{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T08:51:11Z","timestamp":1771577471709,"version":"3.50.1"},"reference-count":37,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2022,9,3]],"date-time":"2022-09-03T00:00:00Z","timestamp":1662163200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"project PCIF\/GFC\/0078\/2018: influence of forest VOCs (volatile organic compounds) on extreme fire behavior at Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia (FCT)","award":["UIDB\/FIS\/04559\/2020"],"award-info":[{"award-number":["UIDB\/FIS\/04559\/2020"]}]},{"name":"project PCIF\/GFC\/0078\/2018: influence of forest VOCs (volatile organic compounds) on extreme fire behavior at Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia (FCT)","award":["UIDP\/FIS\/04559\/2020"],"award-info":[{"award-number":["UIDP\/FIS\/04559\/2020"]}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES","doi-asserted-by":"publisher","award":["UIDB\/FIS\/04559\/2020"],"award-info":[{"award-number":["UIDB\/FIS\/04559\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES","doi-asserted-by":"publisher","award":["UIDP\/FIS\/04559\/2020"],"award-info":[{"award-number":["UIDP\/FIS\/04559\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A new theory suggests that flammable gases generated by heated vegetation, in particular the volatile organic compounds (VOC) common to Mediterranean plants, may, under certain topographic and wind conditions, accumulate in locations where, after the arrival of the ignition source, they rapidly burst into flames as explosions. Hence, there is a need for the development of a system that can monitor the development of these compounds. In this work, a sensor\u2019s array is proposed as a method for monitoring the amount of eucalyptol and \u03b1-pinene, the major VOC compounds of the Eucalyptus and Pine trees. The detection of the target compounds was assessed using the impedance spectroscopy response of thin films. Combinations of layers of polyelectrolytes, such as poly(allylamine hydrochloride) (PAH), polyethyleneimine (PEI), poly(sodium 4-sytrenesulfonate) (PSS) graphene oxide (GO), and non\/functionalized multiwall nanotubes (MWCNT-COOH or MWCNT), namely, PAH\/GO, PEI\/PSS, PEI\/GO, PAH\/MWCNT, PAH\/MWCNT-COOH, films, and TiO2 and ZnO sputtered films, were deposited onto ceramic supports coated with gold interdigitated electrodes. The results showed that concentrations of the target VOCs, within the range of 68 to 999 ppmv, can be easily distinguished by analyzing the impedance spectra, particularly in the case of the ZnO- and PAH\/GO-film-based sensors, which showed the best results in the detection of the target compounds. Through principal component analysis (PCA), the best set of features attained for the ZnO and PAH\/GO based sensor devices revealed a linear trend of the PCA\u2019s first principal component with the concentration within the range 109 and 807 ppmv. Thus, the values of sensitivity to eucalyptol and \u03b1-pinene concentrations, which were (2.2 \u00b1 0.3) \u00d7 10\u22124 and (5.0 \u00b1 0.7) \u00d7 10\u22125 per decade, respectively, as well as resolutions of 118 and 136 ppbv, respectively, were identified.<\/jats:p>","DOI":"10.3390\/s22176677","type":"journal-article","created":{"date-parts":[[2022,9,8]],"date-time":"2022-09-08T04:18:32Z","timestamp":1662610712000},"page":"6677","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Volatile Organic Compound Monitoring during Extreme Wildfires: Assessing the Potential of Sensors Based on LbL and Sputtering Films"],"prefix":"10.3390","volume":"22","author":[{"given":"C\u00e1tia","family":"Magro","sequence":"first","affiliation":[{"name":"Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Almada, Portugal"},{"name":"School for International Training, World Learning Inc., Brattleboro, VT 05302, USA"}]},{"given":"Oriana C.","family":"Gon\u00e7alves","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Institute of Molecular Sciences, Departamento de Qu\u00edmica e Bioqu\u00edmica, Faculdade de Ci\u00eancias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal"}]},{"given":"Marcelo","family":"Morais","sequence":"additional","affiliation":[{"name":"Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Almada, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9665-7610","authenticated-orcid":false,"given":"Paulo A.","family":"Ribeiro","sequence":"additional","affiliation":[{"name":"Laboratory of Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys-UNL), Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Almada, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8086-7792","authenticated-orcid":false,"given":"Susana","family":"S\u00e9rio","sequence":"additional","affiliation":[{"name":"Laboratory of Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys-UNL), Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Almada, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3823-1184","authenticated-orcid":false,"given":"Pedro","family":"Vieira","sequence":"additional","affiliation":[{"name":"Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Almada, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4710-0693","authenticated-orcid":false,"given":"Maria","family":"Raposo","sequence":"additional","affiliation":[{"name":"Laboratory of Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys-UNL), Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Almada, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"972","DOI":"10.1038\/s41558-018-0299-2","article-title":"Climate change and interconnected risks to sustainable development in the Mediterranean","volume":"8","author":"Cramer","year":"2018","journal-title":"Nat. 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