Reliability of reflectance measures in passive filters
Autor(a) principal: | |
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Data de Publicação: | 2014 |
Outros Autores: | , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNIFESP |
Texto Completo: | http://repositorio.unifesp.br/handle/11600/38006 http://dx.doi.org/10.1016/j.atmosenv.2014.04.023 |
Resumo: | Measurements of optical reflectance in passive filters impregnated with a reactive chemical solution may be transformed to ozone concentrations via a calibration curve and constitute a low cost alternative for environmental monitoring, mainly to estimate human exposure. Given the possibility of errors caused by exposure bias, it is common to consider sets of m filters exposed during a certain period to estimate the latent reflectance on n different sample occasions at a certain location. Mixed models with sample occasions as random effects are useful to analyze data obtained under such setups. the intra-class correlation coefficient of the mean of the m measurements is an indicator of the reliability of the latent reflectance estimates. Our objective is to determine m in order to obtain a pre-specified reliability of the estimates, taking possible outliers into account. To illustrate the procedure, we consider an experiment conducted at the Laboratory of Experimental Air Pollution, University of São Paulo, Brazil (LPAE/FMUSP), where sets of m = 3 filters were exposed during 7 days on n = 9 different occasions at a certain location. the results show that the reliability of the latent reflectance estimates for each occasion obtained under homoskedasticity is k(m) = 0.74. A residual analysis suggests that the within-occasion variance for two of the occasions should be different from the others. A refined model with two within-occasion variance components was considered, yielding k(m) = 0.56 for these occasions and k(m) = 0.87 for the remaining ones. To guarantee that all estimates have a reliability of at least 80% we require measurements on m = 10 filters on each occasion. (C) 2014 the Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). |
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Andre, Carmen Diva SaldivaAndre, Paulo AfonsoRocha, Francisco Marcelo Monteiro [UNIFESP]Saldiva, Paulo Hilário NascimentoOliveira, Regiani Carvalho deSinger, Julio MottaUniversidade de São Paulo (USP)Universidade Federal de São Paulo (UNIFESP)2016-01-24T14:37:37Z2016-01-24T14:37:37Z2014-08-01Atmospheric Environment. Oxford: Pergamon-Elsevier B.V., v. 92, p. 178-181, 2014.1352-2310http://repositorio.unifesp.br/handle/11600/38006http://dx.doi.org/10.1016/j.atmosenv.2014.04.023WOS000338810800020.pdf10.1016/j.atmosenv.2014.04.023WOS:000338810800020Measurements of optical reflectance in passive filters impregnated with a reactive chemical solution may be transformed to ozone concentrations via a calibration curve and constitute a low cost alternative for environmental monitoring, mainly to estimate human exposure. Given the possibility of errors caused by exposure bias, it is common to consider sets of m filters exposed during a certain period to estimate the latent reflectance on n different sample occasions at a certain location. Mixed models with sample occasions as random effects are useful to analyze data obtained under such setups. the intra-class correlation coefficient of the mean of the m measurements is an indicator of the reliability of the latent reflectance estimates. Our objective is to determine m in order to obtain a pre-specified reliability of the estimates, taking possible outliers into account. To illustrate the procedure, we consider an experiment conducted at the Laboratory of Experimental Air Pollution, University of São Paulo, Brazil (LPAE/FMUSP), where sets of m = 3 filters were exposed during 7 days on n = 9 different occasions at a certain location. the results show that the reliability of the latent reflectance estimates for each occasion obtained under homoskedasticity is k(m) = 0.74. A residual analysis suggests that the within-occasion variance for two of the occasions should be different from the others. A refined model with two within-occasion variance components was considered, yielding k(m) = 0.56 for these occasions and k(m) = 0.87 for the remaining ones. To guarantee that all estimates have a reliability of at least 80% we require measurements on m = 10 filters on each occasion. (C) 2014 the Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).INAIRA - Instituto Nacional de Avaliacao Integrada de Risco AmbientalConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ São Paulo, Inst Math & Stat, BR-05508 São Paulo, BrazilUniv São Paulo, Sch Med, BR-05508 São Paulo, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilUniversidade Federal de São Paulo, EPPEN, Osasco, BrazilCNPq: 15/2008FAPESP: 2008/57717-6CNPq: 308613/2011-2Web of Science178-181engElsevier B.V.Atmospheric Environmenthttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policyinfo:eu-repo/semantics/openAccessPassive filtersAir pollutionReliabilityOutliersRandom effectsReliability of reflectance measures in passive filtersinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlereponame:Repositório Institucional da UNIFESPinstname:Universidade Federal de São Paulo (UNIFESP)instacron:UNIFESPORIGINALWOS000338810800020.pdfapplication/pdf213456${dspace.ui.url}/bitstream/11600/38006/1/WOS000338810800020.pdf687a85a7fac96dedc92fafd9aebe79b0MD51open accessTEXTWOS000338810800020.pdf.txtWOS000338810800020.pdf.txtExtracted texttext/plain19523${dspace.ui.url}/bitstream/11600/38006/12/WOS000338810800020.pdf.txt79f04cbe6e0f7d612b0b26f648bef7d5MD512open accessTHUMBNAILWOS000338810800020.pdf.jpgWOS000338810800020.pdf.jpgIM Thumbnailimage/jpeg7261${dspace.ui.url}/bitstream/11600/38006/14/WOS000338810800020.pdf.jpgbb442e938a9145d85681fbb4bbcb5a94MD514open access11600/380062023-06-05 19:33:40.161open accessoai:repositorio.unifesp.br:11600/38006Repositório InstitucionalPUBhttp://www.repositorio.unifesp.br/oai/requestopendoar:34652023-06-05T22:33:40Repositório Institucional da UNIFESP - Universidade Federal de São Paulo (UNIFESP)false |
dc.title.en.fl_str_mv |
Reliability of reflectance measures in passive filters |
title |
Reliability of reflectance measures in passive filters |
spellingShingle |
Reliability of reflectance measures in passive filters Andre, Carmen Diva Saldiva Passive filters Air pollution Reliability Outliers Random effects |
title_short |
Reliability of reflectance measures in passive filters |
title_full |
Reliability of reflectance measures in passive filters |
title_fullStr |
Reliability of reflectance measures in passive filters |
title_full_unstemmed |
Reliability of reflectance measures in passive filters |
title_sort |
Reliability of reflectance measures in passive filters |
author |
Andre, Carmen Diva Saldiva |
author_facet |
Andre, Carmen Diva Saldiva Andre, Paulo Afonso Rocha, Francisco Marcelo Monteiro [UNIFESP] Saldiva, Paulo Hilário Nascimento Oliveira, Regiani Carvalho de Singer, Julio Motta |
author_role |
author |
author2 |
Andre, Paulo Afonso Rocha, Francisco Marcelo Monteiro [UNIFESP] Saldiva, Paulo Hilário Nascimento Oliveira, Regiani Carvalho de Singer, Julio Motta |
author2_role |
author author author author author |
dc.contributor.institution.none.fl_str_mv |
Universidade de São Paulo (USP) Universidade Federal de São Paulo (UNIFESP) |
dc.contributor.author.fl_str_mv |
Andre, Carmen Diva Saldiva Andre, Paulo Afonso Rocha, Francisco Marcelo Monteiro [UNIFESP] Saldiva, Paulo Hilário Nascimento Oliveira, Regiani Carvalho de Singer, Julio Motta |
dc.subject.eng.fl_str_mv |
Passive filters Air pollution Reliability Outliers Random effects |
topic |
Passive filters Air pollution Reliability Outliers Random effects |
description |
Measurements of optical reflectance in passive filters impregnated with a reactive chemical solution may be transformed to ozone concentrations via a calibration curve and constitute a low cost alternative for environmental monitoring, mainly to estimate human exposure. Given the possibility of errors caused by exposure bias, it is common to consider sets of m filters exposed during a certain period to estimate the latent reflectance on n different sample occasions at a certain location. Mixed models with sample occasions as random effects are useful to analyze data obtained under such setups. the intra-class correlation coefficient of the mean of the m measurements is an indicator of the reliability of the latent reflectance estimates. Our objective is to determine m in order to obtain a pre-specified reliability of the estimates, taking possible outliers into account. To illustrate the procedure, we consider an experiment conducted at the Laboratory of Experimental Air Pollution, University of São Paulo, Brazil (LPAE/FMUSP), where sets of m = 3 filters were exposed during 7 days on n = 9 different occasions at a certain location. the results show that the reliability of the latent reflectance estimates for each occasion obtained under homoskedasticity is k(m) = 0.74. A residual analysis suggests that the within-occasion variance for two of the occasions should be different from the others. A refined model with two within-occasion variance components was considered, yielding k(m) = 0.56 for these occasions and k(m) = 0.87 for the remaining ones. To guarantee that all estimates have a reliability of at least 80% we require measurements on m = 10 filters on each occasion. (C) 2014 the Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). |
publishDate |
2014 |
dc.date.issued.fl_str_mv |
2014-08-01 |
dc.date.accessioned.fl_str_mv |
2016-01-24T14:37:37Z |
dc.date.available.fl_str_mv |
2016-01-24T14:37:37Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
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article |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
Atmospheric Environment. Oxford: Pergamon-Elsevier B.V., v. 92, p. 178-181, 2014. |
dc.identifier.uri.fl_str_mv |
http://repositorio.unifesp.br/handle/11600/38006 http://dx.doi.org/10.1016/j.atmosenv.2014.04.023 |
dc.identifier.issn.none.fl_str_mv |
1352-2310 |
dc.identifier.file.none.fl_str_mv |
WOS000338810800020.pdf |
dc.identifier.doi.none.fl_str_mv |
10.1016/j.atmosenv.2014.04.023 |
dc.identifier.wos.none.fl_str_mv |
WOS:000338810800020 |
identifier_str_mv |
Atmospheric Environment. Oxford: Pergamon-Elsevier B.V., v. 92, p. 178-181, 2014. 1352-2310 WOS000338810800020.pdf 10.1016/j.atmosenv.2014.04.023 WOS:000338810800020 |
url |
http://repositorio.unifesp.br/handle/11600/38006 http://dx.doi.org/10.1016/j.atmosenv.2014.04.023 |
dc.language.iso.fl_str_mv |
eng |
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eng |
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Atmospheric Environment |
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http://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy info:eu-repo/semantics/openAccess |
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http://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy |
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openAccess |
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178-181 |
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Elsevier B.V. |
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Elsevier B.V. |
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