Post on 30-May-2018
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NASAs Research ProgramNASAs Research Program
in Tropospheric Chemistry:in Tropospheric Chemistry:
How are Human InfluencesHow are Human Influences
Changing EarthsChanging EarthsAtmosphere?Atmosphere?
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Emission Transformation/Oxidation Removal(NOx, CO, Hydrocarbons) (O3, OH, CH2O, HO2, RO2) (HNO3, H2O2, ROOH)
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Global NOx Sources
(teragrams of nitrogen per year)
Source Magnitude (uncertainty)
Fossil Fuels 22 (13-31)
Biomass Burning 8 (3-15)
Soil Emissions 7 (4-12)
Aircraft 0.85 (0.5-1)
Lightning 5 (2-20)
Global Hydrocarbon Sources
(teragrams of carbon per year)
Source Possible Range
Fossil Fuels 46-95
Biomass Burning 25-80
Emission from Foliage 800-1500
Soils/Oceans/Grasslands 15-30
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Emission Transformation/Oxidation Removal(NOx, CO, Hydrocarbons) (O3, OH, CH2O, HO2, RO2) (HNO3, H2O2, ROOH)
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Tropospheric Ozone Significance:
Environmentally Important: Ozone is a pollutant
adversely impacting health and agriculture
Chemically Important: Ozone initiates the
oxidation cycles responsible for removing most
polluting gases from the atmosphere. Theseoxidation cycles also influence ozone itself.
Climatically Important: Ozone influences climate
directly as a greenhouse gas and is mostimportant in the upper troposphere where
temperatures are cold. Ozone exerts an indirect
influence through the oxidation of other
greenhouse gases.
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HNO3
X
XOHCl
NH2
NO
H2SO4
HSO3
SO2
CO
H2O
HO2
HH2O2
O3O(1D)
O(3P)
HO2
NO
H2
Multi-stepprocess
O3
CH3CCl3
HXNO2
N2,O2O2
hv
H2O CXHY
CO
hv
Removal byprecipitation
O2
SO2
NH3
Multi-stepprocess
Multi-stepprocess
Multi-stepprocess
Removal byprecipitation
Multi-stepprocess
Removal byprecipitation Removal by pre-
existing
particles or
nucleation
OHCH3SCH3
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Emission Transformation/Oxidation Removal(NOx, CO, Hydrocarbons) (O3, OH, CH2O, HO2, RO2) (HNO3, H2O2, ROOH)
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Satellites: mainly column amountsSatellites: mainly column amountsOO33, CO, NO, CO, NO22, HCHO, HCHO Aerosol optical depth, propertiesAerosol optical depth, properties
Aircraft: DC-8, P-3B, B200Aircraft: DC-8, P-3B, B200Comprehensive in situ chemical and aerosolComprehensive in situ chemical and aerosol
measurementsmeasurements
Lidar remote sensing of ozone, water vaporLidar remote sensing of ozone, water vapor
and aerosol optical propertiesand aerosol optical properties
Solar radiation measurementsSolar radiation measurements
Global and Regional ModelsGlobal and Regional Models
Source-receptor relationships for pollutionSource-receptor relationships for pollution
Inverse modeling for estimating emissionsInverse modeling for estimating emissions
Aerosol radiative forcingAerosol radiative forcing
Detailed chemical processingDetailed chemical processing
Model error characterizationModel error characterization
Data assimilationData assimilationDiagnostic studiesDiagnostic studies
Calibration and ValidationCalibration and Validation
Retrieval developmentRetrieval development
Correlative informationCorrelative informationSmall scale structure and processesSmall scale structure and processes
Airborne Field Campaign Strategy: Maximize the value of satelliteAirborne Field Campaign Strategy: Maximize the value of satellite
data for improving models of atmospheric composition and climatedata for improving models of atmospheric composition and climate
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Ozone (O3): Aura-MLS, Aura-TES
Carbon Monoxide (CO): Terra-MOPITT, Aqua-AIRS, Aura-TES
Nitrogen Dioxide (NO2): Aura-OMI
Formaldehyde (CH2O): Aura-OMI
Aerosols: Terra-MODIS and MISR, Aqua-MODIS, CALIPSO, Glory-APS,
Aura-OMI
NASA satellite observations of Atmospheric Composition
Terra
10:30
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OMI & MLS produce aOMI & MLS produce a
tropospheric ozonetropospheric ozoneproduct by subtractingproduct by subtracting
the MLS stratosphericthe MLS stratospheric
ozone from OMIozone from OMI
column ozone.column ozone.
This can be comparedThis can be compared
to the more sparse butto the more sparse but
direct observationsdirect observations
from TESfrom TES
OMI & MLS: Global Tropospheric Ozone Residual
Mark Schoeberl, NASA GSFC*Notice that largest ozone enhancements are downwind of source regions
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CO observations from MOPITT and AIRS: Tracing
pollution transport from combustion sources
Strengths:
-Atmospheric lifetime of ~2 months is ideal for observing
long-range transport which takes place in mid-troposphere.
-Excellent detection of enhanced CO from fires
-4.2m thermal emission allows detection both day and nightLimitations:
-Sensitivity limited mainly to middle troposphere
-No significant vertical resolution
Future observations aim to provide additional
detection for 2.3 m channelStrengths:
-Solar reflection at 2.3 m will be sensitive to total columnextending down to the surface
-Information on surface concentrations may be derived in
combination with
4.6m observations
Limitations:-Solar reflection limits
detection to daytime
mainly over land
20
10
0
Altitude(km)
250200150100500
CO, ppb
4.6m
Avg. Kernel
2.3m
Avg. Kernel
Avg. CO
profile Los
Angeles (July
2004)
MOPITT Seasonal Average CO (850mb)
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Strengths:
-Atmospheric NO2 abundance is weighted toward surface,
therefore column measurement can yield useful information onvariability in surface emissions
-Atmospheric lifetime of NO2 is less than one day near the
surface, therefore observed enhancements are in close proximity
to sources.
Limitations:
-Stratospheric abundance of NO2 must be subtracted to give a
tropospheric residual (similar to ozone), however, troposphericNO2 dominates the column in polluted areas.
-Partitioning between NO2 and NO must be assessed to estimate
total NOx, although NO2 typically constitutes ~80% of near-
surface NOx
-Emission of NOx undergoes large diurnal variability
NO2 observations from OMI: High
resolution information on anthropogenic
emissions
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OMI NO2: Beijing Olympics
Br an Duncan, NASA GSFC
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A 50% reduction
in NO2!
A 20-40%
reduction in SO2!
Beijing Olympics:
Pollution Reduction Efforts
OMI Tropospheric NO2 around Beijing, China
x1015m
olec/cm2
Month
Bryan Duncan, NASA GSFC
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Formaldehyde observations from OMI: Oxidation of biogenic and
other hydrocarbon emissions
Strengths:
-Atmospheric CH2O abundance is weighted
toward surface with no significant stratospheric
burden-Oxidation of most hydrocarbons result in CH2O,
therefore it is an excellent proxy for the
integrated influence of hydrocarbons on ozone
photochemistry
Limitations:
-CH2O is not directly emitted, but rather is abyproduct of photochemistry. With a short
lifetime (hours), it undergoes large changes
throughout the day.
-Atmospheric lifetime of CH2O is less than one
day, observed enhancements occur at variable
distances from hydrocarbon sources, depending
on their atmospheric lifetime.
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NASA Tropospheric Chemistry Field Campaigns (1983-2008)
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INTEX B Fli ht P id S i F d V lid ti
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INTEX-B Flights Provide Science-Focused Validation
Opportunities: DC-8 Flight 16 from Anchorage
MLS
TES-LAsian pollution
Large concentrations of ozone
in the Pacific troposphere
Multiple satellite tracks
are examined for validation
DIAL O3 (E. Browell, NASA LaRC)
CO prediction from the RAQMS
model (R. B. Pierce, NASA LaRC)
0
2
4
6
8
10
12
Altitude(km)
0
50
100
150
200
250
300
CO(ppbv)
DACOM CO (G. Sachse and G. Diskin, NASA LaRC)
Large concentrations of ozone are associated
with high CO suggesting Asian pollution
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OMI NO Tropospheric Column Compared with GEOS Chem
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OMI NO2 Tropospheric Column Compared with GEOS-Chem
Asian NOx anthropogenic
emissions for the year 2000
2 x 2000 Asian NOx
emissions
OMI NO2 tropospheric column observations suggest a factor of 2 increase of
Asian anthropogenic NOx emissions from 2000 to 2006.
D. Jacob, Harvard
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Satellite observations reveal
increasing Asian NO2 emissions
Transport of Asian Ozone and its Precursors
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The mean Asian ozone, CO, NOx, and PAN enhancements at 800 hPa for INTEX-B
Latitudinal distribution of NO2 and PAN at 1.5 -5 km
Transport of Asian Ozone and its Precursors
Ozone CO
NOx PAN
NO2 PAN
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HOW DO AIRBORNE FIELD CAMPAIGNS AFFECT POLICY?HOW DO AIRBORNE FIELD CAMPAIGNS AFFECT POLICY?
Information synthesis
Improved knowledge;publications in scientific journals
Summary assessments for policymakers:Intergovernmental Panel on Climate ChangeArctic Council
UNEP Hemispheric Transport of Pollution Assessment
Better-informed decisions to protect the environment
Satellites
Models Aircraft
Improved model predictions
2 yrs
5 yrs
10 yrs
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Contrasting Conditions
along a Frontal Zone
P-3B Flight 19
100 150 200 250 300 350 400 450 500 550 600CO (ppbv)
0
1
2
3
4
5
Altitude
(km)
10 10
DC-8 DC-8
Cl d bi
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Jan. 27 - Feb. 2, 2003 (1 week)
Feb. 1 - 25, 2004 (3.5 weeks)
10-11 km
9-10km
8-9 km
7-8 km
6-7 km
5-6 km
4-5 km
3-4 km
2-3km
1-2 km
0-1 km
0 100 200 300
CO (ppbv)
In CloudAbove CloudClearBelow Cloud
Median CO (ppbv) Enhancement in Cloudy Regions
Clear Cloudy Enhancement
1-5 km 135 178 32%5-11 km 101 116 15%
0 100 200 300 400
CO (ppbv)
0
1
2
3
4
5
6
7
8
9
Altitude(km)
0 10 20 30 40 50 60 70 80 90 100
Relative Humidity (percent)
0
1
2
3
4
5
6
7
8
9
Altitude(km)
DC 8P-3B
DC 8P-3BClouds may bias
satellite estimates
of pollution in
Asian outflow
observations in
cloudy areas areneeded
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Arctic Research of the Composition of the Troposphere fromArctic Research of the Composition of the Troposphere from
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DC-8
P-3B
B200
Terra
10:30
Arctic Research of the Composition of the Troposphere fromArctic Research of the Composition of the Troposphere from
Aircraft and Satellites (ARCTAS) conducted flights during SpringAircraft and Satellites (ARCTAS) conducted flights during Spring
(Arctic Haze) and Summer (Boreal Fires)(Arctic Haze) and Summer (Boreal Fires)
http://fuelberg.met.fsu.edu/gallery/arctas/Thule_to_Cold_Lake_+_P-3_and_Tar_Sands/thule-to-cold-lake%20030.jpg8/14/2019 Crawford SARP
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LIDAR INSTRUMENTS ON THE AIRCRAFT OBSERVE ARCTIC HAZEFROM THE SURFACE TO 30,000 FEET
Iqaluit-Fairbanks DC-8 transit, April 9;Yellow-green colors indicate Arctic haze
Asia
NorthAmerica
Europe
Fires
Johnathan Hair, NASA/LaRC
Other instruments on the aircraft pinpoint the origin of this haze
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High Spectral Resolution Lidar Observations ofArctic Haze from the NASA B200 aircraft
cloud
cloud
Long-range transport from mid-latitudes into the Arctic
results in an aerosol haze (in blue) that is mixed
throughout the troposphere.
Intense aerosol plumes originating from fires were
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10
8
6
4
2
0
Altitude(km)
100806040200
Aerosol Extinction (Mm-1
)
Median
10th
and 90th
Percentile
0.100.050.00
Black Carbon (g/m3)
Aerosol Extinction
Intense aerosol plumes originating from fires were
superimposed on the background arctic hazehow
important are they?
Anomalies in fire counts from MODIS and Carbon
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Anomalies in fire counts from MODIS and Carbon
Monoxide from MOPITT corroborate unusually strong
fire emissions over Siberia in April 2008.
Comparison of CALIPSO satellite observations and
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CALIPSO (observations)
GMAO (model)
RAQMS (model)
Eastern Asia (110E 130E)
Comparison of CALIPSO satellite observations and
models suggests that transport of aerosols to the
arctic from Siberian
fires is too strong inmodels .
Sharp gradient observed by
CALIPSO not seen in model
predictions.
Preliminary model results for
carbon monoxide indicate that
fire emissions are
overestimated by factors of
2 to 3. For aerosols,
scavenging and removal by
precipitation is an additional
concern requiring attention.
Closing points:
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0
5
10
15
20
25
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Area Burned over Time (M ha)
Russia
Canada andAlaska
Closing points:
ARCTAS observations show a larger than expected contribution
from fire emissions in Spring, although this may not be
inconsistent with recent trends in boreal fires.Models appear to do a reasonable job of reproducing observed
carbon monoxide distributions, but require estimated fire
emissions to be reduced by factors of 2 to 3.
Scavenging is an additional factor critical to understanding
aerosol impacts. What fraction
of the aerosol transported to
the arctic is ultimately
deposited to the snowpack?
V DIAL Ozone Depletion Events (ODE) 17 April 200
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NO Low Ozone Event measured by:
UV-DIAL orNCAR CLD
Low Ozone Event measured by:
UV-DIAL orNCAR CLD
V DIAL Ozone Depletion Events (ODE) 17 April 200Extending UV DIAL measurements near surface
UV DIAL O one
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NO Low Ozone Event measured by:
UV-DIAL orNCAR CLD
Low Ozone Event measured by:
UV-DIAL orNCAR CLD
UV DIAL OzoneDepletion Events
(ODE) 8 April 2008
Extending UV DIALmeasurements near
surface
5/1/2006 Fli h (RF 06)
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5/1/2006 Flight (RF 06)
Pre-flight modeling showed Asian influenced air mass off coast
of Northwest U.S.
Flight plan chosen to intercept it
Pollution seen in layer at 20,000 ft early and late in flight
J. Jimenez, CU-Boulder
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Forecast E al ation Ma 4 DC8
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MOZART Forecast CO
interpolated to flight track
compared to preliminary
data from DACOM*
MOZART Forecast CO
along flight track(Fx initialized 0502 12UTC)
* Data from Glen Sachse, NASA Langley
Forecast Evaluation - May 4 - DC8
05/04 12Z Forecast: Valid for 05/05 18-24Z05/04 12Z Forecast: Valid for 05/05 18-24Z
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05/04 12Z Forecast: Valid for 05/05 18 24Z05/04 12Z Forecast: Valid for 05/05 18 24Z
24Z: 700 hPa18Z: 700 hPa
L. Emmons, NCAR
F id 5/5 18Z
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5/ 5 00Z fo re ca st Friday, 5/5, 18Z
1
CO
1 2
CO
23
4
3 4
GEOS-Chem and FLEXPART
forecasts were very similar to
MOZART for this flight
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7
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0 100 200 300 400 5000
1
2
3
4
5
6
7
100 200 300 400 500 100 200 300 400 500 100 200 300 400 500 100 200 300 400 500
0 250 500 750 10000
1
2
3
4
5
6
250 500 750 1000 250 500 750 1000 250 500 750 1000 250 500 750 1000
Altitude(km)
Altitud
e(km)
NOy (pptv)
PAN (pptv)
A. Weinheimer, NCAR
F. Flocke, NCAR
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.
The 2004 Alaska Fires
MOPITT 700 hPa CO mixing ratio for the period 15-23 July, 2004,
during the INTEX-A field campaign. The intense wildfires in Alaska
produced plumes of carbon monoxide pollution that can be traced
across North America and the Atlantic Ocean.David Edwards, NCAR
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Long-range transport of smoke affects air quality
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Comparison of MODIS and GOCART
Pollutants from forest fires (e.g.,aerosol particles and ozone) can betransported long distances, affectingsurface air quality downwind.
In July 2004, large forest fires
occurred in Alaska and westernCanada. Smoke aerosols weretransported across Canada and tolarge areas of continental U.S.,affecting regional air quality.
Event was observed by MODIS andsimulated by the GOCART model,which showed a similar pattern andintensity for aerosol optical thickness.
MODIS AOT 550 nm 200407
GOCART AOT 550 nm 200407
Mian Chin, NASA GSFC
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Taken from National Air Quality-Status and Trends through 2007 (http://www.epa.gov/airtrends/2008/)
Ozone concentrations in ppm, 2007
(fourth highest daily max 8-hour concentration).
Annual average PM2.5 concentrations in g/m3, 2007
Violations of National Ambient
Air Quality Standards (NAAQS)
are primarily related to ozone
and fine particulate matter.
* Yellow and Red symbols represent levels in violation of NAAQS
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Aerosols Significance:
Environmentally Important: Aerosols adverselyimpact health, reduce visibility, and acidify
precipitation
Chemically Important: Aerosols are critical toatmospheric removal processes.
Climatically Important: Aerosols influence Earths
energy balance directly through the scattering
and absorption of radiation as well as indirectly
through modification of clouds (e.g., distribution
and optical properties).
URGENT NEED TO BETTER UNDERSTANDURGENT NEED TO BETTER UNDERSTAND
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URGENT NEED TO BETTER UNDERSTANDURGENT NEED TO BETTER UNDERSTAND
CHANGES IN THE ARCTIC ATMOSPHERECHANGES IN THE ARCTIC ATMOSPHERE
Receptor and accumulator of pollution fromReceptor and accumulator of pollution fromnorthern mid-latitudes continents: arctic haze,northern mid-latitudes continents: arctic haze,mercury,mercury,
Increasing forest fires in Siberia, Canada, AlaskaIncreasing forest fires in Siberia, Canada, Alaskablanket large areas with smokeblanket large areas with smoke
Rapid warming over the past decades fasterRapid warming over the past decades fasterthan anywhere else on Earththan anywhere else on Earth
Arctic haze and other pollution may be anArctic haze and other pollution may be animportant contributor to the warming, withimportant contributor to the warming, withcomplicated feedbackscomplicated feedbacks
Our goal is to test and improve the models used toOur goal is to test and improve the models used to
predict changes in Arctic pollution and climatepredict changes in Arctic pollution and climate
THE ARCTIC IS A BEACON OF GLOBAL CHANGE
ining pollution transport with aircraft, models, and satellites
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DC-8 in situ CO GEOS-Chem Column COAIRS 500 mb CO (ascending
g p p
Characteristics of the pollution plume: Observed at ~4-6 km
Elevated CO, SO4, and HCN
Source could be: anthropogenic emissions from easternAsia
biomass burning from southernSiberia
50 75 100 125 150 175 200ppbv
0.5 0.9 1.3 1.7 2.1 2.51018 molec/cm2
50 100 150 200 2500ppbv
Jenny A. Fisher [Harvard], Glenn Diskin [LaRC], Juying Warner [UMBC]
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Atmospheric Temperature
and Pressure
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O3
h H2O
OH
O3
NO NO2
h
Dominant Source of OH NOx Partitioning
Tropospheric Photochemistry
Key Roles for Ozone:
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O3
HO2 OH
O3
Oxidation of Pollutants O3 Destruction
Tropospheric Photochemistry
Key Roles for HOx (OH+HO2):
h, H2O .O3 OH
OH .
CO, CH4, RH .
HO2, CH3O2, RO2
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HO2, RO2
NO NO2
hv
O3
NO
HO2 OH
CO
Ozone Production HOx Partitioning
Tropospheric Photochemistry
Key Roles for NOx (NO+NO2):
Simplified HOxproduction and loss scheme
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OH HO2
O3 CH3COCH3
HNO3 H2O2ROOH
hv
H2O
CO, O3
NO, O3
CH4
NO
hv
NO
NO2
HO2RO2
CH2O
NMHC hv
Example of nonlinear
chemical behaviorNOx
amount for peak ozoneproduction is sensitive to
the source strength for
radicals (OH, HO2, and RO2).
RO2
OH
hv
hv
Simplified HOxproduction and loss scheme
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OH HO2
O3 CH3COCH3
HNO3 H2O2ROOH
hv
H2O
CO, O3
NO, O3
CH4
NO
hv
NO
NO2
HO2RO2
CH2O
NMHC hv
EXAMPLEof nonlinear
chemical behaviorboth
NOx amount for peak ozoneproduction and peak rate
are sensitive to the source
strength for radicals (OH,
HO2, and RO2).
RO2
OH
hv
hv
Tropospheric Ozone Photochemistry
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O3O(1D)
OH
HO2CH3O2RO2
h
NMHCs
HO2
OH
H2O
COCH4
F(O3) = (k[HO2] + k[CH3O2] + k[RO2]) [NO]
D(O3) = k[O(1D)][H2O] + k[HO2][O3] + k[OH][O3]
Net O one Tendenc F(O ) D(O )
Tropospheric Ozone Photochemistry
NO2
NO
h
HO2, CH3O2, RO2
O2