Frank Flocke, Aaron Swanson, Jim Roberts, Greg Huey, David Tanner Tom Ryerson, Andy Neuman ,
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Fast time resolution airborne measurements of PANs during the
New England Air Quality Study 2004 intensive.
Frank Flocke, Aaron Swanson, Jim Roberts, Greg Huey, David TannerTom Ryerson, Andy Neuman,
John Holloway, Joost deGouw, Carsten Warneke
Elliot Atlas, Stephen Donnelly, Sue Schauffler, Verity Stroud
Thanks to: NOAA AOC, Paul Stock (DLR)
New PAN-CIGAR instrument:• Chemical Ionization Mass Spectrometer• Based on reaction of PA radicals with I-
• Fast (time resolution 0.25 – 2 seconds)• Sensitive (10-60 cts/pptv on background of
250 cts or less)• Very selective• Autonomous• Eight different PAN species measured during
ICARTT 2004• don’t miss the PAN-CIGAR Instrument talk:
Swanson et al., A42B-04; Thu, 11:20; MCC 3018Tropospheric Photochemistry II
Which PANs were measured?Example flight 7/20/2004, NYC plume
3000
2500
2000
1500
1000
500
0
PA
N, A
ltitu
de
19:207/20/2004
19:30 19:40
350
300
250
200
150
100
50
0
PP
N, P
BN
, AP
AN
, MoP
AN
, PB
zN
19:157/20/2004
19:20 19:25 19:30 19:35 19:40
dat
PAN (pptv) PPN (pptv) PBN (pptv) PBzN (pptv) APAN (pptv) MoPAN (pptv) Flt. Altitude (m)
Biomass burning plume encountered over Quebec 7/28/2004
Flight alt. const. 3000m
1600
1400
1200
1000
800
600
400
200
PA
N (
pptv
)
16:307/28/2004
16:35 16:40 16:45 16:50 16:55 17:00
150
100
50
0
PP
N, P
BN
, MoP
AN
, AP
AN
, PB
zN (pptv)
PAN PPN PBN APAN PBzN MoPAN
Flight alt. 3000m
Biomass burning plume encountered over Quebec 7/28/2004
Flight Alt. const. 3000m
1600
1400
1200
1000
800
600
400
200
PA
N (
pptv
)
16:307/28/2004
16:35 16:40 16:45 16:50 16:55 17:00
150
100
50
0
PP
N, P
BN
, MoP
AN
, AP
AN
, PB
zN (pptv)
PAN PPN PBN APAN PBzN MoPAN NOy_3
Flight alt. 3000m
PAN transport and NOx release
3500
3000
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500
0
PA
N,
NO
x, N
Oy,
HN
O3
, A
ltitu
de
17:157/20/2004
17:30 17:45Time
100
80
60
40
Ozo
ne
Flight Altitude (m) PAN Ozone (ppbv) NOx (pptv) HNO3 (pptv) NOy (pptv) CH3CN (arb.)
7/20/2004 Biomass burning plume from AK and CDN FiresPAN is dominant NOY component, HNO3 washed out or lost on aerosols,
PAN decomposition maintains NOX on air mass descent
τ(PAN) ≈ 20h
3500
3000
2500
2000
1500
1000
500
0
PA
N, N
Ox,
NO
y, A
ltitu
de
19:507/21/2004
20:00 20:10Time
120
100
80
60
40
20
Ozo
ne
Flight Altitude (m) PAN Ozone (ppbv) NOx (pptv) HNO3 (pptv) NOy (pptv) Acetonitrile (arb.)
7/21/2004 Same biomass burning plume from AK and CDN Fires encountered again over Cape Cod one day later
Some processing has occurred (HNO3 formation), still PAN decomposition maintains NOX on air mass descent
τ(PAN) ≈ 18h
Biomass Burning during ICARTT
don’t miss
Joost de Gouw, A51G-05; Fri, 9:15, MCC 3018Tropospheric Photochemistry VI
PAN / PPN ratio
What controls the PAN / PPN ratio:
Production: -PAN / PPN ratio upon formation depends on availability of source VOC
-Alkanes/Alkenes make PAN and PPN (ratio?)-Isoprene and Terpenes make just PAN
PAN/PPN increases with biogenic HC burden More PAN further away from sources (?)
and loss: warm PBL: -Thermal loss is fastest
-PAN is lost faster than PPN (Kirchner et al., 2000)
PAN / PPN decreases (hours-days)
Upper Troposphere: -Photolysis dominates-PPN photolysis slightly faster than PAN
(Harwood et al., 2003)
PAN / PPN increases very slowly (weeks)
PAN / PPN ratio:
Is there an “anthropogenic” PAN/PPN ratio?
PAN/PPN during TRACE-P
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0
200150100500
pFW_PAN_pptv PAN_100_160 PAN_160_200 PAN_200_240 PAN_US Fit_100_160 slope = 5.6 Fit_160_200 slope = 6.1 Fit_200_240 slope = 9.0 Fit_US slope = 6.2
Slope ~ 6
Similar slopes of PAN / PPN were obtained in Houston (TexAQS 2000),
during TOPSE (Spring 2000) and in/over other urban areas
PAN / PPN ratio:
and in New England?
2500
2000
1500
1000
500
PA
N (
pptv
)
35030025020015010050PPN (pptv)
20x103
151050NOy (pptv)
7/20/2004 flight
Slope~6
Slope~12
Slope~9
60
40
20
0
PP
N (pptv)
04:108/1/2004
04:20 04:30 04:40 04:50 05:00 05:10
dat
3000
2500
2000
1500
1000
500
0
600
500
400
300
200
100
PA
N (
pptv
); F
light
Alti
tude
/ 5
(m)
20
15
10
5
0
-5
Rat
io
PAN PPN Flt. Altitude PAN / PPN MVK + MACR (arbitr.)
7/31/2004 Flt, NYC Plume at NightBiogenic influence reflected in PAN/PPN ratio
PAN / PPN ratio:
Can we see the effect of different thermal loss rates?
Flight 8/10/2004 – NYC Plume at Night
1500
1000
500
0
PA
N (
pptv
), F
light
Alti
tude
(m
)
04:508/10/2004
05:00 05:10 05:20
dat
150
100
50
0
PP
N (pptv)
16
14
12
10
8
6
4
Rat
io PAN PPN PAN/PPN Flt. Altitude
Flight 8/10/2004 – NYC Plume at Night
1500
1000
500
0
PA
N (
pptv
), F
light
Alti
tude
(m
)
04:508/10/2004
05:00 05:10 05:20
dat
150
100
50
0
PP
N (pptv)
16
14
12
10
8
6
4
Rat
io PAN PPN PAN/PPN Flt. Altitude
1500
1000
500
0
PA
N (
pptv
), F
light
Alti
tude
(m
)
05:308/10/2004
05:40 05:50
dat
150
100
50
0
PP
N (pptv)
16
14
12
10
8
6
4
Rat
io
PAN PPN PAN/PPN Flt. Altitude
Flight 8/10/2004 – NYC Plume at Night
1500
1000
500
0
PA
N (
pptv
), F
light
Alti
tude
(m
)
06:108/10/2004
06:20 06:30
dat
150
100
50
0
PP
N (pptv)
16
14
12
10
8
6
4
Rat
io PAN PPN PAN/PPN Flt. Altitude
Flight 8/10/2004 – NYC Plume at Night
SUMMARY• First fast time resolution airborne measurements of
PAN• We observed 8 different PANs including
first observations of MoPAN, PPeN (and PBzN)• Elevated APAN and MoPAN in biomass burning plumes• One can learn a lot about photochemical history of
air masses by just measuring PAN and PPN accurately
• We can do that now at 2 Hz or better• Biomass burning plumes show distinct PAN/PPN
ratio which appears preserved over several days
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