The Seasonality of Tropospheric Ozone and Reactive …...The Seasonality of Tropospheric Ozone and...
Transcript of The Seasonality of Tropospheric Ozone and Reactive …...The Seasonality of Tropospheric Ozone and...
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The Seasonality of Tropospheric Ozone and Reactive Nitrogen: From Measurements to Models
3rd Year Analytical Seminar March 14, 2016
Outline:1) Project #1 – Colorado Emissions & Ozone Photochemistry2) Project #2 – Wintertime Reactive Nitrogen Partitioning
Erin E. McDuffie1,2,3, Steven S. Brown1,3, Jessica B. Gilman2,3, Brian M.Lerner2,3, Peter M. Edwards4, Dorothy Fibiger5, William P. Dubé2,3,Michael Trainer3, Wayne M. Angevine2,3, Stuart McKeen2,3, Daniel E. Wolfe6,Alex G. Tevlin7, Jennifer Murphy7, Emily V. Fischer8, Felipe Lopez-Hilfiker8,Joel A. Thornton8, Jeff Peischl2,3, Andrew O. Langford2,3, Christoph J. Senff2,3,John S. Holloway2,3, Eric J. Williams3, Joost deGouw1,2,3, Thomas B. Ryerson3,Kenneth Aiken2,3, Samuel Hall10, Kirk Ullmann10, Kathy O. Lantz10, BillKuster2,3, Rebecca Hornbrook10, Eric Apel10, Allan Hills10
1Department of Chemistry, University of Colorado, 2Cooperative Institute for Research in Environmental Sciences, University of Colorado, 3NOAA, Chemical Sciences Division, 4Department of Chemistry, University of York, United Kingdom, 5Geospace Postdoctoral Fellow, 6NOAA, Physical Sciences Division, 7Department of Chemistry, University of Toronto, Canada, 8Department of Atmospheric Science, Colorado State University, 9Department of Atmospheric Sciences, University of Washington, 10Atmosperic Chemistry Observations and Modeling Laboratory, NCAR, 11NOAA, Global Monitoring Division
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Tropospheric Ozone: Motivation
‘Oxidized VOCs’ + NOx à O3
Greenhouse Gas + Health Hazard à Regulated by US EPA
Photochemical Source:
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Tropospheric Ozone: Photochemistry
NO NO2
O3
NOzOH
Sunlight, O2
O3
NOxEmissions
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NOxEmissions NO NO2
OH
Sunlight, O2
VOCOHO2
RO2 RO
O3
VOC Emissions
Tropospheric Ozone: Photochemistry
NOz
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NO NO2 NOzOH
Sunlight, O2
VOCOHO2
RO2Organic nitrate
O3
RO
Tropospheric Ozone: Photochemistry
NOxEmissions
VOC Emissions
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NO NO2 NOzOH
Sunlight, O2
VOCOHO2
RO2 RO
O3
Radical Recycling =
More Efficient O3 Production
O2
Tropospheric Ozone: Photochemistry
NOxEmissions
VOC Emissions
Local/Regional Emission Sectors
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increased baseline ozone impacting some regions of the west-ern U.S.[39] Global average surface temperature increased by
0.074!C " 0.18!C per decade when estimated by a lineartrend for the 100 year period,1906–2005 [IntergovernmentalPanel on Climate Change (IPCC), 2007], while the rate ofincrease since the late 1970s is 0.15!C–0.20!C per decade[Hansen et al., 2010]. As global temperatures have increasedsince the 19th century so too has the global troposphericozone burden, primarily due to rising anthropogenic emis-sions of ozone precursors [Lamarque et al., 2005]. Based onthe model studies of ozone response to future climatechange, one might assume that past ozone changes have alsobeen influenced by climate change since the 19th century. Arecent intercomparison of 10 atmospheric chemistry models
run with year 2000 emissions but with 2000s and 1850sclimate shows a range of responses of tropospheric ozone tothe observed temperature increase [Stevenson et al., 2012].Six out of 10 models indicate ozone decreases at the surfaceof the northern hemisphere midlatitudes due to observedclimate change, but the decreases are small (
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• Increased Western Wildfire Activity• Pollution Transport from Asia• Changes in Regional Urban and Oil
and Natural Gas (O&NG) Emissions
increased baseline ozone impacting some regions of the west-ern U.S.[39] Global average surface temperature increased by
0.074!C " 0.18!C per decade when estimated by a lineartrend for the 100 year period,1906–2005 [IntergovernmentalPanel on Climate Change (IPCC), 2007], while the rate ofincrease since the late 1970s is 0.15!C–0.20!C per decade[Hansen et al., 2010]. As global temperatures have increasedsince the 19th century so too has the global troposphericozone burden, primarily due to rising anthropogenic emis-sions of ozone precursors [Lamarque et al., 2005]. Based onthe model studies of ozone response to future climatechange, one might assume that past ozone changes have alsobeen influenced by climate change since the 19th century. Arecent intercomparison of 10 atmospheric chemistry models
run with year 2000 emissions but with 2000s and 1850sclimate shows a range of responses of tropospheric ozone tothe observed temperature increase [Stevenson et al., 2012].Six out of 10 models indicate ozone decreases at the surfaceof the northern hemisphere midlatitudes due to observedclimate change, but the decreases are small (
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4000
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Elev
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Urban Boundaries Active Oil&Gas Wells Agriculture Power Plants Measurement Site
Denver
Boulder
GreeleyFort
Collins
BAO
Ozone Nonattainment Area
Urban NOx + VOC
> 27,000 Active Oil and Natural Gas Wells
Colorado
Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Colorado Northern Front Range (NFR)
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Urban Boundaries Active Oil&Gas Wells Agriculture Power Plants Measurement Site
Denver
Boulder
GreeleyFort
Collins
BAO
Ozone Nonattainment Area
> 27,000 Active Oil and Natural Gas Wells
Colorado
Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Colorado Northern Front Range (NFR)
Urban NOx + VOC
300m Tower
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Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Data: NOx, NOy, O3, Speciated VOCs, CH4, CO, NH3, j(NO2), albedo, meteorological data
2014FRAPPE/DISCOVER-AQ(NOy, no speciated VOCs)
2012 – SONNE (Speciated VOCs, no NOy)
300m
10m
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2014 Chemical Tracers
6090
120150180
60 90120150180
CO 90th, 10th Percentile 75th, 25th Percentile Average
N
E
S
Wppbv
ppbv
3691215
3 6 9 12 15
N
E
S
W
NOy 90th, 10th Percentile75th, 25th Percentile Average
ppbv
ppbv
1.91.95
22.052.1
1.95 2 2.052.1ppmv
N
Methane 90th, 10th Percentile 75th, 25th Percentile Average
E
S
W
ppmv
Composition at BAO characteristic of Urban and O&NG Emission Sectors
Oil and Natural Gas: Enhanced CH4
Urban: NOx and Enhanced CO
Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
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Urban Boundaries Active Oil&Gas Wells Agriculture Power Plants Measurement Site
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Boulder
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Ozone Nonattainment Area
Average
90th, 10th Percentiles
75th, 25th Percentiles
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2012 VOCs
Composition at BAO characteristic of Urban and O&NG Emission Sectors
VOC Distribution (ppbC)SONNE Diurnal Average6am-8pm Avg
82%
1%
3%6%
1%7%
Average Fractional Contribution
O&NG VOC Contribution
Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Gilman, J.B. et al. Environ Sci
Technol, 2013, 43(3), 1297
Alkanes Alkenes/Alkynes
Aromatics Aldehydes/Ketones Alcohols Biogenic VOC
Bar Height: Mean Carbon Mixing Ratio
Alkanes
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Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
OH Reactivity (OHR):
Σ(kOH+VOC *[VOC])
Previously used in O&NG focused O3 studies
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Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
OH Reactivity (OHR):
Σ(kOH+VOC *[VOC])
Previously used in O&NG focused O3 studies
Commonly used as a metric for ‘O3 forming potential’
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Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Marcellus Basin, PA• O&NG: 7%• Biogenic: 47%
Barnett Basin, TX• O&NG: 13-20%• Biogenic: 70%
Comparison to other US O&NG Basins:
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Rutter, A. P., et al. Atmospheric Environment, 2015, 120, 89
O&NG VOCs contribute ~ 50% to OH Reactivity
OH Reactivity (OHR):
Swarthout, R. F., et al. Environ. Sci. Technol., 2015, 49(5), 3175
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OPE: Slope of Ox ( = O3 + NO2) against NOz (= NOy- NOx ) as a measure of the number of O3 molecules produced per NOx molecules oxidized
Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
NOT previously used in O&NG focused O3 studies
Local/Regional Emission Sectors
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OPE: Slope of Ox ( = O3 + NO2) against NOz (= NOy- NOx ) as a measure of the number of O3 molecules produced per NOx oxidized
Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Average of 80 Individual OPEs = 5.3 ± 3.6 ppbv/ppbv
100
90
80
70
60
50
40
Ox (
ppbv
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6543210NOz = (NOy - NOx) (ppbv)
100
90
80
70
60
50
40
Ox (
ppbv
)
6543210NOz = (NOy - NOx) (ppbv)
Individual 15-min OPE
2014: 12pm-6pm (MDT) 16 July-15 August
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Boulder
GreeleyFort
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Ozone Nonattainment Area
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90
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Ox (
ppbv
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6543210NOz = (NOy - NOx) (ppbv)
North East South West
Wind Diretion
OPE vs. Wind Direction
Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Urban and O&NG OPEs not distinguished by wind direction
OPE Differences:1) Obscured by air mixing 2) < 1.4 ppbv/ppbv
100
90
80
70
60
50
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Ox (
ppbv
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6543210NOz = (NOy - NOx) (ppbv)
North East South West
Wind Diretion
Individual 15-min OPE
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Combined Wind Direction & Chemical Tracer Analysis Results:
1) Mixed air masses at BAO2) O&NG and Urban sectors do not uniquely influence OPE by > 1.4 ppbv/ppbv
OPE vs. Chemical Tracers
Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Urban and O&NG OPEs are not distinguished by simple chemical tracers
• O&NG: Enhanced CH4
• Urban: Enhanced CO and NOx
r2 + N àp-values > 0.05
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Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Photochemical Box-Model: Dynamically Simple Model of Atmospheric Chemical Complexity (DSMACC) - Emmerson, K. M., Evans, M. J., Atmos. Chem. Phys., 2009
NOT previously used in O&NG focused SUMMER O3 studies
Photolysis – NCAR’s TUV à Scaled to j(NO2)/j(O1D) observations Chemistry – Master Chemical Mechanism (MCM) à 4002 species, 15555 reactions
Wintertime O3 Production in Utah’s Uintah O&NG BasinEdwards, P. M. et al., Nature, 2014, and Edwards, P. M. et al., Atmos. Chem. Phys., 2013
Base Case Simulated O3
70
60
50
40
30O
zone
(ppb
v)
00:00 06:00 12:00 18:00 00:00Local Time (MDT)
Model
Observations
-2.5%
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Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
On Average, Oil and Natural Gas (O&NG) VOC Emissions Contribute ~19%* to Maximum O3 Photochemically Produced at BAO
The Northern Front Range of Colorado is in a NOx Sensitive Regime
Alkanes Alkenes/Alkynes Aromatics Aldehydes/Ketones Alcohols Biogenic VOC
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10
8
6
4
2
0
OPE
(ppb
v/pp
bv)
frap_obs frap_modl son_mod
2014 2012
Location Field Measurements OH Reactivity O3 Production Efficiency Box-Model
Modeled OPE: Dependent on NOx mixing ratio and temperature
Observed Modeled Modeled
Average OPE vs Base Case
1) Modeled OPEs within 1 standard deviation of Observed 2014 Average (accurate Base Case)
10
8
6
4
2
0O
PE (p
pbv/
ppbv
)fb fx sb sx
Base Case No O&NG VOC
2014 Modeled 2012 Modeled
Base Case vs No O&NG VOCs
2) O&NG Emissions influence OPE by ~1.0 ppbv/ppbv(consistent with OPE vs wind direction analysis)
6.2 vs 5.2 ppbv/ppbv
6.3 vs 5.3 ppbv/ppbv
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Project #1: Summary and Conclusions
Regional O3 photochemistry is dependent on local NOx and VOC emission sources
BAO experiences both O&NG & urban emissions
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Urban Boundaries Active Oil&Gas Wells Agriculture Power Plants Measurement Site
Denver
Boulder
GreeleyFort
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Ozone Nonattainment Area
At BAO:1) O3 production is sensitive to NOx emissions
2) O&NG VOC emissions contribute:~ 80% to observed carbon mass (ppbC)~ 50% to O3 forming potential (OHR) ~ 19% to maximum photochemical O3~ 1.0 ppbv/ppbv OPE
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Project #2: Influence of Reactive Nitrogen Chemistry on Wintertime Tropospheric O3
NOzNOx
Emissions NO NO2OH
Sunlight, O2
O3
VOCOH
O2RO2 RO
VOC Emissions
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NOzNOx
Emissions NO NO2OH
Sunlight, O2
O3
VOCOH
O2RO2 RO
VOC Emissions
Project #2: Quantify the Influence of Heterogeneous Reactive Nitrogen Mechanisms on Winter O3
Tropospheric Ozone: Dark Chemistry
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NOxEmissions NO NO2
Tropospheric Ozone: Dark Chemistry
O3
Sunlight, O2
O3
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NO3NOx
Emissions NO NO2
Tropospheric Ozone: Dark Chemistry
O3
O3+ N2O5
HNO3
ClNO2Sunlight, O2
O3
Consequences for:
• Wintertime tropospheric O3 budget• Lifetime and distribution of NOx, O3, and additional tropospheric oxidants (i.e. OH)• Magnitude and mechanisms for sources of tropospheric halogens
Reactive Nitrogen Partitioning
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NO3NOx
Emissions NO NO2 O3+ N2O5
HNO3
ClNO2
VOCOH
O2RO2 RO
VOC Emissions
O3 NOx Reservoir
NOx Sink
Consequences for:
• Wintertime tropospheric O3 budget• Lifetime and distribution of NOx, O3, and additional tropospheric oxidants (i.e. OH)• Magnitude and mechanisms for sources of tropospheric halogens
Sunlight, O2
Reactive Nitrogen Partitioning
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Heterogeneous N2O5 Processes: Key Parameters
γϕ
γ(N2O5) Reactive Uptake
Coefficient
ϕ(ClNO2)Production Yield
Range γ(N2O5):
10-3 – 0.04
Range ϕ(ClNO2):
0 – 1
NO3 N2O5
HNO3
ClNO2NOx
Reservoir
NOx Sink
NOxReservoir
Remaining Scientific Uncertainties: γ, ϕ in different ambient environments (e.g. temperature, RH, aerosol composition)
…Approach… field data to constrain values
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February – March 2015• 6 weeks – 13 research flights
• Day and Night• Coastal and Interior Environments
Campaign: Wintertime Investigation of Transport, Emissions, and Reactivity (WINTER)
6-Channel CRD: N2O5, NO3, NOx, O3, NOy
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US East CoastNO3 N2O5
HNO3
ClNO2NOx
Reservoir
NOx Sink
NOxReservoir
Heterogeneous N2O5 Processes: Observed Variability
3 Examples from WINTER:
γϕ
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2.01.51.00.5N2O5 (ppbv)
N2O5 as NOxreservoir
Feb. 24th
Washington DC
*HNO3 and ClNO2 from University of Washington CIMS
5048
4644
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-128 -124 -120 -116 -112 -108 -104 -100 -96 -92 -88 -84 -80 -76 -72 -68 -64
US East CoastNO3 N2O5
HNO3
ClNO2NOx
Reservoir
NOx Sink
NOxReservoir
Heterogeneous N2O5 Processes: Observed Variability
N2O5 HNO3 ClNO2
3 Examples from WINTER:
γϕ
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2.01.51.00.5N2O5 (ppbv)
N2O5 as NOxreservoir
2.01.51.00.5N2O5 (ppbv)
N2O5conversion to
HNO3
Feb. 24th Feb. 23rd
Washington DC
*HNO3 and ClNO2 from University of Washington CIMS
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4644
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-128 -124 -120 -116 -112 -108 -104 -100 -96 -92 -88 -84 -80 -76 -72 -68 -64
US East CoastNO3 N2O5
HNO3
ClNO2NOx
Reservoir
NOx Sink
NOxReservoir
Heterogeneous N2O5 Processes: Observed Variability
N2O5 HNO3 ClNO2
3 Examples from WINTER:
γϕ
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N2O5 HNO3 ClNO2
2.01.51.00.5N2O5 (ppbv)
N2O5 as NOxreservoir
2.01.51.00.5N2O5 (ppbv)
N2O5conversion to
HNO3
6.7%
39.6% 53.7%
2.01.51.00.5N2O5 (ppbv)
N2O5 conversion to ClNO2
Feb. 24th Feb. 23rd Feb. 8thWashington DC
New York City
*HNO3 and ClNO2 from University of Washington CIMS
5048
4644
4240
3836
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-128 -124 -120 -116 -112 -108 -104 -100 -96 -92 -88 -84 -80 -76 -72 -68 -64
US East CoastNO3 N2O5
HNO3
ClNO2NOx
Reservoir
NOx Sink
NOxReservoir
Heterogeneous N2O5 Processes: Observed Variability
3 Examples from WINTER:
γϕ
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Reactive Nitrogen Chemistry not well quantified or parameterized, important to winter O3 budgetObservational Winter data collected during recent campaign
• Goals:– Constrain observed gamma– Model gamma under different observed conditions
Project #2: Summary and Future Work
Scientific Questions1) What drives Reactive Nitrogen Partitioning (i.e. differences in γ and ϕ)?2) Can we associate certain partitioning with certain ambient conditions?3) Can we use conditions/chemistry to predict γ and ϕ?
WINTER data show: γ and ϕ are highly variable
Methods1) Derive γ, ϕ from N2O5, ClNO2,
aerosol observations2) Box - Model γ
Model Output:
k(N2O5) = 14*c*SA *γ (N2O5 )
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Questions?
*NYC from the C130 cockpit, photo courtesy of Joel Thornton