Method for evaluating data quality of automatic gas monitoring equipment

Abstract

The invention relates to the technical field of environment monitoring, in particular to a method for evaluating data quality of automatic gas monitoring equipment. According to the technical scheme, the method comprises the steps that S1, at least two to-be-tested devices of the same model are deployed under the same sampling branch pipe of the same sampling main pipe and run at the same time; s2, carrying out the following single tests on each device: a single-point check test, a real-time to-be-tested gas standard addition recovery test and a device measurement value correlation test; s3, according to the comparison result of the average concentration of the gas to be detected and the equipment quantitation limit, calculating the comprehensive score of the single equipment by adopting different weighting modes; and S4, outputting a rating result for the equipment according to the comprehensive score.

Description

Technical Field

[0001] The present invention relates to the field of gas monitoring, and particularly to a method for evaluating the data quality of gas automatic monitoring equipment. Background Art

[0002] Currently, the methods for evaluating the data quality of gas automatic monitoring equipment mainly rely on single-performance tests such as method detection limits, precision, accuracy, and system residues, or single-point verification to determine whether the requirements are met.

[0003] Generally, before performance testing, the instrument and equipment to be tested need to be calibrated first. For example, in single-performance testing, after the equipment to be tested is calibrated, a standard substance is continuously introduced into the equipment to be tested multiple times, and then the corresponding performance indicators are calculated based on the equipment response and the calculation method of the corresponding test. Single-point verification is to introduce a standard substance with a known target concentration into the equipment to be tested once or multiple times after calibration, and calculate the relative error between the equipment response and the target concentration.

[0004] Currently, these evaluation methods mainly use standard substances for relevant tests and evaluations. It is true that using standard substances can reflect some instrument performance, but compared with the gas samples to be tested, the composition of standard substances is relatively simple. Generally, it only contains the target substances that can be measured by the instrument and diluents that clearly do not interfere with the measurement. Therefore, the relevant tests carried out using standard substances can only reflect the accuracy of the instrument for measuring standard substances, and cannot reflect the reliability of its actual measurement of the samples to be tested. Moreover, the evaluation results of existing evaluation methods are not intuitive enough, and the threshold and cost of result reading are high.

[0005] In summary, the purpose of the present invention is to provide a method for evaluating the data quality of gas automatic monitoring equipment that can comprehensively reflect the equipment reliability and can quickly and intuitively reflect the data quality results of the equipment. Summary of the Invention

[0006] In view of the above analysis, an embodiment of the present invention aims to provide a method for evaluating the data quality of gas automatic monitoring equipment, including: S1. Deploy at least two devices of the same model to be tested under the same sampling branch of the same sampling main pipe and run them simultaneously; S2. Conduct the following single tests on each device respectively: (1) Single-point verification test: Introduce a standard substance with a known target concentration, obtain the equipment response value and calculate the relative error with the target concentration; count the proportion of errors falling within the set range in all test times to obtain the single-point verification score; (2) Real-time spiked recovery test of the gas to be tested: Select one device as the spiked recovery device and the rest as reference devices; The spiked recovery equipment is fed with a mixed gas of the gas to be measured and a standard substance with a known concentration, and the reference equipment is fed with the gas to be measured; Based on the measured values of the two types of equipment and the concentration of the standard substance, calculate the spiked recovery rate; count the proportion of the spiked recovery rates within the range, and obtain the spiked recovery score; (3)Correlation test of equipment measured values: Count the measured values of each equipment during the monitoring period except for the spiked recovery test and the single-point verification test; Conduct a correlation analysis on the measured values, and calculate the correlation coefficient R² and the slope k; Multiply the weighted R² and k by a percentage according to the preset weights to obtain the correlation score; S3. According to the comparison result between the average concentration of the gas to be measured and the equipment quantification limit, calculate the comprehensive score of a single equipment by using different weighting methods; S4. Output the rating result for the equipment according to the comprehensive score.

[0007] In some embodiments, the single-point verification score is calculated based on the proportion of the number of tests with a relative error lower than 50%.

[0008] In some embodiments, the spiked recovery score is calculated based on the proportion of the number of tests with the spiked recovery rate within the range of 60% - 140%.

[0009] In some embodiments, in the correlation score of the equipment measured values, the weight of the correlation coefficient R² ranges from 0.2 to 0.8, and the weight of the slope k ranges from 0.2 to 0.8.

[0010] In some embodiments, when the average concentration of the gas to be measured is lower than the equipment quantification limit, the comprehensive score of a single equipment consists of the single-point verification and the spiked recovery scores, the weight of the single-point verification is 20% - 80%, and the weight of the spiked recovery score is 20% - 80%.

[0011] In some embodiments, when the average concentration of the gas to be measured is higher than the equipment quantification limit, the comprehensive score is composed of the single-point verification score, the spiked recovery score and the correlation score of the equipment measured values, and their respective weights are 20% - 40%, 20% - 40%, and 20% - 40% in sequence.

[0012] In some embodiments, the correlation test is based on the monitoring data collected at corresponding times by two or more pieces of equipment for correlation analysis.

[0013] In some embodiments, outputting the rating result for the equipment according to the comprehensive score includes: The mapping relationship between the score and the rating result includes: A: Score > 90; B: 70 - 90; C: 50 - 70; D: <50.

[0014] In some embodiments, the total cycle of the single test is not less than 7 consecutive days.

[0015] The method provided by the present invention has at least the following advantages: 1. This evaluation method combines the test results of three major indicators: single-point verification, spiking recovery of the gas to be measured, and the correlation between the equipment for the gas to be measured, so as to comprehensively and objectively evaluate the reliability of the equipment for measuring the gas to be measured; 2. The evaluation result of the final equipment is reflected by specific rating levels, intuitively and quickly reflecting the reliability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings are only for the purpose of showing specific embodiments, and are not considered as a limitation of the present invention. Throughout the drawings, the same reference signs denote the same components.

[0017] Figure 1 It is a schematic flow chart of the method for evaluating the data quality of gas automatic monitoring equipment provided by the embodiment of the present invention; Figure 2 It is a schematic flow chart of a specific embodiment provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following will specifically describe the preferred embodiments of the present invention in conjunction with the drawings, where the drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principle of the present invention, rather than to limit the scope of the present invention.

[0019] In the description of the embodiments of the present invention, it should be noted that unless otherwise clearly defined and limited, the term "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the present invention can be understood according to specific circumstances.

[0020] The terms "top", "bottom", "above", "below", and "on" described throughout the text are relative positions with respect to the components of the device, such as the relative positions of the top and bottom substrates inside the device. It can be understood that the device is multifunctional and is independent of its orientation in space.

[0021] The normal working surface of the present invention can be a plane or a curved surface, can be inclined, or can be horizontal. For the convenience of description, the embodiments of the present invention are placed on a horizontal plane and used on the horizontal plane, and "high and low" and "up and down" are defined accordingly.

[0022] An embodiment of the present invention aims to provide a method for evaluating the data quality of gas automatic monitoring equipment, as Figure 1 shown, including: S1. Deploy at least two devices of the same model to the same sampling branch pipe of the same sampling main pipe and run them simultaneously; S2. Conduct the following individual tests on each device respectively: (1) Single-point verification test: Introduce a standard substance with a known target concentration, obtain the device response value and calculate the relative error from the target concentration; count the proportion of errors falling within the set range in all test times to obtain the single-point verification score.

[0023] Single-point verification refers to evaluating whether the device to be tested can accurately measure the standard substance with a known concentration. Specific operation method: After calibrating the device to be tested, introduce the standard substance with a known target concentration into the device to be tested once or multiple times, and calculate the relative error between the device response and the target concentration; count all the single-point verification results, and assign scores by multiplying the proportion of the number of times the relative error of the single-point verification result is within a certain range to the total number of single-point verifications by one hundred. The assigned score is the single score of the single-point verification index.

[0024] (2) Real-time spiked recovery test for the gas to be measured: Select one device as the spiked recovery device, and the rest as reference devices; The spiked recovery device is introduced with a mixed gas of the gas to be measured and a standard substance with a known concentration, and the reference devices are introduced with the gas to be measured; Calculate the spiked recovery rate based on the measured values of the two types of devices and the concentration of the standard substance; count the proportion of spiked recovery rates within the range to obtain the spiked recovery score.

[0025] The real-time spiked recovery index for the gas to be measured evaluates whether the device to be tested can accurately measure the gas sample to be measured. Specific operation method: Select one of the multiple devices of the same model deployed at the same sampling branch pipe opening of the same sampling main pipe as the spiked recovery device, and the rest of the devices as reference devices. Among them, the reference devices only collect and analyze the gas to be measured, while the spiked recovery device is responsible for collecting and analyzing the mixed gas of the gas to be measured and the standard substance with a known concentration. Calculate the actual spiked amount based on the response of the reference device and the spiked device, and then further calculate the spiked recovery rate based on the known concentration of the added standard substance. Count all the spiked recovery results, and assign scores by multiplying the proportion of the number of times the spiked recovery rate is within a certain range to the total number of spiked recoveries by one hundred. The assigned score is the single score of the real-time spiked recovery index for the gas to be measured.

[0026] (3) Device measurement value correlation test: Count the measured values of each device during the monitoring period except for the spiked recovery test and the single-point verification test; Perform a correlation analysis on the measured values, and calculate the correlation coefficient R² and the slope k; Multiply the weighted R² and k by a percentage to obtain a correlation score; The correlation index of the measured values of the gas to be measured equipment evaluates whether the measured values between the equipment to be measured are comparable. Specific operation method: During the test period, except for single-point verification and spike recovery, count the monitoring data of the gas to be measured under the same sampling main pipe and the same sampling branch pipe of multiple equipment to be measured. Perform a correlation analysis on all the monitoring data of multiple equipment to be measured, and calculate the correlation coefficient R 2 And the slope k. According to the correlation coefficient R 2 And the calculation result of the slope k is multiplied by one hundred for scoring, and the scoring result is the single score of the real-time correlation index of the measured values of the gas to be measured equipment.

[0027] S3. According to the comparison result between the average concentration of the gas to be measured and the equipment quantification limit, calculate the comprehensive score of a single device using different weighting methods; After obtaining the scores of each single index, perform a comprehensive evaluation on a single device to be measured. The specific algorithm is as follows: First, count the overall average concentration of the gas to be measured during the test period.

[0028] 1. If the average concentration of the gas to be measured during the test period < the equipment quantification limit, the comprehensive score of a single device to be measured is calculated from the two indexes of single-point verification and spike recovery; 2. If the average concentration of the gas to be measured during the test period ≥ the equipment quantification limit, the comprehensive score of a single device to be measured is calculated from the three indexes of single-point verification, spike recovery, and the correlation of the measured values of the gas to be measured equipment.

[0029] S4. Output a rating result for the equipment according to the comprehensive score.

[0030] After calculating the comprehensive score of each single device to be measured, perform a weighted conversion on the comprehensive scores of all single devices to obtain the overall score result of this type of equipment. Finally, rate the equipment according to the score result. Specifically as follows: When the score > 90, the rating is A; when the score is in the range of 70 - 90, the rating is B; when the score is in the range of 50 - 70, the rating is C; when the score < 50, the rating is D. Among them, the rating of A: The measurement result of the equipment is reliable; the rating of B: The measurement result of the equipment has a certain reliability; the rating of C: The measurement result of the equipment is for reference; the rating of D: The measurement result of the equipment is unreliable.

[0031] In order to further improve the scientificity and accuracy of the evaluation method of the present invention, the embodiments of the present invention consider different situations of the average concentration of the gas to be measured when calculating the comprehensive score.

[0032] In the field of environmental monitoring, the "Limit of Quantification" (LOQ) is the lowest concentration at which an instrument can perform reliable quantitative analysis. If the actual sampled gas concentration is lower than this value: the equipment response signal is weak and is easily affected by noise, fluctuations, or interference; at this time, if the measured value correlation (such as the correlation coefficient R² or slope) is used to analyze the differences between equipment, the data itself is actually unstable and incomparable, and the evaluation made may be about "noise quality" rather than "performance quality".

[0033] This is like evaluating whether two thermometers are accurate. If you let them measure the tiny difference of "0.001℃" and their measurement ranges can only be accurate to ±0.1℃, it is meaningless to compare whether their measured values are consistent. At this time, it should be to see whether they have response capabilities by letting them measure the standard water sample temperature + artificially set offsets (similar to spiking) respectively, rather than comparing who is closer to the "true value".

[0034] In summary, such a design has the following benefits: 1. Avoid meaningless correlation analysis: If the sampling concentration is too low and both equipment A and B are in the limit response state, the correlation between the measured values cannot represent the true performance - it is reasonable and professional not to include the correlation score at this time.

[0035] 2. Improve the accuracy and scientific nature of the evaluation: By judging the concentration to dynamically adjust the evaluation structure, it shows that this is a mechanism that adaptively adjusts the evaluation dimension according to the data quality, rather than a one-size-fits-all scoring method.

[0036] 3. Provide a basis for grading the equipment application scenarios: Even if some equipment has excellent performance at high concentrations, but performs poorly in low-concentration scenarios, this mechanism can identify the "applicable concentration scenarios" in advance.

[0037] In some embodiments, the single-point verification score is calculated based on the proportion of test times with a relative error lower than 50%. Preferably, in some embodiments, the single-point verification score is calculated based on the proportion of test times with a relative error lower than 20%.

[0038] In some embodiments, the spike recovery score is calculated based on the proportion of test times with a spike recovery rate in the range of 60% - 140%. Preferably, in some embodiments, the spike recovery score is calculated based on the proportion of test times with a spike recovery rate in the range of 80% - 120%.

[0039] In some embodiments, in the device measurement correlation score, the weight of the correlation coefficient R² is between 0.2 and 0.8 and the weight of the slope k is between 0.2 and 0.8. Preferably, in some embodiments, the weights of the correlation coefficient R² and the slope k are both 0.5.

[0040] In some embodiments, when the average concentration of the gas to be tested is lower than the quantitative limit of the device, the comprehensive score of a single device is composed of a single-point verification and a spike recovery score, the weight of the single-point verification is 20% to 80%, and the weight of the spike recovery score is 20% to 80%. Preferably, in some embodiments, the weight of the single-point verification is 30%, and the weight of the spike recovery score is 70%.

[0041] In some embodiments, when the average concentration of the gas to be measured is higher than the quantitative limit of the device, the comprehensive score is composed of the single-point verification score, the spike recovery score and the device measurement value correlation score, and the weights of each are 20% to 40%, 20% to 40%, and 20% to 40%, respectively. Preferably, in some embodiments, the weights of the above three are 30%, 40%, and 30%, respectively.

[0042] In some embodiments, the correlation test performs correlation analysis based on monitoring data collected by two or more devices at corresponding moments.

[0043] In some embodiments, the total period of the single test is no less than 7 consecutive days.

[0044] In a specific embodiment provided by the present invention, Figure 2 As shown, the following process is included: Two devices of the same model to be tested are deployed under the same branch of the same sampling main pipe, and the two devices to be tested are operated and monitored at the same time for 7 days. During the test, single-point verification, real-time test gas spike recovery and test of correlation between the measured values ​​of the gas equipment to be tested are carried out as planned. The specific methods and scoring rules for each test are as follows.

[0045] Specific operation method of single-point verification: After the equipment to be tested is calibrated, standard substances with known target concentrations are introduced into the equipment to be tested multiple times every day as planned, and the relative error between the equipment response and the target concentration is calculated; the results of all single-point verifications during the 7-day test are counted, and points are assigned according to the ratio of the number of single-point verification results with a relative error within 20% to the total number of single-point verifications multiplied by 100, which is the single score of the single-point verification indicator; Specific operation method of real-time test gas spike recovery: During the test period, one of the two test devices of the same model is selected as the spike recovery device every day, and the other device is the reference device. The reference device only collects and analyzes the test gas, while the spike recovery device is responsible for collecting and analyzing the mixed gas of the test gas and the standard substance of known concentration (introducing multiple standard substances of known concentrations at different concentrations), and the actual spike amount is calculated based on the response of the reference device and the response of the spike device, and then the spike recovery rate is further calculated based on the known concentration of the added standard substance. The results of all spike recovery are counted, and points are assigned according to the ratio of the number of times the spike recovery rate is between 80% and 120% to the total number of spike recovery times multiplied by one hundred, which is the single score of the real-time test gas spike recovery index; Specific operation method of correlation of measured values ​​of the gas equipment to be tested: Statistic the monitoring data of the gas to be tested of the two equipments to be tested under the same sampling main pipe and the same sampling branch pipe, except for single-point verification and spike recovery during the test period, draw a scatter plot for all the monitoring data of the two equipments to be tested for correlation analysis, and calculate the correlation coefficient R 2 And the slope k. According to R 2 The weights of and k are 0.5 respectively. After weighted calculation, they are multiplied by 100 to assign points, which is the single score of the correlation index of the measured value of the real-time gas equipment to be tested; After obtaining the score of each individual indicator, a comprehensive score is given to the single device under test. The specific algorithm is as follows: First, the overall average concentration of the gas under test during the test period is statistically analyzed.

[0046] 1. If the average concentration of the gas to be tested during the test is less than the quantitative limit of the equipment, the comprehensive score of the single equipment to be tested is calculated by weighted calculation of the two indicators of single-point verification and spike recovery: Comprehensive score of single equipment = single-point verification score * 30% + spike recovery score * 70%; 2. If the average concentration of the gas to be tested during the test period is ≥ the quantitative limit of the equipment, the comprehensive score of a single device to be tested is calculated based on the three indicators of single-point verification, spike recovery and correlation with the measured value of the gas equipment to be tested: Comprehensive score of a single device = single-point verification score*30%+spiked recovery score*40%*correlation of equipment measurement value*40%.

[0047] After calculating the comprehensive score of each single device under test, the comprehensive scores of the two devices are averaged to obtain the overall score of the device. Finally, the device is rated according to the score results, as follows: A when the score is >90, B when the score is between 70 and 90, C when the score is between 50 and 70, and D when the score is <50. Rating A: The device measurement result is reliable; rating B: The device measurement result has a certain degree of reliability; rating C: The device measurement result is for reference; rating D: The device measurement result is unreliable.

[0048] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for evaluating the data quality of gas automatic monitoring equipment, characterized in that, Including: S1. Deploy at least two devices of the same model under the same sampling branch pipe of the same sampling main pipe and run them simultaneously. S2. Conduct the following individual tests on each device respectively: (1) Single-point verification test: Introduce a standard substance with a known target concentration, obtain the device response value and calculate the relative error from the target concentration; count the proportion of errors falling within the set range in all test times to obtain the single-point verification score. (2) Real-time spiked recovery test for the gas to be measured: Select one device as the spiked recovery device and the others as reference devices. The spiked recovery device is introduced with a mixed gas of the gas to be measured and a standard substance with a known concentration, and the reference devices are introduced with the gas to be measured. Calculate the spiked recovery rate based on the measured values of the two types of devices and the concentration of the standard substance; count the proportion of spiked recovery rates within the compliance range to obtain the spiked recovery score. (3) Correlation test of device measured values: Count the measured values of each device during the monitoring period except for the spiked recovery test and the single-point verification test. Conduct a correlation analysis on the measured values and calculate the correlation coefficient R² and the slope k. Multiply the weighted R² and k by a percentage according to the preset weights to obtain the correlation score. S3. According to the comparison result between the average concentration of the gas to be measured and the equipment quantification limit, calculate the comprehensive score of a single device using different weighting methods. S4. Output the rating result for the device according to the comprehensive score.

2. The method for evaluating the data quality of a gas automatic monitoring device according to claim 1, characterized in that: The single-point verification score is calculated based on the proportion of test times with a relative error lower than 50%.

3. The method for evaluating the data quality of a gas automatic monitoring device according to claim 1, wherein: The spiked recovery score is calculated based on the proportion of test times with a spiked recovery rate within the range of 60% - 140%.

4. The method for evaluating the data quality of a gas automatic monitoring device according to claim 1, characterized in that: In the correlation score of device measured values, the weight of the correlation coefficient R² ranges from 0.2 to 0.8 and the weight of the slope k ranges from 0.2 to 0.

8.

5. The method for evaluating the data quality of a gas automatic monitoring device according to claim 1, characterized in that: When the average concentration of the gas to be measured is lower than the equipment quantification limit, the comprehensive score of a single device consists of the single-point verification and spiked recovery scores, with the weight of the single-point verification ranging from 20% to 80% and the weight of the spiked recovery score ranging from 20% to 80%.

6. The method for evaluating the data quality of the automatic gas monitoring device according to claim 1, wherein: When the average concentration of the gas to be measured is higher than the equipment quantification limit, the comprehensive score consists of the single-point verification score, the spiked recovery score, and the correlation score of device measured values, with their respective weights being 20% - 40%, 20% - 40%, and 20% - 40% in sequence.

7. The method for evaluating the data quality of a gas automatic monitoring device according to claim 1, characterized in that: The correlation test is based on the monitoring data collected at corresponding times by two or more devices for correlation analysis.

8. The method for evaluating the data quality of the gas automatic monitoring device according to claim 1, characterized in that: Output the rating result for the device according to the comprehensive score, including: The mapping relationship between the score and the rating result includes: A: Score > 90; B：70~90； C：50~70； D：<50。 9. The method for evaluating the data quality of a gas automatic monitoring device according to claim 1, wherein: The total cycle of the individual test is not less than 7 consecutive days.

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