, spores such as mold spores, in particular Aspergillus fumigatus, Alternaria alternata, Penicillium notatum and Cladosporium herbarum, bacteria, excrement of house dust mites, allergens from pets, viruses, fine dust, smoke, in particular cigarette smoke, combustion gas and flue gas, soot and oil fumes from combustion engines such as car exhaust, sulfur dioxide, ash such as volcanic ash, and / or nanoparticles, which can be produced industrially, for example.

[0035] Preferred materials (2) comprise fluorescent organic and / or inorganic pure substances or mixtures and may be in the form of a solid, liquid, dispersion, suspension, paste, and / or in the form of air-dispersed bioaerosol particles such as pollen, flower dust, spores, fungal spores, plant spores, proteins, DNA, RNA, organisms, tissues, cells, bacteria, viruses and / or mineral dust and may optionally have been pre-treated with a fluorophore. Light source (3)

[0036] The measuring device (1) of the aerosol particle measuring device (20) comprises, among other things, at least one light source (3) and at least one detector (4). The light (31) emitted by the light source (3) typically has a wavelength in the UV and near-UV range. If several light sources (3) are used, the light (31) emitted by the light sources (3) can have the same wavelength or different wavelengths.

[0037] In a preferred embodiment, the light (31) emitted by the light source (3) is intensity-modulated, i.e., the fluorescence excitation is intensity-modulated, in particular sinusoidally intensity-modulated, wherein the modulation is generally carried out by the electronics present in the measuring device (1). Alternatively or additionally, the light source (3) is a diode laser, in particular a UV diode laser, an LED, in particular a UV LED, and / or a diode-pumped solid-state laser, in particular a diode-pumped UV solid-state laser.

[0038] UV LEDs are particularly preferred, with the term UV LED referring to a light-emitting diode emitting light in the UV wavelength range. Diode-pumped solid-state lasers are also known by the English term diode-pumped solid state, abbreviated as DPSS or DPSSL. LEDs and UV LEDs are semiconductor-based and can be produced cost-effectively. UV LEDs are also significantly smaller than conventional UV lasers or UV lamps, which helps to keep the measuring device (1) small. In addition, the emission power of a single LED, especially a UV LED, is usually sufficient because, according to the invention, the available power of the light source is used efficiently for excitation. Alternatively, two or even more than two light sources (3), such as UV LEDs or laser diodes of the same or different wavelengths, can be used.

[0039] In a preferred embodiment, which is particularly useful for measuring fluorescent biological aerosol particles, two or more light sources (3) with different wavelengths, preferably with different modulation frequencies, are used to excite different chemical groups and measure their fluorescence lifetime. In addition to sequential excitation with different wavelengths, parallel excitation is also possible. This is because simultaneous excitation and fluorescence measurement of different chemical groups is possible if the modulation frequency of the different wavelengths is different. A non-limiting example is a laser diode emitting light with a wavelength of 405 nm, a UV LED emitting light with a wavelength of 365 nm, and another UV LED emitting light with a wavelength of 280 nm. Detector (4)

[0040] The detector (4) measures the light (31) emitted by the light source (3) that reaches the detector (4). If the emitted light (31) excites fluorescent materials (2) under investigation, these materials emit photons, also called light quanta or light particles, which have a wavelength different from the emitted light (31). These photons can also be measured by the detector (4).

[0041] The aerosol particle measuring device (20), and thus the detector (4) used in the measuring device (1) according to the invention, is a semiconductor-based electronic photon detector for light detection, in particular a silicon photomultiplier (SiPM). Such silicon photomultipliers (SiPM) are also known as pixelated Geiger-mode avalanche photodiodes (PPDs), silicon photomultipliers (SPM), multi-pixel photon counters (MPPCs), multi-pixel avalanche photodiodes (PMADs), Geiger-mode avalanche photodiodes (G-APDs), or multi-pixel Geiger-mode avalanche photodiodes (MPGM APDs).

[0042] Electronic multi-pixel detectors (4) based on semiconductor technology, such as silicon photomultipliers (SiPMs), have a smaller volume compared to photomultiplier tubes (PMTs), which allows the measuring device (1) to be made smaller and more portable compared to conventional devices. Furthermore, SiPMs are also less expensive and do not require a high-voltage source of typically several thousand volts for operation; for example, 40 to 70 volts are sufficient. They exhibit, in some cases, better quantum efficiency and are more robust against mechanical influences such as vibration or shock, as well as against magnetic fields.

[0043] Although the detectors (4) used according to the invention, such as SiPM, exhibit a higher dark current and a longer dead time compared to PMTs, it was surprisingly found that the effects of the higher dark current and dead time do not adversely affect the fluorescence lifetime in the frequency domain when using the detectors (4). Therefore, a compact, robust, and thus mobile, low-maintenance, and cost-effective measuring device (1), and thus a fluorescence lifetime measurement system, can be provided using one or more detectors (4). Other components of the measuring device (1)

[0044] In a preferred embodiment, the measuring device (1) further comprises at least one excitation optic (6), at least one detector optic (7), a program for data processing, an opaque housing and electronics for device control, signal measurement, signal conditioning, signal evaluation and data storage.

[0045] Furthermore, the measuring device (1) advantageously does not include any optical fibers or optical waveguides or fiber optic cables, such as optical focusing fibers that guide the light from an external source to the illumination optics, or optical detection fibers that guide the light to an external detector; i.e., the detectors (4) are preferably integrated into the device. This makes the device more sensitive because the losses due to the optical fibers are eliminated. The long-term stability of the measurement results is also increased, which is particularly advantageous for long-term operation in the field.

[0046] The optional, but often preferred, data storage allows data to be stored locally without having to be transmitted directly. This makes it possible to measure data in a first step and only analyze it locally and / or at an external location in a second step. Suitable data storage solutions are known to experts.

[0047] The optional, but often preferred, data processing program allows for immediate on-site data processing, i.e., at the location of the aerosol particle measuring device (20). This is particularly helpful for mobile and / or stand-alone devices, such as aerosol particle measuring devices (20) stationed outdoors. Suitable data processing programs are known to those skilled in the art.

[0048] The optional, but often preferred, electronics advantageously allow the desired settings to be made and parameters to be varied. Non-limiting examples include controlling the light source, setting, amplifying, and / or modulating the required frequency, typically in the high MHz range, and processing the measured light with fluorescence excitation compared to the emitted light (31) without fluorescence excitation. A person skilled in the art can provide suitable electronics specifically for the measuring instrument (1) and / or the entire aerosol particle measuring instrument (20) without inventiveness.

[0049] The measuring instrument (1) advantageously also includes an opaque housing to keep interfering effects, such as ambient light, away from the measuring arrangement. Suitable materials for such housings are known to those skilled in the art. They can also create opaque housings without inventive step. Excitation optics (6) and detector optics (7)

[0050] The optional, but preferred, excitation optics (6) have the task of focusing the light (31) emitted by the light source (3) and directing it in a highly focused manner onto the material (2) to be examined, i.e., the sample to be measured. In the aerosol particle measuring device (20) according to the invention, the sample, i.e., the aerosol particles with the aerosol, is conveyed through the measuring chamber (8) in flight. The excitation optics (6) focus the emitted and focused light (31) onto a location in the measuring chamber (8) through which the aerosol particles to be measured are conveyed. This automatically excites the aerosol particles with the emitted light (31).

[0051] The excitation optics (6) of the measuring device (1) is advantageously arranged between the light source (3) and the material (2) to be determined, wherein the excitation optics (6) comprises at least one optical lens (9) and preferably at least one optical filter (10), and optionally at least one reflector (11).

[0052] The measuring instrument (1) can comprise one or more identical and / or different excitation optics (6). The excitation optics (6) can be the same or different, regardless of the type of light source (3), i.e., whether the light source (3) is a diode laser, a diode-pumped solid-state laser, or a UV LED. It is possible for each light source (3) to have a separate excitation optic (6), or for two or more light sources (3) to share a common excitation optic (6).

[0053] In a preferred embodiment of the aerosol particle measuring device (20), the measuring device (1) comprises two or more light sources (3) and at least one excitation optic (6), wherein i) a separate excitation optics (6) is arranged between each light source (3) and the material (2) to be determined, and / or ii) a common excitation optics (6) is arranged between two or more light sources (3) and the material (2) to be determined, iii) the light sources (3) have different modulation frequencies, and / or iv) the light sources (3) emit different wavelengths.

[0054] If the light sources (3) have different modulation frequencies, at least two light sources (3) with the same and / or different emission wavelengths can be active simultaneously. This allows at least two phase measurements to be performed at the same time, enabling even faster measurements.

[0055] The wavelengths emitted by the light sources (3), which may differ, can be such as 315-380nm (UV-A range), 280-315nm (UV-B range), 100-280nm (UV-C range) and 380nm to 410nm (near-UV range), although other wavelengths are also possible.

[0056] The optional, but preferred, detector optics (7) have the task of focusing the light scattered, reflected and / or emitted by the material (2) under investigation and sending it in a highly focused manner to the detector (4).

[0057] Thus, the detector optics (7) of the measuring device (1) is advantageously arranged between the material (2) to be determined and the detector (4), wherein the detector optics (7) comprise at least two optical lenses (9), and preferably at least one optical filter (10) and / or at least one spectral divider (12), in particular an interference mirror, a prism, optical grating, diffraction grating and / or multiple slit, wherein the spectral divider (12) redirects a portion of the light, preferably via an optical lens (9), to at least one further detector (4).

[0058] In a further preferred embodiment of the aerosol particle measuring device (20), the measuring device (1) comprises two or more detectors (4), wherein between i) a separate detector optic (7) is arranged between the material (2) to be determined and one or more detectors (4), and / or ii) only one detector optic (7) is arranged between the material (2) to be determined and several detectors (4), wherein the detector optic (7) comprises a separate optical filter (12) for the second and each subsequent detector (4).

[0059] In another preferred embodiment of the aerosol particle measuring device (20), the measuring device (1) comprises a further reflector (11) to reflect light coming from the material (2), optionally via the detector optics (7), to the detector (4).

[0060] Suitable lenses (9) are known to those skilled in the art and are commercially available. Non-limiting examples of suitable lenses (9) include achromats, aspherics, plano-convex lenses, plano-concave lenses, bi-convex lenses, bi-concave lenses, cylindrical lenses, spherical or condenser lenses and / or Fresnel lenses, wherein the lenses (9) may optionally be provided with at least one anti-reflective coating, for example for the ultraviolet (UV), visible (VIS) and / or infrared (IR) spectrum.

[0061] Suitable optical filters (10) are known to those skilled in the art and are commercially available. Non-limiting examples of suitable optical filters (10) include bandpass filters, longpass filters, shortpass filters, notch filters, dichroic color filters, color filters and / or special filters, wherein the filters (10) may optionally be provided with at least one antireflective coating, for example for the ultraviolet (UV), visible (VIS) and / or infrared (IR) spectrum.

[0062] Suitable reflectors (11) are known to those skilled in the art and are commercially available. Non-limiting examples of suitable reflectors (11) include plane mirrors, laser mirrors, off-axis parabolic mirrors, focusing (concave) mirrors, elliptical reflectors, concave spherical mirrors, retroreflectors, and / or specialty mirrors, wherein the reflectors (11) may optionally be provided with at least one coating. Non-limiting, suitable coatings filter unwanted wavelengths and include, for example, antireflective coatings to filter out wavelengths of the ultraviolet (UV), visible (VIS), and / or infrared (IR) spectrum.

[0063] Suitable spectral splitters (12) are known to those skilled in the art and are commercially available. Non-limiting examples of suitable spectral splitters (12) include dichroic beam splitters, prism beam splitters, prisms, right-angled prisms, dispersion prisms, pentaprisms, diffraction gratings, grooved diffraction gratings, transmission gratings, reflective diffraction gratings, reflective concave diffraction gratings and / or special prisms, wherein the spectral splitters (12) may optionally be provided with at least one coating, such as antireflective coatings, to reduce losses. Measuring chamber (8)

[0064] In the measuring chamber (8) of the measuring device (1) of the aerosol particle measuring device (20), the material (2) to be determined is examined, i.e., measured. The measuring chamber (8) essentially encloses the location where the light (31) emitted by the light source (3) – and advantageously focused by the excitation optics (6) – strikes the material (2) and the light (31) emitted by the material (2) is directed – typically via the detector optics (7) – to the detector (4).

[0065] The measuring chamber (8) has an inlet and an outlet which are connected to the aerosol inlet (21) and the aerosol outlet (22) of the aerosol particle measuring device (20), respectively.

[0066] The measuring chamber (8) of the aerosol particle measuring device (20) typically has an elongated shape with a constant cross-section, along the center of which the aerosol particles fly through, i.e., are guided through. During their passage, they are excited by the emitted light (31) of the light source (3), thereby generating fluorescence, and the fluorescence lifetime of the aerosol particles can then be measured in the frequency domain. Suitable measuring chambers (8) are known to those skilled in the art.

[0067] Surprisingly, the measuring chamber can have small dimensions, for example 5 x 2 x 2 cm 3< , although larger or smaller dimensions are also possible.

[0068] In particular, in aerosol measurements where the individual aerosol particles are dispersed in a gas, such as pollen in the air, the measuring chamber (8) allows the aerosol particles to be focused at the point where the focused emitted light (31) hits the material (2), i.e. the aerosol particles.

[0069] The light source (3), the detector (4), the optional excitation optics (6), the optional detector optics (7) and the electronics (23) of the aerosol particle measuring device (20) can be arranged inside and / or outside the measuring chamber (8).

[0070] In a preferred embodiment of the aerosol particle measuring device (20), the material (2) to be measured is located inside the measuring chamber (8), and at least one light source (3), at least one detector (4), and / or at least one reflector (11) is arranged outside the measuring chamber (8). The light (31) enters and / or exits the measuring chamber through an optical lens (9) and / or a window (13). Optionally, the excitation optics (6) and / or the detector optics (7) may be arranged inside and / or outside the measuring chamber (8). It is often particularly preferred if all the light sources (3), detectors (4), and optionally the reflectors (11) are arranged outside the measuring chamber (8).

[0071] Suitable windows (13) are known to those skilled in the art and are commercially available. Non-limiting examples of suitable windows (13) include windows made of optical glass, quartz glass, fluorine crown glass, crown glass, borosilicate crown glass, ZERODUR®, barium crown glass, light flint glass, heavy crown glass, flint glass, heavy flint glass or lanthanum heavy flint glass, wherein the windows (13) may optionally be provided with one or more coatings, for example to filter out wavelengths of the ultraviolet (UV), visible (VIS) and / or infrared (IR) spectrum. Detector assembly (40)

[0072] In a preferred embodiment, the detector (4) of the measuring device (1) is a silicon photomultiplier (SiPM) and is arranged in a detector assembly (40). The detector assembly (40) comprises a housing (41) with an optical element (42), the detector (4), a temperature sensor (43), a cooling element (44), and a flexible or rigid printed circuit board for electrical contacting (45).

[0073] Advantageously, the detector assembly (40) comprises a silicon photomultiplier (SiPM) with a design suitable for surface mounting. Thus, it typically has no connecting wires or leads for electrical contact.

[0074] The housing (41) of the detector assembly (40) advantageously forms the outer shell of the detector assembly (40) and thus protects the optical element (42), the detector (4), the temperature sensor (43), and the circuit board (45) carefully arranged therein from interfering effects. It is often helpful if the cooling element (44) is arranged both inside and outside the housing (41), or at least has contact with both the inner and outer areas of the housing (41). Suitable housings (41) are known to those skilled in the art. They can also design a suitable housing (41) without inventive step.

[0075] The optical element (42) of the detector assembly (40) preferably comprises an optical lens (9), an optical filter (10) and / or a window (13).

[0076] Suitable temperature sensors (43) and circuit boards for electrical contacting (45) of the detector assembly (40) are known to those skilled in the art and are commercially available.

[0077] To increase the signal-to-noise ratio of the detector (4), it is often advantageous to cool the detector (4), typically to a temperature of about -20°C to about 10°C. Cooling is preferably achieved using the cooling element (44) of the detector assembly (40). Suitable cooling elements are known to those skilled in the art. In particular, one or more Peltier elements and / or passive heat sinks are preferred. The Peltier element is preferably attached to the circuit board for electrical contact (45) and / or has a planar contact with the detector and / or the outside of the housing (41). Digital holography (26) and time-resolved scattered light measurement (27)

[0078] In a preferred embodiment, the aerosol particle measuring device (20) comprises, in addition to the measuring device (1) for fluorescence lifetime measurement, at least one module for digital holography (26) and / or at least one module for time-resolved scattered light measurement (27), wherein the scattered light measurement (27) may optionally be supplemented by a polarization measurement. These modules may be part of the measuring device (1) or arranged as separate modules in the aerosol particle measuring device (20). With these modules, the material (2) can also be qualitatively and / or quantitatively determined in real time. This provides additional information, enabling the determination of a significantly larger number of materials (2). Furthermore, the use of at least one such module can significantly increase the probability of correctly determining different materials (2).

[0079] The digital holography assembly (26) typically uses an optical setup according to the in-line or Gabor method. Coherent light from a light source – optionally focused by lenses – is directed through windows in the wall of the measurement chamber (8) and across the chamber to an opposite detector, where the windows can also be replaced by lenses. In the measurement chamber (8), the light strikes the aerosol particles of the aerosol under investigation, with some of the light being diffracted by the aerosol particles. This light, influenced by the aerosol particles, superimposes itself on the coherent background light from the light source and is detected together by the opposite imaging detector. This detector produces a hologram of the aerosol particle under investigation, resulting in an additional imaging characterization of the aerosol particles.The digital holography assembly (26) can have one or more in-line arrangements. Part of the light striking the aerosol particles is scattered and detected by a trigger receiver. This controls the acquisition time of the imaging detector.

[0080] Using the time-resolved scattered light measurement assembly (27), light from a light source, so-called excitation light, is collimated (i.e., focused) by a lens and directed through a window parallel to the axis of the aerosol flow containing larger aerosol particles into the measuring channel. This illuminates the particles over a longer distance within the measuring channel. Alternatively, the excitation light can be directed into the measuring channel through a lateral window or lens, and a mirror in the measuring channel deflects the light by 90° against or in the direction of flight of the aerosol particles. This illuminates the aerosol particles as they pass by. Scattered light is generated, some of which escapes laterally from the measuring chamber (8) through another window in the wall of the measuring chamber (8).The window can optionally be shaped to act as a collimating lens, or the emitted scattered light can be collimated with a lens and, if necessary (i.e., if polarization measurement is performed), separated into vertically and horizontally polarized light using a polarization filter, with one polarized light beam being deflected by 90°. The two polarized light beams are then focused onto separate receivers using another lens and detected. This allows for the measurement of scattered light intensity profiles of the particle as it passes by, for each polarization of the light, which are characteristic of the aerosol particle.

[0081] The methods of digital holography and time-resolved scattered light measurement with and without polarization measurement are known to those skilled in the art. They are also familiar with suitable assemblies for digital holography (26) and for time-resolved scattered light measurement (27) with and without polarization measurement, which are commercially available or which they can assemble without unreasonable effort and without inventive step. Aerosol particle measuring device (20)

[0082] The aerosol particle measuring device (20) according to the invention comprises the measuring device (1) with light source (3), detector (4) and measuring chamber (8), as well as an aerosol inlet (21), an aerosol outlet (22), an airflow generation and control device with electronics (23), and is particularly suitable for the qualitative and / or quantitative determination of fluorescent materials (2) in real time by means of fluorescence lifetime measurement in the frequency domain, wherein the materials (2) represent aerosol particles of an aerosol, in particular bioaerosol particles dispersed in air such as pollen and / or mold spores.

[0083] The aerosol inlet (21), i.e., the inlet or entry of the aerosol into the measuring chamber (8), and the aerosol outlet (22), i.e., the outlet or exit of the aerosol from the measuring chamber (8), are known to a person skilled in the art. They can also determine the optimal shape for the respective aerosol particle measuring device (20).

[0084] The airflow generation and control device with electronics (23) of the aerosol particle measuring device (20) causes aerosols, typically air containing the materials (2) to be tested, i.e., aerosol particles, to be conveyed through the aerosol inlet (21) into the measuring chamber (8), along the measuring chamber (8) to the aerosol outlet (22), and thus out of the measuring chamber (8) again. The aerosol particle measuring device (20) can have one or more airflow generation and control devices with electronics (23). Preferably, it is arranged in the region of the aerosol inlet (21) and / or the aerosol outlet (22) of the measuring chamber (8), but can also be arranged in the region of the aerosol inlet (21) and / or the particle concentrator (24). Suitable airflow generation and control devices (23) are known to those skilled in the art.

[0085] The electronics of the airflow generation and control device (23) thus preferably serve to control the sensors and control elements for regulating and controlling the airflow and thus the aerosol particles which are conveyed through the measuring chamber (8) of the aerosol particle measuring device (20).

[0086] The airflow generation and control device (23) comprises, in particular, a pump, nozzle, and control elements, as well as typically at least one sensor, in particular an air velocity sensor, flow sensor, current sensor, air pressure sensor, and / or differential pressure sensor. The airflow generation and control device with electronics (23) can be used to control and / or regulate the airflow.

[0087] The aerosol particle measuring device (20) also advantageously comprises a particle concentrator (24), a particle collector (25) and a particle focusing nozzle (28).

[0088] The particle concentrator (24) of the aerosol particle measuring device (20) is optional, but often preferred. It allows the aerosol particles to be concentrated within the aerosol, enabling faster measurements, as a larger number of aerosol particles can be analyzed per unit of time, thus providing more measurement data per unit of time. This allows low particle concentrations to be determined more quickly and with greater accuracy.

[0089] Suitable particle concentrators (24) include virtual impactors and cyclones. They are known to those skilled in the art and are commercially available.

[0090] The particle collector (25) of the aerosol particle measuring device (20) is optional and allows the separation, i.e., collection, of the aerosol particles transported through the measuring chamber (8) of the aerosol particle measuring device (20). This can be helpful if the aerosol particles examined by fluorescence measurement are to be subsequently examined further, for example for a duplicate determination and / or microscopy.

[0091] If the aerosol particle measuring device (20) has a particle collector (25), no or only a part of the aerosol particles passed through the measuring chamber (8) will exit at the aerosol outlet (22).

[0092] Suitable particle collectors (25) are known to those skilled in the art and are commercially available.

[0093] The at least one particle focusing nozzle (28) of the aerosol particle measuring device (20) is optional, but often preferred. It enables the aerosol particles in the aerosol to be focused along the trajectory of the measuring chamber (8), so that ideally all, or at least a large proportion, of the aerosol particles in the measuring chamber can be measured. The particle focusing nozzle (28) is preferably arranged between the aerosol inlet (21) or the particle concentrator (24) and the measuring chamber (8). Suitable particle focusing nozzles (28) are known to those skilled in the art.

[0094] In a preferred embodiment, the aerosol particle measuring device (20) i) at least one particle concentrator (24) for concentrating the aerosol particles in the aerosol, wherein the particle concentrator (24) may be a virtual impactor and / or a cyclone, and / or includes, ii) optionally a particle collector (25) for collecting the measured materials (2), iii) at least one particle focusing nozzle (28) for focusing the aerosol particles in the aerosol in the trajectory of the measuring chamber (8), iv) at least one digital holography assembly (26), v) at least one time-resolved scattering measurement assembly (27) for qualitative and / or quantitative determination of the material (2) in real time, wherein the scattering measurement may optionally include a polarization measurement, and / or vi) a further light source (3'), in particular a laser, the emitted light (31') of which travels in the form of a light beam along the trajectory of the measuring chamber (8).Such a laser can, for example, be arranged in the aerosol inlet (21).

[0095] The listed additions i) to v) can be installed alone and / or in any combination in the aerosol particle measuring device (20) and increase the number of different detectable aerosol particles as well as the measurement accuracy of the aerosol particle measuring device (20). Proceedings

[0096] The inventive method surprisingly allows for the qualitative and / or quantitative determination of fluorescent materials (2) in real time by means of fluorescence lifetime measurement using the inventive aerosol particle measuring device (20) comprising the measuring device (1). The fluorescence lifetime measurement is performed in the frequency domain, and the light (31) emitted by the light source (3) is intensity-modulated. At least one diode laser, in particular a UV diode laser, a diode-pumped solid-state laser, and / or an LED is used as the light source (3). The materials (2), in the form of aerosol particles of an aerosol, are measured in the measuring chamber (8) of the measuring device (1) – and thus in the aerosol measuring device (20). The aerosol particles in the measuring chamber (8) are exposed to the light (31) of the light source (3), whereby the aerosol particles absorb and partially re-emit the light.The emitted light is detected by the detector (4), wherein the detector (4) is a semiconductor-based electronic photon detector for light detection, in particular a silicon photomultiplier (SiPM). Subsequently, the obtained data are processed with a data processing program.

[0097] In a preferred embodiment of the method according to the invention The aerosol is conveyed into and out of the measuring chamber (8) by means of an airflow generation and control device (23), and the aerosol particles, i.e. the material (2), of the aerosol in the measuring chamber (8) are qualitatively and / or quantitatively determined in flight and in real time with the measuring instrument (1), and optionally i) the aerosol particles in the aerosol are concentrated in at least one particle concentrator (24), wherein the particle concentrator (24) comprises at least one virtual impactor and / or at least one cyclone, wherein the concentration step preferably takes place before the fluorescence lifetime measurement, and / or ii) optionally the aerosol particles in the aerosol are bundled in the trajectory of the measuring chamber (8) with at least one particle focusing nozzle (28). use

[0098] The inventive aerosol particle measuring device (20) and the inventive method can surprisingly be used in a wide variety of applications. They are ideally suited for the qualitative and / or quantitative determination, by means of fluorescence lifetime measurement in the frequency domain, and in particular in real time, of fluorescent materials (2) in the form of aerosol particles of an aerosol, i.e., aerosol particles dispersed in a gas phase, especially airborne pollen and / or spores, as well as in process engineering, for example for process and / or quality control of materials (2).

[0099] The inventive use of the aerosol particle measuring device (20) allows the direct measurement of aerosol particles dispersed in the gas phase, and thus of aerosol particles in flight. By determining the fluorescence lifetime, additional information about the chemical composition of the particle becomes available, thereby significantly improving the correct identification of the particle. The inventive use of the aerosol particle measuring device (20) thus enables real-time particle detection, thereby facilitating the continuous monitoring of materials (2), in particular particles in gases, in real time.

[0100] The following reference symbols are used: 1 Measuring instrument 2 Fluorescent materials 3 Light source 3' Additional light source 4 Detector 6 Excitation optics 7 Detector optics 8 Measuring chamber 9 Optical lens 10 Optical filter 11 Reflector 12 Spectral divider 13 Window 20 Aerosol particle measuring device 21 Aerosol inlet 22 Aerosol outlet 23 Airflow generation and control device with electronics 24 Particle concentrator 25 Particle collector 26 Digital holography 27 Time-resolved scattered light measurement 28 Particle focusing nozzle 31 Emitted light from the light source (3) 31' Emitted light from the light source (3') 40 Detector assembly 41 Housing of the detector assembly (40) 42 Optical element 43 Temperature sensor 44 Cooling element 45 Carrier material for electrical contacting

[0101] Non-limiting, preferred embodiments of the aerosol particle measuring device (20) and the measuring device (1) according to the invention are described below with reference to the following drawings. These are not to be interpreted restrictively and are understood as part of the description: Fig. 1 shows the external view of an exemplary aerosol particle measuring device (20) according to the invention, comprising the aerosol inlet (21), the particle concentrator (24), the measuring device (1) according to the invention, the particle collector (25), the airflow generation and control device with electronics (23), and the aerosol outlet (22), wherein the particle concentrator (24) is arranged between two mounting plates. The illustrated aerosol particle measuring device (20) with the measuring device (1) is arranged in an opaque housing, wherein this is Fig. 1For the sake of clarity, the details have been omitted. The measuring device (1) shown in the aerosol particle measuring device (20) includes the light source (3) with the excitation optics (6) and four detector assemblies (40) with the detector (4). Between the detector assembly (40) and the measuring chamber (8) is the detector optics (shown hatched) for the detectors (7). The aerosol particle measuring device (20) and the measuring device (1) also include a data processing program and electronics for device control, signal measurement, signal conditioning, signal evaluation, and data storage. The electronics and the data processing program are typically located with the aforementioned components and / or in a separate electronic component.In the area of ​​the measuring chamber (8) of the measuring device (1) – and thus of the aerosol particle measuring device (20) – an assembly for digital holography (26) and an assembly for time-resolved scattered light measurement (27), optionally with additional polarization measurement, are arranged for the qualitative and / or quantitative determination of the material (2) in real time. Fig. 2 shows an exemplary schematic representation of the aerosol particle measuring device (20) according to the invention with the measuring device (1) shown in the central area of ​​the measuring chamber (8). In the illustrated embodiment, the measuring device (1) comprises an excitation optic (6) and a detector optic (7). The light source (3) of the excitation optic (6) emits light in the direction of a reflector (11). There, the emitted light (31) is reflected and focused, i.e.,The light (31) is collimated and directed to the optical filter (10) and the optical lens (9), from where it is focused through the lens (9) and a window (13) into the center of the measuring chamber (8), where the light (31) strikes the material (2), i.e., in the case of the aerosol particle measuring device (2), passing aerosol particles. The window (13) serves as the boundary between the measuring chamber (8) and the outer area of ​​the measuring device (1). The schematic representation of the aerosol particle measuring device (20) also includes an aerosol inlet (21) and an optional particle concentrator (24), for example, a cyclone and / or virtual impactor, in the upper area. This concentrator directs the aerosol particles into the measuring chamber (8) in a concentrated manner, while excess gas, such as separated air, can escape laterally from the aerosol particle measuring device (20).By means of the optional, but preferred, particle focusing nozzle (28), which typically has an optimized geometry known to those skilled in the art and is arranged, by way of example, between the particle concentrator 24 and the measuring chamber (8), the aerosol particles can be conveyed in a highly focused manner through the center of the measuring chamber (8). Along the measuring chamber (8), the optional assemblies for digital holography (26) and time-resolved scattered light measurement (27), optionally with additional polarization measurement, are also arranged, by way of example and in any order, providing further additional information to further increase the reliability of the determination of the materials to be examined and the number of material types, for example, the number of identifiable pollen species. In the end region of the measuring chamber (8) – shown here in the lower part of the illustration – an optional particle collector (25) is shown, where the aerosol particles can be collected.The airflow generation and control device with electronics (23), which may, for example, include a suction pump that causes the aerosol to flow into the aerosol inlet (21), through the measuring chamber (8) to the aerosol outlet (22), is shown by way of example in the region of the aerosol outlet (22). In addition, an optional further light source (3') is shown by way of example in the region of the aerosol inlet (21), wherein the further light source (3') is preferably a laser. The light (31') emitted by the light source (3') is typically directed to an optical lens (9) and then, in the form of a collimated light beam, guided together with the aerosol particles along their trajectory through the measuring chamber (8) towards the aerosol outlet (22). Fig.Figure 3 shows an exemplary schematic setup of a detector optic (7) of the measuring instrument (1), which is arranged between the material (2) and one or more detectors (4) or detector assemblies (40), and comprises the optical lenses (9), an optical filter (10), and the spectral dividers (12). The light emitted by the material (2), including the fluorescence light emitted by the material (2), passes through a window (13), which serves as a boundary between the measuring chamber (8) and the outer region of the measuring instrument (1), to a first optical lens (9), which collimates the light and directs it to an optical filter (10), whereby more than one filter (10) can also be arranged in series. The filter(s) (10) filter out interfering light and thus suppress unwanted spectral components of the light, so that only the light with wavelengths relevant for the measurement is transmitted towards the detectors (4).The spectral dividers (12) arranged between the filter (10) and the lenses (9) split the light to be analyzed into two spectral wavelength ranges, whereby one spectral range of the light is deflected and the other range is allowed to pass through the spectral divider (12). After the spectral divider (12), the light is guided through another lens (9) to the detector (4). Another portion of the light emitted by the material (2) reaches the reflector (11), which is arranged opposite the detector optics (7) with respect to the material (2), for example through a window (13). The reflector (11) is advantageously arranged such that as much of the light as possible reflected by the material (2) is reflected back by the reflector (11) to the detector optics (7), where it then reaches the detectors (4) and can be evaluated. Fig. 4 shows an example of a schematic mechanical setup of a detector assembly (40).The detector (4) is mounted on a substrate for electrical contact (45), for example, by soldering. Next to the detector (4), a temperature measurement element, i.e., a temperature sensor (43), is mounted. Between the surface of the substrate (45) opposite the detector (4) and the housing (41) is a portion of the cooling element (44), which serves to cool the detector (4). The other portion of the cooling element (44) is arranged on the opposite side of the housing (41), with both portions of the cooling element (44) typically connected to each other. On the side of the housing (41) opposite the cooling element (44) and facing the detector (4), an optical element (42) is arranged. The optical element (42) is preferably an optical lens (9), an optical filter (10), or a window (13).Outside the housing of the detector assembly (41) a connector is arranged on the carrier material for electrical contacting (45).

Claims

1. An aerosol particle measuring device (20) for the qualitative and / or quantitative determination of fluorescent materials (2) in real time by means of frequency domain fluorescence lifetime measurement, comprising a measuring device (1) with a light source (3), detector (4) and measuring chamber (8), an aerosol inlet (21), an aerosol outlet (22) as well as an airflow generation and control device with electronics (23), characterized in that i) the detector (4) is an electronic photon detector for light detection based on semiconductor technology, in particular a silicon photomultiplier (SiPM), and ii) the materials (2) are aerosol particles of an aerosol and therefore are dispersed in a gas phase, whereupon the aerosol particles are determined in flight, which allows for permanent monitoring of particles in gases and in real time.

2. The aerosol particle measuring device (20) as claimed in claim 1, characterized in that the light (31) emitted from the light source (3) is intensity-modulated, in particular sinusoidally intensity-modulated, and / or the light source (3) is a diode laser, an LED and / or a diode-pumped solid state laser.

3. The aerosol particle measuring device (20) as claimed in claim 1 or claim 2, characterized in that the materials (2) in the form of aerosol particles of an aerosol are fluorescent organic and / or inorganic pure substances or mixtures and are present in the form of a solid, a liquid, a dispersion, a suspension, a paste and / or in the form of bioaerosol particles dispersed in air, such as pollen, flower pollen, spores, fungal spores, plant spores, proteins, DNA, RNA, organisms, tissues, cells, bacteria, viruses and / or minerals, and optionally have been pretreated with a fluorophore.

4. The aerosol particle measuring device (20) as claimed in at least one of claims 1 to 3, characterized in that the measuring device (1) comprises at least one excitation optics unit (6), at least one detector optics unit (7), a measuring chamber (8), a data processing program, a lightproof housing as well as electronics for controlling the device, for signal measurement, for signal preparation, for signal analysis and for data storage.

5. The aerosol particle measuring device (20) as claimed in at least one of claims 1 to 4, characterized in that the aerosol particle measuring device (20) comprises a digital holography assembly (26) and / or a time-resolved light scattering measurement assembly (27), optionally with additional polarisation measurement, for the qualitative and / or quantitative determination of the material (2) in real time.

6. The aerosol particle measuring device (20) as claimed in at least one of claims 1 to 5, characterized in that the excitation optics unit (6) is disposed between the light source (3) and the material (2) to be determined and / or the detector optics unit (7) is disposed between the material (2) to be determined and the detector (4), wherein i) the excitation optics unit (6) comprises at least one optical lens (9) and preferably at least one optical filter (10), optionally as well as at least one reflector (11), and / or ii) the detector optics unit (7) comprises at least two optical lenses (9), preferably as well as at least one optical filter (10) and / or at least one spectrum divider (12), in particular an interference mirror, a prism, an optical grating, a diffraction grating and / or a multiple slit, wherein the spectrum divider (12) diffracts a portion of the light, preferably via an optical lens (9), to at least one further detector (4).

7. The aerosol particle measuring device (20) as claimed in at least one of claims 1 to 6, characterized in that the measuring device (1) comprises two or more light sources (3) and at least one excitation optics unit (6), wherein i) a separate excitation optics unit (6) is disposed between each light source (3) and the material (2) to be determined, and / or ii) a common excitation optics unit (6) is disposed between two or more light sources (3) and the material (2) to be determined, iii) the light sources (3) have different modulation frequencies, and / or iv) the light sources (3) emit different wavelengths.

8. The aerosol particle measuring device (20) as claimed in at least one of claims 1 to 7, characterized in that the measuring device (1) comprises two or more detectors (4), wherein i) a separate detector optics unit (7) is disposed between the material (2) to be determined and one or more detectors (4), and / or ii) only one detector optics unit (7) is disposed between the material (2) to be determined and a plurality of detectors (4), wherein the detector optics unit (7) comprises a separate optical filter (12) for the second and each further detector (4).

9. The aerosol particle measuring device (20) as claimed in at least one of claims 1 to 8, characterized in that the measuring device (1) comprises a further reflector (11) in order to reflect light arriving from the material (2) to the detector (4), optionally via the detector optics unit (7).

10. The aerosol particle measuring device (20) as claimed in at least one of claims 1 to 9, characterized in that the material (2) to be determined is disposed inside the measuring chamber (8) and at least one light source (3), at least one detector (4) and / or at least one reflector (11) is disposed outside the measuring chamber (8), wherein the light (31) enters or exits the measuring chamber through an optical lens (9) and / or a window (13), wherein optionally, the excitation optics unit (6) and / or the detector optics unit (7) may be disposed inside and / or outside the measuring chamber (8).

11. The aerosol particle measuring device (20) as claimed in at least one of claims 1 to 10, characterized in that the detector (4) is disposed in a detector assembly (40), wherein the detector assembly (40) comprises a housing (41) with an optical element (42), the detector (4), a temperature sensor (43), a cooling element (44), in particular a Peltier element and / or a passive cooling body, as well as a circuit board for electrical contact (45), wherein the detector (4) is a silicon photomultiplier (SiPM).

12. The aerosol particle measuring device (20) as claimed in at least one of claims 1 to 11, characterized in that the aerosol particle measuring device (20) comprises at least i) a particle concentrator (24) for concentrating the aerosol particles in the aerosol, wherein the particle concentrator (24) is preferably a virtual impactor and / or a cyclone, ii) a particle collector (25) for collecting the measured materials (2), iii) a particle focussing nozzle (28) for concentrating the aerosol particles in the aerosol in the trajectory of the measuring chamber (8), iv) a digital holography assembly (26), v) a time-resolved light scattering measurement assembly (27), optionally with additional polarisation measurement, for the qualitative and / or quantitative determination of the material (2) in real time, and / or vi) a further light source (3'), in particular a laser, from which the light (31') which is emitted passes along the trajectory of the measuring chamber (8) in the form of a beam of light.

13. A method for the qualitative and / or quantitative determination of fluorescent materials (2) in real time by means of fluorescence lifetime measurement with the aerosol particle measuring device (20) as claimed in at least one of claims 1 to 12, characterized in that i) the fluorescence lifetime measurement is carried out in the frequency domain and the light (31) emitted by the light source (3) is intensity-modulated, ii) a diode laser, a diode-pumped solid state laser and / or an LED is used as the light source (3), iii) the materials (2), in the form of aerosol particles of an aerosol, are measured in the measuring chamber (8) of the measuring device (1), iv) in the measuring chamber (8), the aerosol particles are exposed to the light (31) from the light source (3), wherein the aerosol particles absorb the light and partly re-emit it, v) the emitted light is detected with the detector (4), wherein the detector (4) used is an electronic photon detector for light detection based on semiconductor technology, in particular a silicon photomultiplier (SiPM), and vi) the data obtained are processed with a data processing program.

14. The method as claimed in claim 13, characterized in that - the aerosol is conducted into the measuring chamber (8) through the aerosol inlet (21) and conducted out again through the aerosol outlet (22) by means of an airflow generation and control device (23), and - the aerosol particles of the aerosol in the measuring chamber (8) are determined qualitatively and / or quantitatively in flight and in real time using the measuring device (1), - as well as, optionally i) the aerosol particles in the aerosol are concentrated in at least one particle concentrator (24), wherein the particle concentrator (24) comprises at least one virtual impactor and / or at least one cyclone, wherein the concentration step is preferably carried out before the fluorescence lifetime measurement, and / or ii) optionally, the aerosol particles in the aerosol are concentrated in the trajectory of the measuring chamber (8) with at least one particle focussing nozzle (28).

15. Use of the aerosol particle measuring device (20) as claimed in at least one of claims 1 to 12 and / or of the method as claimed in claim 13 or claim 14, for the qualitative and / or quantitative determination, by means of frequency domain fluorescence lifetime measurement, in particular in real time, of fluorescent materials (2) in the form of aerosol particles of an aerosol, in particular of pollen and / or spores suspended in the air, as well as in process engineering such as, for example, for the process control and / or quality control of materials (2).