{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,16]],"date-time":"2026-07-16T04:05:08Z","timestamp":1784174708192,"version":"3.55.0"},"reference-count":23,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T00:00:00Z","timestamp":1784073600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper presents the design, development, and large-scale deployment of a vehicular IoT-based methane sensing system for urban environmental monitoring. The proposed solution integrates a low-cost metal oxide semiconductor (MOS) methane sensor with a dual chamber gas sampling mechanism, embedded processing, and wireless communication via 4G\/5G networks using a smartphone as a gateway. Methane concentration data are collected from sensors installed in moving vehicles, georeferenced in real time using GNSS, and transmitted to a cloud-based platform for storage and analysis. Field experiments were conducted in the metropolitan region of S\u00e3o Paulo, Brazil, using 16 instrumented vehicles over a 20-month period, covering approximately 192,274 km and generating more than 48 million measurements. The results reveal spatially consistent methane concentration patterns and identify urban areas with elevated levels exceeding global background concentrations. A comparative analysis with a commercial infrared-based mobile methane monitoring system showed consistent agreement in the identification of spatial methane concentration patterns and potential emission hotspots. These results demonstrate the effectiveness of the proposed system for scalable urban methane monitoring.<\/jats:p>","DOI":"10.3390\/s26144491","type":"journal-article","created":{"date-parts":[[2026,7,16]],"date-time":"2026-07-16T03:34:23Z","timestamp":1784172863000},"page":"4491","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Vehicular IoT-Based Methane Sensing System for Large-Scale Urban Environmental Monitoring"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-0747-1648","authenticated-orcid":false,"given":"Nuncio","family":"Perrella","sequence":"first","affiliation":[{"name":"Polytechnic School, University of Sao Paulo, Sao Paulo 05508-010, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5142-9964","authenticated-orcid":false,"given":"Fuad","family":"Kassab","sequence":"additional","affiliation":[{"name":"Polytechnic School, University of Sao Paulo, Sao Paulo 05508-010, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Angelo","family":"Zanini","sequence":"additional","affiliation":[{"name":"Maua Institute of Technology, Sao Caetano do Sul 09580-900, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2805","DOI":"10.1073\/pnas.1814297116","article-title":"Interpreting contemporary trends in atmospheric methane","volume":"116","author":"Turner","year":"2019","journal-title":"Proc. Nat. Acad. Sci. USA"},{"key":"ref_2","unstructured":"National Oceanic and Atmospheric Administration (NOAA) (2024, May 28). Trends in Atmospheric Methane, Available online: https:\/\/gml.noaa.gov\/ccgg\/trends_ch4\/."},{"key":"ref_3","first-page":"153","article-title":"Corre\u00e7\u00e3o Atmosf\u00e9rica: Conceitos e Fundamentos","volume":"5","author":"Latorre","year":"2002","journal-title":"Espa\u00e7o Geogr."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Shimanoe, K., Yuasa, M., Kida, T., and Yamazoe, N. (2011, January 18\u201321). Semiconductor Gas Sensor Using Nano-Sized Oxide for High-Sensitive Detection of Environment-Related Gases. Proceedings of the 2011 IEEE Nanotechnology Materials and Devices Conference, Jeju, Republic of Korea.","DOI":"10.1109\/NMDC.2011.6155309"},{"key":"ref_5","unstructured":"Bretschneider, T.R., and Shetti, K. (2015). UAV-Based Gas Pipeline Leak Detection, Airbus Group Innovations."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"670","DOI":"10.21533\/pen.v7.i2.1573","article-title":"GSM Based Gas Leak Monitoring System","volume":"7","author":"Ishak","year":"2019","journal-title":"Period. Eng. Nat. Sci."},{"key":"ref_7","unstructured":"Kessel, T.G., Ramachandran, M., Klein, L.J., Nair, D., Hinds, N., Hamann, H., and Sosa, N.E. (2018, January 28\u201331). Methane Leak Detection and Localization Using Wireless Sensor Networks for Remote Oil and Gas Operations. Proceedings of the 2018 IEEE SENSORS, New Delhi, India."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"4091","DOI":"10.1021\/acs.est.6b06095","article-title":"Rapid, Vehicle-Based Identification of Location and Magnitude of Urban Natural Gas Pipeline Leaks","volume":"51","author":"Cooley","year":"2017","journal-title":"Environ. Sci. Technol."},{"key":"ref_9","unstructured":"(2026, April 23). TGS2611-C00 Datasheet. Available online: https:\/\/www.figarosensor.com\/product\/docs\/tgs2611-c00_product%20information%28fusa%29rev01.pdf."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1925","DOI":"10.5194\/amt-5-1925-2012","article-title":"Performance of a Low-Cost Methane Sensor for Ambient Concentration Measurements in Preliminary Studies","volume":"5","author":"Eugster","year":"2012","journal-title":"Atmos. Meas. Tech."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Aldhafeeri, T., Tran, M., Vrolyk, R., Pope, M., and Fowler, M. (2020). A Review of Methane Gas Detection Sensors: Recent Developments and Future Perspectives. Inventions, 5.","DOI":"10.3390\/inventions5030028"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2548","DOI":"10.1364\/AO.56.002548","article-title":"Multiband infrared inversion for low-concentration methane monitoring in a confined dust-polluted atmosphere","volume":"56","author":"Wang","year":"2017","journal-title":"Appl. Opt."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1016\/j.snb.2016.12.146","article-title":"Development and field deployment of a mid-infrared methane sensor without pressure control using interband cascade laser absorption spectroscopy","volume":"244","author":"Zheng","year":"2017","journal-title":"Sens. Actuators B Chem."},{"key":"ref_14","unstructured":"(2026, April 23). HGS Protheo Huberg. Available online: https:\/\/www.hgs.it\/it\/protheo\/."},{"key":"ref_15","unstructured":"(2026, April 23). INIR-ME5% Datasheet. Available online: https:\/\/www.sgxsensortech.com\/uploads\/f_note\/ds-0229-INIR.pdf."},{"key":"ref_16","unstructured":"Leonardo, F., Manuel, F., Laercio, F., and Get\u00falio, I. (2018, January 8\u201312). Aplica\u00e7\u00e3o e Avalia\u00e7\u00e3o de um Sensor de Baixo Custo para Identifica\u00e7\u00e3o de Perdas de Metano em Redes Urbanas de Distribui\u00e7\u00e3o de G\u00e1s Natural. Proceedings of the Confer\u00eancia Internacional de Ambiente em L\u00edngua Portuguesa, XX Encontro REALP, Aveiro, Portugal."},{"key":"ref_17","unstructured":"(2026, June 12). Portable Gas Detector GT Series. Available online: https:\/\/www.teledynegasandflamedetection.com\/en-us\/gt-7-applications-portable-gas-detection."},{"key":"ref_18","unstructured":"Sivathanu, Y. (2005). Technology Status Report on Natural Gas Leak Detection in Pipelines."},{"key":"ref_19","unstructured":"(2026, March 25). Computational Fluid Dynamics Software Simulation. Available online: https:\/\/www.ansys.com\/products\/fluids\/ansys-fluent."},{"key":"ref_20","unstructured":"(2026, March 25). ESP32-WROOM 32D Datasheet. Available online: https:\/\/documentation.espressif.com\/esp32-wroom-32d_esp32-wroom-32u_datasheet_en.pdf."},{"key":"ref_21","unstructured":"Aosong Electronics Co., Ltd. (2024, November 15). AHT10 Technical Manual. Available online: https:\/\/server4.eca.ir\/eshop\/AHT10\/Aosong_AHT10_en_draft_0c.pdf."},{"key":"ref_22","unstructured":"Guo, K., Yang, P., Guo, D.H., and Liu, Y. (2019, January 27\u201328). Gas Leakage Monitoring with Mobile Wireless Sensor Networks. Proceedings of the 8th International Congress of Information and Communication Technology (ICICT-2019), London, UK."},{"key":"ref_23","first-page":"2320","article-title":"Internet of Things (IoT) Based Gas Leakage Monitoring and Alerting System with MQ-6 Sensor","volume":"6","author":"Pandey","year":"2018","journal-title":"Int. J. Creat. Res. Thoughts"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/14\/4491\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,16]],"date-time":"2026-07-16T03:37:44Z","timestamp":1784173064000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/14\/4491"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,15]]},"references-count":23,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2026,7]]}},"alternative-id":["s26144491"],"URL":"https:\/\/doi.org\/10.3390\/s26144491","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,15]]}}}