Improving Emission Profiles of Secondary Organic Aerosol ...lar.wsu.edu/nw-airquest/docs/20170614_meeting/NWAQ_Lee...2017/06/14  · Improving Emission Profiles of Secondary Organic

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