JP6626621B2 - Suspended particulate matter measuring device by optical method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a suspended particulate matter measuring device that collects particulate matter suspended in the atmosphere and measures a carbon component of the collected particulate matter.

  In the atmosphere, ultra-fine particles formed by the oxidation, condensation and aggregation of volatile gases generated during the fuel combustion process, and fine particles such as black smoke particles formed by the fuel combustion process and the gas phase chemical reaction There are various kinds of suspended particulate matter, so-called dust, such as particles and coarse particles such as sea salt particles and yellow sand generated by natural phenomena. Such suspended particulate matter in the atmosphere is known to deposit on the human nose and pharynx, bronchi, lungs, etc. and affect health. It has been taken up as a problem and has been measured as one indicator of the state of air pollution.

  The suspended particulate matter in the atmosphere is collected in a filter at predetermined intervals, for example, by exchanging a dust collection filter at predetermined intervals, and the mass concentration (total amount) in the atmosphere has been measured. With the development of measurement technology in recent years, not only the total amount of suspended particulate matter present in the atmosphere, but also the content of fine particles that are likely to deposit on the lungs of the human body and affect health over a long period of time among suspended particulate matter There has been proposed an apparatus for measuring separately from the total amount and measuring continuously (see Patent Document 1).

  Suspended particulate matter is not only a problem in Japan, but in China, its high concentration causes epidemiologic findings to cause respiratory and cardiovascular diseases, and it is extremely large that mortality is increasing. It is a problem. In studying the mechanism and behavior of suspended particulate matter, there are few monitoring data on organic carbon in suspended particulate matter. The problem is that not only is it expensive because of the complexity of existing devices, but also the running cost is high, and the sensitivity is low for continuous monitoring.

  As described above, the technology for measuring suspended particulate matter has made great strides, but the technique disclosed in Patent Document 1 is merely a measurement of the mass concentration of suspended particulate matter in the atmosphere, It does not refer to the composition therein. For example, suspended particulate matter originating from exhaust gas of a vehicle equipped with a diesel engine includes elemental carbon (abbreviated as EC) and organic carbon (abbreviated as OC). It is considered that organic carbon (OC) adsorbs substances harmful to health, such as nitrogen oxides and sulfur oxides. Therefore, if the content of, for example, elemental carbon (EC) and organic carbon (OC) in suspended particulate matter can be known, the source and mechanism of generation can be estimated, and measures for reduction can be established. Becomes possible. In particular, organic carbon compounds are one of the main components in suspended particulate matter, but knowledge of their sources and mechanisms of formation is poor, and compositional analysis of suspended particulate matter in the atmosphere, Monitoring is strongly desired.

As a device capable of analyzing the composition of suspended particulate matter, a carbon separation analyzer (carbon analyzer) equipped with a pyrolysis tube and a CO ₂ analyzer, in which organic carbon (OC) is volatilized in the pyrolysis tube・ It has a low-temperature heating section for thermal decomposition and a high-temperature heating section for thermal decomposition of elemental carbon (EC). Organic carbon (OC) is separated at the low-temperature heating section, and elemental carbon is heated at the high-temperature heating section. A carbon fractionation analyzer for separating (EC) has been proposed (see Patent Document 2).

According to the technique disclosed in Patent Literature 2, an inert gas such as helium or nitrogen, or an auxiliary combustion gas such as oxygen or air is alternatively introduced into the pyrolysis tube as a carrier gas, and is heated to, for example, about 400 ° C. the concentration of CO ₂ by thermal decomposition of the set organic carbon at low temperature heating unit (OC) is measured by CO ₂ analyzer, elemental carbon in (EC) at a high temperature heating part, which for example is set to about 1000 ° C. the concentration of CO ₂ by thermal decomposition is measured by CO ₂ analyzer.

JP 2001-343319 A JP 2000-241404 A

  The technique disclosed in Patent Document 2 can measure the elemental carbon (EC) content and the organic carbon (OC) content in the suspended particulate matter, but the elemental carbon (EC) and the organic carbon ( A heating device for thermally decomposing OC) is required, which complicates the structure of the device, and requires expensive operating gas such as helium gas and oxygen cylinder. Maintenance is also difficult.

  An object of the present invention is to provide a suspended particulate matter measuring device capable of measuring at least the amount of organic carbon (OC) in particulate matter suspended in the atmosphere.

The present invention
a sheet-like trapping filter 4 for trapping particulate matter floating in the atmosphere;
b light source means 6, 7 for emitting two types of light having different wavelengths λ1, λ2, respectively, and irradiating the light toward one main surface of the collection filter 4,
c, which is disposed to face the other main surface of the collection filter 4 opposite to the one main surface, receives light transmitted through the collection filter 4 where particulate matter is collected, and receives the received light. Transmitted light intensity detecting means 8 for detecting the light intensity of
d arithmetic means 11, 12, 13;
The output from the transmitted light intensity detecting means 8 is provided, and the attenuation ratios Tatn (λ1) and Tatn (λ2) of the detected transmitted light intensity for each wavelength λ1 and λ2, and the respective wavelengths λ1 and λ2 of the organic carbon. A predetermined transmitted light attenuation coefficient ε (OC, λ1), ε (OC, λ2), and a predetermined transmitted light attenuation coefficient ε (EC, λ1), ε (EC, λ2) for each wavelength λ1, λ2 of elemental carbon. ) And based on
The difference between the transmitted light attenuation coefficient ε (OC, λ1) of the organic carbon of one wavelength λ1 and the transmitted light attenuation coefficient ε (OC, λ2) of the other wavelength λ2 organic carbon is calculated,
Calculate the difference between the transmitted light attenuation coefficient ε (EC, λ1) of the elemental carbon of one wavelength λ1 and the transmitted light attenuation coefficient ε (EC, λ2) of the other wavelength λ2,
Calculating means for calculating the amount [OC] t of organic carbon in the particulate matter collected by the collection filter using the difference between the two elements; It is a measuring device.

The present invention
e a sheet-shaped collection filter 4 for collecting particulate matter floating in the atmosphere;
f light source means 6, 7 for emitting two types of light having different wavelengths λ1 and λ2, respectively, and irradiating the light toward one main surface of the collection filter;
g Reflection disposed opposite to the one main surface of the collection filter 4 for receiving light reflected by the collection filter 4 from which particulate matter has been collected, and detecting the light intensity of the received light. Light intensity detecting means 9;
h arithmetic means 11, 12, 13;
The output from the reflected light intensity detecting means 9 is given, and the attenuation rates Ratn (λ1) and Ratn (λ2) of the detected reflected light intensity for each wavelength λ1 and λ2, and for each wavelength λ1 and λ2 of the organic carbon. Predetermined reflected light attenuation coefficient σ (OC, λ1), σ (OC, λ2), and predetermined reflected light attenuation coefficient σ (EC, λ1) for each wavelength λ1, λ2 of elemental carbon, σ (EC, λ2 ) And based on
Calculate the difference between the reflected light attenuation coefficient σ (OC, λ1) of organic carbon of one wavelength λ1 and the reflected light attenuation coefficient σ (OC, λ2) of organic carbon of the other wavelength λ2,
The difference between the reflected light attenuation coefficient σ (EC, λ1) of the elemental carbon of one wavelength λ1 and the reflected light attenuation coefficient σ (EC, λ2) of the other wavelength λ2,
Calculating means for calculating the amount [OC] r of the organic carbon in the particulate matter collected by the collection filter using the difference between the two elements; It is a measuring device.

The present invention
i. a sheet-shaped collection filter 4 for collecting particulate matter floating in the atmosphere;
j light source means 6 and 7 for emitting two types of light having different wavelengths λ 1 and λ 2 respectively and irradiating the light to one main surface of the collection filter 4;
k is disposed opposite the other main surface of the collection filter 4 opposite to the one main surface, receives light transmitted through the collection filter 4 where the particulate matter is collected, and receives the received light. Transmitted light intensity detecting means 8 for detecting the light intensity of
L: a reflected light disposed opposite to the one main surface of the collection filter 4 for receiving light reflected by the collection filter from which particulate matter has been collected, and detecting the light intensity of the received light Intensity detection means 9;
m arithmetic means 11, 12, 13;
Each output from the transmitted light intensity detecting means and the reflected light intensity detecting means is given, and the attenuation rate Tatn (λ1), Tatn (λ2) of the detected transmitted light intensity for each wavelength λ1, λ2, and organic carbon A predetermined transmitted light attenuation coefficient ε (OC, λ1) and ε (OC, λ2) for each wavelength λ1 and λ2, and a predetermined transmitted light attenuation coefficient ε (EC and λ1) for each wavelength λ1 and λ2 of elemental carbon. ), Ε (EC, λ2), each wavelength λ1, attenuation rate of detected reflected light intensity Ratn (λ1) for each λ2, Ratn (λ2), and each predetermined wavelength λ1, λ2 of organic carbon. Determined reflected light attenuation coefficient σ (OC, λ1), σ (OC, λ2), and predetermined reflected light attenuation coefficient σ (EC, λ1), σ (EC, λ2) for each wavelength λ1, λ2 of elemental carbon And based on
The first difference between the transmitted light attenuation coefficient ε (OC, λ1) of the organic carbon having one wavelength λ1 and the transmitted light attenuation coefficient ε (OC, λ2) of the organic carbon having the other wavelength λ2 is calculated,
Calculate the second difference between the transmitted light attenuation coefficient ε (EC, λ1) of one elemental carbon of wavelength λ1 and the transmitted light attenuation coefficient ε (EC, λ2) of the other wavelength λ2,
The third difference between the reflected light attenuation coefficient σ (OC, λ1) of the organic carbon of one wavelength λ1 and the reflected light attenuation coefficient σ (OC, λ2) of the organic wavelength of the other wavelength λ2 is calculated,
Calculate the fourth difference between the reflected light attenuation coefficient σ (EC, λ1) of the elemental carbon having one wavelength λ1 and the reflected light attenuation coefficient σ (EC, λ2) of the elemental carbon having the other wavelength λ2,
Calculating means for calculating the amount of organic carbon in the particulate matter collected by the collection filter using the first to fourth differences; It is a substance measuring device.

Further, in the suspended particulate matter measuring device of the present invention, the first wavelength band is 220 nm or more and 500 nm or less,
The second wavelength band is not less than 650 nm and not more than 1000 nm.

  According to the suspended particulate matter measurement device of one embodiment of the present invention, the suspended particulate matter collected on the collection filter includes light emitted from a light source and having a wavelength within the first wavelength band. Light having a wavelength within two wavelength bands is alternately irradiated. Then, based on the transmitted light intensity of the transmitted light from the suspended particulate matter on the collection filter detected by the transmitted light intensity detection unit, the computing unit computes at least the amount of organic carbon in the suspended particulate matter. .

  Further, according to the suspended particulate matter measuring device according to another aspect of the present invention, the suspended particulate matter collected on the collection filter has a wavelength in the first wavelength band emitted from the light source. Light and light having a wavelength within the second wavelength band are alternately irradiated. Then, based on the reflected light intensity of the reflected light from the suspended particulate matter on the collection filter detected by the reflected light intensity detection unit, the computing unit computes at least the amount of organic carbon in the suspended particulate matter. .

  Further, according to the suspended particulate matter measuring device according to another aspect of the present invention, the suspended particulate matter collected on the collection filter has a wavelength in the first wavelength band emitted from the light source. Light and light having a wavelength within the second wavelength band are alternately irradiated. Then, the transmitted light intensity of the transmitted light from the suspended particulate matter on the collection filter detected by the transmitted light intensity detection unit, and the suspended particulate matter on the collection filter detected by the reflected light intensity detection unit The calculation unit calculates at least the amount of organic carbon in the suspended particulate matter based on the reflected light intensity of the reflected light from.

  The suspended particulate matter measuring device of the present invention thus configured does not thermally decompose elemental carbon and organic carbon as in the prior art, and does not require a carrier gas. At least the amount of organic carbon in the particulate matter can be measured.

  Further, according to the present invention, regarding the wavelength of the light emitted from the light source, the first wavelength band is 220 nm or more and 500 nm or less, and the second wavelength band is 650 nm or more and 1000 nm or less. It is possible to more reliably and efficiently measure the amount of at least the organic carbon in the substance.

It is a figure showing roughly composition of suspended particulate matter measuring device 1 concerning one embodiment of the present invention. It is a figure which expands and shows the vicinity of the collection filter 4 in the suspended particulate matter measuring device 1. It is a graph which shows an example of the measurement result regarding the change of the attenuation rate of the transmitted light intensity for every measurement date. It is a graph which shows an example of the measurement result regarding the change of the attenuation rate of the reflected light intensity for every measurement date. It is a graph which shows an example of a measurement result about change of an organic carbon (OC) density for every measurement date. It is a graph which shows an example of a measurement result about change of elemental carbon (EC) concentration for every measurement date. It is a graph which shows an example of the measurement result regarding the change of the mass concentration of PM2.5 for every measurement date. It is a graph which shows the correlation between light intensity and fWSOC. The concentration of the calculated organic carbon based on the transmitted light intensity by suspended particulate matter measuring apparatus 1 [OC] t (μgC / m 3), the concentration of organic carbon in PM2.5 by the carbon analyzer (μgC / m ³ FIG. The concentration of elemental carbon [EC] r (μgC / m ³ ) calculated based on the reflected light intensity by the suspended particulate matter measuring device 1 and the concentration of elemental carbon in PM2.5 (μgC / is a graph showing the correlation between m ^3).

  FIG. 1 is a diagram schematically showing a configuration of a suspended particulate matter measuring device 1 according to one embodiment of the present invention. FIG. 2 is an enlarged view showing the vicinity of the collection filter 4 in the suspended particulate matter measuring device 1. The suspended particulate matter measuring device 1 according to the present embodiment measures at least the amount (concentration) of organic carbon (OC) in particulate matter suspended in the air (hereinafter referred to as “suspended particulate matter”). Used for In the present embodiment, the suspended particulate matter measuring device 1 is configured to measure the amounts (concentrations) of elemental carbon (EC) and organic carbon (OC) in the suspended particulate matter.

  The suspended particulate matter measuring device 1 generally includes a suspended particulate collection means 2 for trapping suspended particulate matter floating in the atmosphere, and classifies the suspended particulate matter collected by the suspended particulate collection means 2. A classifier 3 to be separated, a trapping filter 4 to which the suspended particulate matter classified by the classifier 3 is supplied and trapping the supplied suspended particulate matter, and a part of the trapping filter 4 A light source 6 that emits light, a composite optical fiber 7, a transmitted light detector 8 having a function as a transmitted light receiver and a transmitted light intensity detector, and a function as a reflected light intensity detector. Including the reflected light detector 9, the arithmetic unit 11 having the first arithmetic unit 111 and the second arithmetic unit 112, the control unit 12, the storage unit 13, and the suction pump 14 for reducing the pressure inside the container 5. Be composed. In the suspended particulate matter measuring device 1, each part other than the suspended particle collecting means 2 and the suction pump 14 is housed in a housing 15.

  The collection filter 4 is a filter made of a fluororesin, has a thin film sheet shape (tape shape), and is mounted on the rewind reel 41 in a coil state wound around a core material. The collection filter 4 rewound from the outer periphery of the coil on the rewind reel 41 is engaged and wound on a take-up reel 42 provided at a position separated by a predetermined distance. The take-up reel 42 is connected to an electric motor (not shown) for driving the take-up reel 42 to rotate, and a control power supply is further connected to the electric motor. The motor operates to rotate a predetermined number of times at predetermined time intervals in accordance with an operation command from the control power supply. As a result, the take-up reel 42, which is rotationally driven by the electric motor, winds the collecting filter 4 at a predetermined time interval for a predetermined length, so that the collecting filter 4 is continuously fed. The collection filter 4 that is continuously fed detects whether breakage such as cutting has occurred by the filter breakage detection sensor 44.

  As shown in FIG. 2, the collection filter 4 is supported by a collection filter support network 43 from the other main surface side opposite to the one main surface facing the composite optical fiber 7 described below. I have. The collection filter support net 43 includes a plurality of linear members 432 arranged in a lattice, and has openings 431 between the linear members 432. The trapping filter 4 can be continuously fed with a filter holding block (not shown) raised, and the filter holding block is lowered and the filter holding block contacts the collection filter 4. Makes continuous feeding impossible.

  The floating particle collecting means 2 collects the floating particulate matter floating in the air, and causes the air containing the floating particulate matter to flow into the classifier 3 through the pipe 21.

  The classifier 3 classifies, for example, particles having a particle size (strictly, aerodynamic particle size) of 2.5 μm or less and other particles. The suspended particulate matter measuring device 1 according to the present embodiment is configured to classify suspended particulate matter having a particle size of 2.5 μm or less, which is classified by the classifier 3 and is said to be deposited on the lungs of a human body and affect health. It is configured to measure the concentrations of elemental carbon (EC) and organic carbon (OC) contained in the suspended particulate matter.

  The container 5 is connected to a downstream side of the classifier 3 in the air flow direction, is a box-shaped member having a rectangular parallelepiped shape made of metal, for example, and is disposed on a feed path of the collection filter 4. Filter insertion holes 5a and 5b are formed on a pair of opposed wall surfaces of the container 5 located on the feed path of the collection filter 4, respectively. The collection filter 4 unwound from the rewind reel 41 passes through the space inside the container 5 by being inserted through the filter insertion holes 5a and 5b, and is wound on the take-up reel 42. The air flowing through the space inside the container 5 is filtered by the collection filter 4, and the filtering position of the collection filter 4 in the space inside the container 5 is the collection position of the suspended particulate matter. The space inside the container 5 includes a space into which the air containing suspended particulate matter having a particle size of 2.5 μm or less that has been classified by the classifier 3 flows (hereinafter, referred to as a “measurement target space”), and other remaining spaces. And is divided into.

  The suction pump 14 is connected to the container 5 via a pipeline 51 connected to the measurement target space side and a pipeline 52 connected to the remaining space side. A pressure sensor 511 for monitoring the pressure in the container 5 is provided in the pipes 51 and 52. The pipe 51 has a filter 511 for filtering suspended particulate matter flowing from the container 5, a flow sensor 512 for detecting a flow rate of a fluid flowing through the pipe 51, and a flow sensor 512 for detecting a flow rate of the fluid flowing through the pipe 51. A flow control solenoid valve 513 for controlling the flow rate of the passing fluid is provided. In the pipe 52, a filter 521 for filtering suspended particulate matter flowing from the container 5, a flow sensor 522 for detecting a flow rate of a fluid flowing in the pipe 52, and a flow in the pipe 52 A flow control solenoid valve 523 for controlling the flow rate of the fluid is provided.

  The suction amount of the suction pump 14 is preferably set to 1 to 20 L (liter) / min by the flow control solenoid valves 513 and 523. When the suction pump 14 sucks the air in the container 5 through the pipes 51 and 52, the air containing the floating particulate matter is sucked into the pipe 21 from the floating particle collecting means 2. The air sucked into the pipe 21 is separated by the classifier 3 into an air containing suspended particulate matter having a particle size of 2.5 μm or less and an air containing other particles, and a particle size of 2.5 μm or less. When the air containing suspended particulate matter flows through the measurement target space in the container 5, the air is filtered by the collection filter 4 sent into the measurement target space in the container 5, and the collection filter 4 Suspended particulate matter is collected on top.

  A light source 6 is provided above one main surface of the collection filter 4 (the side on which the classifier 3 is provided). The light source 6 is controlled by the control unit 12 described later, and emits light having a wavelength within a predetermined first wavelength band (for example, 375 nm) and a wavelength within a predetermined second wavelength band different from the first wavelength band ( (E.g., 890 nm) are emitted alternately. The light source 6 may be configured to emit a plurality of lights having different wavelengths in the first wavelength band and a plurality of lights having different wavelengths in the second wavelength band. Further, the light source 6 may be configured to be able to emit light having a wavelength in a wavelength band (third wavelength band, fourth wavelength band) different from the first wavelength band and the second wavelength band. The first wavelength band is from 220 nm to 500 nm, and the second wavelength band is from 650 nm to 1000 nm. The third wavelength band is 400 nm or more and 600 nm or less, and the fourth wavelength band is 200 nm or more and 300 nm or less. The light source 6 includes an LED (light emitting diode) capable of emitting light having a wavelength within the first wavelength band, and an LED capable of emitting light having a wavelength within the second wavelength band. It is configured to include an LED capable of emitting light having a wavelength within the wavelength band and an LED capable of emitting light having a wavelength within the fourth wavelength band. In addition, the light source 6 is not limited to being realized by the LED, and for example, a xenon lamp may be used.

  A composite optical fiber 7 is connected to the light source 6. The composite optical fiber 7 is an optical fiber in which a light receiving fiber is arranged around a light emitting fiber. One end of the composite optical fiber 7 is connected to the light source 6 and the reflected light detector 9, and the other end is formed of the container 5. An emission light propagation unit which is inserted into the measurement target space and is provided to face one main surface of the collection filter 4 and propagates light emitted from the light source 6 toward one main surface of the collection filter 4. It has a function as a reflected light receiving unit that receives the reflected light from the floating particulate matter on the collection filter 4 and a reflected light propagation unit that propagates the reflected light to the reflected light detector 9. As such a composite optical fiber 7, E32-D32L 2M manufactured by OMRON Corporation can be used.

  The transmitted light detector 8 is realized by, for example, a silicon photodiode, a photomultiplier, a multi-spectrometer having optical resolution, and the like, and is opposite to one main surface of the collection filter 4 in the measurement target space of the container 5. Is disposed opposite to the other main surface of the side, receives the transmitted light transmitted through the collection filter 4 that captures the suspended particulate matter, and reduces the light intensity of the light corresponding to the transmitted light from the suspended particulate matter. A corresponding voltage value (mV) is detected.

  The reflected light detector 9 is realized by, for example, a silicon photodiode, a photomultiplier, a multi-spectrometer having optical resolution, etc., is connected to one end of the composite optical fiber 7, and propagates through the light receiving fiber of the composite optical fiber 7. The reflected light reflected by the collection filter 4 that has collected the suspended particulate matter is received, and a voltage value (mV) corresponding to the light intensity of the light corresponding to the reflected light from the suspended particulate matter is detected. .

  The transmitted light detector 8 and the reflected light detector 9 can instantaneously receive light of a plurality of wavelengths by using a multi-spectrometer. A plurality of transmitted light detectors 8 and a plurality of reflected light detectors 9 may be set, and light of a plurality of wavelengths may be instantaneously received using a bandpass filter. Furthermore, the light source 6 is configured to include a plurality of LEDs having different wavelengths of emitted light so that each LED is individually turned on or off. It may be configured. In the present embodiment, the suspended particulate matter measurement device 1 has a configuration in which one transmitted light detector 8 and one reflected light detector 9 are provided, and the light source 6 has a plurality of LEDs having different emission light wavelengths. is there.

  The reflected light detector 9 has a function as a reference detector, receives a part of the light emitted from the light source 6, and outputs a voltage value (mV) corresponding to the light intensity of the received emitted light. To detect.

  The calculation unit 11, the control unit 12, and the storage unit 13 are realized by a personal computer (PC) or the like. The operation unit 11 includes a first operation unit 111 and a second operation unit 112, and executes an operation for calculating the amounts (concentrations) of elemental carbon (EC) and organic carbon (OC) in suspended particulate matter. Circuit.

  The first calculation unit 111 is connected to the transmitted light detector 8 and the reflected light detector 9, and detects a voltage value according to the transmitted light intensity detected by the transmitted light detector 8 and a reflected light detection functioning as a reference detector. The concentration of elemental carbon (EC) and organic carbon (OC) in the suspended particulate matter on the collection filter 4 is calculated based on the voltage value corresponding to the intensity of the emitted light detected by the detector 9.

  The second operation unit 112 is connected to the reflected light detector 9 and detects a voltage value corresponding to the intensity of the reflected light detected by the reflected light detector 9 and the voltage value detected by the reflected light detector 9 functioning as a reference detector. The concentrations of elemental carbon (EC) and organic carbon (OC) in the suspended particulate matter on the collection filter 4 are calculated based on the voltage value corresponding to the intensity of the emitted light.

  The storage unit 13 is realized by a non-volatile semiconductor memory such as a flash memory or a non-volatile memory such as a hard disk drive (HDD: Hard Disk Drive). Information on the light attenuation coefficient, an operating system (OS) program, a program for causing a computer to function as the suspended particulate matter measurement device 1 (hereinafter, referred to as a “suspended particulate matter measurement processing program”), and various types. Is stored.

  The control unit 12 is a processing unit that controls the operation of each unit of the suspended particulate matter measurement device 1, and includes, for example, a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM). ) Is a processing circuit realized by a microcomputer, a microprocessor, or the like. The control unit 12 executes an OS program, a suspended particulate matter measurement processing program, and various application programs loaded from the storage unit 13 to the RAM.

  Hereinafter, a specific measurement processing operation of the suspended particulate matter measuring device 1 will be described. In order to facilitate understanding of the measurement processing operation by the suspended particulate matter measuring device 1, the measurement processing operation will be described using the following terms.

(1) Detected value of each detector when light of wavelength λ is emitted by light source 6 Detected value of transmitted light detector 8 (voltage value: mV): Itrans (means, λ)
• Detection value of reflected light detector 9 (voltage value; mV): Ireflect (means, λ)
A detection value (voltage value; mV) of the reflected light detector 9 functioning as a reference detector: Irefer (means, λ)

(2) Detected value of each detector when no light is emitted from light source 6 Detected value of transmitted light detector 8 (voltage value; mV): Itrans (dark)
-Detected value of reflected light detector 9 (voltage value: mV): Ireflect (dark)
A detection value (voltage value; mV) of the reflected light detector 9 functioning as a reference detector: Irefer (dark)

(3) Light intensity according to transmitted light and reflected light from the trapping filter 4 in a state where no suspended particulate matter is trapped • Transmitted light intensity: T (λ, 0)
・ Reflected light intensity: R (λ, 0)

(4) The light intensity according to the transmitted light and the reflected light from the collection filter 4 after t seconds from the start of the collection of the suspended particulate matter by the collection filter 4. The transmitted light intensity: T (λ, t)
・ Reflected light intensity: R (λ, t)

(5) Attenuation rate of light intensity t seconds after the start of collection of suspended particulate matter by the collection filter 4 • Attenuation rate of transmitted light intensity: Tatn (λ, t)
・ Attenuation rate of reflected light intensity: Ratn (λ, t)

(6) Set value regarding collection filter support network 43 ・ Area of opening 431 in collection filter support network 43: Asample
-Area of linear member 432 in collection filter support net 43: Asupport
The ratio of meshes in the collection filter support network 43: α = Asupport / (Asample + Asupport)

(7) Concentration of elemental carbon, organic carbon and other components in suspended particulate matter ・ Concentration of elemental carbon calculated based on transmitted light intensity: [EC] t
・ Concentration of organic carbon calculated based on transmitted light intensity: [OC] t
・ Concentration of other components calculated based on transmitted light intensity: [M] t
・ Concentration of elemental carbon calculated based on reflected light intensity: [EC] r
・ Concentration of organic carbon calculated based on reflected light intensity: [OC] r
・ Concentration of other components calculated based on reflected light intensity: [M] r

(8) Attenuation coefficient of elemental carbon, organic carbon, and other components ・ Attenuation coefficient of transmitted light of elemental carbon: ε (EC, λ)
・ Attenuation coefficient of transmitted light of organic carbon: ε (OC, λ)
・ Attenuation coefficient of transmitted light of other components: ε (M, λ)
-Reflection attenuation coefficient of elemental carbon: σ (EC, λ)
-Reflection attenuation coefficient of organic carbon: σ (OC, λ)
・ Reflection light attenuation coefficient of other components: σ (M, λ)

  The control unit 12 drives the take-up reel 42 to rotate the take-up reel 42 in a state where the filter holding block is raised, so that the collection filter 4 is taken up by a predetermined length, and the collection filter 4 is fed. The holding block is lowered, and the measurement processing operation by the suspended particulate matter measuring device 1 is started.

Next, the control unit 12 controls the light source 6, the composite optical fiber 7, the transmitted light detector 8, the reflected light detector 9, and the arithmetic unit 11 to capture the state in which suspended particulate matter is not collected. The first computing unit 111 calculates the transmitted light intensity T (λ, 0) according to the transmitted light from the collection filter 4 according to the following equation (1), and calculates the reflected light intensity R (λ, 0) in the second computing unit 112. Is calculated according to the following equation (2).
T (λ, 0) = [Itrans (means, λ) -Itrans (dark)] / [Irefer (means, λ) -Irefer (dark)]
… (1)
R (λ, 0) = [Ireflect (means, λ) -Ireflect (dark)] / [Irefer (means, λ) -Irefer (dark)]
… (2)

  Note that the control unit 12 performs the operation of detecting Itrans (dark) by the transmitted light detector 8 and the operation of detecting Ireflect (dark) by the reflected light detector 9 during 300 ms when light is not emitted from the light source 6. The detection operation of Irefer (dark) is performed by the reflected light detector 9 functioning as the reference detector, and the light having the wavelength λ in the first wavelength band is emitted from the light source 6 during 300 ms. The operation of detecting Itrans (means, λ) by the photodetector 8, the operation of detecting Ireflect (means, λ) by the reflected light detector 9, and the detection of Irefer (means, λ) by the reflected light detector 9 functioning as a reference detector. The detection operation is executed, and during the 300 ms when the light having the wavelength λ in the second wavelength band is emitted from the light source 6, the detection operation of Itrans (means, λ) by the transmitted light detector 8 and the detection of the reflected light are performed. (Means, λ) The detection operation and the detection operation of Irefer (means, λ) by the reflected light detector 9 functioning as the reference detector are executed, and the transmitted light intensity T (λ, 0) and the reflected light intensity R (λ, 0) are set to 1 Acquire in seconds.

  Next, the control unit 12 starts the operation of sucking the atmosphere in the container 5 by the suction pump 14 and starts the collection of the suspended particulate matter by the collection filter 4.

Next, the control unit 12 controls the light source 6, the composite optical fiber 7, the transmitted light detector 8, the reflected light detector 9, and the arithmetic unit 11 so that the trapping filter 4 collects the suspended particulate matter. At t seconds after the start, the transmitted light intensity T (λ, t) according to the transmitted light from the collection filter 4 is calculated by the first arithmetic unit 111 according to the following equation (3), and the reflected light intensity R ( λ, t) is calculated by the second calculation unit 112 according to the following equation (4).
T (λ, t) = [Itrans (means, λ) -Itrans (dark)] / [Irefer (means, λ) -Irefer (dark)]
… (3)
R (λ, t) = [Ireflect (means, λ) -Ireflect (dark)] / [Irefer (means, λ) -Irefer (dark)]
… (4)

  Note that the control unit 12 performs the operation of detecting Itrans (dark) by the transmitted light detector 8 and the operation of detecting Ireflect (dark) by the reflected light detector 9 during 300 ms when light is not emitted from the light source 6. The detection operation of Irefer (dark) is performed by the reflected light detector 9 functioning as the reference detector, and the light having the wavelength λ in the first wavelength band is emitted from the light source 6 during 300 ms. Itrans (means, λ) detection operation by photodetector 8, Ireflect (means, λ) detection operation by reflected light detector 9, Ire fer (means, λ) by reflected light detector 9 functioning as a reference detector During the 300 ms in which the light having the wavelength λ in the second wavelength band is emitted from the light source 6, the operation of detecting the Itrans (means, λ) by the transmitted light detector 8 and the reflected light Ireflect by detector 9 (means, λ) And the reflected light detector 9 functioning as a reference detector performs the operation of detecting Irefer (means, λ), and the transmitted light intensity T (λ, t) and the reflected light intensity R (λ, t) are calculated. Acquired at one-second intervals.

Based on the transmitted light intensity T (λ, 0), reflected light intensity R (λ, 0), transmitted light intensity T (λ, t), and reflected light intensity R (λ, t) thus obtained. Then, the control unit 12 sends the attenuation factor Tatn (λ, t) of the transmitted light intensity t seconds after the start of the collection of the suspended particulate matter by the collection filter 4 to the first calculation unit 111 using the following equation. The calculation is performed according to (5), and the attenuation rate Ratn (λ, t) of the reflected light intensity is calculated by the second calculation unit 112 according to the following equation (6).
Tatn (λ, t) =-Ln [T (λ, t) / T (λ, 0)] (5)
Ratn (λ, t) =-Ln [{R (λ, t) -αR (λ, 0)} / {R (λ, 0) -αR (λ, 0)}] (6)

  Next, the control unit 12 controls the concentration [EC] t of the elemental carbon in the suspended particulate matter, the concentration [OC] t of the organic carbon, and The concentration [M] t of the other component is calculated by the first computing unit 111, and the concentration [EC] r of the elemental carbon in the suspended particulate matter is calculated based on the attenuation rate Ratn (λ, t) of the reflected light intensity. , The concentration of organic carbon [OC] r and the concentration of other components [M] r are calculated by the second computing unit 112.

For example, when light of three wavelengths λ1, λ2, λ3 is alternately emitted from the light source 6, the control unit 12 stores the transmitted light attenuation coefficient ε (EC, λ1) of the elemental carbon stored in the storage unit 13. ), Ε (EC, λ2), ε (EC, λ3), transmission light attenuation coefficient of organic carbon ε (OC, λ1), ε (OC, λ2), ε (OC, λ3), transmission light attenuation of other components Referring to the coefficients ε (M, λ1), ε (M, λ2), and ε (M, λ3), the first arithmetic unit 111 gives the concentration [EC of the elemental carbon according to the following equations (7) to (9). ], The concentration of organic carbon [OC] t, and the concentration of other components [M] t.
Tatn (λ1) = ε (OC, λ1) · [OC] t + ε (EC, λ1) · [EC] t + ε (M, λ1) · [M] t (7)
Tatn (λ2) = ε (OC, λ2) · [OC] t + ε (EC, λ2) · [EC] t + ε (M, λ2) · [M] t (8)
Tatn (λ3) = ε (OC, λ3) · [OC] t + ε (EC, λ3) · [EC] t + ε (M, λ3) · [M] t… (9)

The control unit 12 also stores the reflected light attenuation coefficients σ (EC, λ1), σ (EC, λ2), σ (EC, λ3) of the elemental carbon and the reflected light attenuation of the organic carbon stored in the storage unit 13. Coefficients σ (OC, λ1), σ (OC, λ2), σ (OC, λ3), and other component reflected light attenuation coefficients σ (M, λ1), σ (M, λ2), σ (M, λ3) For reference, the second arithmetic unit 112 calculates the concentration of elemental carbon [EC] r, the concentration of organic carbon [OC] r, and the concentration of other components [M] r according to the following equations (10) to (12). Let it be calculated.
Ratn (λ1) = σ (OC, λ1) · [OC] r + σ (EC, λ1) · [EC] r + σ (M, λ1) · [M] r… (10)
Ratn (λ2) = σ (OC, λ2) · [OC] r + σ (EC, λ2) · [EC] r + σ (M, λ2) · [M] r… (11)
Ratn (λ3) = σ (OC, λ3) · [OC] r + σ (EC, λ3) · [EC] r + σ (M, λ3) · [M] r… (12)

  When two components M1 and M2 are present in the suspended particulate matter as components other than the elemental carbon (EC) and the organic carbon (OC), the above equations (7) and (8) are used. , Equations (10) and (11), the concentrations of the other components M1 and M2 can be calculated.

  A more specific example for measuring the concentrations of elemental carbon (EC) and organic carbon (OC) in the suspended particulate matter by the suspended particulate matter measurement device 1 is as follows. In the following example, only two components, elemental carbon (EC) and organic carbon (OC), are present in the suspended particulate matter, and the light emitted from the light source 6 has a wavelength of λ = 375 nm and a wavelength of λ = Assume 890 nm light.

  FIG. 3 shows the measured data of the attenuation rates Tatn (λ375 nm) and Tatn (λ890 nm) of the transmitted light intensity in this case. FIG. 3 is a graph illustrating an example of a measurement result regarding a change in the attenuation rate of the transmitted light intensity for each measurement date and time. FIG. 4 shows the measured data of the attenuation rates Ratn (λ375 nm) and Ratn (λ890 nm) of the reflected light intensity. FIG. 4 is a graph illustrating an example of a measurement result regarding a change in the attenuation rate of the reflected light intensity for each measurement date and time.

The control unit 12 causes the first calculation unit 111 to calculate the concentration [EC] t of the elemental carbon and the concentration [OC] t of the organic carbon according to the following equations (13) and (14).
Tatn (λ375nm) = ε (OC, λ375nm) · [OC] t + ε (EC, λ375nm) · [EC] t ... (13)
Tatn (λ890nm) = ε (OC, λ890nm) · [OC] t + ε (EC, λ890nm) · [EC] t ... (14)

The control unit 12 causes the second calculation unit 112 to calculate the concentration [EC] r of the elemental carbon and the concentration [OC] r of the organic carbon according to the following Expressions (15) and (16).
Ratn (λ375nm) = σ (OC, λ375nm) · [OC] r + σ (EC, λ375nm) · [EC] r… (15)
Ratn (λ890nm) = σ (OC, λ890nm) · [OC] r + σ (EC, λ890nm) · [EC] r… (16)

  In this case, the transmitted light attenuation coefficient ε (EC, λ 375 nm) of elemental carbon is “0.30”, ε (EC, λ 890 nm) is “0.30”, and the transmitted light of organic carbon is The attenuation coefficient ε (OC, λ 375 nm) is “0.10”, ε (OC, λ 890 nm) is “0”, and the reflected light attenuation coefficient σ (EC, λ 375 nm) of elemental carbon is “0.32”. Σ (EC, λ 890 nm) is “0.20”, the reflection attenuation coefficient σ (OC, λ 375 nm) of the organic carbon is “0.20”, and σ (OC, λ 890 nm) is “0”. Is required experimentally.

  The calculation results of the concentration of elemental carbon and the concentration of organic carbon are shown in FIGS. FIG. 5 is a graph showing an example of a measurement result regarding a change in organic carbon (OC) concentration at each measurement date and time. FIG. 6 is a graph showing an example of a measurement result regarding a change in elemental carbon (EC) concentration at each measurement date and time. FIG. 7 is a graph illustrating an example of a measurement result regarding a change in the mass concentration of PM2.5 at each measurement date and time.

FIG. 8 shows the correlation between the measurement result by the suspended particulate matter measuring device 1 and fWSOC. FIG. 8 is a graph showing a correlation between light intensity and fWSOC. FIG. 8A shows a correlation with fWSOC corresponding to transmitted light intensity, and FIG. 8B shows a correlation with fWSOC corresponding to reflected light intensity. In addition, fWSOC represents the molar concentration (μmol / m ³ ) of water-soluble organic carbon in fine particulate matter having a particle diameter equal to or less than the particle diameter corresponding to PM2.5. As is clear from the graph shown in FIG. 8, the measurement result corresponding to the transmitted light intensity and the fWSOC by the suspended particulate matter measurement device 1 show a good correlation, and the measurement result corresponding to the reflected light intensity and fWSOC correspond to each other. Indicates a good correlation.

FIG. 9 shows the concentration [OC] t (μgC / m ³ ) of the organic carbon calculated based on the transmitted light intensity by the suspended particulate matter measuring device 1 and the concentration of the organic carbon in PM2.5 by the carbon analyzer. It is a graph which shows a correlation with a density | concentration (microgram C / m < ³ >). The carbon analyzer includes a pyrolysis tube and a CO ₂ analyzer, and thermally decomposes organic matter in PM2.5 to measure the concentration of organic carbon in PM2.5.

  In FIG. 9, the concentration [OC] t of the organic carbon by the suspended particulate matter measuring device 1 is a value calculated as follows.

That is, in the above equations (13) and (14), ε (OC, λ375 nm) −ε (OC, λ890 nm) = 1 / 17.5 and ε (EC, λ375 nm) −ε (EC, λ890 nm) = 0, The concentration [OC] t (μgC / m ³ ) of the organic carbon was calculated according to the following equation (17).
[OC] t = 17.5 [Tatn (λ375 nm) −Tatn (λ890 nm)] (17)

  As is clear from the graph shown in FIG. 9, there is a good correlation between the concentration [OC] t of the organic carbon obtained by the suspended particulate matter measuring device 1 and the concentration of the organic carbon obtained by the carbon analyzer.

FIG. 10 shows the concentration [EC] r (μgC / m ³ ) of elemental carbon calculated based on the reflected light intensity by the suspended particulate matter measuring device 1 and the elemental carbon content in PM2.5 by the carbon analyzer. It is a graph which shows the correlation with the density | concentration (microgram C / m < ³ >) of carbon. The carbon analyzer includes a pyrolysis tube and a CO ₂ analyzer, and thermally decomposes elemental carbon in PM2.5 to measure the concentration of elemental carbon in PM2.5.

  In FIG. 10, the concentration [EC] r of elemental carbon by the suspended particulate matter measuring device 1 is a value calculated as follows.

That is, in the above equation (16), σ (EC, λ890 nm) ≫σ (OC, λ890 nm), σ (EC, λ890nm) = 1 / 4.99, and the concentration of elemental carbon [EC] according to the following equation (18): r (μgC / m ³ ) was calculated.
Ratn (λ890nm) = σ (EC, λ890nm) ・ [EC] r… (18)

  As is clear from the graph shown in FIG. 10, there is a good correlation between the concentration [EC] r of the elemental carbon by the suspended particulate matter measuring device 1 and the concentration of the elemental carbon by the carbon analyzer.

  In addition, in the suspended particulate matter measuring device 1 of the present embodiment, as described above, the calculation unit 11 calculates the concentration of the elemental carbon (EC) and the concentration of the organic carbon (OC) based on the transmitted light intensity. Although it is configured to calculate based on the reflected light intensity, the average value of the density value calculated based on the transmitted light intensity and the density value calculated based on the reflected light intensity is finally calculated. It may be configured to process as a simple measurement result.

  According to the suspended particulate matter measuring device 1 of the present embodiment configured as described above, the elemental carbon (EC) and the organic carbon (OC) are not thermally decomposed unlike the related art, and the carrier gas is also used. Without the need, it is possible to measure at least the concentration of organic carbon (OC) in the particulate matter suspended in the atmosphere, preferably to measure the concentration of elemental carbon (EC) and organic carbon (OC) Can be.

DESCRIPTION OF SYMBOLS 1 Suspended particulate matter measuring device 2 Suspended particle collection means 3 Classifier 4 Collection filter 5 Container 6 Light source 7 Composite optical fiber 8 Transmitted light detector 9 Reflected light detector 11 Operation unit 12 Control unit 13 Storage unit 14 Suction pump 15 Housing 41 Rewind reel 42 Take-up reel 43 Collection filter support net

Claims (4)

a sheet-like trapping filter 4 for trapping particulate matter floating in the atmosphere;
b light source means 6, 7 for emitting two types of light having different wavelengths λ1, λ2, respectively, and irradiating the light toward one main surface of the collection filter 4,
c, which is disposed to face the other main surface of the collection filter 4 opposite to the one main surface, receives light transmitted through the collection filter 4 where particulate matter is collected, and receives the received light. Transmitted light intensity detecting means 8 for detecting the light intensity of
d arithmetic means 11, 12, 13;
The output from the transmitted light intensity detecting means 8 is provided, and the attenuation ratios Tatn (λ1) and Tatn (λ2) of the detected transmitted light intensity for each wavelength λ1 and λ2, and the respective wavelengths λ1 and λ2 of the organic carbon. A predetermined transmitted light attenuation coefficient ε (OC, λ1), ε (OC, λ2), and a predetermined transmitted light attenuation coefficient ε (EC, λ1), ε (EC, λ2) for each wavelength λ1, λ2 of elemental carbon. ) And based on
The difference between the transmitted light attenuation coefficient ε (OC, λ1) of the organic carbon of one wavelength λ1 and the transmitted light attenuation coefficient ε (OC, λ2) of the other wavelength λ2 organic carbon is calculated,
Calculate the difference between the transmitted light attenuation coefficient ε (EC, λ1) of the elemental carbon of one wavelength λ1 and the transmitted light attenuation coefficient ε (EC, λ2) of the other wavelength λ2,
Calculating means for calculating the amount [OC] t of organic carbon in the particulate matter collected by the collection filter using the difference between the two elements; measuring device. e a sheet-shaped collection filter 4 for collecting particulate matter floating in the atmosphere;
f light source means 6, 7 for emitting two types of light having different wavelengths λ1 and λ2, respectively, and irradiating the light toward one main surface of the collection filter;
g Reflection disposed opposite to the one main surface of the collection filter 4 for receiving light reflected by the collection filter 4 from which particulate matter has been collected, and detecting the light intensity of the received light. Light intensity detecting means 9;
h arithmetic means 11, 12, 13;
The output from the reflected light intensity detecting means 9 is given, and the attenuation rates Ratn (λ1) and Ratn (λ2) of the detected reflected light intensity for each wavelength λ1 and λ2, and for each wavelength λ1 and λ2 of the organic carbon. Predetermined reflected light attenuation coefficient σ (OC, λ1), σ (OC, λ2), and predetermined reflected light attenuation coefficient σ (EC, λ1) for each wavelength λ1, λ2 of elemental carbon, σ (EC, λ2 ) And based on
Calculate the difference between the reflected light attenuation coefficient σ (OC, λ1) of organic carbon of one wavelength λ1 and the reflected light attenuation coefficient σ (OC, λ2) of organic carbon of the other wavelength λ2,
The difference between the reflected light attenuation coefficient σ (EC, λ1) of the elemental carbon of one wavelength λ1 and the reflected light attenuation coefficient σ (EC, λ2) of the other wavelength λ2,
Calculating means for calculating the amount [OC] r of the organic carbon in the particulate matter collected by the collection filter using the difference between the two elements; measuring device. i. a sheet-shaped collection filter 4 for collecting particulate matter floating in the atmosphere;
j light source means 6 and 7 for emitting two types of light having different wavelengths λ 1 and λ 2 respectively and irradiating the light to one main surface of the collection filter 4;
k is disposed opposite the other main surface of the collection filter 4 opposite to the one main surface, receives light transmitted through the collection filter 4 where the particulate matter is collected, and receives the received light. Transmitted light intensity detecting means 8 for detecting the light intensity of
L: a reflected light disposed opposite to the one main surface of the collection filter 4 for receiving light reflected by the collection filter from which particulate matter has been collected, and detecting the light intensity of the received light Intensity detection means 9;
m arithmetic means 11, 12, 13;
Each output from the transmitted light intensity detecting means and the reflected light intensity detecting means is given, and the attenuation rate Tatn (λ1), Tatn (λ2) of the detected transmitted light intensity for each wavelength λ1, λ2, and organic carbon A predetermined transmitted light attenuation coefficient ε (OC, λ1) for each wavelength λ1, λ2, ε (OC, λ2), and a predetermined transmitted light attenuation coefficient ε (EC, λ1) for each wavelength λ1, λ2 of elemental carbon. ), Ε (EC, λ2), each wavelength λ1, attenuation rate of detected reflected light intensity Ratn (λ1) for each λ2, Ratn (λ2), and each predetermined wavelength λ1, λ2 of organic carbon. Determined reflected light attenuation coefficient σ (OC, λ1), σ (OC, λ2), and predetermined reflected light attenuation coefficient σ (EC, λ1), σ (EC, λ2) for each wavelength λ1, λ2 of elemental carbon And based on
The first difference between the transmitted light attenuation coefficient ε (OC, λ1) of the organic carbon having one wavelength λ1 and the transmitted light attenuation coefficient ε (OC, λ2) of the organic carbon having the other wavelength λ2 is calculated,
Calculate the second difference between the transmitted light attenuation coefficient ε (EC, λ1) of one elemental carbon of wavelength λ1 and the transmitted light attenuation coefficient ε (EC, λ2) of the other wavelength λ2,
The third difference between the reflected light attenuation coefficient σ (OC, λ1) of the organic carbon of one wavelength λ1 and the reflected light attenuation coefficient σ (OC, λ2) of the organic wavelength of the other wavelength λ2 is calculated,
Calculate the fourth difference between the reflected light attenuation coefficient σ (EC, λ1) of the elemental carbon having one wavelength λ1 and the reflected light attenuation coefficient σ (EC, λ2) of the elemental carbon having the other wavelength λ2,
Calculating means for calculating the amount of organic carbon in the particulate matter collected by the collection filter using the first to fourth differences; Substance measuring device.   4. The floating device according to claim 1, wherein the one wavelength λ1 has a wavelength band of 220 nm or more and 500 nm or less, and the other wavelength λ2 has a wavelength band of 650 nm or more and 1000 nm or less. 5. Particulate matter measuring device.

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