简介：Weconductedmeasurementsofblackcarbon（BC）aerosolinJiaxing,ChinaduringautumnfromSeptember26toNovember30,2013.WeinvestigatedtemporalanddiurnalvariationsofBC,anditscorrelationswithmeteorologicalparametersandothermajorpollutants.ResultsshowedthathourlymassconcentrationsofBCrangedfrom0.2to22.0μg/m3,withanaverageof5.1μg/m3.ThediurnaivariationofBCexhibitedabimodaldistribution,withpeaksat07:00and18:00.Themorningpeakwaslargerthantheeveningpeak.ThemasspercentagesofBCinPM2.5andPM10were7.1%and4.8%,respectively.TheabsorptioncoefficientofBCwascalculatedtobe44.4Mm-1,whichaccountedfor11.1%ofthetotalaerosolextinction.BCwasmainlyemittedfromlocalsourcesinsouthwesternJiaxingwhereBCconcentrationsweregenerallygreaterthan11μg/m3duringthemeasurementperiod.CorrelationanalysisindicatedthatthemainsourcesofBCweremotorvehicleexhaust,anddomesticandindustrialcombustion.

简介：Chemicalcomposition,hourlycounts,andsizesofatmosphericcarbonaceousparticlesweremeasuredtoinvestigatetheirmixingstateonclearandhazydays.623,122carbonaceousparticleswithsizes0.2-2.0μmwasanalyzedusingasingle-particleaerosolmassspectrometerfrom1stto17thJanuary2013.Particletypesincludedbiomass/biofuelburningparticles(biomass),elementcarbon(EC-dominant)particlesthatwerealsomixedwithbiomass/biofuelburningspecies(EC-biomass)orsecondaryspecies(EC-secondary),organiccarbon(OC),internallymixedOCandEC(OCEC),ammonium-containing(ammonium)andsodium-containing(sodium)particles.Oncleardaysthetoprankedcarbonaceousparticletypeswerebiomass(48.2%),EC-biomass(15.7%),OCEC(11.1%),andsodium(9.6%),whileonhazydaystheywerebiomass(37.3%),EC-biomass(17.6%),EC-secondary(16.6%),andsodium(12.7%).ThefractionsofEC-secondary,ammonium(10%),andsodiumparticletypeswereelevatedonhazydays.NumbersofEC-secondaryparticlesweremorethanfourtimesthoseoncleardays(4.1%).Thus,carbonaceousparticlesmixedwithammonium,nitrateandsulfateduringagingandtransport,enhancingtheirlightextinctioneffectsandhygroscopicgrowthunderhighrelativehumidityonhazydays,furtherreducingvisibility.Ourreal-timesingle-particledatashowedthatchangestomixingstatehadasignificantimpactonlightextinctionduringhazeeventsinNanjing.

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