An overview of outdoor low-cost gas-phase air quality sensor deployments: current efforts, trends, and limitations

Okorn, Kristen; Iraci, Laura T.

doi:https://doi.org/10.5194/amt-17-6425-2024

Articles | Volume 17, issue 21

https://doi.org/10.5194/amt-17-6425-2024

© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/amt-17-6425-2024

© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 17, issue 21

Review article

| Highlight paper

|

08 Nov 2024

Review article | Highlight paper |

| 08 Nov 2024

An overview of outdoor low-cost gas-phase air quality sensor deployments: current efforts, trends, and limitations

Kristen Okorn and Laura T. Iraci

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Final revised paper (published on 08 Nov 2024)
Preprint (discussion started on 08 Apr 2024)
Supplement to the preprint

Interactive discussion

Status: closed

CC1:
'Comment on egusphere-2024-1004 [Labzovskii et al.]', Lev Labzovskii, 10 Apr 2024

We have noticed a citation on the low-cost AQ network from Siberia in your work; the network we used to publish Lin et al. (2020) work about studying AQ using synergy of sensors and satellites in Siberia. I am thinking about this statement you made: "We encountered one PM study in the region (Lin et. al., 2020) and one study using spatially-distributed passive sampling (Khuriganova et. al., 2019), but no true gas-phase low-cost sensor studies, highlighting the need for more monitoring and availability of data in this region.").
Considering this statement, I'd advise to look at another study from our side on the topic of AQ using cheap sensors in Siberia (Labzovskii et al., 2023; https://www.sciencedirect.com/science/article/pii/S146290112200363X). From this study, you can learn more about situation on AQ monitoring in Siberia (in particular in Krasnoyarsk) with its drivers, challenges and pitfalls. In fact, we managed to show that Krasnoyarsk is the first case in the world, where citizen monitoring-driven system by Nebo activists (https://nebo.live/pages/neboair) has led to full-scale decentralization of AQ urban monitoring. You can learn more about this network in the paper, but in short - Nebo sensors are being used alongside governmental sensors in many AQ aggregators like waqi.info and by people to judge about air quality. This comment will help complementing the scarce information your provided about sensors in Russia and Eastern Europe.

P.s. Among the low-cost sensors networks you mentioned I have not noticed not only Nebo, but also Smart Air Bangladesh and this initiative - https://github.com/CodeForAfrica/sensors.AFRICA. There are many more, but its outside of the scope of my comment! Good luck

Citation: https://doi.org/10.5194/egusphere-2024-1004-CC1
- AC1: 'Reply on CC1', Kristen Okorn, 10 Apr 2024
  
  Thank you for your comments! We will add a reference to the Labzovskii et. al. 2023 paper in the Siberia section to mention the Nebo sensors as another PM effort, and add a bit more context as to why sensors are lacking in this region. The paper has a lot of valuable context which will be helpful to the reader. Nebo will remain a reference for future reading and not a full review, however, since it only measures PM rather than gas-phase compounds.
  Thank you for mentioning the additional sensor networks as well. SmartAir Bangladesh seems to be made for indoor and wearable monitoring – we did not encounter any studies using these sensors in a stationary outdoor deployment, so it does not seem to meet our criteria for inclusion as detailed in section 1.4.
  Thank you for mentioning sensors.africa as well. This network seems to only measure PM, so it is also outside the scope of our review, but I can add a reference for further reading where appropriate.
  
  Citation: https://doi.org/10.5194/egusphere-2024-1004-AC1
RC1:
'Comment on egusphere-2024-1004', Anonymous Referee #1, 15 Jun 2024

The manuscript devoted to an impressive review on sensor networks and related efforts to monitor air quality worldwide. Significant analysis has been done by deep approach and methodology. Many features have been outlined in different Countries: particulate matter and gases have been reviewed as deployed by universities, research groups and private companies. Some key references should be added to complement the full list:
M. Penza (2020). Low-cost sensors for outdoor air quality monitoring - Book Chapter - Advanced Nanomaterials for Inexpensive Gas Microsensors (2020) 235-288 - Editor E. Llobet. DOI: https://doi.org/10.1016/B978-0-12-814827-3.00012-8
Philipp Schneider, Alena Bartonova, Nuria Castell, Franck R. Dauge, Michel Gerboles, Gayle S.W. Hagler, Christoph Hüglin, Roderic L. Jones, Sean Khan, Alastair C. Lewis, Bas Mijling, Michael Müller, Michele Penza, Laurent Spinelle, Brian Stacey, Matthias Vogt, Joost Wesseling, Ronald W. Williams (2019). Toward a Unified Terminology of Processing Levels for Low-Cost Air-Quality Sensors - Environmental Science and Technology, 2019, 53, 15, 8485-8487. DOI: https://doi.org/10.1021/acs.est.9b03950
C. Borrego, J. Ginja, M. Coutinho, C. Ribeiro, K. Karatzas, Th Sioumis, N. Katsifarakis, K. Konstantinidis, S. De Vito, E. Esposito, M. Salvato, P. Smith, N. André, P. Gérard, L.A. Francis, N. Castell, P. Schneider, M. Viana, M.C. Minguillón, W. Reimringer, R.P. Otjes, O. von Sicard, R. Pohle, B. Elen, D. Suriano, V. Pfister, M. Prato, S. Dipinto, M. Penza (2018). Assessment of air quality microsensors versus reference methods: The EuNetAir joint exercise - Part II - Atmospheric Environment, 2018, 193, 127-142. DOI: https://doi.org/10.1016/j.atmosenv.2018.08.028
World Meteorological Organization, 2021 WMO Report No. 1215 - An update on low-cost sensors for the measurement of atmospheric composition. Editor: Richard E. Peltier. Lead Authors: Núria Castell, Andrea L Clements, Tim Dye, Christoph Hüglin, Jesse H Kroll, Shih-Chun Candice Lung, Zhi Ning, Matthew Parsons, Michele Penza, Fabienne Reisen, Erika von Schneidemesser. ISBN 978-92-63-11215-6. https://library.wmo.int/index.php?id=21508&lvl=notice_display#.Yifnz3yZPIU
World Meteorological Organization, 2018 WMO Report No. 1215. Low -cost sensors for the measurement of atmospheric composition: overview of topic and future applications. Editors: Alastair C. Lewis, Erika von Schneidemesser and Richard E. Peltier. Lead Authors: SC Candice Lung, Rod Jones, Christoph Zellweger, Ari Karppinen, Michele Penza, Tim Dye, Christoph Hüglin, Zhi Ning, Alastair C. Lewis, Erika von Schneidemesser, Richard E. Peltier, Roland Leigh, David Hagan, Olivier Laurent and Greg Carmichael. ISBN 978-92-63-11215-6. http://www.aqmd.gov/docs/default-source/aq-spec/resources-page/low_cost_sensors_post_review_final.pdf?sfvrsn=6
Minor typo: at page 17, the reference Sun et al., 2016 is related to "Hong Kong Marathon" and not related to "Beijing Marathon". Please, amend properly the text.
I kindly suggest Minor Revisions before publication.

Citation: https://doi.org/10.5194/egusphere-2024-1004-RC1
- AC2: 'Reply on RC1', Kristen Okorn, 04 Sep 2024
  
  Reviewer 1 comment #1: The manuscript devoted to an impressive review on sensor networks and related efforts to monitor air quality worldwide. Significant analysis has been done by deep approach and methodology. Many features have been outlined in different Countries: particulate matter and gases have been reviewed as deployed by universities, research groups and private companies. Some key references should be added to complement the full list.
  Author Response #1: Thank you for your thoughtful review of our manuscript. The 2019 Schneider paper is an excellent addition to section 5, where we discuss recent sensor data harmonization efforts. We appreciate your pointing out the newest WMO/IGAC report; it has been cited in section 1.5. Because we were unable to obtain a copy of the book chapter that was mentioned, we do not feel comfortable citing it in any specific way here, but we do appreciate knowing of its existence.
  Reviewer 1 comment #2: Minor typo: at page 17, the reference Sun et al., 2016 is related to "Hong Kong Marathon" and not related to "Beijing Marathon". Please, amend properly the text.
  Author Response #2: Thank you for catching this error. We have corrected it.
  
  Citation: https://doi.org/10.5194/egusphere-2024-1004-AC2
RC2:
'Comment on egusphere-2024-1004', Anonymous Referee #2, 20 Aug 2024

The manuscript provides a comprehensive review of stationary, low-cost gas-phase sensor networks deployed in outdoor environments globally. It categorizes these networks based on their deployment type—quasi-permanent and campaign—and discusses their common practices, strengths, and weaknesses. The paper also highlights the historical development of low-cost gas sensors, the need for gas-phase sensor networks, and the importance of environmental justice in air quality monitoring. Furthermore, it examines the types of pollutants measured, the calibration methods used, and the data quality assurance practices within these networks. The review overall presents the community with good insights on the status of sensor network development and its data quality control, aiming to guide scientists and end-users in building and utilizing sensor networks effectively. I kindly suggest a minor revision before publication on AMT journal.
Section2&3: It is informative that authors outline the sensor networks according to the organization operating them and the regions of deployment in these two sections. While the readers can obtain plentiful information from the text, I would suggest providing a detailed table in the maintext showing key characteristics of these network, such as the data access, calibration procedure, data quality and better grading the network for scientific researcher.
Line 495: It seems like most of East Asia deployment of sensor networks authors reviewed were based in China instead of out of China.
Suggest adding more information about current status and future trend on the scenarios of sensor deployment, such as UAV and ship.

Citation: https://doi.org/10.5194/egusphere-2024-1004-RC2
- AC3: 'Reply on RC2', Kristen Okorn, 04 Sep 2024
  
  Reviewer 2 comment #1: It is informative that authors outline the sensor networks according to the organization operating them and the regions of deployment in these two sections. While the readers can obtain plentiful information from the text, I would suggest providing a detailed table in the maintext showing key characteristics of these network, such as the data access, calibration procedure, data quality and better grading the network for scientific researcher.
  Author response #1: Thank you for this feedback. We have moved the table with the requested information from the supplemental to the main text of the manuscript (Tables 1&2) and have added some formatting changes for clarity. Regarding which columns are included, we have opted to only include information that is succinct (i.e., does not necessarily require context and caveats for the reader to understand) and unlikely to change. While adding data access information is a valuable suggestion, networks may publish data only from certain nodes, may technically be available but hard to find, or have inconsistent availability of live and historical data. We feel that this information needs to be distilled with the proper context in the text for each network, and have included as much information as possible on sensors with available data in the main text. As an example, since the publication of our preprint in April, PurpleAir has made significant changes to their API system that would already be out of date and also difficult to encapsulate in a few words in the table. Since the intention of the table is to be quick access information for the reader, we would like to keep it free of additional context and caveats that can be better explained elsewhere.
  Reviewer 2 comment #2: Line 495: It seems like most of East Asia deployment of sensor networks authors reviewed were based in China instead of out of China.
  Author response #2: Thank you for bringing this to our attention. We meant to state that the majority of these networks were based in China, but see that the verbiage was confusing and have corrected this.
  Reviewer 2 comment #3: Suggest adding more information about current status and future trend on the scenarios of sensor deployment, such as UAV and ship.
  Author response #3: We appreciate this comment, and have added a paragraph on the use of sensors onboard UAV and recent deployments on ships and in ports to section 6.
  
  Citation: https://doi.org/10.5194/egusphere-2024-1004-AC3

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

AR by Kristen Okorn on behalf of the Authors (04 Sep 2024) Author's response Author's tracked changes Manuscript

ED: Publish as is (10 Sep 2024) by Haichao Wang

AR by Kristen Okorn on behalf of the Authors (11 Sep 2024) Manuscript

Post-review adjustments

AA: Author's adjustment | EA: Editor approval

AA by Kristen Okorn on behalf of the Authors (04 Nov 2024) Author's adjustment Manuscript

EA: Adjustments approved (04 Nov 2024) by Haichao Wang

Short summary

We reviewed 60 sensor networks and 17 related efforts (sensor review papers and data accessibility projects) to better understand the landscape of stationary low-cost gas-phase sensor networks deployed in outdoor environments worldwide. Gaps in monitoring efforts include the availability of gas-phase measurements compared to particulate matter (PM) and geographic coverage gaps (the Global South, rural areas). We conclude with a summary of cross-network unification and quality control efforts.