organic carbon chemistry in the valley atmosphere
TRANSCRIPT
Organic Carbon Chemistry in the Valley Atmosphere: Quinones and Peroxides
Alam
Hasson
Department of Chemistry
California State University, Fresno
Quinones and Peroxides are minor components of PM
Polyaromatic
Hydrocarbons (PAH)
Quinones
Hydrogen Peroxide (H2
O2
)
Annual Average PM2.5
~25 g.m‐3
Typical mass loading for quinones
and PAH < 1 ng.m‐3 (0.004% of PM
mass) Typical mass loading for H2
O2
* < 30 ng.m‐3
(0.1% of PM mass)(*
for
Southern
California)
O
O
OO
O
O
O
O
OH
OH
O2. ‐ H2
O2
Atmos.Ox. ?
Fe3+
Fe2+
Reducing Agent
.OH
O2. ‐O2
CellDamage
Reducing AgentReducing AgentPrimary
Emissions
Also present
in PM
Key Questions to address:1.
Do all quinones
behave the same?2.
What is the relative importance of emissions vs. chemistry?3.
What is the relative importance of H2
O2
production in atmosphere vs. in lung?
Quinones and Hydrogen Peroxide
Hydrogen Peroxide Generation in the Atmosphere
Hydrogen Peroxide in PM
• Fine aerosols contain high concentrations of liquid water, so H2
O2
may
partition between the gas phase and the aerosol according to Henry’s law:
Organics
Emissions
OxidationHO2 + Other Products
H2 O2Self Reaction
Uptake intoAqueous Aerosol
H2 O2 (g) H2 O2 (l) HA .PH2O2 = [H2 O2 ]aq
Hydrogen Peroxide• H2
O2
levels are up to 100
times higher in PM than
expected in LA basin.
5/8 5/13 5/18 5/23 5/28 6/2 6/70
2
4
6
8
10
12
14
Aerosol Phase H2O2
Aero
sol H
2O2 /
ng
m-3
Date
0.5
1.0
1.5
2.0
2.5
3.02 2
Gas Phase H2O2
Gas Phase H
2 O2 / ppb
2.0x10-9 4.0x10-90.0
1.0x10-3
2.0x10-3
3.0x10-3
HA x [H
2O
2]gas
= [H2O
2]liquid
[H2O
2] aero
sol /
M
[H2O
2]gas
/ atm.
• Measurements imply that H2
O2
is generated
within the particles themselves.
• Metals and/or organics (including quinones)
may undergo reactions to form H2
O2
in
particles.
(Hasson
and Paulson, J. Aerosol Sci, 459‐68, 2003.)
Endo‐
vs. Exo‐ROS Generation
1E-7 1E-6 1E-5 1E-4 1E-31E-8
1E-7
1E-6
1E-5
1E-4
1E-3ApproximateRange ofAmbient H2O2
Measurements
Approximate Range ofAmbient QuinoneMeasurements
H2O
2 Pro
duct
ion
Rat
e / M
hr-1
[Quinone]aerosol / M
Lower Limit Upper Limit
(Ascorbate‐only Chemistry)
Hydrogen peroxide in PM may
be as important as hydrogen peroxide formed by PM.
O
O
O
O
5,12‐NaphthacenequinoneAnthraquinone
O O
Acenaphthenequinone
OO
PhenanthraquinoneO
O
1,4‐Naphthoquinone
O
O
1,2‐Naphthoquinone
O
O
1,4‐Chrysenequinone
O
O
2,6‐Dtb‐1,4‐Benzoquinone
H3C
O
O
2‐Methyl Anthraquinone
H3C
O
O
H3C
2,3‐Dimethyl Anthraquinone
O
O
Benz[a]anthracene‐7,12‐dione
Quinones Identified in Fresno Air:Do they all behave in the same way?
DTT (Dithiothreitol) Assay
• Provides information on the potential of PM extracts to cause cell injury.
• Quinones/PM oxidize DTT, generating H2
O2
.
•
The reaction rate is correlated with bronchial epithelial cell injury by ROS (Li
et al., Environ. Health Perspect. 2003).
HO
HOSH
SHHO
HOS
SHO
HOS
S
O
O
R1
R2
R4
R3
O
O
R1
R2
R4
R3
O
O
R1
R2
R4
R3
O
O
R1
R2
R4
R3
O2.‐ O2
.‐
O2 O2
O2H2O2
DTT (Dithiothreitol) Assay
0.0 2.0x10-6 4.0x10-6 6.0x10-60.0
1.0x10-6
2.0x10-6
3.0x10-6
4.0x10-6
5.0x10-6
Slope = 0.75 +/- 0.15 min-1
R2 = 0.74P = 6 x 10-4
Mea
sure
d R
ate
/ M.m
in-1
Calculated Rate / M.min-1
Rate = k’PQ
[PQ]0
+ k’1,4‐NQ
[1,4‐NQ]0
+ k’1,2‐NQ
.[1,2‐NQ]0
Measured quinones account for all of the reactivity of the PM samples collected.Phenanthraquinone dominates the reactivity of these samples.
Origins of Atmospheric Quinones: Emissions vs. Chemistry
Sources of Quinones and PAH
• Samples Collected at Fresno
State (November 2005 – June
2006).
• Lundgren Impactor
with four
size cuts (10, 3, 1 and 0.3 m).
• ~50 chemical compounds
monitored.
Sources of Quinones and PAH: 11/2005 –
7/2006
Gasoline vehicles
Wood CombustionDiesel
Vegetation
Road Dust
Meat Cooking0.0
0.2
0.4
0.6
0.8
1.0
R-V
alue
Gasoline vehicles
Wood CombustionDiesel
Vegetation
Road Dust
Meat Cooking
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
P-Va
lue
Wood Combustion
Gasoline vehiclesDiesel
Vegetation
Road DustMeat
0.0
0.2
0.4
0.6
0.8
1.0
R-V
alue
Wood Combustion
Gasoline vehiclesDiesel
Vegetation
Road DustMeat
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
P-Va
lue
Wood combustion correlation is strongly dependent on a few data points.
PAH and quinone
mass loadings are strongly correlated (R2
= 0.98; P = 2 x 10‐4).
Quinones
PAH
Some Quinones Expected From PAH Oxidation Chemistry
• PAH oxidation chemistry is
complicated.
• Quinones have been observed in low yield (a few percent or less)
from several PAHs.
• Because PAH emissions are much
greater than quinone
emissions,
chemical formation of quinones
in
the atmosphere may exceed
primary emissions.
(Lee and Lane, Atmospheric Environment, 43, 4886‐93, 2009.)
Evidence for Photochemistry from Southern California
• Role of photochemistry estimated from relative levels of phenanthrene,
phenanthraquinone
and benzo[g,h,i]perylene.• ~90% of phenanthraquinone
is from phenanthrene
oxidation.
(Eiguren‐Fernandez et al, Atmospheric Environment, 42, 2312‐19, 2008.)
PM in Southern and Central California not the same
Jan
Feb MarApri
lMayJu
ne Jul
Aug Sep OctNov Dec
0
10
20
30
40
50Av
erag
e PM
2.5 M
ass
Load
ing
/ g.
m-3
San Joaquin Valley Los Angeles Basin
Jan
FebMarApri
lMayJu
ne Jul
AugSep OctNovDec
0
10
20
30
40
50
Mass Loadings for 2009 (California Air Resources Board)
6/17/2
008
6/20/2
008
6/23/2
008
6/26/2
008
6/29/2
008
7/2/20
087/5
/2008
7/8/20
087/1
1/200
87/1
4/200
87/1
7/200
8 --
0
20
40
60
80PM
2.5 /
g.m
-3
0.0
2.0x105
4.0x105
6.0x105
Levo
gllu
cosa
n / A
U
0.05.0x104
1.0x105
1.5x105
2.0x105
Phe
nant
hren
e / A
U
No Phenanthraquinone
observed: Not present or all in the gas phase?
Field Data –
Summer 2008
Summer A
Summer
B
Field Data –
Summer 2004
6/8/2004
6/14/2004
6/16/2004
6/18/2004
6/20/2004
6/22/2004
6/24/2004
6/26/2004
6/28/2004
6/30/20047/2/2004
7/4/20047/6/2004
0
1
2
3
4
5
6
7
8
9
10
Mas
s Lo
adin
g / n
g.m
-3
Date
Anthraquinone Naphthacenequinone
A A
A
A A
A
BBBBBBB
Daytime vs. Nighttime Chemistry
• OH and O3
are the major daytime oxidants; NO3
is the main nighttime oxidant.
Gas Phase Phenanthraquinone
from Phenanthrene
Gas Phase Reaction with
OH NO3 O3
Yield 3% 33% 2%
Reaction Rates(cm3.mol‐1.s‐1)
3.2 x 10‐11 1.2 x 10‐13 4.0 x 10‐19
Formation Rate(pg.m‐3.hr‐1)
80 800 0.2
(Wang et al, Atmospheric Environment, 41, 2025‐35, 2007.)
Daytime vs. Nighttime Quinone
Levels
6-Mar
7-Mar
8-Mar
9-Mar
12-M
ar13
-Mar
14-M
ar15
-Mar
16-M
ar19
-Mar
20-M
ar21
-Mar
22-M
ar23
-Mar
0
5
10
15
20
25
Mas
s Lo
adin
g / n
g.m
-3
Central Fresno (Day) Fresno State (Day) Fresno State (Night)
Fresno State
Central Fresno
Chrysenequinone
• Samples collected at both sites 6:00 am – 6:00 pm. Samples also collected at Fresno State
site 6pm – 6 am.• Chrysenequinone, Phenanthraquinone
and 1,2‐Naphthoquinone levels were higher during
day (although not statistically significant).
Conceptual Model for Secondary PM Formation
Inversion Layer
PhotooxidationProducts (e.g., Nitrate)
Primary Emissionse.g., NOx
Primary Emissions
PhotooxidationProducts (e.g., Nitrate)
(Watson and Chow, Atmospheric Environment, 36, 177‐201, 2002.)
Summary
• Certain quinones
such as
phenanthraquinone
likely
play a greater role in ROS
production than others.
• Some evidence for quinone
production from chemical
reactions, but more work is
needed to understand this.
• Hydrogen Peroxide in
atmospheric particles may
play an important role in
particle chemistry and health
effects, but levels and origins
are not well understood.
Acknowledgements
Akihiro Ikeda
Kennedy Vu
Akiteru
Ikeda
Julie Lyon
Enrique Lopez
Rick Lazaro
Dora Rendulic
Mark Sorenson
Christina Sabado
Dianne Lim
Joscelyn
Jackson
Saddam Muthana
Rodhelen
Paluyo
Denise Soria
Juan Camacho
Dr. Myeong
Chung
Dr. Thomas Cahill (UC Davis)
Tim Tyner (UCSF‐Fresno)
Funding
San Joaquin Valley Air Pollution Control District
College of Science and Mathematics and the Provost’s Office, California State
University, Fresno