the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 29 Sep 2022
A novel analytical method to detect Ozone depleting substances and Fluorine-containing greenhouse gases in the atmosphere
Abstract. Fluorine-containing greenhouse gases (F-GHGs) and ozone layer substances (ODS) are being monitored without a global commercial monitoring system. In this study, the existing commercial volatile organic compounds (VOCs) monitoring system is modified in hardware and optimized in methodology to provide high-precision monitoring of 33 types of ODS and F-GHGs in the atmosphere. Moreover, the system eliminates the issue of excessive costs and lengthy development cycles associated with special monitoring equipment. Pre-concentration can enhance the enrichment of low boiling point and low concentration components by increasing the injection volume, improving water removal efficiency, and improving adsorption capacity. It is significant to be noted that InertCap 624MS is a one-dimensional column, while GASPRO is a two-dimensional column. It is possible to separate 33 target compounds completely and stably by Heart-cut and TwinLine using dual-column separation and single-detector detection mode. Experimental findings indicate that this monitoring technology has an accuracy of 0.22~3.70 %. To accurately observe the changing trend of atmospheric concentration and trace the emission sources over time, a background gas with a known concentration has been used as a standard gas, and background atmospheric samples with unknown concentrations have been quantitatively tested using a single-point external standard method.
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CC1: 'Comment on egusphere-2022-783', Jens Mühle, 30 Sep 2022
The authors describe a new analytic system to measure a range of ODSs and synthetic GHGs in atmospheric samples. Analytical systems to measure atmospheric abundances with high precision, accuracy and, most importantly, long-term stability are one key component to determine emissions of these compounds to the atmosphere. While I will not review the whole manuscript here, I would like to point out that the authors seem to be confusing accuracy and precisions at times. For example, in Section 3.1, the authors talk about high-precision monitoring, but then cite Table 4, which has a header stating "... test accuracy ...". It should be noted that typical precisions achieved by Medusa systems are better for many compounds than what is stated in Table 4 by the authors for Medusa systems. The authors should therefore revisit Miller et al., 2008 and Prinn et al. (Earth Syst. Sci. Data, 10(2), 985-1018, 10.5194/essd-10-985-2018, 2018), where typical precisions for Medusa systems are given, and update Table 4 accordingly.
Citation: https://doi.org/10.5194/egusphere-2022-783-CC1 -
AC1: 'Reply on CC1', Danying Shan, 30 Sep 2022
Thank you very much for your suggestions. In response to your questions, we will further optimize the manuscript. 1. We have some problems with the expression of precision and accuracy. Table 4 should be corrected to "... test precision ...". 2. The accuracy of Medusa systems in this paper refers to the test results of Medusa systems currently in use in China. We will review the published related data again, and combine the latest test results available in AGAGE network, and finally update our comparison data.
Citation: https://doi.org/10.5194/egusphere-2022-783-AC1
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AC1: 'Reply on CC1', Danying Shan, 30 Sep 2022
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RC1: 'Comment on egusphere-2022-783', Anonymous Referee #1, 05 Dec 2022
The manuscript by Danying et al. touches on an important point, i.e. that there is to date no commercially available system for measurements of ODS and fluorinated GHGs. Unfortunately, the paper is very poorly written and lacks a lot of details necessary in order to understand what has beeen done and also in order to advance our understanding of analytical options. Therefore in its present form I do not find the manuscript near enough to being in a form ready for publication that a continuation of the review process makes sense. I suggest to reject the manuscript, but encourage the authors to add details and explanations to what they have done and then to resubmit the manuscript. I add some more detailed below which may help the authors in revising the manuscript so it would be ready for a review process. I suggest the authors look at the excellent paper by Miller et al. on the MEDUSA system to get an impression how detailed such a description should be.
Specific points
The authors need to incorporate much more scientific literature and in particular they should cite scientific peer-reviewed literature instead of unreviewed web ressources.
The authors need to distinguish between accuracy and precision. What they refer to to as accuracy is in most cases precision.
The different methods used and the approaches taken need to be explained in much more details, so that they could be reproduced by another laboratory.
The most up to date citation for the AGAGE network (and the precisions of the MEDUSA) is Prinn et al., 2018. Please refer to this when comparing your results.
Table 2: The chemical names of a number of compounds is not correct
Fig. 1 (and the text referring to this Figure): much more detail is needed on the set-up, e.g. the deydration Module1, Modules 2 and 3. Also in such an analytical paper it is important to e.g. specify which Nafion dryer was use and how this was operated.
There are also many half-sentences in the manuscript which either do not make sense or are gramatically incorrect.
L. 91.: This statement makes no sense. For a quantitative analytical system, trapping must be quantitative, which means that an improvement in absorption efficiency will not improve detection limits.
l. 99: why have the authors used 1/8" tubing? This results in a large volume and makes injection on a capillary system difficult. It is actually common to use 1/16" tubing for this.
Fig 2: A table would allow to show these results more quantitatively.
L. 168: SIM stands for Selected Ion Monitoring (not scanning).
Fig. 4: (left): one compound is missing in the legend
l. 200 (and other places): mixing ratios (given in ppm) are not concentrations.
Table 4: please refer to updated values from Prinn et al., 2018.
Section 3.2.: I found this whole section extremely difficult to understand. E.g. the peak areas given in l. 225 for CCl4 would indicate extremely poor precision in contradiction to what is shown in the table.
l. 225: SF6 has actually received a lot of attention as it is a very long lived gas and has a very high GWP.
Fig 6: is not explained or discussed at al. in the text. The meaning of the Hysplit trajectory in unclear to me.
Citation: https://doi.org/10.5194/egusphere-2022-783-RC1 -
AC2: 'Reply on RC1', Danying Shan, 08 Feb 2023
Thank you for your suggestion. I am very sorry for the language problem. I will further modify the language of the manuscript and make corrections.We added more details and explanations in the revised manuscript.
We've replaced unreviewed web ressources with scientific literature.
We have corrected “precision “ in the manuscript.
We have added the sources of the materials used in the manuscript and added more details and explanations so that readers can understand them and reproduce them in the laboratory.
We refer to Prinn et al., 2018 for updating comparison of monitoring precision and atmospheric concentration ratios.
Table 2: The chemical names of a number of compounds was updated.
We added more explanations to the system flow diagram shown in Fig. 1. The flow of the test process and M1/M2/M3 materials are described in detail. The introduction and operating principles of Nafion dryer are supplemented in section 2.2.1.
Correct and polish the manuscript language problems.
We have changed the statement “The absorption efficiency and the elimination of interfering impurities in the preconcentration process are critical factors in improving the analysis sensitivity.”
We're doing it in a commercial preconcentration system. Due to the structure of the preconcentration system, the adsorption tubing can only choose 1/8 inch inert stainless steel tubing.
Fig 2 was changed to a table.
"SIM" was revised to Select Ion Monitoring
“concentrations” were changed to “concentrations ratios” in the manuscript.
Revise the explanation in Section 3.2. If the peak area fluctuation of the standard gas is close to the continuous test precision of the instrument.Formula (1) can be used to calculate the sample concentration ratios.However, the process of MS has appropriate volatility, repeated tests of standard gas twice before and after can be used as a quality control measure to judge whether the error is caused by the normal fluctuation of MS, or the sample cannot be analyzed due to system anomalies. For example, the peak areas of CCl4 before and after injection are 212,168, and 210,523, respectively, and 203,186, and 204,637, respectively. The repeatability of the standard gas test meets the requirement, but there were fluctuations between the standard gas before and after the sample, which may be caused by the normal attenuation of the mass spectrum response. It could be assumed that the peak area was decayed in a gradient, so as to correct the concentration ratios of the intermediate sample to reduce the deviation caused by system fluctuations.
We have revised the interpretation of SF6.”With its extremely long atmospheric lifetime and high global warming potential (GWP), its emissions could bring a serious threat to climate change.”
We revised the Hysplit trajectory. “The Hysplit trajectory shown in Fig. 7 was used to find the pollution source, and the source of the polluted air mass may be the southeastern region of Fujian Province.”
Citation: https://doi.org/10.5194/egusphere-2022-783-AC2
-
AC2: 'Reply on RC1', Danying Shan, 08 Feb 2023
-
RC2: 'Comment on egusphere-2022-783', Anonymous Referee #2, 06 Dec 2022
This manuscript aims to provide a new methodology for the measurements of F-GHGs and ODs. This is an interesting topic, and should be encouraged to publish. I tried to understand this logic flow of this manuscript, but the language and writing of this manuscript are both quite poorly. In most sections, I nearly hard to understand the authors’ idea. So, I strongly recommend to further polish the language and logic flow of this manuscript, otherwise I cannot give the constructive comments for this manuscript. In addition, the setup of the pre-concentration system seems to the foundation of this new methodology, however the authors did not clearly display what’s the really new in this method.
Citation: https://doi.org/10.5194/egusphere-2022-783-RC2 -
AC3: 'Reply on RC2', Danying Shan, 08 Feb 2023
Thank you for your suggestion. I am very sorry for the language problem. I will further modify the language and logic flow of the manuscript and make corrections. The significance of this manuscript is how to transform the commercial monitoring system to achieve high precision monitoring of trace ODS and F-GHGs, and solve the expensive equipment development problem. In the revised manuscript, we have added sources of various materials and added more explanations of methods, so that another laboratory could reproduced. We have improved the stability of monitoring from the pre-concentration system and GCMS to ensure the precision of instrumental analysis and data integration.
Citation: https://doi.org/10.5194/egusphere-2022-783-AC3
-
AC3: 'Reply on RC2', Danying Shan, 08 Feb 2023
Status: closed
-
CC1: 'Comment on egusphere-2022-783', Jens Mühle, 30 Sep 2022
The authors describe a new analytic system to measure a range of ODSs and synthetic GHGs in atmospheric samples. Analytical systems to measure atmospheric abundances with high precision, accuracy and, most importantly, long-term stability are one key component to determine emissions of these compounds to the atmosphere. While I will not review the whole manuscript here, I would like to point out that the authors seem to be confusing accuracy and precisions at times. For example, in Section 3.1, the authors talk about high-precision monitoring, but then cite Table 4, which has a header stating "... test accuracy ...". It should be noted that typical precisions achieved by Medusa systems are better for many compounds than what is stated in Table 4 by the authors for Medusa systems. The authors should therefore revisit Miller et al., 2008 and Prinn et al. (Earth Syst. Sci. Data, 10(2), 985-1018, 10.5194/essd-10-985-2018, 2018), where typical precisions for Medusa systems are given, and update Table 4 accordingly.
Citation: https://doi.org/10.5194/egusphere-2022-783-CC1 -
AC1: 'Reply on CC1', Danying Shan, 30 Sep 2022
Thank you very much for your suggestions. In response to your questions, we will further optimize the manuscript. 1. We have some problems with the expression of precision and accuracy. Table 4 should be corrected to "... test precision ...". 2. The accuracy of Medusa systems in this paper refers to the test results of Medusa systems currently in use in China. We will review the published related data again, and combine the latest test results available in AGAGE network, and finally update our comparison data.
Citation: https://doi.org/10.5194/egusphere-2022-783-AC1
-
AC1: 'Reply on CC1', Danying Shan, 30 Sep 2022
-
RC1: 'Comment on egusphere-2022-783', Anonymous Referee #1, 05 Dec 2022
The manuscript by Danying et al. touches on an important point, i.e. that there is to date no commercially available system for measurements of ODS and fluorinated GHGs. Unfortunately, the paper is very poorly written and lacks a lot of details necessary in order to understand what has beeen done and also in order to advance our understanding of analytical options. Therefore in its present form I do not find the manuscript near enough to being in a form ready for publication that a continuation of the review process makes sense. I suggest to reject the manuscript, but encourage the authors to add details and explanations to what they have done and then to resubmit the manuscript. I add some more detailed below which may help the authors in revising the manuscript so it would be ready for a review process. I suggest the authors look at the excellent paper by Miller et al. on the MEDUSA system to get an impression how detailed such a description should be.
Specific points
The authors need to incorporate much more scientific literature and in particular they should cite scientific peer-reviewed literature instead of unreviewed web ressources.
The authors need to distinguish between accuracy and precision. What they refer to to as accuracy is in most cases precision.
The different methods used and the approaches taken need to be explained in much more details, so that they could be reproduced by another laboratory.
The most up to date citation for the AGAGE network (and the precisions of the MEDUSA) is Prinn et al., 2018. Please refer to this when comparing your results.
Table 2: The chemical names of a number of compounds is not correct
Fig. 1 (and the text referring to this Figure): much more detail is needed on the set-up, e.g. the deydration Module1, Modules 2 and 3. Also in such an analytical paper it is important to e.g. specify which Nafion dryer was use and how this was operated.
There are also many half-sentences in the manuscript which either do not make sense or are gramatically incorrect.
L. 91.: This statement makes no sense. For a quantitative analytical system, trapping must be quantitative, which means that an improvement in absorption efficiency will not improve detection limits.
l. 99: why have the authors used 1/8" tubing? This results in a large volume and makes injection on a capillary system difficult. It is actually common to use 1/16" tubing for this.
Fig 2: A table would allow to show these results more quantitatively.
L. 168: SIM stands for Selected Ion Monitoring (not scanning).
Fig. 4: (left): one compound is missing in the legend
l. 200 (and other places): mixing ratios (given in ppm) are not concentrations.
Table 4: please refer to updated values from Prinn et al., 2018.
Section 3.2.: I found this whole section extremely difficult to understand. E.g. the peak areas given in l. 225 for CCl4 would indicate extremely poor precision in contradiction to what is shown in the table.
l. 225: SF6 has actually received a lot of attention as it is a very long lived gas and has a very high GWP.
Fig 6: is not explained or discussed at al. in the text. The meaning of the Hysplit trajectory in unclear to me.
Citation: https://doi.org/10.5194/egusphere-2022-783-RC1 -
AC2: 'Reply on RC1', Danying Shan, 08 Feb 2023
Thank you for your suggestion. I am very sorry for the language problem. I will further modify the language of the manuscript and make corrections.We added more details and explanations in the revised manuscript.
We've replaced unreviewed web ressources with scientific literature.
We have corrected “precision “ in the manuscript.
We have added the sources of the materials used in the manuscript and added more details and explanations so that readers can understand them and reproduce them in the laboratory.
We refer to Prinn et al., 2018 for updating comparison of monitoring precision and atmospheric concentration ratios.
Table 2: The chemical names of a number of compounds was updated.
We added more explanations to the system flow diagram shown in Fig. 1. The flow of the test process and M1/M2/M3 materials are described in detail. The introduction and operating principles of Nafion dryer are supplemented in section 2.2.1.
Correct and polish the manuscript language problems.
We have changed the statement “The absorption efficiency and the elimination of interfering impurities in the preconcentration process are critical factors in improving the analysis sensitivity.”
We're doing it in a commercial preconcentration system. Due to the structure of the preconcentration system, the adsorption tubing can only choose 1/8 inch inert stainless steel tubing.
Fig 2 was changed to a table.
"SIM" was revised to Select Ion Monitoring
“concentrations” were changed to “concentrations ratios” in the manuscript.
Revise the explanation in Section 3.2. If the peak area fluctuation of the standard gas is close to the continuous test precision of the instrument.Formula (1) can be used to calculate the sample concentration ratios.However, the process of MS has appropriate volatility, repeated tests of standard gas twice before and after can be used as a quality control measure to judge whether the error is caused by the normal fluctuation of MS, or the sample cannot be analyzed due to system anomalies. For example, the peak areas of CCl4 before and after injection are 212,168, and 210,523, respectively, and 203,186, and 204,637, respectively. The repeatability of the standard gas test meets the requirement, but there were fluctuations between the standard gas before and after the sample, which may be caused by the normal attenuation of the mass spectrum response. It could be assumed that the peak area was decayed in a gradient, so as to correct the concentration ratios of the intermediate sample to reduce the deviation caused by system fluctuations.
We have revised the interpretation of SF6.”With its extremely long atmospheric lifetime and high global warming potential (GWP), its emissions could bring a serious threat to climate change.”
We revised the Hysplit trajectory. “The Hysplit trajectory shown in Fig. 7 was used to find the pollution source, and the source of the polluted air mass may be the southeastern region of Fujian Province.”
Citation: https://doi.org/10.5194/egusphere-2022-783-AC2
-
AC2: 'Reply on RC1', Danying Shan, 08 Feb 2023
-
RC2: 'Comment on egusphere-2022-783', Anonymous Referee #2, 06 Dec 2022
This manuscript aims to provide a new methodology for the measurements of F-GHGs and ODs. This is an interesting topic, and should be encouraged to publish. I tried to understand this logic flow of this manuscript, but the language and writing of this manuscript are both quite poorly. In most sections, I nearly hard to understand the authors’ idea. So, I strongly recommend to further polish the language and logic flow of this manuscript, otherwise I cannot give the constructive comments for this manuscript. In addition, the setup of the pre-concentration system seems to the foundation of this new methodology, however the authors did not clearly display what’s the really new in this method.
Citation: https://doi.org/10.5194/egusphere-2022-783-RC2 -
AC3: 'Reply on RC2', Danying Shan, 08 Feb 2023
Thank you for your suggestion. I am very sorry for the language problem. I will further modify the language and logic flow of the manuscript and make corrections. The significance of this manuscript is how to transform the commercial monitoring system to achieve high precision monitoring of trace ODS and F-GHGs, and solve the expensive equipment development problem. In the revised manuscript, we have added sources of various materials and added more explanations of methods, so that another laboratory could reproduced. We have improved the stability of monitoring from the pre-concentration system and GCMS to ensure the precision of instrumental analysis and data integration.
Citation: https://doi.org/10.5194/egusphere-2022-783-AC3
-
AC3: 'Reply on RC2', Danying Shan, 08 Feb 2023
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