CN103234882A

CN103234882A - Method for inverting mass concentration of atmospheric particulates based on flight time of particulates

Info

Publication number: CN103234882A
Application number: CN2013101392852A
Authority: CN
Inventors: 桂华侨; 李德平; 刘建国; 程寅; 王杰; 陆亦怀; 伍德侠
Original assignee: Hefei Institutes of Physical Science of CAS
Current assignee: Hefei Institutes of Physical Science of CAS
Priority date: 2013-04-21
Filing date: 2013-04-21
Publication date: 2013-08-07
Anticipated expiration: 2033-04-21
Also published as: CN103234882B

Abstract

A method for retrieving the mass concentration of atmospheric particulate matter based on the time of flight of particulate matter. Based on the aerodynamic particle spectrometer, the mass concentration of particulate matter can be retrieved according to the flight speed and sampling flow rate. According to the working principle of the aerodynamic particle spectrometer, after the particles pass through the acceleration nozzle, at any point on the airflow trajectory, the particles of each particle size have a unique speed u _p , and the flight speed of the particles can be obtained through the flight time. The relationship between the flight speed and mass of particles can be obtained from the principle of conservation of momentum, aerodynamics and fluid mechanics, so the mass concentration of particles can be inverted through the flight speed and sampling flow. The invention inverts the mass concentration of the atmospheric particulate matter according to the dynamic characteristics of the particulate matter, and provides an inversion algorithm capable of accurately, real-time and online measuring the mass concentration of the atmospheric particulate matter.

Description

A Retrieval Method of Atmospheric Particulate Mass Concentration Based on Particulate Time-of-Flight

技术领域technical field

本发明涉及大气颗粒物质量浓度实时测量方法，属于大气环境监测技术领域。The invention relates to a real-time measurement method for the mass concentration of atmospheric particulate matter, and belongs to the technical field of atmospheric environment monitoring.

背景技术Background technique

近年来，随着我国大部分地区特别是发达城市和地区的雾霾天气频繁出现，人们对空气质量越来越重视。形成灰霾天气的主要原因是大气颗粒物浓度上升，特别是PM2.5浓度的上升，引起空气质量恶化和能见度急剧下降等不利影响。灰霾天气中颗粒物的粒径大小与人体健康有着密切的关系，它决定其最终进入呼吸道的部位及沉积量。灰霾天气中的有毒、有害颗粒物散播在空气中，对人类和生态系统会造成不同程度的危害。当前，大气颗粒物的检测已成为环境、气候和健康等领域的重要内容。In recent years, with the frequent occurrence of smog in most parts of our country, especially in developed cities and regions, people pay more and more attention to air quality. The main reason for the formation of haze weather is the increase in the concentration of atmospheric particulate matter, especially the increase in the concentration of PM2.5, which causes adverse effects such as deterioration of air quality and sharp drop in visibility. The particle size of particulate matter in haze weather is closely related to human health, and it determines the location and deposition amount of particles that eventually enter the respiratory tract. Toxic and harmful particles in the haze weather are scattered in the air, causing varying degrees of harm to humans and ecosystems. At present, the detection of atmospheric particulate matter has become an important content in the fields of environment, climate and health.

目前，大气颗粒物监测的主要测量方法有：振荡天平法、Beta射线法、光散射法。振荡天平法可以直接测量颗粒物的浓度，与颗粒物粒径、颜色等无关，但是其受采样温度、湿度、振动、噪声等影响比较大，特别是采样过程中大气颗粒物中挥发性有机物损失引起测量误差较大。Beta射线法与颗粒物的种类、粒径、形状、颜色和化学组成等无关，只与粒子的质量有关，但受射线源、滤纸个体差别影响很大。另外，振荡天平法和Beta射线法都要配合PM10，PM2.5等切割器，由于切割器的误差也会造成测量结果误差。并且，振荡天平法和Beta射线法无法给出大气颗粒物各粒径的数浓度和粒径分布信息，而这两个参数都是影响人体健康的重要参数之一。光散射法是通过测量颗粒物受光照射后发出的散射光信号的强度大小来测量颗粒物的质量浓度。目前，基于光散射法的大气颗粒物计数仪较多，如德国Grimm公司的1.109、美国TSI公司的3330和美国Metone公司的3413等。光散射法测颗粒物的质量浓度主要是通过特定角度的散射光强大小来测量颗粒物光学粒径，并进一步反演颗粒物的质量浓度，激光器光强的波动、粒子的折射率和几何形状的不同均会引起测量误差。At present, the main measurement methods for monitoring atmospheric particulate matter are: oscillating balance method, Beta ray method, and light scattering method. Oscillating balance method can directly measure the concentration of particulate matter, which has nothing to do with particle size, color, etc., but it is greatly affected by sampling temperature, humidity, vibration, noise, etc., especially the measurement error caused by the loss of volatile organic compounds in atmospheric particulate matter during the sampling process larger. The Beta ray method has nothing to do with the type, particle size, shape, color and chemical composition of the particles, but only with the quality of the particles, but it is greatly affected by the individual differences of the radiation source and filter paper. In addition, the vibration balance method and the Beta ray method must be used with PM10, PM2.5 and other cutters, and the error of the cutter will also cause errors in the measurement results. Moreover, the oscillating balance method and the Beta ray method cannot give the number concentration and particle size distribution information of each particle size of atmospheric particulate matter, and these two parameters are one of the important parameters that affect human health. The light scattering method measures the mass concentration of particulate matter by measuring the intensity of the scattered light signal emitted by the particulate matter after it is irradiated by light. At present, there are many atmospheric particle counters based on the light scattering method, such as the 1.109 of the German Grimm Company, the 3330 of the American TSI Company and the 3413 of the American Metone Company. The light scattering method to measure the mass concentration of particulate matter is mainly to measure the optical particle size of the particulate matter through the intensity of scattered light at a specific angle, and to further invert the mass concentration of the particulate matter. will cause measurement errors.

发明内容Contents of the invention

本发明技术解决问题：克服上述的问题的不足，提供一种基于颗粒物飞行时间的大气颗粒物质量浓度反演方法，能实现准确、实时、在线、可连续的大气颗粒物质量浓度监测，能同时测量PM10、PM2.5、PM1的质量浓度，并给出大气颗粒物粒径分布。The technical problem of the present invention is to overcome the above-mentioned deficiencies and provide a method for retrieving the mass concentration of atmospheric particulate matter based on the flight time of particulate matter, which can realize accurate, real-time, online and continuous monitoring of the mass concentration of atmospheric particulate matter, and can simultaneously measure PM10 , PM2.5, PM1 mass concentration, and give the particle size distribution of atmospheric particles.

本发明的技术实施方案：在空气动力学粒径谱仪的基础上，一种基于颗粒物飞行时间的大气颗粒物质量浓度反演方法，实现步骤如下：Technical embodiment of the present invention: on the basis of an aerodynamic particle size spectrometer, a method for inversion of the mass concentration of atmospheric particulate matter based on the flight time of particulate matter, the implementation steps are as follows:

（1）、由空气动力学粒径谱仪可以测出颗粒物在双光斑的飞行时间，根据双光斑的距离L计算出粒子的飞行速度，公式如下：(1) The flight time of particles in the double spot can be measured by the aerodynamic particle size spectrometer, and the flight speed of the particle can be calculated according to the distance L of the double spot. The formula is as follows:

$v v = = \frac{L L}{Δt Δt} - - - - - - ((77))$

其中：v是颗粒物的飞行速度，L是双光斑的距离，Δt是颗粒物在双光斑的飞行时间。由飞行时间可以得出颗粒物的飞行速度，根据飞行速度得出颗粒物的质量。Among them: v is the flight speed of the particles, L is the distance between the double spots, and Δt is the flight time of the particles in the double spots. The flight speed of the particle can be obtained from the flight time, and the mass of the particle can be obtained according to the flight speed.

（2）、根据动量守恒定律、空气动力学和流体力学原理可以得出粒子飞行速度与单个粒子的质量的关系式，公式如下：(2) According to the law of conservation of momentum, the principles of aerodynamics and fluid mechanics, the relationship between the particle flight speed and the mass of a single particle can be obtained, the formula is as follows:

$d d {m m}_{d d} = = \frac{k k}{{C C}_{11} + + {C C}_{22} v v + + {C C}_{33} ln ln ((11 - - {C C}_{44} v v))} - - - - - - ((11))$

其中：dm_d是某一粒径单个粒子的质量，v为颗粒物的飞行速度，C₁为系统误差修正系数，C₂为颗粒物飞行速度修正系数，C₃为气体的速度，C₄为气体速度的修正系数，

L为速度测量点与喷口距离,Z为颗粒物迁移率。得出某一粒径单个颗粒物的质量可以根这一粒径颗粒物的数目经累加计算出这一粒径颗粒物的总质量。Among them: dm _d is the mass of a single particle of a certain particle size, v is the flight speed of the particle, C ₁ is the correction coefficient of the system error, C ₂ is the correction coefficient of the flight speed of the particle, C ₃ is the speed of the gas, and C ₄ is the speed of the gas The correction factor,

L is the distance between the velocity measurement point and the nozzle, and Z is the particle mobility. The mass of a single particle of a certain particle size can be obtained by accumulating the number of particles of this particle size to calculate the total mass of particles of this particle size.

（3）、根据颗粒物的粒径和数浓度信息，计算出某一粒径颗粒物的总质量，计算公式如下：(3) According to the particle size and number concentration information of the particles, calculate the total mass of particles with a certain particle size, the calculation formula is as follows:

${m m}_{d d} = = {Σ Σ}_{i i = = 00}^{N N} d d {m m}_{d d} - - - - - - ((22))$

式中，N是颗粒物粒径为d的粒子总数，dm_d是颗粒物粒径为d的单个颗粒物的质量，m_d是粒径为d所对应所有颗粒物的质量。得出某一粒径颗粒物的总质量后，根据粒径的范围计算出所有粒径对应的颗粒物总质量，把所有粒径对应颗粒物总质量相加得出粒径范围内的颗粒物总质量，最后根据采用的流量和时间得出所测颗粒物的质量浓度。In the formula, N is the total number of particles with particle size d, dm _d is the mass of a single particle with particle size d, and m _d is the mass of all particles with particle size d. After obtaining the total mass of particles of a certain particle size, calculate the total mass of particles corresponding to all particle sizes according to the range of particle sizes, add the total mass of particles corresponding to all particle sizes to obtain the total mass of particles within the particle size range, and finally The mass concentration of the measured particles is obtained according to the flow rate and time used.

（4）、由大气颗粒物粒径的范围，根据采样的流量和采样时间计算出大气颗粒物的质量浓度，计算公式如下：(4) Calculate the mass concentration of atmospheric particulate matter from the particle size range of atmospheric particulate matter according to the sampling flow rate and sampling time. The calculation formula is as follows:

$PM PM = = \frac{{Σ Σ}_{d d = = 00}^{D D.} {m m}_{d d}}{L L \cdot \cdot t t} - - - - - - ((33))$

式中，D是所测得到的大气颗粒物的最大粒径，L是采样流量，t是采样时间，PM是大气颗粒物的质量浓度。In the formula, D is the maximum particle size of the measured atmospheric particulate matter, L is the sampling flow rate, t is the sampling time, and PM is the mass concentration of atmospheric particulate matter.

（5）、采用标准气溶胶粒子发生器产生标准颗粒物。标准气溶胶粒子发生器小孔选择20μm，利用DOP溶液产生20组不同溶液浓度的标准颗粒物。(5) Use a standard aerosol particle generator to generate standard particles. The small hole of the standard aerosol particle generator is selected to be 20 μm, and the DOP solution is used to generate 20 sets of standard particles with different solution concentrations.

（6）、利用空气动力学粒谱仪测量出步骤（5）中得到的20组不同溶液浓度的标准颗粒物的飞行时间，由飞行时间根据公式（6）计算出飞行速度。计算出20组不同溶液浓度的标准颗粒物的质量，粒子质量由下式计算：(6) Use an aerodynamic particle spectrometer to measure the flight time of 20 groups of standard particles with different solution concentrations obtained in step (5), and calculate the flight speed from the flight time according to formula (6). Calculate the mass of 20 groups of standard particles with different solution concentrations, and the particle mass is calculated by the following formula:

${m m}_{p p} = = \frac{π π}{66} \cdot &Center Dot; {D D.}_{d d}^{33} \cdot &Center Dot; ρ ρ - - - - - - ((44))$

式中，ρ是DOP的粒子质量密度；D_d是液滴直径。In the formula, ρ is the particle mass density of DOP; D _d is the droplet diameter.

D_d可由下式得到：D _d can be obtained by the following formula:

${D D.}_{d d} = = {((\frac{66 QC QC}{πf πf}))}^{11 / / 33} - - - - - - ((88))$

式中Q是供液量,即液体流速，f是振动频率，C是体积浓度。In the formula, Q is the liquid supply, that is, the liquid flow rate, f is the vibration frequency, and C is the volume concentration.

（7）、把步骤（6）中得到的20组不同溶液浓度下产生的标准颗粒物的质量和飞行速度数据进行拟合，采用5次多项式拟合：(7) Fit the mass and flight speed data of the standard particles produced under 20 groups of different solution concentrations obtained in step (6), and use a 5th degree polynomial fitting:

y＝A+B₁x¹+B₂x²+B₃x³+B₄x⁴+B₅x⁵ （5）y＝A+B ₁ x ¹ +B ₂ x ² +B ₃ x ³ +B ₄ x ⁴ +B ₅ x ⁵ (5)

其中，y是单个颗粒物的质量的倒数，x是颗粒物的飞行时间，A、B₁、B₂、B₃、B₄、B₅是5次多项式拟合参数，采用最小二乘法进行线性拟合后得到参数A、B₁、B₂、B₃、B₄、B₅，并画出对应的拟合曲线。把公式（1）中的对数部分按泰勒公式展开，根据拟合出来的曲线最终确定公式（1）中C₁、C₂、C₃、C₄、k参数。公式（1）的对数部分按泰勒公式展开公式如下：Among them, y is the reciprocal of the mass of a single particle, x is the flight time of the particle, A, B ₁ , B ₂ , B ₃ , B ₄ , and B ₅ are the fitting parameters of polynomials of degree 5, and the least square method is used for linear fitting Finally, parameters A, B ₁ , B ₂ , B ₃ , B ₄ , and B ₅ are obtained, and the corresponding fitting curves are drawn. Expand the logarithmic part in formula (1) according to Taylor's formula, and finally determine the C ₁ , C ₂ , C ₃ , C ₄ , k parameters in formula (1) according to the fitted curve. The logarithmic part of formula (1) is expanded according to Taylor's formula as follows:

$\frac{11}{d d {m m}_{p p}} = = \frac{{C C}_{11} + + {C C}_{22} v v + + {C C}_{33} ln ln ((11 - - {C C}_{44} v v))}{k k}$

$= = \frac{{C C}_{11}}{k k} + + \frac{{C C}_{22} v v}{k k} + + \frac{{C C}_{33}}{k k} ((- - {C C}_{44} v v - - {C C}_{44}^{22} {v v}^{22} - -$

${C C}_{44}^{33} {v v}^{33} - - {C C}_{44}^{44} {v v}^{44} - - {C C}_{44}^{55} {v v}^{55} . . . . . . . . . . . .))$

$= = \frac{{C C}_{11}}{k k} + + \frac{{C C}_{22} - - {C C}_{33} {C C}_{44}}{k k} v v - - \frac{{C C}_{33} {C C}_{44}^{22}}{k k} {v v}^{22} - - - - - - - - ((66))$

$\frac{{C C}_{33} {C C}_{44}^{33}}{k k} {v v}^{33} - - \frac{{C C}_{33} {C C}_{44}^{55}}{k k} {v v}^{55} . . . . . . . . . . . .$

式中：dm_d是某一粒径单个粒子的质量，v为颗粒物的飞行速度，C₁为系统误差修正系数，C₂为颗粒物飞行速度修正系数，C₃为气体的速度，C₄为气体速度的修正系数，

L为速度测量点与喷口距离,Z为颗粒物迁移率。In the formula: dm _d is the mass of a single particle of a certain particle size, v is the flight speed of the particle, C ₁ is the correction coefficient of the system error, C ₂ is the correction coefficient of the flight speed of the particle, C ₃ is the speed of the gas, and C ₄ is the gas velocity Correction factor for speed,

L is the distance between the velocity measurement point and the nozzle, and Z is the particle mobility.

与现有大气颗粒物质量浓度测量技术相比，本发明的优点在于：Compared with the existing atmospheric particle mass concentration measurement technology, the present invention has the advantages of:

（1）本发明结合光散射和飞行时间原理来反演大气颗粒物质量浓度，能避免受颗粒物折射率和几何形状不同而引起的误差，从而提高大气颗粒物质量浓度的反演精度。(1) The present invention combines the principle of light scattering and time-of-flight to invert the mass concentration of atmospheric particulate matter, which can avoid errors caused by differences in the refractive index and geometric shape of particulate matter, thereby improving the inversion accuracy of the mass concentration of atmospheric particulate matter.

（2）采用本发明拟合得到的参数，无需测量双光斑距离等系统参数即可以实现颗粒物粒径的准确标定。(2) By adopting the parameters obtained by fitting in the present invention, accurate calibration of the particle size of particles can be realized without measuring system parameters such as the distance between two light spots.

（3）本发明实现大气颗粒物PM10、PM2.5、PM1的快速反演。(3) The present invention realizes rapid inversion of atmospheric particulate matter PM10, PM2.5, and PM1.

（4）本发明中的颗粒物质量浓度反演是通过测量飞行时间得到，激光器光强波动会引起散射光强变化，但不会对飞行时间测量结果产生影响，从而降低测量结果对环境变化的敏感性。(4) The inversion of the mass concentration of particulate matter in the present invention is obtained by measuring the time-of-flight. Fluctuations in laser light intensity will cause changes in scattered light intensity, but will not affect the time-of-flight measurement results, thereby reducing the sensitivity of the measurement results to environmental changes sex.

附图说明Description of drawings

图1为本发明方法的实现流程图。Fig. 1 is the realization flowchart of the method of the present invention.

具体实施方式Detailed ways

如图1所示，本发明基于颗粒物飞行时间的大气颗粒物质量浓度反演算法具体步骤如下：As shown in Figure 1, the specific steps of the atmospheric particulate mass concentration inversion algorithm based on the particulate flight time of the present invention are as follows:

第一步、由空气动力学粒径谱仪可以测出粒子在双光斑的飞行时间，根据双光斑的距离L计算出粒子的飞行速度，公式如下：In the first step, the flight time of the particles in the double spot can be measured by the aerodynamic particle size spectrometer, and the flight speed of the particle can be calculated according to the distance L of the double spot. The formula is as follows:

$v v = = \frac{L L}{Δt Δt} - - - - - - ((66))$

第二步、颗粒通过加速喷口后，在气流轨迹上的任意一点，每种粒径的颗粒物都有唯一速度u_p。根据动量定理，颗粒物中每一个颗粒物的微分动量守恒方程都可以用公式（7）来表示：In the second step, after the particles pass through the acceleration nozzle, at any point on the airflow trajectory, the particles of each particle size have a unique velocity u _p . According to the momentum theorem, the differential momentum conservation equation of each particle in the particle can be expressed by formula (7):

$\frac{d d}{dt dt} (({m m}_{p p} {u u}_{p p})) = = < < Δ Δ {m m}_{p p} {u u}_{p p} > > + + {m m}_{p p} g g - - - - - - ((99))$

其中，下标p表示颗粒物；

为气体分子碰撞给颗粒物的平均力；下标g表示携带气体；Z为颗粒物迁移率；m_pg为颗粒物自身的重力。Among them, the subscript p means particulate matter;

is the average force of the collision of gas molecules on the particle; the subscript g represents the carried gas; Z is the mobility of the particle; m _p g is the gravity of the particle itself.

因为相对于气体分子碰撞给颗粒物的平均力来说，颗粒物本身的重力很小，即重力加速度相对于气体分子碰撞带来的加速度很小，在计算过程中，可以忽略重力的影响。公式（9）简化为：Because relative to the average force of the collision of gas molecules on the particles, the gravity of the particles itself is very small, that is, the acceleration of gravity is very small compared to the acceleration brought about by the collision of gas molecules. In the calculation process, the influence of gravity can be ignored. Equation (9) simplifies to:

$\frac{d d}{dt dt} (({m m}_{p p} {u u}_{p p})) = = \frac{{u u}_{g g} - - {u u}_{p p}}{Z Z} - - - - - - ((1010))$

因为双光斑位置距离喷口很近,为了便于计算,认为Z和u_g为常数。最终得出粒子飞行速度与单个粒子的质量的关系式，公式如下：Because the position of the double spot is very close to the nozzle, Z and u _g are considered to be constant for the convenience of calculation. Finally, the relationship between the particle flight speed and the mass of a single particle is obtained, the formula is as follows:

式中：dm_d是某一粒径单个粒子的质量，v为颗粒物的飞行速度，C₁为系统误差修正系数，C₂为颗粒物飞行速度修正系数，C₃为气体的速度，C₄为气体速度的修正系数，L为速度测量点与喷口距离,Z为颗粒物迁移率。得出某一粒径单个颗粒物的质量可以根这一粒径颗粒物的数目经累加计算出这一粒径颗粒物的总质量。In the formula: dm _d is the mass of a single particle of a certain particle size, v is the flight speed of the particle, C ₁ is the correction coefficient of the system error, C ₂ is the correction coefficient of the flight speed of the particle, C ₃ is the speed of the gas, and C ₄ is the gas velocity Correction factor for speed, L is the distance between the velocity measurement point and the nozzle, and Z is the particle mobility. The mass of a single particle of a certain particle size can be obtained by accumulating the number of particles of this particle size to calculate the total mass of particles of this particle size.

第三步、根据颗粒物的粒径和数浓度信息，计算出某一粒径颗粒物的总质量，计算公式如下：The third step is to calculate the total mass of particles with a certain particle size according to the particle size and number concentration information of the particles. The calculation formula is as follows:

${m m}_{d d} = = {Σ Σ}_{i i = = 00}^{N N} d d {m m}_{d d} - - - - - - ((22))$

式中，N是颗粒物粒径为d的粒子总数，dm_d是颗粒物粒径为d的单个粒子的质量，m_d是粒径为d所对应所有粒子的质量。得出某一粒径颗粒物的总质量后，根据粒径的范围计算出所有粒径对应的颗粒物总质量，把所有粒径对应颗粒物总质量相加得出粒径范围内的颗粒物总质量，最后根据采用的流量和时间得出所测颗粒物的质量浓度。In the formula, N is the total number of particles with particle size d, dm _d is the mass of a single particle with particle size d, and m _d is the mass of all particles corresponding to particle size d. After obtaining the total mass of particles with a certain particle size, calculate the total mass of particles corresponding to all particle sizes according to the range of particle sizes, add up the total mass of particles corresponding to all particle sizes to obtain the total mass of particles within the particle size range, and finally The mass concentration of the measured particles is obtained according to the flow rate and time used.

第四步、由大气颗粒物粒径的范围，根据采样的流量和采样时间计算出大气颗粒物的质量浓度，计算公式如下：The fourth step is to calculate the mass concentration of atmospheric particulate matter from the range of atmospheric particulate matter particle size, according to the sampling flow rate and sampling time, and the calculation formula is as follows:

$PM PM = = \frac{{Σ Σ}_{d d = = 00}^{D D.} {m m}_{d d}}{L L \cdot &Center Dot; t t} - - - - - - ((33))$

式中，D是大气颗粒物的最大粒径，L是采样流量，t是采样时间，PM是大气颗粒物的质量浓度。In the formula, D is the maximum particle size of atmospheric particulate matter, L is the sampling flow rate, t is the sampling time, and PM is the mass concentration of atmospheric particulate matter.

第五步、采用标准气溶胶粒子发生器产生标准颗粒物。小孔选择20μm，利用DOP溶液产生20组不同溶液浓度的标准颗粒物。The fifth step is to use a standard aerosol particle generator to generate standard particles. The small hole is selected to be 20 μm, and the DOP solution is used to generate 20 groups of standard particles with different solution concentrations.

第六步、利用空气动力学粒谱仪测量出第五步所述中得到的20组不同溶液浓度的标准颗粒物的飞行时间，由飞行时间根据公式（6）计算出飞行速度。计算出20组不同溶液浓度的标准颗粒物的质量，粒子质量由下式计算：The sixth step is to use the aerodynamic particle spectrometer to measure the flight time of the 20 groups of standard particles with different solution concentrations obtained in the fifth step, and calculate the flight speed according to the formula (6) from the flight time. Calculate the mass of 20 groups of standard particles with different solution concentrations, and the particle mass is calculated by the following formula:

${m m}_{p p} = = \frac{π π}{66} \cdot \cdot {D D.}_{d d}^{33} \cdot \cdot ρ ρ - - - - - - ((44))$

D_d可由下式得到：D _d can be obtained by the following formula:

第七步、把第六步得出的20组不同溶液浓度下产生的标准颗粒物的质量和飞行速度数据进行拟合，采用5次多项式拟合：The seventh step, the mass and flight speed data of the standard particles produced under the 20 groups of different solution concentrations obtained in the sixth step are fitted, and the 5th degree polynomial fitting is adopted:

其中，y是单个颗粒物的质量的倒数，x是颗粒物的飞行时间，A、B₁、B₂、B₃、B₄、B₅是5次多项式拟合参数，采用最小二乘法进行线性拟合后得到参数A、B₁、B₂、B₃、B₄、B₅，并画出对应的拟合曲线，把公式（1）中的对数部分按泰勒公式展开，得到公式（9），根据拟合出来的参数最终确定公式（1）中C₁、C₂、C₃、C₄、k参数。Among them, y is the reciprocal of the mass of a single particle, x is the flight time of the particle, A, B ₁ , B ₂ , B ₃ , B ₄ , and B ₅ are the fitting parameters of polynomials of degree 5, and the least square method is used for linear fitting After obtaining the parameters A, B ₁ , B ₂ , B ₃ , B ₄ , B ₅ , and draw the corresponding fitting curve, expand the logarithmic part in formula (1) according to Taylor's formula, and obtain formula (9), The C ₁ , C ₂ , C ₃ , C ₄ , and k parameters in formula (1) are finally determined according to the fitted parameters.

$= = \frac{{C C}_{11}}{k k} + + \frac{{C C}_{22} - - {C C}_{33} {C C}_{44}}{k k} v v - - \frac{{C C}_{33} {C C}_{44}^{22}}{k k} {v v}^{22} - - - - - - - - ((99))$

y＝A+B₁x¹+B₂x²+B₃x³+B₄x⁴+B₅x⁵公式所有符号的物理含义；y=A+B ₁ x ¹ +B ₂ x ² +B ₃ x ³ +B ₄ x ⁴ +B ₅ x ⁵ The physical meaning of all symbols in the formula;

第八步、根据测得到的大气颗粒物飞行时间，把飞行时间转换成飞行速度，最终由计算机经上述步骤反演出大气颗粒物的质量浓度。The eighth step is to convert the flight time into flight speed according to the measured flight time of the atmospheric particles, and finally the mass concentration of the atmospheric particles is inverted by the computer through the above steps.

本发明未详细阐述部分属于本领域公知技术。Parts not described in detail in the present invention belong to the well-known technology in the art.

以上所述，仅为本发明部分具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本领域的人员在本发明揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本发明的保护范围之内。The above are only some specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. Atmospheric particulates mass concentration inversion method based on the particle flight time is characterized in that performing step is as follows:

(1) data message that measures by the aerodynamic size spectrometer draws the relational expression of the quality of particle flying speed and single particle according to the law of conservation of momentum, aerodynamics and fluid mechanics principle, and formula is as follows:

d m_{d} = \frac{k}{C_{1} + C_{2} v + C_{3} \ln (1 - C_{4} v)} - - - (1)

In the formula, C ₁Be systematic error correction factor, C ₂Be particle flying speed correction factor, C ₃Be the speed of gas, C ₄Be the correction factor of gas velocity,

L is velocity survey point and jet opening distance, and Z is the particle mobility, and v is the flying speed of particle, dm _dIt is the quality of a certain particle diameter individual particle thing; The number that draws this particle diameter particle of quality root of a certain particle diameter individual particle thing goes out the gross mass of this particle diameter particle through accumulation calculating;

(2) according to particle diameter and the number concentration information of particle, calculate the gross mass of a certain particle diameter particle, computing formula is as follows:

m_{d} = Σ_{i = 0}^{N} d m_{d} - - - (2)

In the formula, N is that the particle particle diameter is the particle sum of d, dm _dBe that the particle particle diameter is the quality of the corresponding individual particle thing of d, m _dBe that particle diameter is the gross mass of the corresponding particle of d; After drawing the gross mass of a certain particle diameter particle, go out the particle gross mass of all particle diameter correspondences according to the range computation of particle diameter, the additions of the corresponding particle gross mass of all particle diameters are drawn particle gross mass in the particle size range, at last the mass concentration that draws the particle of surveying according to the flow that adopts and time;

(3) by measured Atmospheric particulates particle size range, according to flow and the sampling time mass concentration that calculates Atmospheric particulates of sampling, computing formula is as follows:

PM = \frac{Σ_{d = 0}^{D} m_{d}}{L \cdot t} - - - (3)

In the formula, D is maximum particle diameter in the measured Atmospheric particulates, and L is sampling flow, and t is the sampling time, and PM is the mass concentration of Atmospheric particulates.

2. according to claims 1 described a kind of Atmospheric particulates mass concentration inversion method based on the particle flight time, it is characterized in that: the system calibrating coefficient method of described step (1) is as follows:

(11) produce the standard particle thing with standard aerosol particle electronic generator, the aperture of standard aerosol particle electronic generator is selected 20 μ m, utilizes DOP solution to produce the standard particle thing of 20 groups of different solutions concentration;

(12) utilize the aerodynamic size spectrometer to measure the flight time of the standard particle thing of the described 20 groups of different solutions concentration that obtain of step (11), calculate flying speed by the flight time, calculate the quality of the standard particle thing of 20 groups of different solutions concentration that obtain described in the step (11), mass particle is calculated by following formula:

m_{p} = \frac{π}{6} \cdot {D_{d}}^{3} \cdot ρ - - - (4)

In the formula, ρ is the mass particle density of DOP; D _dIt is liquid-drop diameter;

(13) quality and the flying speed of the standard particle thing that produces under 20 groups of different solutions concentration that obtain described in the step (12) are carried out match, adopt 5 order polynomial matches:

y＝A+B ₁x ¹+B ₂x ²+B ₃x ³+B ₄x ⁴+B ₅x ⁵ （5）

Wherein, y is the inverse of the quality of individual particle thing, and x is the flight time of particle, A, B ₁, B ₂, B ₃, B ₄, B ₅Be 5 order polynomial fitting parameters, adopt least square method to carry out obtaining parameter A, B behind the linear fit ₁, B ₂, B ₃, B ₄, B ₅, and provide corresponding matched curve, formula (1) fractional part is launched by Taylor's formula, finally determine C in the formula (1) according to the parameter that match is come out ₁, C ₂, C ₃, C ₄, the k parameter; Formula (1) to fractional part by the Taylor's formula expansion formula as follows:

\frac{1}{d m_{p}} = \frac{C_{1} + C_{2} v + C_{3} \ln (1 - C_{4} v)}{k}

= \frac{C_{1}}{k} + \frac{C_{2} v}{k} + \frac{C_{3}}{k} (- C_{4} v - {C_{4}}^{2} v^{2} -

{C_{4}}^{3} v^{3} - {C_{4}}^{4} v^{4} - {C_{4}}^{5} v^{5} . . . . . .)

= \frac{C_{1}}{k} + \frac{C_{2} - C_{3} C_{4}}{k} v - \frac{C_{3} {C_{4}}^{2}}{k} v^{2} - - - - (6)

\frac{C_{3} {C_{4}}^{3}}{k} v^{3} - \frac{C_{3} {C_{4}}^{5}}{k} v^{5} . . . . . .

In the formula: dm _dBe the quality of a certain particle diameter single particle, v is the flying speed of particle, C ₁Be systematic error correction factor, C ₂Be particle flying speed correction factor, C ₃Be the speed of gas, C ₄Be the correction factor of gas velocity,

L is velocity survey point and jet opening distance, and Z is the particle mobility.