This workaimsatgaininginformationontheeffectsofdifferentthermaltreatmentson radiocarbonmeasurementsoforganic(OC)andelemental(EC)carbonfractionsinthe atmosphericaerosol.Improvementstothetraditionalapproachesforthedetermination of thefractionofmoderncarbonofOCandECfm(OC) and fm(EC)- areproposed. As for fm(EC) determination,weproposetoadd aHestepathightemperaturetothe standard oxygentreatment.Ourtestsdemonstrate thattheadditionofahightemperatureHe step (finalchoice:750 1C) totheoxygentreatmentiseffectiveinremovingtherefractoryOC. As for fm(OC) determination,weproposetoquantifyitbymeasuringeitherthefractionof modern carbonofTCandECorthefraction ofmoderncarbonofwatersoluble(fm(WSOC)) andwaterinsoluble(fm(WINSOC))organiccarbontolimittheinfluenceofpossiblepyrolysis on thedirectdeterminationof fm(OC). Testsontheequivalenceoftheapproacheshaveshown good agreementbetweenthem. Our testswerecarriedoutonsamplescollectedinaheavilypollutedarea(Milan,Italy) during wintertime. fm(OC), fm(EC),and fm(TC) valuesobtainedinourtestswerealsousedto attemptapreliminarysourceapportionmentintheareausing 14C measurements. WintertimeECresultedtobemainlyfossil(84%),whereasOCwasdominatedbymodern contribution(63%). Two approachesweretestedfortheevaluation ofthewoodburningcontributiontoOC and agoodagreementwasfound.Woodburning primarycontributionaccountedforabout 18%ofOCinMilanduringwintertime. Secondary OCfrombiomassburningandthecontributionfromotherurbansources were tentativelyidentifiedfollowingliterature approaches,withtheaimofevaluatingthe biogeniccontributiontoOCinthearea,whichwasestimatedtobeabout18%.
Radiocarbon analysis on organic and elemental carbon in aerosol samples and source apportionment at an urban site in Northern Italy / V. Bernardoni;G. Calzolai;M. Chiari;M. Fedi;F. Lucarelli;S. Nava;A. Piazzalunga;F. Riccobono;F. Taccetti;G. Valli;R. Vecchi. - In: JOURNAL OF AEROSOL SCIENCE. - ISSN 0021-8502. - STAMPA. - 56:(2013), pp. 88-99. [10.1016/j.jaerosci.2012.06.001]
Radiocarbon analysis on organic and elemental carbon in aerosol samples and source apportionment at an urban site in Northern Italy
CALZOLAI, GIULIA;CHIARI, MASSIMO;FEDI, MARIAELENA;LUCARELLI, FRANCO;NAVA, SILVIA;TACCETTI, FRANCESCO;
2013
Abstract
This workaimsatgaininginformationontheeffectsofdifferentthermaltreatmentson radiocarbonmeasurementsoforganic(OC)andelemental(EC)carbonfractionsinthe atmosphericaerosol.Improvementstothetraditionalapproachesforthedetermination of thefractionofmoderncarbonofOCandECfm(OC) and fm(EC)- areproposed. As for fm(EC) determination,weproposetoadd aHestepathightemperaturetothe standard oxygentreatment.Ourtestsdemonstrate thattheadditionofahightemperatureHe step (finalchoice:750 1C) totheoxygentreatmentiseffectiveinremovingtherefractoryOC. As for fm(OC) determination,weproposetoquantifyitbymeasuringeitherthefractionof modern carbonofTCandECorthefraction ofmoderncarbonofwatersoluble(fm(WSOC)) andwaterinsoluble(fm(WINSOC))organiccarbontolimittheinfluenceofpossiblepyrolysis on thedirectdeterminationof fm(OC). Testsontheequivalenceoftheapproacheshaveshown good agreementbetweenthem. Our testswerecarriedoutonsamplescollectedinaheavilypollutedarea(Milan,Italy) during wintertime. fm(OC), fm(EC),and fm(TC) valuesobtainedinourtestswerealsousedto attemptapreliminarysourceapportionmentintheareausing 14C measurements. WintertimeECresultedtobemainlyfossil(84%),whereasOCwasdominatedbymodern contribution(63%). Two approachesweretestedfortheevaluation ofthewoodburningcontributiontoOC and agoodagreementwasfound.Woodburning primarycontributionaccountedforabout 18%ofOCinMilanduringwintertime. Secondary OCfrombiomassburningandthecontributionfromotherurbansources were tentativelyidentifiedfollowingliterature approaches,withtheaimofevaluatingthe biogeniccontributiontoOCinthearea,whichwasestimatedtobeabout18%.File | Dimensione | Formato | |
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