ASSESSING ORGANIC MASS FROM MASS CLOSURE:COMPARING ATLANTA ‘99 WITH ESP’01 AND ‘02.

K. Baumann, M.E. Chang, V. Dookwah, S. Lee, A.G. Russell

School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta

Motivation & Instrumentation

Site Locations, Met and Gas Characteristics

Estimate Photochemical Activity

Link to Changing Organic Mass

Acknowledgement: E. Edgerton, ARA Inc.,

M. Bergin, H. Park, K. Patel, L. Sun, R. Weber, W. Younger, all GA Tech

Funding provided by US-EPA and GA-EPD

2

Derived OM/OC from Mass Closure for Urban / Rural Sites

Regional Difference: Higher OM/OC and OC/EC at more rural site!

Seasonal Difference: Lower OM/OC and higher (?) OC/EC in winter. WHY??

3

Particle Composition Monitor “PCM”

Special tests and procedures for eliminating positive water bias, OC artifacts and other details described in paper accepted to JGR “Atlanta Supersite” special section, coming out soon…

For each PCM sample 17 (!) components (incl. 5 field blanks) are being analyzed via IC & TOT.

The following species are being quantified and reported.

Channel 1:

NH3

Na+, K+, NH4+, Ca+2

Channel 2:

HF, HCl, HONO, HNO3, SO2,

HCOOH, CH3COOH, (COOH)2

F-, Cl-, NO3-, SO4

=,

HCOO-, CH3COO-, C2O4=

Channel 3:

EC, OC, “SVOC”

4

Sites Locations and Measurements in Georgia

Name Period Met CO SO2NO NOx NOy O3 PM2.5

Atlanta JST 08/99 X X X X X X X XX

Atlanta TUC Since 03/99 XX

Atlanta FTM Since 03/99 XX

Atlanta SDK Since 03/99 XX

Griffin Since 06/01 X X X X (X) X X XX

Macon Since 06/00 X X X X X

Columbus Since 07/00 X X X X X

Augusta Since 07/00 X X X X X

Tifton Since 07/01 X

Atlanta Supersite (Solomon) ASACA (Russell) FAQS (Chang)

5

Site Locations and PM2.5 Wind Roses: Summer / Winter34.6

34.4

34.2

34.0

33.8

33.6

33.4

33.2

33.0

32.8

32.6

32.4

32.2

32.0

31.8

31.6

-85.5 -85.0 -84.5 -84.0 -83.5 -83.0 -82.5 -82.0 -81.5

Atlanta

FAQS ASACA sites significant point sources point sources w/ CO:NOx > 1

Wind Roses with avg [PM2.5] for

summer & winter in µg m-3

and wind frequency in %.

20x20 km

Augusta

Macon

Columbus

Griffin

Tifton

JSTAug'99

N

E

S

W9 18

17.9 7.8

N

E

S

W9 18

17.214.1

N

E

S

W9 18

18.215.9

N

E

S

W9 18

16.214.2

N

E

S

W18 36

36.8

6

Summertime PM2.5 – Max(O3) Relationship

Tighter correlation in July 2001.

“Downwind” Griffin site offset to higher PM2.5 mass.

What was different in August 1999?

7

Comparison of Average Diurnal Meteorological Conditions

30

25

20

15

10

5

Te

mp

era

ture

(

C)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

Atlanta Aug'99 Jul'01 Dec'01Griffin Jul'01 Jan'02

2.5

2.0

1.5

1.0

H2O

(

%v

)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

Atlanta Aug'99 Jul'01 Dec'01Griffin Jul'01 Jan'02

3.5

3.0

2.5

2.0

1.5

1.0

Win

d S

pe

ed

(

m/s

)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

2.5

2.0

1.5

1.0

0.5

0.0

UV

B

(W

/m2 )

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

Atlanta Aug'99Griffin Jul'01 Jan'02

8

Comparison of Average Diurnal Trace Gas Concentrations

8

6

4

2

SO

2

(pp

bv

)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

700

600

500

400

300

CO

(

pp

bv

)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

AtlantaAug'99Dec'01Jul'01GriffinJan'02 *2Jul'01 *2

80

60

40

20

NO

y

(p

pb

v)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

AtlantaAug'99Dec'01Jul'01GriffinJan'02 *2Jul'01 *2

3.0

2.5

2.0

1.5

1.0

0.5

0.0

NH

3

(pp

bv

)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

AtlantaAug'99GriffinJul'01Jan'02

9

Comparison of Average Diurnal Photochemical Products

6

5

4

3

2

1

0

HN

O3

(p

pb

v)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

AtlantaAug'99Jul'01Dec'01GriffinJul'01Jan'02

100

80

60

40

20

O3

(p

pb

v)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

AtlantaAug'99Jul'01Dec'01GriffinJul'01Jan'02

0.9

0.8

0.7

0.6

0.5

0.4

0.3

NO

x/N

Oy

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

AtlantaAug'99Jul'01Dec'01GriffinJul'01

20

18

16

14

12

10

8

6

4

NO

z

(pp

bv)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time (EST)

Atlanta GriffinAug'99 Jul'01 *10Dec'01Jul'01

10

Summary of Met and Trace Gas Comparison

August 1999 in Atlanta was…

Hotter, dryer, more polluted with precursor species, incl. NH3!

How can this, in addition to higher [O3] and [PM2.5], lead to the observed differences, suggesting more OC (SOA?) in Aug’99 and more oxygenated POCs away from Atlanta?

11

Source – Receptor Considerations: CO/NOy

Atlanta JST

Air mass arriving at Griffin has significantly higher CO/NOy ratio in summer than in winter:Loss of more abundant summertime HNO3 due to surface deposition!

Griffindownwind

300

250

200

150

100

CO

(

pp

bv

)302520151050

NOy (ppbv)

Northerly flowexcl SO2 >3 ppbvJul 2001slope = 31.1 +-1.51intcept= 106 +-4r = 0.77Jan 2002slope = 7.2 +-0.45intcept= 159 +-4r = 0.74

1400

1200

1000

800

600

400

200

0

CO

(

pp

bv)

200150100500

NOy (ppbv)

August 1999slope = 6.3 +-0.08intcept= 189 +-5r = 0.81December 2001slope = 6.5 +-0.09intcept= 129 +-8r = 0.94

July 2001slope = 9.0 +-0.18intcept= 86 +-7r = 0.88

Higher intercept points to elevated regional background CO!

Long-range transport of wild fires’ plumes (see SOS’95)?

Or other high-CO/low-NOx sources?

12

Atlanta JST Griffindownwind

120

100

80

60

40

20

0O

3

(p

pb

v)

35302520151050

NOz (ppbv)

July 2001Sunny daytimesNortherly flowslope = 13.7 +-0.59intcept= 34 +-1.5r = 0.86incl "lost" HNO3

slope = 2.9 +-0.21intcept= 34 +-2.4r = 0.72

120

100

80

60

40

20

0

O3

(

pp

bv

)

35302520151050

NOz (ppbv)

Sunny daytimesAugust 1999slope = 3.6 +-0.14intcept= 59 +-1.5r = 0.59July 2001slope = 2.7 +-0.28intcept= 38 +-2.7r = 0.50December 2001slope = -0.6 +-0.09intcept= 33 +-1.1r = -0.42

Elevated regional O3 background reflected in regression’s intercept: higher in Aug 99!

At JST higher intercept and slope during Aug ’99 (OPE= 4 vs 3): more efficient P(O3).

OPE in air mass arriving at Griffin is likely larger given by upper and lower limits.

Lower limit assumes 1st order loss of HNO3 due to surface deposition at k ≈ 0.22 h-1.

Source – Receptor Considerations: O3/NOz as “OPE”

13

Summary

• Photochemical processes leading to high ozone levels also lead to high PM fine.

• Elevated levels of primary pollutants (CO, NOx, SO2 and NH3) under hot and relatively dry

conditions responsible for high PM fine mass concentrations during August 1999.

• Possible regional impact from distant wild fires (similar to 1995?) causing high OC/EC and

elevated background CO in August 1999?!

• As the Atlanta urban plume is advected over BHC-rich terrain, it transitions to a more NOx-

limited regime, i.e. with greater RO2 abundance, indicated by an increasing OPE.

• This transition bears great potential for the formation of SOA and more oxygenated POC,

explaining the observed increase in OM/OC downwind from Atlanta.

• Subset of Jul’01 and Jan’02 Griffin samples show 65 vs 55 ±5 % WSOC fraction.

• No biomass burn ban in winter causing a shift to higher OC/ECp

Investigate influence from distant plumes of wild fires in August ’99.

Quantify SOA by careful determination of (OC/EC)p.

Detailed analyses of selected days/episodes for OPE and WSOC.

Air quality impacts of biomass burning (in collab w/ M. Zheng).

Outlook

14

Supplementary Material

15

Assessing Accuracy of PCM Measurements

S-compounds and mass agree well, volatile species esp. NO3- more difficult to measure accurately

15

10

5

0

30 m

in P

ILS

(u

g m

-3)

12108642

discrete PCM (ug m-3

)

SO42-

r = 0.97

slope = 1.04 +-0.04i-cept = 0.12 +-0.21

70

60

50

40

30

20

10

0

30 m

in T

EO

M (

ug

m-3

)

403020100

discrete PCM (ug m-3

)

Will. TowerMass r = 0.92slope = 0.96 +-0.07i-cept = 2.52 +-1.23

3

2

1

0

30 m

in P

ILS

(u

g m

-3)

1.51.00.50.0

discrete PCM (ug m-3

)

NO3- r = 0.61

slope = 0.47 +-0.09i-cept = 0.18 +-0.05

excl 1st 2 PCM

30

20

10

0

30 m

in T

EC

O (

pp

bv)

1086420

discrete PCM (ppbv)

SO2 r = 0.99

slope = 1.38 +-0.033i-cept = 0.00 +-0.08

70

60

50

40

30

20

10

0

30 m

in T

EO

M (

ug

m-3

)

403020100

discrete PCM (ug m-3

)

LaPorteMass r = 0.95slope = 1.01 +-0.05i-cept = 0.98 +-0.81

excl 1st 3 PCM

6

5

4

3

2

1

0

30 m

in P

ILS

(u

g m

-3)

4321

discrete PCM (ug m-3

)

NH4+

r = 0.92

slope = 0.91 +-0.06i-cept = 0.26 +-0.11

16

PCM

17

OM/OC Estimates With & Without “SVOC”

    OM/OC for closure OM/OC {svoc} for closure

  AVG STD AVG STD

August-99 Atlanta 2.1 0.7 1.5 0.3Summer-00 Macon 2.5 0.6 1.7 0.1

Augusta 3.4 1.7 1.7 0.3

  Columbus 2.0 0.5 1.6 0.5  LaPorte 3.5 3.8 2.3 2.6  W.Tower 3.5 3.2 2.4 2.3

July-01 Atlanta JST 2.3 1.2 2.0 1.2

Atlanta TUC 2.4 1.5 - -

Atlanta FTM 2.4 1.0 - -

Griffin 2.7 0.6 2.4 0.6

Dec-01 Atlanta JST 1.1 0.1 0.9 0.1Jan-02 Griffin 1.8 0.8 1.5 0.6

18

Seasonal and Regional Differences in Composition

19

Seasonal and Regional Differences in OC/EC

20

Seasonal/Regional Aerosol Acidity Based on [SO4=/NO3

-/NH4+]

•Aerosol is closely neutralized / slightly alkaline in winter but more acidic in summer•Acidity caused by insufficient NH3, or unaccounted for organic amines (with higher OM/OC)?

21

From CO/NOy regressions JST vs GRF:

NOyinit = 31/9 *NOy

NOylost = NOyinit - NOy

= NOyinit*(1-9/31)

= 0.71*NOyinit

Assume 1st order loss:

NOyinit = NOy / exp(-kt)

Assume 2.5 m/s N-ly flow throughout CBL:

Then t = 5.6 h

And k = 0.22 h-1