Organic aerosol source analysis method and system based on online observation of organic molecular marker

Abstract

The invention belongs to the technical field of air quality management, and discloses an organic aerosol source analysis method based on online observation of an organic molecular marker. According to the method for realizing high-time-resolution on-line real-time observation and measurement of the concentration of the organic aerosol molecular marker, on the basis of original PM2.5 conventional component concentration data, concentration data of the organic aerosol organic molecular marker, which has high recognition degree and is obtained based on high-time-resolution on-line real-time observation, is added. According to the method, accurate identification and scientific and quantitative source analysis of the source of the atmospheric organic aerosol can be realized, a more scientific, accurate and rich quantitative source analysis result is obtained, more scientific and accurate prevention and control suggestions are provided for atmospheric environment quality management, and important scientific and technological support is provided for atmospheric environment quality management of government departments.

Description

Technical Field

[0001] The present invention belongs to the technical field of air quality management, and in particular relates to an organic aerosol source analysis method and system based on online observation of organic molecular markers. Background Art

[0002] Air pollution source analysis is an important prerequisite for quantitatively identifying the sources of air pollutants and proposing targeted air pollution prevention and control plans. 2.5 Source apportionment methods usually include the PMF (Positive Matrix Factorization) receptor model method based on water-soluble inorganic ions, inorganic elements or large categories of organic matter, as well as the emission inventory method and source diffusion model method. However, none of the existing source apportionment methods (including the PMF receptor model) can accurately apportion the source of organic aerosols to the level of refined information of a single compound, and there is a lack of source apportionment of organic aerosol concentrations with multiple types and high temporal resolution. This has, to a certain extent, limited people's understanding of the sources of atmospheric organic aerosols and further hindered the government's scientific and precise development of air pollution prevention and control.

[0003] With the continuous deepening of air pollution prevention and control work, the PM 2.5 The demand for refined, real-time online source analysis of organic aerosols, which are important components of air pollution, is becoming more and more urgent. The concentration data of organic molecular markers in organic aerosols measured online with high time resolution rate can be used to improve the scientificity and accuracy of organic aerosol source analysis and achieve accurate source tracing, which can provide a more scientific and accurate basis for air pollution prevention and control and air quality management.

[0004] Through the above analysis, the problems and defects of existing source analysis technology are as follows:

[0005] (1) Existing organic aerosol source analysis technologies lack the ability to use quantitative organic aerosol single compound concentration data as input to participate in the receptor model source analysis of atmospheric pollutants.

[0006] (2) Existing source analysis technologies lack online real-time observation of concentration information of organic molecular markers of organic aerosols, including multiple types of aerosol organic compounds and high time resolution.

[0007] The difficulty in solving the above technical problems and defects is that there are many types of organic aerosols, and organic aerosols continue to undergo chemical reactions in the atmosphere, which makes it difficult for general instruments and technologies to capture accurate measurement information at the molecular level of organic aerosols. This is also a common difficulty internationally. In addition, the existing PM 2.5The source analysis technology of organic aerosol lacks high-resolution real-time measurement of the concentration information of organic molecules in organic aerosol, which makes it impossible to accurately analyze the source of organic aerosol. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides an organic aerosol source analysis method and system based on online observation of organic molecular markers.

[0009] The present invention is implemented as follows: a method for organic aerosol source analysis based on online observation of organic molecular markers comprises:

[0010] Step 1, constructing an organic aerosol high time resolution online monitoring system device including a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head;

[0011] Step 2, preparing the solvents, internal standard solutions, external standard solutions and derivatization reagents required for qualitative and quantitative determination of various organic molecular markers;

[0012] Step 3, performing hourly resolution continuous online observation of the target organic molecular markers based on thermal desorption aerosol gas chromatography-mass spectrometry;

[0013] Step 4: Analyze and process the online hourly observation data of organic molecular marker concentrations, and combine them with PM 2.5 The conventional component concentration data are used to obtain the source analysis results of organic aerosols through the PMF receptor model.

[0014] Furthermore, an in-situ instrument with high time resolution for hours that can measure specific organic molecules is built, namely an organic aerosol online monitoring system including a thermal desorption aerosol chromatography-mass spectrometry system and a high-purity helium output device. The connection methods of the high time resolution online observation instrument include ventilation / liquid pipeline connection and control line connection.

[0015] Furthermore, the concentrations of various organic molecular markers are measured with high time resolution for hours. These organic molecules include sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes, and secondary organic aerosol tracers. Specific organic molecular markers include but are not limited to n-19-n-triacontane, αβ-hopane, αβ-norhopane, 17α(H)-22,29,30-trinorhopane, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, 1,2-benzo[A]anthracene, (1,2,5,6-dibenzonaphthalene), benzo(B)fluoranthene, benzo(K)fluoranthene, benzo(a)pyrene, dibenzo[ah]anthracene, benzo(G,H,I)perylene, indeno(1,2,3-CD)pyrene, cholesterol, oleic acid / octadecenoic acid, hexadecanoic acid / palmitic acid / palmitic acid, octadecanoic acid / stearic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, L- 61 substances including dextran, mannitol, sucrose, mannan, D-anhydrous glucose, glycerol (propylene glycol), terephthalic acid, phthalic acid, isophthalic acid, syringic acid, 4-hydroxybenzoic acid, 3-trihydroxybenzoic acid, malic acid, tartaric acid, 2-methylglyceric acid, 3-methyl-1,2,3-butyltricarboxylic acid, 2,3-dihydroxy-4-oxopentanoic acid, pinic acid, and pinonic acid.

[0016] Furthermore, the concentration data obtained by real-time online observation and analysis of organic molecular markers with high time resolution is compared with PM 2.5 Conventional component concentration data are integrated and used as input data for PMF receptor model simulation to obtain accurate and scientific source analysis results of atmospheric organic aerosol.

[0017] Furthermore, the step 1 constructs an organic aerosol online monitoring system device which mainly includes a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head, and the connection methods include ventilation / liquid pipeline connection and control line connection.

[0018] Furthermore, the various organic molecular markers for qualitative and quantitative analysis in step 2 are sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes, and secondary organic aerosols;

[0019] The solvent required for the preparation of qualitative and quantitative organic molecular markers is a mixture of acetonitrile and dichloromethane in a volume ratio of 1:4;

[0020] Dilute the high concentration sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes and secondary organic aerosol tracer internal standard reagents, usually to about 500-1000 ppm;

[0021] Dissolve or dilute high concentration sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes, and secondary organic aerosol markers to the required mass concentration;

[0022] The derivatization reagent required for preparing qualitative and quantitative organic molecular markers is N-methyl-N-(trimethylsilyl) trifluoroacetamide.

[0023] The step 3 includes collecting ambient air particulate matter samples into a thermal desorption aerosol gas chromatography-mass spectrometer through a cyclone separator with cutting heads of different particle sizes; effectively removing gas phase compounds through a multi-channel carbon remover to determine the separation of the gas phase and the particle phase; collecting the ambient air samples into a thermal desorption chamber through humidification and inertial collision methods; transferring the samples to a gas chromatography column with helium after thermal desorption; and detecting with a quadrupole mass spectrometer and a flame ionization detector to obtain initial observation data.

[0024] The step 4 includes converting the initial data format into a cdf format using GC / MS converter software; processing the cdf format file using IgorPro software to obtain the sample peak area; establishing a calibration curve using an internal standard method; importing the sample peak area data obtained by actual observation into the calibration curve to obtain the molecular marker concentration data;

[0025] The cdf format file was processed by IgorPro software to solve the integral and obtain the sample peak area;

[0026] The method of establishing a calibration curve by using the internal standard method is to analyze and process different amounts of external standard solutions and a quantitative internal standard solution to obtain a calibration curve;

[0027] Different amounts of external standard solution are divided by the volume multiples of the external standard solution, such as 1 μl, 2 μl, 3 μl, etc.;

[0028] Combine organic aerosol measurements and hourly concentration data of molecular markers with other PM 2.5 The conventional component concentration data are used as input data, and the PMF receptor model is used to perform source analysis of organic aerosols at the observation site.

[0029] Another object of the present invention is to provide an organic aerosol source analysis system based on online observation of organic molecular markers, comprising:

[0030] Building modules for building an organic aerosol high time resolution online monitoring system device, which mainly includes a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head;

[0031] Preparation module, used to prepare solvents, internal standard solutions, external standard solutions and derivatization reagents required for qualitative and quantitative analysis of various organic molecular markers;

[0032] An observation module is used to continuously observe the target organic molecular markers online with hourly resolution based on a thermal desorption aerosol gas chromatography-mass spectrometry;

[0033] The analysis and processing module is used to analyze and process the online hourly observation data of organic molecular marker concentrations, combined with PM 2.5The conventional component concentration data are used to obtain the source analysis results of organic aerosols through the PMF receptor model.

[0034] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0035] First, the present invention uses the latest internationally advanced thermal desorption aerosol gas chromatography-mass spectrometry instrument for high-resolution online real-time concentration observation of aerosol organic molecular markers, and realizes high-time resolution online real-time observation and measurement of the concentration of organic aerosol molecular markers. Then, on the basis of the original water-soluble inorganic ions, inorganic elements and other substances, by adding the concentration data of organic aerosol organic molecular markers with high recognition based on high-time resolution online real-time observation, the PMF receptor model is used to analyze the source of organic aerosol, and more scientific, accurate and rich quantitative source analysis results are obtained, which puts forward more scientific and accurate prevention and control suggestions for atmospheric environmental quality management.

[0036] The present invention provides a method for establishing an organic aerosol source analysis method based on high time resolution online observation of organic molecular markers. By adopting the most advanced thermal desorption aerosol gas chromatography-mass spectrometry newly developed in the world, a method for high time resolution online real-time observation and measurement of organic aerosol molecular marker concentration is realized. 2.5 On the basis of the conventional component concentration data, the concentration data of organic aerosol organic molecule markers with high recognition obtained based on high time resolution online real-time observation are added, and the PMF receptor model is used to realize the method of accurate and scientific source analysis of organic aerosol. The present invention can realize the accurate identification of the source of atmospheric organic aerosol, scientific and quantitative source analysis, and obtain more scientific, accurate and rich quantitative source analysis results, which can put forward more scientific and accurate prevention and control suggestions for atmospheric environmental quality management, and provide important scientific and technological support for atmospheric environmental quality management of government departments.

[0037] Second, the technical solution of the present invention mainly improves the problems existing in the organic aerosol source analysis process in the prior art, and has achieved significant technical progress, which is specifically reflected in the following aspects:

[0038] Technical problems existing in the existing technology:

[0039] Traditional organic aerosol source analysis methods usually rely on offline sampling and laboratory analysis. These methods have problems such as low time resolution (resolution in days), data lag, and complex operation, making it difficult to capture the dynamic information of organic aerosols that change rapidly in the environment. In addition, online measurements can be performed through aerosol mass spectrometers (AMS) to obtain organic aerosol data and then perform source analysis, but their organic aerosol concentration data are based on a mixture of large categories of substances, such as (aerosols related to biomass combustion, aerosols related to coal burning, etc.), rather than at the molecular level, and cannot be qualitatively and quantitatively analyzed for organic molecular markers (molecular level), affecting the accuracy of source analysis results. At the same time, existing monitoring technologies are often unable to monitor organic aerosol molecular markers at the molecular level in real time and analyze the sources of organic aerosols, and lack effective identification of the complex organic aerosol components in complex atmospheric environments.

[0040] Significant progress in technical solutions:

[0041] 1. The present invention significantly improves the timeliness and accuracy of organic aerosol source analysis by introducing a high-time resolution online monitoring system. The system uses a thermal desorption organic aerosol gas chromatography-mass spectrometer to achieve continuous hourly resolution online observation of molecular markers of organic aerosols and capture the dynamic changes in organic aerosol concentrations. This high-time resolution monitoring method avoids the lag of traditional offline analysis, ensures the real-time and continuity of data, and greatly improves the accuracy of source analysis.

[0042] 2. By optimizing the preparation method of qualitative and quantitative reagents, including internal standard solution, external standard solution and derivatization reagent, the present invention enhances the detection sensitivity and resolution of organic molecular markers. The application of internal and external standards not only corrects the errors in the analysis process, but also ensures the accuracy of quantitative analysis through the establishment of standard curves. The use of derivatization reagents improves the detection performance of markers in gas chromatography-mass spectrometry, so that trace components in complex sample matrices can also be accurately identified and quantified.

[0043] 3. The present invention utilizes the PMF (positive matrix factorization) receptor model, combined with PM 2.5 Conventional component concentration data is used to analyze the source of organic aerosols. This method can accurately identify pollution sources and quantify their contribution rates through multi-dimensional analysis of data. Compared with traditional methods, this method improves the reliability and scientificity of source analysis under complex environmental conditions, providing a more accurate basis for environmental monitoring and pollution control.

[0044] In summary, the technical solution of the present invention effectively solves the problems in the prior art such as low online monitoring accuracy, difficulty in obtaining molecular-level organic aerosol source information, poor time resolution, and inaccurate organic aerosol source analysis, and significantly improves the efficiency and accuracy of organic aerosol source analysis, providing important technological progress for research and application in the field of environmental science. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flow chart of an organic aerosol source analysis method based on online observation of organic molecular markers provided in an embodiment of the present invention.

[0046] Figure 2 It is a structural block diagram of an organic aerosol source analysis system based on online observation of organic molecular markers provided in an embodiment of the present invention.

[0047] Figure 3 It is a detailed flow chart of a method for establishing source analysis of organic aerosols based on molecular marker measurement provided by an embodiment of the present invention.

[0048] Figure 4 This is a geographical area map of Zibo City provided by an embodiment of the present invention.

[0049] Figure 5 It is a device diagram and a flow chart provided by an embodiment of the present invention.

[0050] Figure 6 is the atmospheric PM in Zibo during the observation period provided by the embodiment of the present invention. 2.5 The percentage of organic aerosol concentration in the air.

[0051] Figure 7 is the atmospheric PM in Zibo during the observation period provided by the embodiment of the present invention. 2.5 Time series of organic aerosol concentration in the atmosphere.

[0052] Figure 8 is the atmospheric PM in Zibo during the observation period provided by the embodiment of the present invention. 2.5 Source analysis situation diagram.

[0053] Fig. 9 is the atmospheric PM in Zibo during the observation period provided by the embodiment of the present invention. 2.5 Source parsing contribution graph. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0055] Example 1: Source analysis of organic aerosols in urban environments

[0056] In a certain urban environment, air pollution is becoming increasingly serious. Organic aerosols as PM 2.5 Organic aerosols are an important component of air pollution, and their sources are complex and diverse. In order to effectively control and manage air pollution, it is necessary to accurately analyze the sources of organic aerosols.

[0057] 1) Build an online monitoring system: Establish an online monitoring system for organic aerosols with high time resolution in the city center. The system includes a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head. The monitoring system is connected through pipelines and control lines to collect air samples in the urban environment in real time.

[0058] 2) Prepare reagents: According to the requirements of the system, prepare the solvent (acetonitrile and dichloromethane mixture), internal standard solution and derivatization reagent (N-methyl-N-(trimethylsilyl) trifluoroacetamide) for qualitative and quantitative analysis. Dilute high-concentration organic molecular markers (such as normal alkanes, polycyclic aromatic hydrocarbons, fatty acids, etc.) to prepare a 500-1000 ppm standard solution.

[0059] 3) Online observation: The particulate matter samples in the urban air are collected by cyclone separators, and the thermal desorption aerosol gas chromatography-mass spectrometry is used for continuous observation with hourly resolution. The gas phase compounds are removed by a multi-channel carbon remover to ensure the accuracy of the particle phase samples.

[0060] 4) Data analysis and source apportionment: IgorPro software was used to process the observed data, extract the peak area of ​​the molecular markers, establish the calibration curve using the internal standard method, and calculate the concentration of each molecular marker. 2.5 Conventional component data, using the PMF receptor model to analyze the sources of organic aerosol in urban environments. The results show that the main sources include motor vehicle exhaust emissions, industrial emissions, and biomass burning.

[0061] Effect: Through the method of this embodiment, the main sources of organic aerosols in the urban environment can be accurately analyzed, providing a scientific basis for the control and treatment of urban air pollution.

[0062] Example 2: Source analysis of organic aerosols in industrial environments

[0063] In a certain industrial area, due to intensive industrial activities, the concentration of organic aerosols in the air is high and its sources are complex, so detailed source analysis is needed to determine the main sources of pollution.

[0064] 1) Build an online monitoring system: Install an organic aerosol high time resolution online monitoring system in the industrial zone. The system includes a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device and a sampling head. The system is connected through ventilation pipes and control lines to achieve continuous online monitoring of air samples in the industrial zone.

[0065] 2) Reagent preparation: Based on the characteristics of air samples in industrial areas, suitable solvents, internal standard solutions and derivatization reagents are prepared for qualitative and quantitative analysis. High-concentration organic molecular markers such as aromatic acids, dibasic acids, fatty acids, etc. are diluted and prepared into standard solutions to ensure that these markers can be accurately detected in high-concentration industrial pollution environments.

[0066] 3) Online observation: The monitoring system continuously collects particulate matter samples from industrial areas and conducts online observation of organic molecular markers in these samples with hourly resolution. After thermal desorption, the samples are sent into a gas chromatography-mass spectrometer with helium for analysis.

[0067] 4) Data processing and source analysis: Use Igor Pro software to process the obtained cdf format data, establish an internal standard calibration curve, and calculate the concentration of molecular markers. 2.5 The conventional component concentration data were combined with the PMF receptor model to analyze the sources of organic aerosol in industrial areas. The analysis results showed that the main sources were petrochemical industry emissions, coal combustion emissions and motor vehicle exhaust emissions.

[0068] This embodiment can successfully identify the main pollution sources of organic aerosols in industrial areas, providing data support and decision-making basis for subsequent pollution control measures.

[0069] like Figure 1 As shown, an organic aerosol source analysis method based on online observation of organic molecular markers provided by an embodiment of the present invention comprises the following steps:

[0070] S101, build an organic aerosol high time resolution online monitoring system including a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device and a sampling head;

[0071] S102, preparing solvents, internal standard solutions, external standard solutions and derivatization reagents required for qualitative and quantitative analysis of various organic molecular markers;

[0072] S103, based on thermal desorption aerosol gas chromatography-mass spectrometry, continuous online observation of target organic molecular markers with hourly resolution;

[0073] S104, analyzes and processes the online hourly observation data of organic molecule marker concentration, and combines PM 2.5The conventional component concentration data are used to obtain the source analysis results of organic aerosols through the PMF receptor model.

[0074] The organic aerosol source analysis method based on online observation of organic molecular markers provided in the embodiment of the present invention aims to accurately analyze the source of organic aerosol and its changes in the environment through an online monitoring system with high time resolution. The method comprehensively utilizes advanced gas chromatography-mass spectrometry technology and receptor model analysis to ensure accurate analysis of complex organic aerosol sources.

[0075] 1. Construction of high time resolution online monitoring system

[0076] First, an online monitoring system with high time resolution is built. The system mainly consists of a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device and a sampling head. The thermal desorption device is used to separate organic molecular markers from the collected aerosol samples and introduce them into the gas chromatography-mass spectrometer for analysis. High-purity helium is used as a carrier gas to ensure that the markers are well separated in the gas chromatography column. The sampling head is responsible for continuously collecting aerosol samples from the environment to ensure that the monitoring system can capture the changes in organic aerosols in the air in real time.

[0077] 2. Preparation of reagents for qualitative and quantitative analysis

[0078] In order to accurately identify and quantify various organic molecular markers during the monitoring process, a series of reagents required for analysis need to be prepared, including solvents for qualitative analysis, internal standard solutions and external standard solutions for quantitative analysis, and reagents for chemical derivatization. The internal standard solution helps to correct instrument drift or loss during the analysis, and the external standard solution is used to establish a standard curve for marker concentration. Derivatization reagents modify markers through chemical reactions to enhance their detection sensitivity and resolution in gas chromatography-mass spectrometry, thereby ensuring the accuracy of the analysis.

[0079] 3. Online hourly resolution observation

[0080] Online observation of organic aerosols is carried out by gas chromatography-mass spectrometry, with continuous monitoring in hours. Through the thermal desorption device, the organic molecular markers in the collected aerosol samples are heated and decomposed and converted into gaseous state, then enter the gas chromatography for separation, and finally detected and quantitatively analyzed in the mass spectrometer. This high-time resolution monitoring method can accurately capture the dynamic changes in organic aerosol concentrations, provide continuous and detailed observation data, and lay a data foundation for subsequent source analysis.

[0081] 4. Data Analysis and Source Analysis

[0082] Finally, the organic molecular marker concentration data obtained by online monitoring were analyzed and combined with PM 2.5The concentration data of conventional components are analyzed by using the PMF (Positive Matrix Factorization) receptor model for source apportionment. 2.5 The correlation of concentration changes can decompose multiple potential pollution sources and their contribution rates, thereby identifying the main sources of organic aerosols. This analysis result not only helps to understand the source of pollutants, but also provides a scientific basis for the formulation of environmental management and pollution control measures.

[0083] The embodiment of the present invention provides an organic aerosol online monitoring system device for building an in-situ instrument with high time resolution for hours that can measure specific organic molecules, namely a thermal desorption aerosol chromatography-mass spectrometry system, and a high-purity helium output device. The connection method of the high time resolution online observation instrument includes ventilation / liquid pipeline connection and control line connection.

[0084] The embodiment of the present invention provides hourly high time resolution measurement of the concentrations of various organic molecular markers. These organic molecules include sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes, and secondary organic aerosol tracers. Specific organic molecular markers include but are not limited to n-19-n-triacontane, αβ-hopane, αβ-norhopane, 17α(H)-22,29,30-trinorhopane, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, 1,2-benzo[A]anthracene, (1,2,5,6-dibenzonaphthalene), benzo(B)fluoranthene, benzo(K)fluoranthene, benzo(a)pyrene, dibenzo[ah]anthracene, benzo(G,H,I)perylene, indeno(1,2,3-CD)pyrene, cholesterol, oleic acid / octadecenoic acid, hexadecanoic acid / palmitic acid / palmitic acid, octadecanoic acid / stearic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, L- 61 substances including dextran, mannitol, sucrose, mannan, D-anhydrous glucose, glycerol (propylene glycol), terephthalic acid, phthalic acid, isophthalic acid, syringic acid, 4-hydroxybenzoic acid, 3-trihydroxybenzoic acid, malic acid, tartaric acid, 2-methylglyceric acid, 3-methyl-1,2,3-butyltricarboxylic acid, 2,3-dihydroxy-4-oxopentanoic acid, pinic acid, and pinonic acid.

[0085] The embodiment of the present invention provides a method for analyzing the concentration data obtained by real-time online observation and analysis of organic molecular markers with high time resolution, and PM 2.5 Conventional component concentration data are integrated and used as input data for PMF receptor model simulation to obtain accurate and scientific source analysis results of atmospheric organic aerosol.

[0086] The construction of S101 provided in the embodiment of the present invention mainly includes an organic aerosol online monitoring system device including a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head, and the connection method includes a ventilation / liquid pipeline connection and a control line connection.

[0087] The various qualitative and quantitative organic molecular markers provided by the embodiments of the present invention are sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes, and secondary organic aerosols;

[0088] The solvent required for the preparation of qualitative and quantitative organic molecular markers is a mixture of acetonitrile and dichloromethane in a volume ratio of 1:4;

[0089] Dilute the high concentration sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes and secondary organic aerosol tracer internal standard reagents, usually to about 500-1000 ppm;

[0090] Dissolve or dilute high concentration sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes, and secondary organic aerosol markers to the required mass concentration;

[0091] The derivatization reagent required for preparing qualitative and quantitative organic molecular markers is N-methyl-N-(trimethylsilyl) trifluoroacetamide.

[0092] S103 provided in an embodiment of the present invention includes collecting ambient air particulate samples into a thermal desorption aerosol gas chromatography-mass spectrometer through a cyclone separator with cutting heads of different particle sizes; effectively removing gas phase compounds through a multi-channel carbon remover to determine the separation of the gas phase and the particle phase; collecting ambient air samples into a thermal desorption chamber through humidification and inertial collision methods; transferring the samples to a gas chromatography column with helium after thermal desorption; and detecting with a quadrupole mass spectrometer and a flame ionization detector to obtain initial observation data.

[0093] S104 provided in the embodiment of the present invention includes using GC / MS converter software to convert the initial data format into a subsequently processable data format (cdf format); using software (IgorPro) to process the cdf format file to obtain the sample peak area; using the internal standard method to establish a calibration curve; importing the sample peak area data actually observed into the calibration curve to obtain the molecular marker concentration data;

[0094] The cdf format file was processed by IgorPro software to solve the integral and obtain the sample peak area;

[0095] The method of establishing a calibration curve by using the internal standard method is to analyze and process different amounts of external standard solutions and a quantitative internal standard solution to obtain a calibration curve;

[0096] Different amounts of external standard solution are divided by the volume multiples of the external standard solution, such as 1 μl, 2 μl, 3 μl, etc.;

[0097] Combine organic aerosol measurements and hourly concentration data of molecular markers with other PM 2.5 The conventional component concentration data are used as input data, and the PMF receptor model is used to perform source analysis of organic aerosols at the observation site.

[0098] like Figure 2 As shown, an organic aerosol source analysis system based on online observation of organic molecular markers provided by an embodiment of the present invention includes:

[0099] Building modules for building an organic aerosol high time resolution online monitoring system device, which mainly includes a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head;

[0100] Preparation module, used to prepare solvents, internal standard solutions, external standard solutions and derivatization reagents required for qualitative and quantitative analysis of various organic molecular markers;

[0101] An observation module is used to continuously observe the target organic molecular markers online with hourly resolution based on a thermal desorption aerosol gas chromatography-mass spectrometry;

[0102] The analysis and processing module is used to analyze and process the online hourly observation data of organic molecular marker concentrations, combined with PM 2.5 The conventional component concentration data are used to obtain the source analysis results of organic aerosols through the PMF receptor model.

[0103] like Figure 3 As shown, the present invention provides a detailed method for establishing source apportionment of organic aerosol based on molecular marker measurement, including:

[0104] 1) According to the needs of air pollution prevention and control, select observation points and build an organic aerosol online monitoring system including a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head;

[0105] 2) Prepare the solvents, internal standard solutions, external standard solutions and derivatization reagents required for qualitative and quantitative determination of various organic molecular markers, mainly by directly purchasing high-concentration organic substances and diluting organic substances;

[0106] 3) Based on the surrounding environment of the observation point and the requirements for observing pollutants, continuous online observation of the target organic molecular markers with hourly resolution is performed;

[0107] 4) Using GC / MS software and IgorPro and other software, combined with the calibration curve obtained by the internal standard method, the online observation data of organic molecular markers are processed for concentration;

[0108] 5) Based on the processing results of organic molecular marker concentrations and the concentration data of other substances in the monitoring area, the PMF source analysis method is used to obtain source analysis results. According to the contribution of various pollution sources, references and suggestions are provided for the local atmospheric environmental pollution prevention and control plan.

[0109] The present invention provides a method for source analysis of organic aerosols based on molecular marker measurement. Ordinary technicians in the industry can also use other steps to implement it. Figure 3 It is only a specific embodiment provided by the present invention.

[0110] The present invention is further described below in conjunction with implementation examples.

[0111] Embodiment 3:

[0112] Establish a source apportionment method for organic aerosol based on the measurement of organic molecular markers at the Zibo Atmospheric Environment Comprehensive Observation and Research Station from November 2022 to February 2023

[0113] 1. Selection of research area and preparation of data

[0114] Select the atmospheric environment observation and research stations in Zibo City, Shandong Province as follows Figure 4 Atmospheric PM was obtained from the Zibo Atmospheric Environment Observation and Research Station. 2.5 Hourly concentration data as well as concentration data for gaseous pollutants, inorganic ions and elemental substances. Figure 4 This is the geographical location map of the atmospheric environment observation and research station in Zibo City, Shandong Province.

[0115] (II) Technical methods used in this implementation case

[0116] 1) Thermal desorption aerosol gas chromatography-mass spectrometry online monitoring technology

[0117] The sampling head is with PM 2.5The cyclone separator of the cutting head, the particulate sample is collected into the TAG-GC / MS system pipeline at a flow rate of 5-10L / min through the cyclone separator, and the gaseous VOC is removed by the filter to ensure the separation of the gas and particle phases. Then the particulate matter is collected into a 9-hole nozzle impactor and a thermal desorption (Collection and thermal desorption, CTD) unit by inertial collision. After thermal desorption, in situ derivatization is carried out in a helium flow saturated with a derivatization reagent. The analyte is then re-concentrated into a focusing trap at 45°C. Subsequently, the focusing trap is heated to 315°C and transferred to the gas chromatography column with the carrier gas, and then detected by GC / MS. The GC / MS analysis time for each sample is 60 minutes. While analyzing, TAG is also being collected on the other side. The two processes do not interfere with each other and are carried out simultaneously. For the actual object and structure, please see Figure 5 , the specific parameter settings of GC / MS are shown in Appendix 1.

[0118] 2) Calculation of organic molecule marker concentration using the internal standard method

[0119] The internal standard method is a highly accurate quantitative method that uses area ratio or height ratio for quantitative calculation to obtain the injection correction factor. The internal standard (ISTD) substance should be a stable compound whose peak can be completely separated from other peaks in the sample and has similar chemical properties and can be eluted near the substance to be quantified. This standard solution is made using one or more target substances (hereinafter referred to as "X") of known concentration and an internal standard substance (hereinafter referred to as "ISTD") of a specified concentration. Then, data is collected for a certain amount of standard solution. The ratio of "X concentration / ISTD concentration" in the standard solution is used as the horizontal axis, and the ratio of "X peak area / ISTD peak area" is used as the vertical axis to create a calibration curve. The names of the internal and external standard solutions required for measuring organic molecular markers are shown in Appendix 2.

[0120] 3) Characteristic ratio method

[0121] The feature ratio method is a method used for data analysis and statistical modeling, usually for classification problems. In the feature ratio method, the feature ratio refers to the ratio of a certain event or phenomenon between two different groups. In this study, different diagnostic parameters (feature ratios) were selected and analyzed to analyze and identify PM. 2.5 The source of a certain type of organic molecular tracer in the sample.

[0122] 4) PMF source analysis

[0123] The positive definite matrix factorization (PMF) model is a multivariate statistical analysis method that estimates the composition of pollution sources and their contribution to environmental concentrations based on a large amount of observational data at receptor sites. The principle is to quantify the contribution of sources to the concentration of ambient air pollutants around the receptor site under the assumption of mass conservation and chemical mass balance between emission sources and receptors. This method has the advantage of not requiring the input of pollution source spectrum information in advance and is widely used in atmospheric PM 2.5 Source analysis research.

[0124] The mathematical expression of the PMF model is as follows:

[0125]

[0126] Where, X ij is the measured concentration of the jth component in the i-th sample; G ik is the contribution of the kth pollution source in the i-th sample; F kj is the concentration of the jth component of the kth pollution source; E ij is the residual between the measured concentration of the jth component in the ith sample and its analyzed value; P is the number of sources.

[0127] The PMF model obtains the number of pollution source factors and the pollution source contribution spectrum by seeking the solution that minimizes the objective function Q:

[0128]

[0129] Where U ij is the uncertainty of the jth component in the i-th sample, and its value is calculated from the species concentration (c), method detection limit (MDL) and analytical error (EF) by the following formula:

[0130]

[0131] (III) Implementation process of this implementation case

[0132] Figure 6 is the atmospheric PM in Zibo during the observation period provided by the embodiment of the present invention. 2.5 Source analysis situation.

[0133] First, an organic aerosol online monitoring system was built at the Zibo Atmospheric Environment Comprehensive Observation and Research Station in Shandong Province, which mainly includes a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head. The concentration data from November 2022 to February 2023, as well as the concentration data of gaseous pollutants, inorganic ions, and elemental substances were obtained from the official website of the Zibo Atmospheric Environment Comprehensive Observation and Research Station, and basic statistical analysis was performed to understand the spatiotemporal distribution characteristics of the pollution.

[0134] The constructed system device was used to observe various types of sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes and secondary organic aerosol tracers obtained from November 2022 to February 2023. The obtained data were integrated and calculated using GC / MS software and IgorPro software. The obtained sample peak area was imported into the molecular marker calibration curve obtained by the internal standard method to obtain the concentration data of the molecular marker. The characteristic value method was used to analyze the pollution source types represented by different molecular markers, and preliminary source analysis was performed. The molecular marker concentration data and PM 2.5 , gaseous pollutants, inorganic ions and elemental substance concentration data are used as input data and input into the PMF source analysis model to obtain the pollution contribution of various pollution sources. 2.5 and organic matter, and put forward targeted suggestions for air pollution prevention and control.

[0135] (IV) Implementation results of this implementation case

[0136] This implementation case is based on the results of the source analysis method of organic aerosol measured by organic molecular markers at the Zibo Atmospheric Environment Comprehensive Observation and Research Station from November 2022 to February 2023.

[0137] During the observation period, 61 organic molecular markers (n-alkanes, polycyclic aromatic hydrocarbons, sugars, hopanes, fatty acids, dibasic acids, aromatic acids, hydroxycarboxylic acids and secondary organic aerosol tracers) increased during the heavy pollution period. Among the organic components, the average concentration of sugar organic matter was the highest, accounting for 22.7% of the total organic matter, followed by n-alkanes, accounting for 21.2%, hydroxycarboxylic acids and aromatic acids accounting for 11.2% and 13.9% respectively. Fatty acids, polycyclic aromatic hydrocarbons, dibasic acids and secondary organic aerosol tracers accounted for a small proportion, and hopanes had the lowest proportion, only 0.4%. During the heavy pollution period, the carbon advantage index of n-alkanes was close to 1, indicating that it was greatly affected by anthropogenic sources (such as fossil fuel combustion, automobile exhaust emissions, etc.). The analysis of PAHs showed that 3- and 4-ring PAHs dominated the heavy pollution events, and the contribution of coal combustion sources to PAHs was particularly prominent during the observation period, which was related to the increased heating demand during the northern winter. The ratio of adipic acid (C6) to azelaic acid (C9) was high, indicating that anthropogenic sources contributed more to dibasic acids.

[0138] PMF source analysis results show that secondary sulfate and secondary nitrate contribute to PM 2.5 concentrations, accounting for 27.0% and 31.4% of the pollution sources, respectively, indicating that secondary transformation is the main factor affecting PM during heavy pollution. 2.5In addition, industrial emissions, biomass burning, road mobile sources and fireworks are also important pollution sources, accounting for 6.8%, 9.7%, 5.5% and 6.6% respectively.

[0139] Appendix 1 GC / MS main parameters

[0140]

[0141] Appendix 2: External and internal standard solutions required for measuring organic molecular markers

[0142]

[0143]

[0144]

[0145] The relevant evidence of the technical effects obtained by the embodiments of the present invention can be found in the attached Figure 6 , 7 , 8, 9.

[0146] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for organic aerosol source analysis based on online observation of organic molecular markers, characterized in that: The following steps are involved: Step 1, constructing an organic aerosol high time resolution online monitoring system device including a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head; Step 2, preparing the solvents, internal standard solutions, external standard solutions and derivatization reagents required for qualitative and quantitative determination of various organic molecular markers; Step 3, performing hourly resolution continuous online observation of the target organic molecular markers based on thermal desorption aerosol gas chromatography-mass spectrometry; Step 4: Analyze and process the online hourly observation data of organic molecular marker concentrations, and combine them with PM 2.5 The conventional component concentration data are used to obtain the source analysis results of organic aerosols through the PMF receptor model.

2. The method for organic aerosol source analysis based on online observation of organic molecular markers according to claim 1, characterized in that: Build an in-situ instrument with high time resolution for hours that can measure specific organic molecules, namely a thermal desorption aerosol chromatography-mass spectrometry system, and an organic aerosol online monitoring system including a high-purity helium output device. The connection methods of the high time resolution online observation instrument include ventilation / liquid pipeline connection and control line connection.

3. The method for organic aerosol source analysis based on online observation of organic molecular markers according to claim 1, characterized in that: Organic molecules include sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes, and secondary organic aerosol tracers. Specific organic molecule markers include but are not limited to nonadecadecane to tetratriacontane, αβ-hopane, αβ-norhopane, 17α(H)-22,29,30-trinorhopane, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, 1,2-benzo[A]anthracene, (1,2,5,6-dibenzonaphthalene), benzo(B)fluoranthene, benzo(K)fluoranthene, benzo(a)pyrene, dibenzo[ah]anthracene, benzo(G,H,I)perylene, indeno(1,2,3-CD)pyrene, cholesterol, oleic acid / octadecenoic acid, hexadecanoic acid / palmitic acid / palmitic acid, octadecanoic acid / stearic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, L- 61 substances including dextran, mannitol, sucrose, mannan, D-anhydrous glucose, glycerol (propylene glycol), terephthalic acid, phthalic acid, isophthalic acid, syringic acid, 4-hydroxybenzoic acid, 3-trihydroxybenzoic acid, malic acid, tartaric acid, 2-methylglyceric acid, 3-methyl-1,2,3-butyltricarboxylic acid, 2,3-dihydroxy-4-oxopentanoic acid, pinic acid, and pinonic acid.

4. The method for organic aerosol source analysis based on online observation of organic molecular markers according to claim 1, characterized in that: The concentration data obtained by real-time online observation and analysis of organic molecular markers with high time resolution is compared with PM 2.5 Conventional component concentration data are integrated and used as input data for PMF receptor model simulation to obtain accurate and scientific source analysis results of atmospheric organic aerosol.

5. The method for organic aerosol source analysis based on online observation of organic molecular markers according to claim 1, characterized in that: The step 1 constructs an organic aerosol online monitoring system device which mainly includes a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head, and the connection methods include ventilation / liquid pipeline connection and control line connection.

6. The method for organic aerosol source analysis based on online observation of organic molecular markers according to claim 1, characterized in that: The various organic molecular markers for qualitative and quantitative analysis in step 2 are sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes, and secondary organic aerosols; The solvent required for the preparation of qualitative and quantitative organic molecular markers is a mixture of acetonitrile and dichloromethane in a volume ratio of 1:4; Dilute the high concentration sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes and secondary organic aerosol tracer internal standard reagents, usually to about 500-1000 ppm; Dissolve or dilute high concentration sugars, normal alkanes, oxygen-containing acids, aromatic acids, polycyclic aromatic hydrocarbons, dibasic acids, fatty acids, hopanes, and secondary organic aerosol markers to the required mass concentration; The derivatization reagent required for preparing qualitative and quantitative organic molecular markers is N-methyl-N-(trimethylsilyl) trifluoroacetamide. The step 3 includes collecting ambient air particulate matter samples into a thermal desorption aerosol gas chromatography-mass spectrometer through a cyclone separator with different particle size cutting heads; effectively removing gas phase compounds through a multi-channel carbon remover to determine the separation of the gas phase and the particle phase; Ambient air samples were collected into a thermal desorption chamber by humidification and inertial impaction methods; The sample was thermally desorbed and transferred to a gas chromatography column with helium; initial observation data were obtained by detection using a quadrupole mass spectrometer and a flame ionization detector. The step 4 includes converting the initial data format into a cdf format using GC / MS converter software; processing the cdf format file using Igor Pro software to obtain the sample peak area; establishing a calibration curve using an internal standard method; importing the sample peak area data obtained by actual observation into the calibration curve to obtain the molecular marker concentration data; The cdf format file was processed by IgorPro software to solve the integral and obtain the sample peak area; The method of establishing a calibration curve by using the internal standard method is to analyze and process different amounts of external standard solutions and a quantitative internal standard solution to obtain a calibration curve; Different amounts of external standard solution are divided by the volume multiples of the external standard solution, such as 1 μl, 2 μl, 3 μl, etc.; Combine organic aerosol measurements and hourly concentration data of molecular markers with other PM 2.5 The conventional component concentration data are used as input data, and the PMF receptor model is used to perform source analysis of organic aerosols at the observation site.

7. An organic aerosol source analysis system based on online observation of organic molecular markers for implementing the organic aerosol source analysis method based on online observation of organic molecular markers as described in any one of claims 1 to 6, characterized in that: The organic aerosol source analysis system based on online observation of organic molecular markers includes: Building modules for building an organic aerosol high time resolution online monitoring system device, which mainly includes a thermal desorption aerosol gas chromatography-mass spectrometer, a high-purity helium output device, and a sampling head; Preparation module, used to prepare solvents, internal standard solutions, external standard solutions and derivatization reagents required for qualitative and quantitative analysis of various organic molecular markers; An observation module is used to continuously observe the target organic molecular markers online with hourly resolution based on a thermal desorption aerosol gas chromatography-mass spectrometry; The analysis and processing module is used to analyze and process the online hourly observation data of organic molecular marker concentrations, combined with PM 2.5 The conventional component concentration data are used to obtain the source analysis results of organic aerosols through the PMF receptor model.

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