IMPROVE Ion Studyand

Other IMPROVE Special Studies

Jeffrey L. Collett, Jr.Colorado State University(with contributions fromcollaborators at CSU, NPS, and UCDavis)

Funding: NPS/IMPROVE Western Resource Advocates

Outline

The IMPROVE Ion/Nitrate Study– Motivation– Questions and approach– Findings and implications

Other IMPROVE special studies– Yosemite smoke study– IMPROVE denuder tests– Coarse particle speciation– Mobile air quality lab

Ion StudyMotivation

Nitrate is animportantcontributor toPM at manylocationsNitrate maybe present infine orcoarsemodesSamplingmethodologyissues

HNO3(g) + NH3(g) NH4NO3(p)

HNO3(g) + NaCl(p) NaNO3(p) + HCl(g)

2 HNO3(g) + CaCO3(p) Ca(NO3)2(p) + CO2 + H2O

Nitrate inBig Bend

High PM2.5nitrateassociatedwith flowfrom Gulf

Nitratereplacedchloride insea saltaerosol

y = 1.14xR2 = 0.72

y = 0.33xR2 = 0.69

0

20

40

60

80

100

120

140

160

180

200

0 20 40 60 80 100 120 140 160 180 200

Na+(neq/m3)

([Cl- ]+

[NO

3- ] ) o

r [C

l- ] (ne

q/m

3 )([C-]l+[NO3-]) vs [Na+]Sea water ratio(Cl-/Na+)[Cl-] vs [Na+]Linear (([C-]l+[NO3-]) vs [Na+])Linear ([Cl-] vs [Na+])

slope for sea water1.164 ([Cl-]/[Na+])

NaCl NaNO3

HNO3 HCl

Nitrate in Big Bend

Nitrate foundin coarsemodeparticles

– Mode size~4-5 µm

– Sizedistributionsimilar to Na+

PM2.5 includestail of coarsemode

0

50

100

150

200

250

300

350

0.1 1 10 100

dC/d

log(

Dp)

(neq

/m3) sulfate

0

50

100

150

200

250

0.1 1 10 100

Aerodynam ic Diam eter (µm )

dC/d

log(

Dp)

(neq

/m3)

ammonium

0

5

10

15

20

25

0.1 1 10 100

nitrate

0

5

10

15

20

25

30

0.1 1 10 100

Aerodynam ic Diam eter (µm )

sodium

0

5

10

15

20

0 5 10 15 20Na+ (neq/m3)

Cl-

or (

(NO

3-)+

(Cl-)

)(n

eq/m

3)

Na+ vs. Cl-

Na+ vs.((NO3-)+(Cl-))

Slope for sea water (1.164)

NH4NO3

Yosemiteresults

Carbon-dominated aerosol(NH4)2SO4 dominant saltNO3

- replaced Cl- in sea salt

0

5

10

15

20

25

30

8/12 8 /13 8 /14 8 /15 8 /16 8 /17 8 /18 8 /19 8 /20 8 /21 8 /22 8 /23 8 /24 8 /25 8 /26 8 /27

neq/

m3

C l- NO 3- Na+

2-week excerpt, PILS 15-min data

IMPROVE ion special study goals

Determine characteristics of ionic aerosol present atselected IMPROVE sites

– Ionic composition– Ion size distributions– Gas-particle distribution of NH3(g)/NH4

+(p) and HNO3(g)/NO3-(p)

Evaluate IMPROVE ion sampling and analysisapproach

– Combination of field and lab studies– Filter choice, filter extraction method, and denuder protocol

Ion study locations

San Gorgonio

Bondville

Big Bend

Yosemite

Grand Canyon

Brigantine

Sequoia

Study equipment

• 24 hr URG PM2.5 cyclone/annular denuder/ filter pack sampler

• MOUDI impactor (10-stage)

• 15 min PM2.5 PILS/IC system• Particle into Liquid Sampler• Ion Chromatograph

36

31

26

21

16

11

6

1

Conc

entra

tion,

ug/

m3

2/2/

2003

2/3/

2003

2/4/

2003

2/5/

2003

2/6/

2003

2/7/

2003

2/8/

2003

2/9/

2003

2/10

/200

3

2/11

/200

3

2/12

/200

3

2/13

/200

3

2/14

/200

3

2/15

/200

3

2/16

/200

3

2/17

/200

3

2/18

/200

3

2/19

/200

3

2/20

/200

3

2/21

/200

3

2/22

/200

3

2/23

/200

3

Date

NH4+_ug/m3 NO3-_ug/m3 SO4=_ug/m3

Bondville 2/03

NO3- and SO4

2- both importantNH4NO3 in submicron mode

0

10

20

30

40

50

< 0.

18

0.18

-0.3

2

0.32

-0.5

6

0.56

-1.0

1.0-

1.8

1.8-

3.2

3.2-

5.6

5.6-

10.0

10.0

-18.

0

>18.

0

NO3-, neq/m3SO4=, neq/m3Na+, neq/m3NH4+, neq/m3

Aver

age

Con

cent

ratio

n, n

eq/m

3

Aerodynamic Diameter, µm

San Gorgonio4/03

Large diurnal variabilitySubmicron NH4NO3 dominant

0

5

10

15

20

25

< 0.

18

0.18

-0.3

2

0.32

-0.5

6

0.56

-1.0

1.0-

1.8

1.8-

3.2

3.2-

5.6

5.6-

10.0

10.0

-18.

0

>18.

0

NO3-, neq/m3SO4=, neq/m3Na+, neq/m3NH4+, neq/m3

Aver

age

Con

cent

ratio

n, n

eq/m

3

Aerodynamic Diameter, µM

700

600

500

400

300

200

100

0

Con

cent

ratio

n, n

eq/m

3

NH4+ , neq/m3 NO 3-, neq/m 3 SO 4=, neq/m3

4/4

4/5

4/6

4/7

4/8

4/9

4/10

4/11

4/12

4/13

4/13

4/14

4/15

4/16

4/17

4/18

4/19

4/20

4/21

4/22

4/23

4/24

4/25

4/26

4/27

30

20

10

0

Con

cent

ratio

n, u

g/m

3

NO3-, ug/m3 SO4=, ug/m3 NH4+, ug/m3 K+, ug/m3

7/2

7/3

7/4

7/5

7/6

7/7

7/8

7/9

7/10

7/11

7/12

7/13

7/14

7/15

7/16

7/17

7/19

7/18

7/20

7/21

7/22

7/23

7/24

7/25

7/26

7/27

7/28

7/29

San Gorgonio 7/03

More regular diurnal variabilitySome days sulfate-dominated

K+ spikes

Grand Canyon

0

2

4

6

8

10

12

0 2 4 6 8 10

Na+ (neq/m3)

Con

cent

ratio

n (n

eq/m

3)

Cl-NO3- + Cl-sea salt

Grand Canyon MOUDI average

0

2

4

6

8

10

12

< 0.18 0.18 - 0.32 0.32 - 0.56 0.56 - 1.0 1.0 - 1.8 1.8 - 3.2 3.2 - 5.6 5.6 - 10.0 10.0 - 18.0 >18.0

aerodynamic diameter (µm)

neq/

m3

SO4=NH4+NO3-Na+Ca2+

GrandCanyon

Nitrate in coarse modeAppears to beassociated with Na+

and Ca2+

Sampling and extraction issues

Does water efficiently extractnitrate from nylon filters?

– HNO3 not efficientlyrecovered with waterextraction

– Typically useNaHCO3/Na2CO3

What happens to NH4NO3volatilized from nylon filters?

– HNO3 trapped? Decrease inwater extraction efficiency?

– NH3 lost? Bias in measuredPM2.5 ammonium?

NH4NO3

NH3(g)

NH3(g) + HNO3 (g) NH4NO3(p)

NO3- & NH4

+

on nylon

Nylon filterextraction by watershowed no bias infirst three studies

Significant NH4+

lost from nylonfilter

– Nylon recapturesvolatilized NO3

-

0

2

4

6

8

10

12

14

16

0 2 4 6 8 10 12 14 16

Nylon D.I. H2O, ug/m3, BondvilleNO3-, D.I. H2O, ug/m3, SG AprilNO3- D.I. H2O, ug/m3, Grand Canyon1:1 Line

Nyl

on b

y D

.I. H

2O e

xtra

ctio

n, u

g/m

3

Nylon by IC extraction, µg/m3

0

10

20

30

40

50

60

70

0 5 10 15 20 25 30

BNH4+%, BondvilleBNH4+%, SG AprilBNH4+%, GC

NH

4+ loss

from

Nyl

on fi

lter,

%

Day of Month

0

20

40

60

80

100

Jul/1 Jul/6 Jul/11 Jul/16 Jul/21 Jul/26 Jul/31

BNH4+%BNO3-%

Date

San GorgonioJuly (latest results)

~ 25% of nitrate not extractedfrom nylon filter with water

NH4+ loss ~ 20-50%

0

1

2

3

4

5

0 1 2 3 4 5

NO3-, D.I. 1:1

NO3-(IC), µg/m3

y = m2 * M0ErrorValue

0.0212750.75792m2 NA1.6439Chisq

NA0.92249R2

Yosemitespecial study

July-September2002Focus onsmokeAerosoldominatedby OC

POM73%

Black C2%

Soil6% NH4+

4%

Na+1%

K+0%

Ca2+0%

NO2-0%

Cl-0%

Mg2+0%

NO3-3%

Oxalate1%

Ions19%

SO42-10%

POMBlack CSoilCl-NO2-NO3-SO42-OxalateNa+NH4+K+Mg2+Ca2+

Study average PM2.5 composition

Yosemitespecial study

Large changes in OC– EC remained small

“Contemporary” carbondominant

– Wood smoke– Biogenic production

Molecular markers indicatepresence of wood smokeand secondary biogenicparticles

– Vehicle contribution appearssmall

0

2

4

6

8

10

12

14

7/10 7/15 7/20 7/25 7/30 8/4 8/9 8/14 8/19 8/24 8/29 9/3

Car

bon

( µg

m-3

)

Yosemite size distributions

Size distributionsmeasured withDifferential MobilityAnalyzer (DMA)Two submicron modespresent during smokeperiod

SMOKE

16 Aug 2002 (DOY 228) 22:30 PST08 Aug 2002 (DOY 220) 03:45 PST

“CLEAN”

Yosemite size distributions - II

Aerosol Mass Scattering Efficiency– increases during smoky periods

K+

(µg/

m3 )

Mas

s sca

tterin

g ef

ficie

ncy

(m2 /g

)

Yosemite aerosol hygroscopicity

Hygroscopicity of100 and 200 nmparticles measuredwith HygroscopicTandem DifferentialMobility Analyzer(HTDMA)

Smoke-dominatedaerosol much lesshygroscopic than“normal” Yosemitesummer aerosol

0 2 4 6 8 10 12 14

1.05

1.10

1.15

1.20

1.25

1.30

1.35

1.40

Equation: y = A1*exp(-x/t1) + y0

Chi 2/DoF = 0.001R 2 = 0.723 y0 1.102 ±0.007A1 0.434 ±0.067t1 1.386 ±0.201

GF

(RH

=80%

)

Carbon/Ionic Mass Ratio

IMPROVE denuder tests (UC Davis)

Differentdenuderconfigurationstested

– Noperformancedifferencesobserved

– Lab testsplanned atCSU

HANC

0100200300400500600700800900

5/1/

03

5/3/

03

5/5/

03

5/7/

03

5/9/

03

5/11

/03

5/13

/03

5/15

/03

5/17

/03

5/19

/03

5/21

/03

5/23

/03

5/25

/03

5/27

/03

5/29

/03

5/31

/03

ng/m

3HNO3(g)

None

New

Bare Al

No glyc

Used

Coarse particle speciation (UC Davis)

PM10 speciation9 sites

– Bondville– Great Smokies– Grand Canyon– San Gorgonio– Sequoia– Brigantine– Upper Buffalo– Bridger– Mount Rainier

Operational by 1/1/04– Several sites already

operating– Overlap with ion study

Will run for 1 year

New IMPROVE mobileair quality lab

Mobile platform– Special study deployment– Some on-road

measurement capabilities

Measurement capabilities– Particle and trace gas

composition– Aerosol size distributions– Particle hygroscopicity– Trace gases

Summary

Nitrate present in– Submicron ammonium nitrate particles

Bondville, ILSan Gorgonio, CA

– Coarse mode sodium or calcium nitrate particlesBig Bend NP, TX Yosemite NP, CAGrand Canyon NP, AZ

Nylon filter– DI water extraction may not always fully recover NO3

-

– Yields negatively biased NH4+ concentrations

Yosemite aerosol dominated by modern carbon– Particles slightly hygroscopic

HNO3 denuder tests show little dependence on coatingCoarse particle speciation study beginningMobile lab being constructed for future special studies

IMPROVE ion study fieldcampaigns

6 one-month campaignsBondville (midwest) - February2003San Gorgonio (southern CA) –April and July 2003Grand Canyon – May 2003 (co-sponsored by LAWFR)

– Brigantine (NE coastal) –November 2003

– Sequoia (Sierra Nevada) –February 2004

Measurements– MOUDI sampler – ion size

distributions– 3 Parallel URG denuder/filter-

pack samplers running differentprotocols

– PILS sampler – 15 minute PM2.5anions and cations

Mobile laboratory

Nitrate replacement

NH4NO3 formation not favoredthermodynamically in acidicaerosol

– NH3(g) will first neutralize sulfateH2SO4 NH4HSO4 (NH4)2SO4

Once aerosol is neutralized,NH4NO3 formation may occur

– f(T,RH)If SO4

2- is decreased, NO3- may

replace it– Two NO3

- replace each SO42-

– Sulfate reduction could producePM mass increase

SO42-

98 g/mole

NO3-

62 g/moleNO3

-

62 g/mole

HN

O3 denuder

NH

3 denuder PM

2.5 N

H3 denuder

HN

O3 denuder

NH

3 denuder

N filter (IC)

PM2.5

HN

O3 denuder

NH

3 denuder

Filter A

PM2.5

NH

3 denuder

N filter (H2O)

HN

O3 denuder

HN

O3 denuder

•Modules 1 and 2

•Daily, 24 hr samples

•Compare nylon filterextraction (H2O vs.carbonate/bicarbonate)

•Examine loss of HNO3 andNH3 from nylon filter

•Provide gas-particle phasedistribution for N(-III) andN(V)

•Module 3

•Day/night sampling

•Replicates for precision

•Aerosol acidity/NH4NO3volatilization

•Undenuded sampling onTeflon filter

Initial findings

Nylon filter extraction by water?– EPA study of fall filters collected at numerous STN

and IMPROVE sites gave average 90% extractionefficiency

– CSU Fort Collins samples (Spring 2002) yielded noevidence of lower water extraction efficiency

Fate of volatilized NH4NO3?– EPA study indicated significant ammonia loss

IMPROVE sampling approach

4 modulesModule B for PM2.5 ions– Carbonate-coated denuder removes acidic gases– Nylon filter

Extracted with carbonate/bicarbonate solution (anion ICeluent) for anion analysisExtracted with water for anion + cation analysis

– Sodium interference from IC eluentAnalyzed by IC