novel measurements of volatility- and polarity-separated ... · masters: xiaochen zuo, mayura...

Novel Measurements of Volatility- and Polarity-Separated Organic Aerosol Composition and Associated Hygroscopicity to

Investigate the Influence of Mixed Anthropogenic-Biogenic Emissions on Atmospheric Aging Processes

Brent J. WilliamsWashington University in St. Louis

Department of Energy, Environmental and Chemical Engineering

U. Colorado – Boulder and CIRES (Jimenez)U. California – Berkeley (Goldstein)Aerosol Dynamics Inc. (Berkeley, CA)Aerodyne Research Inc. (Billerica, MA)

U. Minnesota (Millet)Georgia Tech (Ng, Weber)Penn State University (Brune)WashU (Turner)

R835402

Acknowledgements: Participating Lab Members

Research Scientist: Munkhbayar BaasandorjMasters: Xiaochen Zuo, Mayura PatankarUndergrads: Hagan, Dhawan, Geyer, Streff, Sussman, Wilcosky

PhD

• Atmospheric primary and secondary organic gases and particles originate from biogenic and anthropogenic emissions, and bio/anthro interactions have been observed to alter production of secondary organic aerosol (SOA).

• Impacts health and climate

• *Uncertainty remains in determining sources and evolution of organic aerosol (OA)

• *There is a need for improved chemical characterization of complex OA composition

• *We want manageable parameterizations of this chemistry to enable modeling of complex atmospheric OA (mixture can contain tens of thousands of compounds). Approach through novel data analysis methods and new measurement techniques.

Motivation

Organic aerosol is an intermediate in the oxidationof most organics to CO2.

Secondary Organic Aerosol (SOA)

CO2

CO

C40

Organic Aerosol

gas

particle

Adapted from Kroll et al., Nature Chemistry, 2011

Oxidative Evolution of Organic Material in Atmosphere

CH4

Oxidative Evolution of Organic Material in Atmosphere

• A small molecule like isoprene (C5) only crosses edge of the condensed phase• More likely for larger molecules (e.g., C10, C15) to cross through condensed phase• Aerosol Yield from smaller molecules may be very sensitive to altered reaction paths

OrganicAerosol

Organic Gases

Adapted from Kroll et al., Nature Chemistry, 2011

Spracklen et al., ACPD, 2011

Our goal is to contribute to a better understanding of the anthropogenic

enhancement of biogenic SOA production

Primary Organic Aerosol Secondary Organic Aerosol

OUTLINE

• Instrument Development

• Novel Data Analysis Methods

• Field observations: SOAS – Centreville, AL

• Field observations: SLAQRS – East St. Louis, IL

• Laboratory-based oxidation studies

• Conclusions

Our methods for In-Situ Organic Aerosol Chemical Characterization

Thermal desorption Aerosol Gas chromatograph (TAG)

Volatility and Polarity Separator (VAPS)

Aerosol Mass Spectrometer (AMS)

Collection and Thermal Desorption Cell

GC Oven

QuadMS

30m Non-Polar Column

Helium

Pola

rity

Volatility

R+

ToF-MS

Particle Time of Flight Chamber

Displaying Organic Ions Only

High Resolution MS Vol. & Pol.- Separated MS

Canagaratna et al, MS Reviews

2007

Williams et al, AS&T 2006

Goldstein et al, J.ChromA 2008Martinez et al, AS&T 2016

15.00 20.00 25.00 30.00 35.00 40.00 45.000

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

4500000

5000000

Time-->

AbundanceTIC: 33702-12.DTIC: 33702-13.D (*)

Chromatography-Separated MS

Collection and Thermal Desorption Cell

Transfer Line

Polar Column

Modulator

ToFMS

Helium

- Faster- More Mass- Parameterized Chemistryfor models

Organic Aerosol Analysis in Perspective

Tim

e R

eso

luti

on

High

Low

100

80

60

40

20

0

Co

mp

lete

nes

s(%

of

Mas

s A

nal

yzed

)

Chemical Resolution

Useless

Instrument

AMS

Useless

Instrument

Perfect

Instrument

TAG

AMS

Increase

completeness

Increase

classification

Adapted from Hallquist et al., ACP, 2009

VAPS – Martinez et al., AS&T, 2016

VAPS1 second

1 hour

1-5 minute

20-30 minute

Aerodyne Research Inc. (US-DOE – SBIR, Phases I, II): Volatility and polarity separated total organic aerosol using thermal desorption modulated chromatography

In-Situ Measurements

TAGAMS VAPS


Vehicle

Secondary Vehicle

Biogenic

Secondary Biogenic

Biomass Burn

SecondaryBiomass Burn

Industrial

Secondary Industrial

Group covarying chemical signals:Positive Matrix Factorization (PMF)

Match to known source profiles Factors can also represent atmospheric transformation processes

Sample and separate using complementary techniques:AMS (Mass Spec. of organic and inorganic components)VAPS (organic components with additional chemical separation)TAG (individual organic “marker” compounds)


x Time Series

OUTLINE






• Conclusions

New binning method developed to directly insert a collection of TAG chromatograms or VAPS “vapograms” into PMF.

• Saves from having to integrate individual compounds• Incorporates the unresolved complex mixture (UCM)

Zhang et al, AS&T 2014

Chromatogram “Vapogram”

600x103

500

400

300

200

100

0

TIC

50403020

Retention Time (min)

Total signal Column bleed

Resolved peaks

UCM

Bin size determines degree of chemical resolution

Pola

rity

Volatility

Binned PMF data matrix can be arranged to separate for:

Zhang et al, AS&T 2014 + In-Prep.

1) Major chromatogram components(e.g., compounds with similar mass spectral features or functionality)

Chromatogram Deconvolution PMF

2) Major study-time components(e.g., Sources or Transformations)

Source Apportionment PMF

10

8

6

4

2

0

Mass C

once

ntr

atio

n (

mg m

-3)

12:00 AM6/21/13

12:00 AM6/22/13

12:00 AM6/23/13

12:00 AM6/24/13

12:00 AM6/25/13

12:00 AM6/26/13

CDT

AMS Organics VAPS_Isoprene SOA VAPS_Terpene SOA3 VAPS_Terpene SOA2 VAPS_BBOA VAPS_Alkanes VAPS_Terpene SOA1

Alkanes

Acids

OUTLINE






• Conclusions

Observations from two recent field studies

St. Louis Air Quality Regional Study (SLAQRS) Aug.3 – Oct.15, 2013

Southern Oxidant and Aerosol Study (SOAS) Jun.1 – July.15, 2013

Modeled Isoprene Emissions

Millet et al. (2008)

SLAQRS

SOAS

Now known that isoprene can produce SOA….

Formation of Isoprene SOA(anthropogenic influences)

isoprene+OH,O2

+H2O

+SO4-2

+NO3-

+H2O

+SO4-2

+NO3-

RO2

+HO2

IEPOX

+NO

+OH, NO2

MPAN

+OH

MAE

Low

-NO

xPa

thH

igh

-NO

xPa

th Gas phase

Pa

rtic

le p

ha

se

Emission

Organosulfates?Organonitrates?Oligomers?

Figure from Surratt et al.

Goldstein, Fung, et al, 2009

(satellite observations)

+NO3,O2

…some to

Particle

12

8

4

0

6/1/13 6/21/13 7/11/13 7/31/13 8/20/13 9/9/13 9/29/13

20

15

10

5

0

6/1/13 6/21/13 7/11/13 7/31/13 8/20/13 9/9/13 9/29/13

120

80

40

0

6/1/13 6/21/13 7/11/13 7/31/13 8/20/13 9/9/13 9/29/13

Alabama ground site (SOAS) East St. Louis (SLAQRS)

SOAS Isoprene (deGouw & Goldstein et al.)

SOAS NOx from SEARCH CTR database (ARA)

pp

bp

pb

SOAS SO2 from SEARCH CTR database (ARA)

pp

b

Isoprene

NOx

SO2Precursor to Anthropogenic Sulfate Aerosol

Xu et al., PNAS, 2015AMS Factors from SOAS

AMS only finds 1 type of isoprene SOA, although there are various formation pathways. AMS may not easily differentiate.

Some lab evidence showing LO-OOA may be terpene SOA.

Can VAPS offer more information?

VAPS - SOASRural Alabama(lots of Isoprene and Terpene SOA)

VAPS – SLAQRSUrban St. Louis (more POA)

2D-VBS Oxidation pathways(Donahue et al., ACPD 2012)

B)

Tota

l Io

n S

ign

al

Po

lari

ty

Tota

l Io

n S

ign

al

Martinez et al, AS&T 2016

First Field deployments for VAPS

A)

POA

10.5

0-0.5

-1-1.5

-2

OS c C5H8 Isoprene

C10H16 Terpenes

C)

Column Bleed

TerpeneSOA2 O:C=0.36

TerpeneSOA3 O:C=0.5

Alkanes

Terpenes O:C=0.12

TerpeneSOA1 O:C=0.19

IEPOX-derived

Organic Sulfates

Acetic Acid

Thermal Decomp. – LVOCs (m/z44) NO3

-, SO42-

Decomposition

Acetic Acid

OrganicSulfates

IEPOX-derived

TerpeneSOA1

Terpenes

Alkanes

TerpeneSOA3

TerpeneSOA2

GCColumn

Chromatogram Deconvolution PMF on Binned VAPS Data (SOAS)

Source Apportionment PMF on Binned VAPS Data (SOAS)

10

8

6

4

2

0

Mass C

once

ntr

atio

n (

mg m

-3)

12:00 AM6/21/13

12:00 AM6/22/13

12:00 AM6/23/13

12:00 AM6/24/13

12:00 AM6/25/13

12:00 AM6/26/13

CDT


10

8

6

4

2

0

Mass C

once

ntr

atio

n (

mg

m-3

)

12:00 AM6/21/13

12:00 AM6/22/13

12:00 AM6/23/13

12:00 AM6/24/13

12:00 AM6/25/13

12:00 AM6/26/13

CDT


10

8

6

4

2

0

Mass C

once

ntr

atio

n (

mg m

-3)

12:00 AM6/21/13

12:00 AM6/22/13

12:00 AM6/23/13

12:00 AM6/24/13

12:00 AM6/25/13

12:00 AM6/26/13

AMS Organics GTech_BBOA GTech_Isoprene-OA GTech_LO-OOA GTech_MO-OOA

VAPS PMF

AMS PMF(Ng, GTech)

Correlations (Pearson r)

SV-TAG (UC-Berkeley) AMS

C5

alk

en

e t

rio

l1

C5

alk

en

e t

rio

l2

2-m

eth

ylte

tro

l 1

2-m

eth

ylte

tro

l 2

me

thyl

glyc

eri

cac

id

pin

icac

id

pin

on

icac

id

hyd

roxy

glu

tari

cac

id

levo

glu

cosa

n

Iso

pre

ne

OA

LO-O

OA

MO

-OO

A

BB

OA

Iso

pre

ne

OA

+ M

O-O

OA

VA

PS

Isoprene SOA 0.67 0.67 0.53 0.55 0.45 -0.04 0.29 0.55 0.22 0.43 0.04 0.65 0.28 0.67

Terpene SOA1 -0.18 -0.25 -0.10 -0.28 -0.46 0.56 0.27 0.17 0.19 0.24 0.56 0.14 0.28 0.06

Terpene SOA2 0.43 0.39 0.59 0.50 0.08 0.70 0.40 0.65 0.60 0.23 0.54 0.60 0.30 0.55

Terpene SOA3 0.44 0.32 0.51 0.31 0.17 0.73 0.79 0.55 0.35 0.66 0.86 0.55 0.70 0.65

BBOA 0.25 0.15 0.18 0.08 0.20 0.29 0.63 0.27 0.15 0.37 0.62 0.10 0.67 0.26

IsopreneSOA + TerpeneSOA3 0.78 0.69 0.73 0.60 0.40 0.47 0.75 0.76 0.40 0.80 0.67 0.87 0.73 0.92

TerpeneSOA1+2 + BBOA 0.31 0.20 0.43 0.23 -0.11 0.87 0.70 0.64 0.55 0.45 0.93 0.51 0.67 0.52

AM

S

IsopreneOA 0.78 0.67 0.69 0.61 0.68 0.40 0.62 0.52 0.25

LO-OOA 0.52 0.38 0.53 0.38 0.23 0.83 0.85 0.68 0.51

MO-OOA 0.77 0.74 0.79 0.73 0.43 0.54 0.54 0.85 0.46

BBOA 0.62 0.54 0.50 0.40 0.28 0.51 0.71 0.61 0.50

Isoprene+MO-OOA 0.79 0.70 0.81 0.68 0.40 0.55 0.69 0.80 0.51

Combinations of ComponentsProvides highest correlations

7

6

5

4

3

2

1

0

Ma

ss C

on

cen

tra

tion

(m

g m

-3)

12:00 AM6/21/13

12:00 AM6/22/13

12:00 AM6/23/13

12:00 AM6/24/13

12:00 AM6/25/13

12:00 AM6/26/13

VAPS_Terpene SOA3 VAPS_Isoprene SOA AMS_IsopreneOA AMS_IsopreneOA + MO-OOA

6

5

4

3

2

1

0

Mass C

once

ntr

atio

n (

mg m

-3)

12:00 AM6/21/13

12:00 AM6/22/13

12:00 AM6/23/13

12:00 AM6/24/13

12:00 AM6/25/13

12:00 AM6/26/13

VAPS_Terpene SOA2 VAPS_Terpene SOA1 VAPS_BBOA AMS_LO-OOA

BBOA16%

LO-OOA1.9 mg m-3

Isoprene SOA61%

Terpene SOA339%

Isoprene OA1.1 mg m-3

MO-OOA2.0 mg m-3

AMS VAPS

r = 0.92

r = 0.93

Terpene SOA232%

Terpene SOA152%

VAPS Indicates:

40% Isoprene SOA60% Terpene SOA3

52% Terpene SOA132% Terpene SOA216% BBOA

GTech AMS results (Xu et al., PNAS, 2015)

IEPOXIsoprene SOA

18%

BBOA15%

TerpeneSOA117%

TerpeneSOA210%

TerpeneSOA323%

OtherIsoprene SOA

16%

50%

34%

*VAPS analysis based only on 1 week time period, AMS analysis was over entire month

8

6

4

2

0

Mass C

once

ntr

atio

n (

mg m

-3)

12:00 AM6/21/13

12:00 AM6/22/13

12:00 AM6/23/13

12:00 AM6/24/13

12:00 AM6/25/13

12:00 AM6/26/13

0.4

0.3

0.2

0.1

0.0

AM

S N

O3

+ Mass C

once

ntra

tion (m

g m

-3)

VAPS_Terpene SOA3 VAPS_Terpene SOA2 VAPS_Terpene SOA1 AMS_Particle NO3

+

AMS_LO-OOA

• Xu et al. (2015) suggests LO-OOA is largely from terpene BVOC+NO3 and locally produced.• VAPS Terpene SOA3 is in excess of LO-OOA and has highest O:C ratio. It may represent a

more aged – regional component.• Or altered chemistry……need additional lab studies to test

• Currently developing Isoprene/Terpene + NO3 lab studies + analysis of standards

• Many of the compounds observed by VAPS do not exist in current “underivatized” mass spectral libraries!

OUTLINE






• Conclusions

image: Google Earth

Ozarks Plateau

St. LouisMO

St. Louis Air Quality Regional Study

(SLAQRS)

Aug.3 – Oct.15, 2013

East St. Louis, IL

Millet et al. (U.Minnesota)

Turner et al. (WashU)

Weber et al. (GTech)

0.300.250.200.150.100.050.00

Rela

tive Inte

nsity

1009080706050403020

m/z

0.120.080.040.00

0.100.080.060.040.020.00

0.120.080.040.00

0.120.080.040.00

Isoprene SOA37%

LO-OOA27%

MO-OOA10%

HOA111%

HOA216%HOA

OOA79%

1) PMF results from SLAQRS, East St. Louis: (AMS Data)

TAG chromatogram

Temperature of CTD and GC oven

Williams et al., AMTD 2015

ThermalDecompositionWindow

CompoundWindow

Made an interesting discovery during SLAQRS(TAG and VAPS decomposition signal)

The thermal decomposition signal seems to contain information on the fraction of the aerosol that traditional operation of TAG and VAPS are not capable of detecting

r = 0.56

r = 0.81

r = 0.67

r = 0.65

A large fraction of the IEPOX signal is in the Decomposition Window

m/z 53m/z 82

Tracking major ions in the decomposition window reveals some good correlations to major AMS components:

Nit

rate

Sulf

ate

Org

anic

sIs

op

ren

e IE

PO

X

Williams et al., AMTD 2015

2) PMF results from SLAQRS, East St. Louis: (TAG decomposition signal)

0

30

60

90

120

6.12 7.58 9.04 10.50 11.96 13.43 14.89

Rel

ativ

e si

gnal

(TI

C)

x 1

00

00

Retention time (min)

Nitrate+OOA_carboxylic acidsNitrate+benzene+tolueneIsoprene OOAIsoprene OOA_sulfatesulfate-1Sulfate-2Sulfate-3Carbon-rich sulfateChloroform

Indicators that this factor represents fresh isoprene SOA, not chemically processed

Isoprene SOA enhancement from presence of acidic seed aerosol

Isoprene SOAIsoprene

SOA+sulfate

Zhang et al., In-Prep

Ozarks

3) PMF results from SLAQRS, East St. Louis: (TAG binned compounds)

Isoprene+Terpene SOA compounds

4) PMF results from SLAQRS, East St. Louis: (TAG individual compounds)

30x10-3

20100

Fraction

of sig

nal

octa

no

ic a

cid

be

nzo

ic a

cid

h

exylb

enzen

e

nona

no

ic a

cid

tr

ide

cen

e

na

ph

thale

ne, 1

-meth

yl-

trid

ecan

e

na

ph

thale

ne, 2

-meth

yl-

ph

thalic a

cid

decan

oic

acid

hep

tylb

en

zen

e

1-t

etr

adecen

e

3-m

eth

ylp

hth

alic a

cid

te

tra

de

ca

ne

4-m

eth

ylp

hth

alic a

cid

acen

aph

thyle

ne

acena

ph

the

ne

1-p

enta

decen

e

pen

tade

can

e

do

deca

no

ic a

cid

n

onylb

en

zen

e

1-h

exa

de

cen

e

flu

oren

e

hexa

de

can

e

decylb

enzen

e

1-h

epta

decen

e

hep

tade

can

e

pri

sta

ne

un

decylb

en

zen

e

octa

decen

e

phen

an

thren

e

octa

decan

e

anth

ra

ce

ne

ph

yta

ne

2,3

-na

ph

tho

barre

len

e

do

decylb

en

zen

e

nona

de

cen

e

nona

de

can

e

ph

en

an

thre

ne

, 1

-meth

yl

ph

en

an

thre

ne

, 2

-meth

yl

an

thra

cen

e, 1

-m

eth

yl

an

thra

cen

e, 2

-m

eth

yl

he

xa

de

ca

noic

acid

na

ph

thale

ne, 2

-ph

enyl-

eic

ose

ne

trid

ecylb

en

zen

e

eic

osa

ne

flu

oran

then

e

hen

eic

osen

e

tetr

ad

ecylb

enzen

e

ace

phe

na

nth

ryle

ne

hen

eic

osan

e

pyren

e

ph

en

an

threne

, 2

,3,5

-tr

imeth

yl-

do

co

sen

e

flu

ora

nth

en

e,

1-m

eth

yl-

pe

nta

decylb

en

zen

e

do

co

san

e

flu

ora

nth

en

e,

2-m

eth

yl-

flu

ora

nth

en

e,

4-m

eth

yl-

rete

ne

ph

ena

nth

rene

, 1-e

thyl-2

-meth

yl

pyren

e,

1-m

eth

yl-

pyren

e,

2-m

eth

yl-

pyren

e,

4-m

eth

yl-

tric

osen

e

tric

osan

e

he

xad

ecylb

en

ze

ne

tetr

aco

se

ne

tetr

aco

sa

ne

cyclo

pen

ta(cd)p

yre

ne

he

pta

decylb

en

zen

e

ch

rysen

e

pen

taco

sen

e

pen

taco

san

e

octa

de

cylb

en

ze

ne

hexaco

sen

e

hexaco

san

e

no

nad

ecylb

en

ze

ne

hep

taco

sen

e

hep

taco

san

e

eic

osylb

en

zen

e

octa

co

sen

e

octa

co

san

e

he

ne

ico

sylb

en

ze

ne

nona

co

sen

e

nona

co

san

e

tria

co

nte

ne

tria

co

nta

ne

hen

tria

co

nte

ne

hen

tria

co

nta

ne

dotr

iaco

nte

ne

dotr

iaco

nta

ne

tritria

co

nte

ne

ind

eno

(1,2

,3-cd

)pyre

ne

tritria

co

nta

ne

tetr

atr

iaco

nte

ne

te

tra

tria

co

nta

ne

pe

nta

tria

co

nte

ne

pe

nta

tria

co

nta

ne

m

eth

ylfura

n

ben

zen

e

tolu

en

e

benzald

eh

yd

e

ph

eno

l hyd

roqu

ino

ne

Un

kno

wn

2

Un

kno

wn

4

levo

glu

co

se

non

e

iso

pren

e

trim

eth

ylfuran

on

e

no

na

nal

Eth

ylid

ene

he

pte

nolid

e

naph

thale

ne

M

eth

yle

thylp

he

nol

Be

nzo

thia

zole

C

um

inic

-ald

eh

yd

epin

on

ald

eh

yd

e

Dim

eth

ylp

rop

ylm

eth

ylb

enze

na

min

e

Hep

tam

eth

yln

on

en

e

Bip

he

nyl

Pe

lletie

rin

e

Dio

xa

sp

iron

on

an

edio

ne

Co

um

arin

bis

dim

eth

yle

thylc

yclo

he

xa

die

ne

dio

ne

silo

xa

ne

1

phth

alim

ide

nic

oty

rin

e

ditertb

uty

lphe

no

l dib

en

zofu

ra

n

eth

oxyna

ph

thale

ne

alp

ha

cala

co

ren

e

die

thyltolu

am

ide

d

ieth

ylp

hth

ala

te

fluo

reno

l silo

xa

ne

2

ben

zop

he

no

ne

dih

yd

roo

cty

lfura

non

e

tetr

ahyd

ron

on

ylp

yran

on

e

pen

tade

ca

no

ne

eth

ylh

exylb

en

zoa

te

he

pta

me

thyln

on

ene

_2

flu

oren

on

e

dib

enzo

thio

phe

ne

form

yln

orn

icotin

e

silo

xa

ne

3

hydra

zon

eflu

ore

no

ne

trim

eth

ylp

en

tad

eca

non

e

terp

he

nyl

he

xad

eca

ne

itrile

he

xad

eca

no

ica

cid

-m

eth

yle

ste

r

an

thra

quin

on

e

hexa

de

can

oic

acid

_e

thyle

ste

r no

rab

ieta

tetr

ae

ne

me

thylid

en

e_

mix

ture

2

sim

on

ellite

dip

he

nylc

yclo

he

xan

e

he

pta

de

can

enitrile

be

nzyln

aph

tha

len

e

p_

terp

he

nyl

be

nzo

(a)p

he

na

zin

e

hexa

de

can

oic

acid

_b

uty

leste

r b

en

zylb

iphe

nyl

hexa

hyd

rod

ime

thylp

he

nan

thre

ne

ca

rboxylic

me

thyla

bie

tate

tra

eno

ate

to

dte

nh

au

ptd

op

pe

lto

pfte

er_co

mp

oun

d

de

hyd

roab

ietica

cid

o_

terp

he

nyl

m_

terph

enyl

trip

he

nylh

exan

e2

mon

op

alm

itin

b

is(2

-eth

ylh

exyl)

ph

thala

te

mo

no

ste

ari

n

qua

terp

henyl

ole

an-1

2-e

n-3

.beta

-ol is

om

er1

2

8-nor-1

7.b

eta

.(H

)-h

opa

ne

ole

an-1

2-e

n-3

.beta

-ol is

om

er2

(17.a

lpha

.H,2

1.b

eta

.H)-

hop

an

e

50403020100

x1

0-3

403020100

x10

-3

403020100

x10

-3

30

2010

0

x10

-3

403020100

x10

-3

2520151050

x10

-3

403020100

x1

0-3

30

2010

0

x10

-3

50403020100

x10

-3

403020100

x10

-3 Diesel Trains (hopanes, hydrocarbons, SE point)

Biomass Burning (levoglucosenone)

Isoprene SOA (methylfuran, trimethylfuranone)

BBQ Wood-Charcoal (cuminic aldehyde)

BBQ Meat (heptadecanenitrile, monopalmitin)

Anthropogenic SOA (benzoic acid, phthalic acid)

Terpene SOA (pinonaldehyde, cuminic aldehyde, a-calacorene) + Phthalates

Diesel Vehicle (hopanes)

Volatile Fuel Emissions (C23-26 alkanes, alkenes, monopalmitin)

Traffic (PAH,b-PAH, acephenanthrylene)

Mixed Semivolatile (anthro: benzothiazole, toluene, benzene; bio: pinonaldehyde)

15

10

5

0

Mas

s

2015105

Hour of Day

108

6420

16

12

8

4

0

20

15

10

5

0

20

15

10

5

0

16

12

8

4

0

20

15

10

5

0

15

10

5

0

12

8

4

0

1086420

302520151050

Hour of Day

mid

nig

ht

mid

nig

ht

No

on

Same as Isoprene OOA from Decomp..

Zuo et al., In-Prep

Currently working to combine SLAQRS PMF results from:

1) AMS2) TAG (decomposition signal)3) TAG (binned compounds + UCM)4) TAG (integrated compounds)5) VAPS

Created a bit of a data monster, but learning a lot as we now make comparisons!

Good correlations amongst the various Isoprene SOA factors and major Anthropogenic HOA/POA factors.

Study Average (black dots)

Winds from Ozarks:Active NO3 chemistry to remove Isoprene

Winds from Ozarks:No active NO3 chemistry= results in elevated morning O3

Millet et al., ES&T (In-Review)

Observations of Nighttime Chemistry during SLAQRS

Diurnal Average NO3+Isoprene reaction rateJune 2013 climatology, surface to 20.89 km integral

McKeen, Brown (NOAA)

OUTLINE






• Conclusions

Design for Laboratory-based Oxidation Studies

UV Lamps

PAM ReactorVacuum &Exhaust

O2

UV lamp(O3 generator)

Measurements(Online and Offline)

N2

HumidifierFilter

VOCs, SO2, NOx

PAM Bypass (Optional)

Seed Particles

Denuder

Emissions & Combustion Chamber

Controlled Vent Purified Dry Air Input

Particle/Gas Selection: Cyclone (PM1,PM2.5), DMA (monodispersed), or Teflon Filter (gases only)

Ambient Air,Dilution Air,orNebulized Aerosol

2-way Ball Valve

3-way Ball Valve

POA, SVOCs, IVOCs, VOCs (various sources)

VOC I/SVOC LVOC Real Emissions

Potential Aerosol Mass (PAM) Reactor

O3, NO, NO2, SO2, CO, CO2

Volatility+Hygroscopicity-TDMA, SMPSProton Transfer Reaction Mass Spectrometer (PTR-MS)

Volatility & Polarity Separator – Aerosol Mass Spectrometer (VAPS-AMS)

Thermal desorption Aerosol Gas Chromatograph (TAG)

Building and Adding to Chemical Databases

Diesel

Oak Wood

Hamburger

…..

Thermal desorption Aerosol Gas chromatograph (TAG)

Volatility and Polarity Separator (VAPS)

Aerosol Mass Spectrometer (AMS)

…..

Oak Leaves

Oak Wood

Pine Needles

Toluene SOA

8 6 4 2 0

Volatility

350

300

250

200

150

100

50

0

Polarity

IsopreneSOA

8 6 4 2 0

Volatility

300

250

200

150

100

50

0

Polarity

TolueneSOA

…..

Diesel

For purpose of this project we are characterizing oxidation of Isoprene + several Terpenes(over a range of: oxidation states, humidity, oxidants, acidity, NOx)

Connecting chemistry to hygroscopicity

Currently attempting to map hygroscopicity onto 2D VAPS maps of volatility- and polarity-separated OA functional groups.

Multi-Channel TDMA hygroscopicity, volatility, etc.(developed through EPA Early Career award)

8 6 4 2 0

Volatility

300

250

200

150

100

50

0

Polarity

VolatilityPo

lari

ty

Conclusions• Our novel research tools are offering new insights on the chemical composition of

atmospheric OA

• A combination of new binning analysis techniques, incorporation of thermal decomposition data, and controlled lab studies are improving our understanding of complex ambient chemical signatures observed by TAG, VAPS, and AMS

• VAPS data from SOAS (Alabama) suggests major contributions to OA loadings from Terpene SOA and additional contributions from Isoprene SOA not previously reported.

• OA observed during SLAQRS (St. Louis Region) was composed of a mix of anthropogenic sources with biogenic events delivered from the Ozarks. Nighttime chemistry plays an important role during these periods of biogenic influence. Larger-scale studies should be performed in this region of interest.

R835402

novel measurements of volatility- and polarity-separated ... · masters: xiaochen zuo, mayura...

Documents