detection of nitrooxypolyols in secondary organic aerosol |formed from the photooxidation of...
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Detection of Nitrooxypolyols in Secondary Organic Aerosol |Formed from the Photooxidation of Conjugated dienes under High-NOx ConditionsKei Sato, Atmospheric Environment, 42 (2008) 6851–6861
6-m3,Teflon-coated, stainless steel laboratory smog chamber
2 ppmv of Isoprene
NO concentrations were ranged from 0.2, 0.5 and 1 ppmv
Particles collected on filters and solvent extracted
Filters cut in small pieces and sonicated in 3ml of methanol for 40 min
What if NO is very low; the primary reaction is with HO2 Jenkin et al, 1997 Atmos. Envir.,
Pitts and Pitts , 186
RO2. + HO2. ROOH + O2
ROOH carbonyl +H2O +O2
and
ROOH alcohol + O3 (dark O3)
does the R group matter???rate constants range: 5.2x10-12 R is CH3
7.7x10-12 R is C2H5
1.5x10-11 larger
What are the reactions of RO2
(self reactions)?
RO2. + RO2. 2RO.+O2
ROH+RCHO + O2
ROOR+ O2 (SMALL)
generally the larger the R group the slower the reaction
Atkinson recommends 2.5x10-13, 5x10-15 and 2x10-17 for primary, secondary and tertiary RO2(s)
Is there data on the branching of 2RO vs. ROH+RCHO??
RO2. + RO2. 2RO.+O2
ROH+RCHO + O2
ROOR+ O2 (SMALL)
See Jenkin, et. al,1997, and Pitts and Pitts, Table 6.6, p 187
2RO. ROH+RCHOCH3OO. 0.35 0.65CH3H7OO. 0.55 0.45
High NOx
RO2 + NO RO + NO2
RO2 + NO RONO2
Low NOx
RO2 + HO2 ROOH + O2
RO2 + ROCH2O2 ROH + O2 ROCHO
RO R=O +HO2
Formation of secondary organic particle phase compounds from isoprene gas-phase oxidation products: An aerosolchamber and field study: Alaf Bo¨ge, Yunkun Miao, Antje Plewka, Hartmut Herrmann, Atmos. Environ. Inpress, 2008)
An overall yield of just 0.01–0.09% was estimated for methyl tetrol formation
How much methyl tetrols forms?
What did Alaf Boge and Hartmut Herrmann do?
9 m3 chamber
Added isoprene + H2O2
Dimethyl tetrol + H2O2
Isoprene epoxide + H2O2
Isoprene in the presence of NOx produces nitric acid, 2-methylglyceric acid, 2-methyltetrols and nitrooxypolyols as the major products in SOA samples.
The concentrations of the nitrooxypolyol products decreased three days after the extraction, whereas the concentrations of nitric acid and 2-methyltetrols increased.
These results suggest that the nitrooxypolyols produced by the diene oxidation in the presence of NOx contribute toward the SOA formation and that they can be decomposed into polyols and nitric acid in the aqueous solution.
It was concluded that the direct formation of 2-methyltetrol by gas-phase diene oxidation is suppressed in the presence of NOx.
October 15, 2008 Run Log Purpose: Isoprene + O3 vs isoprene + NOx with VMU particle instrument to look at differences in particle phase and look for tetrols.. Injected Isoprene (117l) into South or 1 ppmC (Sato article had ~2ppmV) Chamber conditions: vented from 18:00 to 22:37 pm gate valves. At 22:37 chamber gate valves were closed; exhaust blower off; compressor on, clean air generator on.
10 20 30 40
Minutes
-1
0
1
2
3
4
5
6
mVoltset
hyle
ne (4.
326)
4.67
9pr
opan
e (5
.000
)pr
opyl
ene
(5.3
48)
n-bu
tane
(10
.960
)1-
bute
ne (11
.042
)
buta
ne (12
.352
)
2-bu
tene
(13
.315
)
isop
enta
ne (16
.500
)
pent
ane
(17.
368)
met
hylp
enta
ne (20
.891
)
dim
ethy
lpen
tane
(23
.563
)
benz
ene
(25.
850)
cycl
ohex
ane,
trim
epen
tane
(25
.921
)
tolu
ene
(28.
920)
o-xy
lene
(33
.290
)
m-p
xyl
ene
(33.
930)
a-pi
nene
(34
.700
)
tri-m
e be
nz (36
.940
)
b-pi
nene
(37
.547
)
d-lim
onen
e (3
9.12
3) File:Channel:
Last recalc:
c:\saturnws\data\1019.runMiddle = FID ResultsNA
X:Y:
10.1106 Minutes0.944 mVolts
c:\saturnws\data\1019.run
T%:7WI:4 WI:2 GR+
T%:10GR-
WI:4
Chamber Background
10 20 30 40
Minutes
0.0
2.5
5.0
7.5
10.0
12.5
mVolts
ethy
lene
(4.
326)
4.61
14.
660
4.79
2pr
opan
e (5
.000
)pr
opyl
ene
(5.3
48)
n-bu
tane
(10
.960
)1-
bute
ne (11
.042
)
buta
ne (12
.352
)
2-bu
tene
(13
.315
)
14.6
55
isop
enta
ne (16
.500
)
pent
ane
(17.
762)
17.8
76
met
hylp
enta
ne (21
.199
)
dim
ethy
lpen
tane
(23
.563
)
24.3
10
benz
ene
(25.
850)
cycl
ohex
ane,
trim
epen
tane
(25
.921
)
tolu
ene
(28.
920)
o-xy
lene
(33
.318
) m-p
xyl
ene
(33.
930)
a-pi
nene
(34
.634
)34
.805
35.6
07
tri-m
e be
nz (36
.940
)
b-pi
nene
(37
.853
)
d-lim
onen
e (3
9.12
3)
43.6
5543
.717
44.6
60
45.9
21
47.3
47
47.9
10c:\saturnws\data\4016.run File:Channel:
Last recalc:
c:\saturnws\data\4016.runMiddle = FID ResultsNA
X:Y:
8.2134 Minutes-2.09 mVolts
0.0
2.5
5.0
7.5
mVolts
ethy
lene
(4.
326)
4.67
7pr
opan
e (5
.000
)pr
opyl
ene
(5.4
41)
n-bu
tane
(10
.960
)1-
bute
ne (11
.042
)
buta
ne (12
.352
)
2-bu
tene
(13
.315
)
isop
enta
ne (16
.385
)
pent
ane
(17.
806)
18.6
18
met
hylp
enta
ne (21
.232
)
dim
ethy
lpen
tane
(23
.563
)
24.3
10
benz
ene
(25.
850)
cycl
ohex
ane,
trim
epen
tane
(25
.921
)
tolu
ene
(28.
920)
o-xy
lene
(33
.290
)
m-p
xyl
ene
(33.
930)
a-pi
nene
(34
.700
)
35.5
85
tri-m
e be
nz (36
.940
)
b-pi
nene
(37
.547
)
d-lim
onen
e (3
8.84
9)
48.2
96c:\saturnws\data\6012.run File:Channel:
Last recalc:
c:\saturnws\data\6012.runMiddle = FID ResultsNA
X:Y:
11.2452 Minutes-0.213 mVolts
WI:4T%:7VB+GR+
HM+T%:10
HM-VB-GR -
WI:2 WI:4
WI:4T%:7WI:8 WI:4 GR+
HM+T%:10
HM-GR -
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