improving emission profiles of secondary organic aerosol...
TRANSCRIPT
ImprovingEmissionProfilesofSecondaryOrganicAerosolPrecursor
gasesfromBiomassBurning
YunhaLee,SerenaChung*,Tsengel Nergui,BrianLamb-WashingtonStateUniversityKelleyBarsanti,LindsayHatch-UniversityofCaliforniaRiverside
RobertYokelson -UniversityofMontana*NowwithU.S.EPA
NW-AIRQUESTmeetingJune15,2017
Biomassburningaffectsairqualitysignificantly.
AIRPACT-5PM2.5 2pmAugust182015
Challengestomodelingairqualityresultedfrombiomassburning
AIRPACT-5FractionalBiasPM2.5 August2015
Uncertaintyin‘net’SecondaryOrganicAerosol(SOA)productionfrombiomassburning
Twoimportantparameters• ∆OA/ ∆COratioè netSOAformation• OM:OC(O/Cratio)è agingofOA
Outof17publishedaircraftstudiesonagingofWildfireemissions
10:nodetectablenetadditionofOAmass3:adecrease4:anincrease
ThefindingsimplythattheOAmassfrombiomassburningremainsroughlyconstantduringaging
netOA=Dilution/evaporationofOA- SOAformation
Unidentifiedspecies(blue orgreen)
From:Warneke etal.,IJMS,2011
Goal1:ToimprovethechemicalspeciationandemissionfactorsofSOAprecursors• UsedatafromFLAME-4(FourthFireLabatMissoulaExperiment)tocalculateemissionsfactorsandbuildanupdatedemissionsinventoryfor‘borealforest’landcovertype
Goal2:ToassesstheimpactofimprovedSOAprecursorsemissionsonairquality• Runregionalairqualitymodel(CMAQ)withdefaultandupdatedemissions
• EvaluatechangesinSOAandPM2.5formation;comparemodelpredictionswithobservations
Thisstudy:UncertaintyinSOAprecursorsfrombiomassburningemissions
UncertaintyinSOAprecursorsfrombiomassburningemissions
ChemicalComposition,ComplimentaryAnalyticalApproaches
VolatilityDistributionofMeasuredNMOCsLessVolatilethanTypicallyCaptured
LogC*(volatility)
From:Hatchetal.,2017,Atmos.Chem.Phys.
CompositionalRangeofNMOCs VolatilityRangeofNMOCs
SurrogateSAPRCProfiles:Defaultvs.Updated
Default
Updated
%EFbyMassALK5 0.1% 0.6%ARO1 0.5% 0.9%ARO2 0.1% 6.1%BENZ 2.3% 2.3%TERP 1.0% 3.6%ISO 0.5% 2.5%
SOAprecursors:ALK5,ARO1(incl.toluene),ARO2(incl.xylene),BENZ,ISO,TERP(incl.a-pin.),SESQ
3-DModelingDetails
§ AIRPACT-5Domain(4-kmx4-km,21verticallayers)
§ SimulationPeriod:2015-08-10to2015-08-20
§ BiogenicEmissions:MEGANv2.10§ FireEmissions:BlueSkyv.2.5.1§ CMAQv5.0.2
SMARTFire-FireActivityMap
Gas chemicalmechanism
SOAprecursorsEmissions
CB05 Original
SAPRC07 Original
SAPRC07 Updated
ModelResults:ChangesinTotalSOA
ModelResults:ChangesinMonoterpeneSOA
ModelResults:ChangesinARO2SOA
PM2.5FractionalBiasPredictionsvs.Observations
NoChangeinPM2.5PrimaryEmissionsμgm-3>>SecondaryProductionμg m-3
Default Updated
PM2.5SpeciationPredictionsvs.Observations
SAPRC07SAPRC07
Conclusions
Default
Updated
1.Newemissionsdatafundamentallychangeslumpedsurrogatedistribution
2.ChangesinSOA/PM2.5 don’treflectemissions:Oxidantlimited?Current
SOAschemesinsensitive(andarguablyunrepresentative)?
3.YettoConsider…§ compoundsknownyieldsnotwellrepresentedby
lumpedsurrogates(e.g.,monoterpenes,alkanes/alkenes,PAHs)
§ compoundswithunderstudiedSOAyields(seeHatchetal.,ACPD,2016)
• UpdateemissionfactorsoforganicgasesandPMfrombiomass
burning
• UseBBOPfieldcampaignsandMountBachelorOAmeasurementsto
evaluatePOAandSOAseparately
• AccountforPOAevaporation
• RunasensitivityruntotestSOAparameters(e.g.,volatilityand
partitioning)
NextSteps