Yellow sand flying state determination system

Abstract

To provide a system capable of determining a yellow sand flying state using magnetization intensity.SOLUTION: A yellow sand flying state determination system comprises: a creation unit which creates a section of a region using magnetization intensity of aerosol in the atmosphere and a scatter diagram of SPM concentration; and a determination unit which determines a yellow sand flying state in the atmosphere by identifying yellow sand and contamination by a measurement data plot region.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a system for determining the state of yellow sand arrival. [Background technology]

[0002] Yellow sand is an airborne substance that is of concern as it can cause health hazards, including respiratory and circulatory system diseases and allergic symptoms. Conventionally, it has been observed visually or with lidar equipment that uses laser beams. Visual observations have issues with quantitative and objective aspects, and in recent years the number of meteorological observation points conducting visual observations has been decreasing. In addition, with lidar devices that measure and analyze scattered light produced by irradiating laser light, it is difficult to control the scattered light measurement and adjust the interference section. For example, Patent Document 1 discloses an attempt to develop a device that uses an LED or laser as a light source to improve observation accuracy.

[0003] On the other hand, magnetic measurements that can obtain magnetization intensity are rapid and non-destructive testing techniques, and are useful as a means for obtaining indicators of metal contamination, as described in Non-Patent Document 1, for example. The present inventors focused on magnetization intensity because yellow sand contains magnetic particles (for example, iron oxide (magnetite) and the like). Magnetic particles are also associated with pollution caused by various anthropogenic activities (for example, fine particles contained in factory exhaust and automobile exhaust, and dust, dirt, and other particles generated by industrial activities), so distinguishing between yellow sand and pollution is important in observing yellow sand. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-012708 [Non-patent literature]

[0005] [Non-Patent Document 1] Beckwith, et al., 1986, Heavy metal and magnetic relationships for urban source sediments. Physics of the Earth and Planetary Interiors, 42(1-2), 67-75. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a system that can determine the state of yellow sand arrival by utilizing magnetization intensity. [Means for solving the problem]

[0007] The yellow sand arrival state determination system of the present invention includes an area division creation unit that uses a scatter plot of the magnetization intensity and SPM concentration of aerosols in the atmosphere, and a determination unit that distinguishes between yellow sand and pollution based on the plot area of ​​the measurement data and determines the arrival state of yellow sand in the atmosphere.

[0008] Here, the "magnetic intensity" of atmospheric aerosols is the magnetic intensity (Am 2 ) normalized by the cumulative flow rate at the time of sampling. "SPM concentration" refers to the concentration (μg / m 3 ) For example, from the magnetization intensity and SPM concentration of a sample, the y-axis is magnetization intensity (A / m) and the x-axis is SPM concentration (μg / m 3 ) scatter plot is obtained. For the areas divided on this scatter plot, the plot of measurement data (the magnetization intensity and SPM concentration of the sample on the day for which the status of yellow sand arrival is desired) is used to determine whether it is a yellow sand or polluted area.

[0009] In the present invention, the area division creating unit may divide the area into yellow sand areas and polluted areas based on a lead isotope ratio of aerosols in the atmosphere. By using the three elements of magnetic intensity, SPM concentration, and lead isotope ratio, the arrival state of yellow sand can be determined more accurately.

[0010] In the present invention, the area division creating unit divides the yellow sand area and the polluted area with a reference line A, and the reference line A is expressed as {y=(8.1-8.2)×10 -3 x+a}. Reference line A separates the yellow sand area from the polluted area, making it easy to see which area the measurement data plots belong to. In addition, the yellow sand area may be further divided into a large-scale yellow sand area and a background yellow sand area by an auxiliary line B, and the auxiliary line B may be expressed as {y=magnetic intensity of aerosols in the atmosphere on the day yellow sand was observed by visual observation}. Auxiliary line B separates the "large-scale yellow sand area" where the amount of yellow sand can be observed with the naked eye from the "background yellow sand area" where the amount of yellow sand cannot be observed with the naked eye. This makes it possible to detect the arrival of yellow sand, which is difficult to observe with the naked eye, when a plot is present in the "background yellow sand area," enabling more sensitive observation of yellow sand.

[0011] In the present invention, an acquisition unit may further be provided that acquires magnetic data and SPM data of aerosols in the atmosphere, and the area division creation unit may plot magnetization intensity and SPM concentration based on the magnetic data and SPM data. "Magnetic data" of atmospheric aerosols includes, for example, the magnetic moment (M) and sample magnetization strength (Am 2 ), and the integrated flow rate at the time of sampling. The "SPM data" may be, for example, SPM data provided by the National Institute for Environmental Studies, a national research and development agency. In the present invention, the vehicle may further include a display unit that displays information indicating the state of yellow sand arrival based on the result of the determination by the determination unit. This makes it easier to visually grasp the state of yellow sand in flight.

[0012] In one aspect of the present invention, the method may include, for example, a step of dividing an area using a scatter plot of the magnetization intensity and SPM concentration of aerosols in the atmosphere, and a determination step of distinguishing between yellow sand and pollution based on the plot area of ​​the measurement data and determining the state of yellow sand in the atmosphere. This method for determining the state of yellow sand arrival may further include an acquisition step for acquiring magnetic data and SPM data of aerosols in the atmosphere, and may also include a display step for displaying information indicating the state of yellow sand arrival based on the determination result by the determination step. Effect of the Invention

[0013] According to the present invention, it is possible to provide a system for determining the state of arrival of yellow sand, which can determine the state of arrival of yellow sand by utilizing magnetization intensity and has excellent quantitativeness, objectivity, and the like. [Brief description of the drawings]

[0014] [Figure 1] The magnetization intensity and SPM concentration of the samples in this example are shown as a function of time. [Diagram 2] The relationship between the magnetization intensity of the sample and the SPM concentration is shown. [Diagram 3] The relationship between the magnetization intensity and mass of the yellow dust standard sample (CJ-2) is shown. [Figure 4] The relationship between aerosol origin and lead isotope ratios is shown. [Diagram 5] Figure 2 is further divided into sections based on lead isotope ratio measurements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <Atmospheric aerosol sampling> Atmospheric aerosols were collected using a high-volume air sampler (AH-600F, Shibata Scientific Co., Ltd., 700 L / min) and a PM2.5 particle size analyzer (Shibata Scientific Co., Ltd.) to capture particles with an aerodynamic diameter larger than 2.5 μm onto a quartz fiber filter (QR-100, Advantec Toyo Co., Ltd.). The reason why the coarse particles mentioned above were the focus of the study is that the peak of the particle size distribution of yellow sand is found in the vicinity of 4 to 5 μm.

[0016] The sampling location was the third floor rooftop of Kanazawa University's Noto campus (37.45°N, 137.36°E), and sampling (filter replacement) was carried out approximately once a week during the sampling period from August 2014 to March 2016. This sampling site is located at the tip of the Noto Peninsula in Ishikawa Prefecture, far from urban areas, making it suitable for observing aerosols transported long distances from mainland China and other areas.

[0017] <Magnetic strength of atmospheric aerosols> A portion of the collected filter (one of the five strips) was cut out and packed into a plastic cube (manufactured by Natsuhara Giken Co., Ltd.) to prepare a sample. An external magnetic field of 1.2 T was applied to the sample using a pulse magnetizer (PM9, Magnetic Measurements) to obtain saturated isothermal remanent magnetization, which was measured using a SQUID magnetometer (750, 2G Enterprises). Measurements using the magnetometer mentioned above provide magnetic moment (M) along three axes (X, Y, and Z), so (M sample ) 2 = M X 2 + M Y 2 + M Z 2 From M sample (emu) was calculated. Next, the sample magnetization intensity M sample (emu) = 10 3 M sample (Am 2 ) was sought. This is the cumulative flow rate during sampling (700 L / min x time, m 3 ) and the magnetic intensity (A / m) of the sample was calculated.

[0018] <SPM concentration of atmospheric aerosols> SPM data for the sampling period in Hakui City, Ishikawa Prefecture (36.53°N, 136.46°E, approximately 80 km from the sampling point) was obtained from the "Air Pollution Continuous Monitoring Data" provided by the National Institute for Environmental Studies (Environmental Observatory, https: / / tenbou.nies.go.jp / download / ), and the average SPM concentration (μg / m 3 ) was calculated.

[0019] <Magnetic intensity of atmospheric aerosols and SPM concentration> FIG. 1 shows the magnetization intensity and SPM concentration of the above samples versus time. Here, the Ministry of the Environment's "FY2015 Yellow Sand Survey Report" published in March 2017 contains information about the days when yellow sand and haze were observed by visual observation. For example, Kanazawa City in Ishikawa Prefecture was listed as a yellow sand observation site on April 18 and 25, 2015, and Kanazawa was listed as a haze observation site on July 30, August 1, 4, and 5, 2015. In Figure 1, the periods during which yellow sand and haze were observed visually are roughly enclosed in a box, and it can be seen that there is a tendency for magnetic intensity to increase during the yellow sand observation period, and for SPM concentration to increase during the haze observation period. Hereinafter, "pollution" refers mainly to "fume." For example, fume includes fine particles contained in factory exhaust and automobile exhaust, and dust, dirt, and other particles generated by industrial activities.

[0020] Figure 2 shows a scatter plot of the magnetization intensity and SPM concentration of the above samples. Among the plots of the sample's magnetic intensity and SPM concentration, the plots for days when yellow sand was observed visually (observation points were Kanazawa or any other point nationwide) are colored. The colored plots indicate approximately high magnetization intensities.

[0021] <Yellow dust standard sample> For reference, the magnetic intensity of the Asian dust standard sample CJ-2 (see Nishikawa, M., et al., 2000, Preparation and evaluation of certified reference materials for Asian mineral dust. Global Environ. Res., 4, 103-113.) was examined. Specifically, the magnetic moment of the yellow dust standard sample CJ-2 (mass 0 to 0.6 g) was obtained using the above magnetic measurement method, and the sample magnetization intensity (Am 2 ) was sought. Figure 3 shows the relationship between the magnetization intensity and mass of the yellow dust standard sample CJ-2. Strong correlation between sample magnetization intensity and mass (R 2 = 1), it can be seen that magnetic intensity can be used as an indicator of the amount of yellow sand.

[0022] <Lead isotope ratios of atmospheric aerosols> Next, the lead isotope ratios of atmospheric aerosols were measured. It has been reported that lead isotope ratios vary between aerosols from East Asian cities and those from Asian dust origins, and are known to depend on the origin of the aerosol. Examples of prior literature are shown below. East Asian cities ·Bollhoefer, A. and Rosman, KJR, 2001, Isotopic source signatures for atmospheric lead: The Northern Hemisphere. Geochimica et Cosmochimica Acta, 65, 1727-1740. ·Lee, S., et al., 2022, Characterization of trace elements and Pb isotopes in PM2.5 and isotopic source identification during haze episodes in Seoul, Korea. Atmospheric Pollution Research, 13, 101442. ·Mukai, H., et al., 2001, Regional characteristics of sulfur and lead isotope ratios in the atmosphere at several Chinese urban sites. Environmental Science and Technology, 35, 1064-1071. ·Nakano, T., et al., 2006, Determination of seasonal and regional variation in the provenance of dissolved cations in rain in Japan based on Sr and Pb isotopes. Atmospheric Environment, 40, 7409-7420. Origin of yellow sand ·Bory, A. J. M., et al., 2014, A Chinese imprint in insoluble pollutants recently deposited in central greenland as indicated by lead isotopes. Environmental Science and Technology, 48(3), 1451-1457. ·Jones, C.E., et al., 2000, Eolian inputs of lead to the North Pacific. Geochimica et Cosmochimica Acta, 64, 1405-1416. ·Schleicher, NJ, et al., 2020, A Global Assessment of Copper, Zinc, and Lead Isotopes in Mineral Dust Sources and Aerosols. Frontiers in Earth Science, 8, 167.

[0023] Figure 4 shows the relationship between aerosol origin and lead isotope ratio based on previous literature. The lead isotope ratios of this sample were also measured and compared with the lead isotope ratios for each source shown in previous literature (Figure 4), to confirm the origin of the atmospheric aerosols.

[0024] The remaining collected filter pieces (four of the five strips) were cut off and dissolved in 5% acetic acid (10 mL) on a hot plate at 80°C for 12 hours, and the supernatant (dissolved components) and precipitate (residual components) were separated by centrifugation and filtration. The dissolution in acetic acid is intended to remove most of the contaminants and make it easier to identify the lead isotope ratio of the yellow sand in the residual components. After separation, the residual components were washed with ultrapure water, dissolved in a mixture of nitric acid (0.5 mL) and hydrofluoric acid (1 mL) on a hot plate at 140°C for about 1 to 2 days, and then evaporated to dryness. Next, 2 mol / L hydrochloric acid (0.7 mL) was added and left for about 12 hours. After evaporating to dryness again, 3.5 mol / L nitric acid (5 mL) was added, treated in an ultrasonic cleaner for 30 minutes, and then heated and dissolved on a hot plate to obtain a stock solution. This stock solution was appropriately diluted with 1% nitric acid to prepare a sample for lead isotope ratio measurement.

[0025] The above samples were separated using a column, and the lead isotope ratios were measured using a double-focusing multi-collector ICP-MS (NEPTUNE, Thermo Fisher Scientific). The standard sample used was NIST-SRM981. 206 Pb / 204 Pb=16.9245±0.0096(2σ,n=29), 207 Pb / 204 Pb=15.4786±0.0091(2σ,n=29), 208 Pb / 204 Pb=36.663±0.021(2σ,n=29). In addition, NMIJ CRM 3681-a was used as a standard sample for some samples. NMIJ CRM 3681-a value is 206 Pb / 204 Pb=18.05359±0.00094(2σ,n=10), 207 Pb / 204 Pb=15.5888±0.0016(2σ,n=10), 208 Pb / 204 It has been confirmed that Pb = 37.9536 ± 0.0023 (2σ, n = 10).

[0026] By comparing the measured lead isotope ratios of this sample with those reported in previous literature (Figure 4), this sample was classified into four origins: "local," "pollution," "yellow sand + pollution (AD-Pollution)," and "yellow sand (AD)." Figure 5 shows the plots in Figure 2 for the samples for which lead isotope ratios were measured, with the plots marked to indicate the four origins mentioned above. In addition, the lead content in the aerosol in the "local" case is low and is expected to be mainly derived from the soil. However, since the approximation line L for the "local" case is close to the "filter blank" case as shown in Figure 4, it is thought that the contribution of the lead isotope ratio derived from the filter is also large.

[0027] In Figure 5, the yellow sand areas (a) (b) and the polluted area (c) are divided by reference line A. Baseline A is a straight line that separates the plots of "Yellow Sand (AD)" and "Pollution" classified by lead isotope ratio measurement, and is expressed as "y = (8.1-8.2) x 10 -3 x+a" (y-axis is magnetization intensity, x-axis is SPM concentration). The slope of the reference line A is (8.1~8.2) x 10 -3 " refers to a preferred value. For example, by increasing the number of samples and subjecting the magnetic intensity, SPM concentration, and lead isotope ratio to machine learning or the like, the slope of reference line A can be calculated more accurately, or some variation may be acceptable. In addition, in this embodiment, a=0, but this is not necessarily limited to this. In Figure 5, the Asian dust region is further divided into a large-scale Asian dust region (a) and a background Asian dust region (b) by auxiliary line B. The auxiliary line B may be expressed as "y = magnetization intensity of aerosols in the atmosphere on the day when yellow sand is observed by visual observation."

[0028] For confirmation, the plots (sampling dates) indicated by *1, *2, and *3 in Figure 5 were compared with the backward trajectory analysis. For the backward trajectory analysis, archive trajectories of the HYSPLIT Trajectory Model (https: / / www.ready.noaa.gov / HYSPLIT_traj.php) provided by the National Oceanic and Atmospheric Administration were used. The air inflow path was analyzed going back 72 hours from noon on the sampling day during this sampling period, and the starting coordinates were entered as 1000 m above ground at this sampling point (37.45°N, 137.36°E). As a result, similar results were obtained from the backward trajectory analysis.

[0029] Based on the above findings, the present inventors have devised a system that can determine the state of yellow sand arrival by utilizing magnetization intensity.

[0030] The system for determining the status of yellow sand in the atmosphere includes a section for creating area divisions using a scatter plot of the magnetization intensity and SPM concentration of aerosols in the atmosphere, and a determination section for distinguishing between yellow sand and pollution based on the plot area of ​​the measurement data, and determining the status of yellow sand in the atmosphere. The area division creation unit can improve the accuracy of area division by, for example, accumulating past data (magnetic intensity and SPM concentration of a plurality of samples sampled in the past) and obtaining a scatter diagram. It is preferable that measurement data (e.g., magnetic intensity and SPM concentration on a day when you want to know the status of yellow sand) is not sampled in unusual locations (e.g., near the site of a steelworks where there is concern about significant emissions of iron-containing aerosols, or along a highway). As an example, the area division creating unit may divide the area into yellow sand areas and polluted areas based on the lead isotope ratio of aerosols in the atmosphere. As another example, the area division creation unit may divide the yellow sand area and the polluted area with a reference line A, and further divide the yellow sand area into a large-scale yellow sand area and a background yellow sand area with an auxiliary line B. The determination unit determines, for example, whether the plot of the measurement data is a yellow sand or polluted area. The yellow sand flying state determination system may further include an acquisition unit that acquires magnetic data and SPM data of aerosols in the atmosphere. For example, the region division creating section may calculate and plot the magnetization intensity and SPM concentration based on the magnetic data and SPM data acquired by the acquiring section. The acquisition unit may further include a magnetic measurement unit to acquire magnetic data. The yellow sand arrival state determination system may further include a display unit that displays information indicating the yellow sand arrival state based on the determination result by the determination unit. In addition to the scatter diagram, it is preferable that the display unit display the origin of the aerosol, a reference line A, an auxiliary line B, etc.

Claims

1. A part for dividing areas using a scatter plot of the magnetic intensity and SPM concentration of atmospheric aerosols; The system for determining the state of yellow sand arrival includes a determination unit that distinguishes between yellow sand and pollution based on the plot area of ​​the measurement data and determines the state of yellow sand arrival in the atmosphere.

2. 2. The system for determining the state of yellow sand arrival according to claim 1, wherein the area division creating unit divides the yellow sand area and the polluted area based on a lead isotope ratio of aerosols in the atmosphere.

3. The area division creation part divides the yellow sand area and the polluted area with reference line A, and the reference line A is expressed as {y=(8.1-8.2)×10 -3 The system for determining the state of yellow sand arrival according to claim 1, wherein x+a is a function of x+a.

4. The yellow sand area is further divided into a large-scale yellow sand area and a background yellow sand area by an auxiliary line B, and the auxiliary line B is represented by {y=magnetic intensity of aerosols in the atmosphere on the day of yellow sand observation by visual observation}.

5. The system for determining the yellow sand arrival state according to claims 1 to 4, further comprising an acquisition unit that acquires magnetic data and SPM data of aerosols in the atmosphere, and the area division creation unit plots magnetization intensity and SPM concentration based on the magnetic data and SPM data.

6. The yellow sand arrival state determination system according to any one of claims 1 to 4, further comprising a display unit that displays information indicating the yellow sand arrival state based on the determination result by the determination unit.

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