assessing organic mass from mass closure: comparing atlanta ‘99 with esp’01 and ‘02
DESCRIPTION
ASSESSING ORGANIC MASS FROM MASS CLOSURE: COMPARING ATLANTA ‘99 WITH ESP’01 AND ‘02. 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. K. Baumann, M.E. Chang, V. Dookwah, S. Lee, A.G. Russell - PowerPoint PPT PresentationTRANSCRIPT
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