david parrish - noaa aeronomy laboratory
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Today:. Review “Section 6.4: Evaluation of the strengths and weaknesses of current inventories and models.”. Please feel free to provide critiques and feedback!!!. Preview of NARSTO Emission Inventory Assessment. David Parrish - NOAA Aeronomy Laboratory. - PowerPoint PPT PresentationTRANSCRIPT
David Parrish - NOAA Aeronomy Laboratory
• Review “Section 6.4: Evaluation of the strengths and weaknesses of current inventories and models.”
• Please feel free to provide critiques and feedback!!!
Today:
Preview of NARSTO Emission Inventory Assessment
EMIS Meeting, Portsmouth NH, August 3, 2004
1.0 Introduction
2.0 Overview of Emissions Inventories Provide an emissions inventory primer for decision makers
3.0 Vision for Future North American Emission Inventory Programs Set the target: define where we need to be in future years.
4.0 North American Emission Inventories List what currently exists
5.0 Inventory Tools Describe how are inventories constructed
6.0 Strengths and Weaknesses of Current Inventories and Models: Sensitivities, Uncertainties, and Applicability Describe how to evaluate Provide an evaluation of important sectors
7.0 Evolving Tools for Determining Emissions Describe advanced methods and methodologies
8.0 Roadmap for Future Emission Inventory Application and Development
NARSTO Emission Inventory Assessment
Emission Inventory Development
Emission Factors and
Models
Databases for Source Activity Levels
Defaults for Emissions Related
Variables
Point and Non Point
Source Data
Growth Factors
Starting Point for EI
Factor and Model Improvements
Regional/State/Local/Tribe/Provincial Improvements
EI Applications
Forecasting
Measurement Methods
Field Testing and Sampling
Local Activity Levels & Variables
Preliminary EI for Base
20xx
States and Other
Stakeholders
Improved EI for Base Year
20xx
Emissions Processor
Speciation Factors
Temporal Factors
Spatial Factors
Tests, Evaluations and Reviews
Emission Inventory Development
Emission Factors and
Models
Databases for Source Activity Levels
Defaults for Emissions Related
Variables
Point and Non Point
Source Data
Growth Factors
Starting Point for EI
Factor and Model Improvements
Regional/State/Local/Tribe/Provincial Improvements
EI Applications
Forecasting
Measurement Methods
Field Testing and Sampling
Local Activity Levels & Variables
Preliminary EI for Base
20xx
States and Other
Stakeholders
Improved EI for Base Year
20xx
Emissions Processor
Speciation Factors
Temporal Factors
Spatial Factors
Tests, Evaluations and Reviews
Evaluations of Road Transport Emissions:
• U.S. EPA emissions estimates have changed drastically. Danger Sign!!
• Most recent emissions estimates are uncertain by at least ~10% for VOC and NOx and ~50% for CO.
12
10
8
6
4
2
0200019951990198519801975
1989 NAPAP 1990 Trends report 1995 Trends report 2000 Trends report 2003 Trends report
14
12
10
8
6
4
2
0
140
120
100
80
60
40
20
0200019951990198519801975
2000 = MOBILE 52003 = MOBILE 6
• For 1985 the 2003 estimate is higher than previous estimates by factors of up to 1.35, 1.6 and 2.5 for NOx, VOC, and CO
History of temporal trends of road transport emissions in NEI
4
5
6
7
8
9
100
CO emissions (10
6
tons/year)
200019951990198519801975
3
4
5
6
7
8
9
10
Ambient CO levels (ppmv)
U.S. Mean
Ambient
2000 Trends
Report
2003 Trends
Report
• Rural U.S. CO levels have also decreased, but at a rate of only about 3%/yr. [Hallock-Waters et al., GRL, 26, 2861-2864, 1999]
Evaluations of Road Transport Emissions:
Temporal trend of CO emissions in NEI compared to ambient levels
• Trends in 2003 Report agree well with trend of ambient levels, but not 2000 Repoprt.
• Exception is latest 2 years.
• No information regarding the accuracy of the absolute emissions.
2000 = MOBILE 52003 = MOBILE 6
Urban
- 4.2 %/yr
- 4.4 %/yr
- 2.7 %/yr
Evaluations of Road Transport Emissions:
Temporal trend of CO/NOx ratio in NEI compared to ambient ratios
2000199519901985
Nashville, TNSummer
-8.8 ± 1.0 %/yr
Boulder, COWinter
-6.7 ± 0.5 %/yr
L.A., CA
2003 Trends Report-3.8 %/yr
2000 Trends Report-3.5 %/yr
10
7
5
15
20
25
Neither Trends Report matches recent low observed CO/NOx ratios, and 2003 is worse than 2000. Disagreement a factor > 2 by 2000.
(Parrish et al., JGR, 107, 4140, doi:10.1029/2001JD000720, 2002)
Neither Trends Report captures rapid decrease in CO/NOx ratios.
Current U.S. emissions estimates are too high for CO, and/or too low for NOx.
Evaluations of Road Transport Emissions:
Comparison of fuel-based and mileage-based emissions estimates
(Harley et al., JGR, 106, 3559-3567, 2001)
70
60
50
40
30
20
10
0
emissions (tons/day)
Diesel
Gasoline
Fuel-
based
EPA Fuel-
based
Fuel-
based
EPAEPA
CO/10VOC NOx
VOC agree well.
CO ≈ 40% high
Nashville 1995 Road Transport SourcesFuel-based emissions agree with ambient CO/NOx
NOx agree well, but not partitioning
EPA equivalent to 2000 Trends Report
MOBILE 5B emissions vs. Fuel-based in 1995:
MOBILE 6 emissions (2003 Trends Report) would degrade CO comparison
Evaluations of Road Transport Emissions:
Reconciliation of estimated emissions with ambient measurements
140
120
100
80
60
40
20
0
CO emissions
200019951990198519801975
12
10
8
6
4
2
0
NO
x
emissions
2000 Trends report
2003 Trends report
Inferred Emissions
CO emissions trend assumed to be - 5.1 %/yr (1990-2000 temporal trend of ambient CO levels).
CO to NOx emission ratio trend assumed to be - 8.8 %/yr (temporal trend for L.A. Nashville).
1995 NOx emissions from the 2000 Trends Report
are assumed to be accurate.
Assumptions:
CO emissions in the 2003 Trends Report are over estimated by a factor of 2 for 1990-2001 (worse lately).
Conclusions:
NOx emissions are within 20% of the 2003 Trends Report values for all years after 1993, but are increasing rather than decreasing.
Interestingly, the inferred NOx temporal trend closely follows the increasing trend of the first 5 years of the 1990s in the 2000 Trends Report.
Evaluations of Road Transport Emissions:
Reconciliation of estimated emissions with ambient measurements
140
120
100
80
60
40
20
0
CO emissions
200019951990198519801975
12
10
8
6
4
2
0
NO
x
emissions
2000 Trends report
2003 Trends report
Inferred Emissions
No substantial inconsistencies have been identified in the VOC emissions.
Conclusions:
VOC emissions trend for 1990-2000 (2003 Trends Report) is - 5.7 %/yr, very close to - 5.1 %/yr trend of ambient CO levels.
14
12
10
8
6
4
2
0200019951990198519801975
VOC emissions do not increase recently as CO.
Evaluations of Road Transport Emissions:
Evaluation of VOC speciation
• are from road transport
Conclusions: Benzene / acetylene ratio:
• exhibits long-term trends in response to VOC emission control measures
-2.0
-1.5
-1.0
-0.5
0.0
20052000199519901985198019751970
0.1
2
3
4
5
6
7
8
9
1
Mean Ratio
Ambient Measurements
71 U.S. Cities ROSE
SCAB SOS
SCAQS NARE
ITCT NEAQS
TexAQS
Inventory
Mea
n B
enze
ne/A
cety
lene
Rat
io
Assumptions: Benzene & acetylene:
• react slowly in the atmosphere - ambient benzene to acetylene ratio reflects emission ratio
• The inventory values are a factor of 3 to 4 higher than ambient, and trends do not agree.
• There is a critical need for a re- evaluation of the VOC speciation in the NEI.
Evaluations of Power Plant Emissions:
Nearly 50 plume studies on over 30 CEMS-equipped power plants (1995, 1997, 1999, 2000, and 2002).
Flux ratios agree on average within estimated uncertainty of ambient determinations (± 10%).
There are occasional significant discrepancies.
3x10-3
210NOy / CO2 emission ratio tabulated
2.0
1.5
1.0
0.5
0.0
emission ratio tabulated / correlation slope
10x10-3
86420SO2 / CO2 emission ratio tabulated
NOy = 1.10 ± 0.17SO2 = 1.04 ± 0.24
12x1027
86420
CO2 emission (molec/s)
2.0
1.5
1.0
0.5
0.0
emission tabulated / flux measured
80x1024
6040200
NOy, SO2 emission (molec/s)
NOy = 1.10 ± 0.31SO2 = 1.07 ± 0.25CO2 = 0.98 ± 0.29
Absolute NOx, SO2 and CO2 fluxes agree with CEMS data within the estimated uncertainty (±20% for optimum conditions).
CEMS data are accurate
Conclusions:
CEMS data are accurately integrated into the NEI
CO emissions can be more than a factor 10 higher than inventoried.
Evaluations of Power Plant Emissions:
emis
sion
tabu
late
d / f
lux
mea
sure
d
There are occasional significant discrepancies.
25
20
15
10
5
0NOx
,
ethene,
and
propene,
ppbv
12:52 PM8/27/00
12:56 PM 1:00 PM 1:04 PM
70
60
50
40
30
20
10
Ozone, ppbv
Sweeny FreeportChocolateBayou
Ethene
Propene
NOxavg
Isobutane
Inventory alkene emissions are low by the following factors:Sweeny Freeport Choc. Bayou
Ethene: 72 60 25 Propene 67 70 40
Coincident, highly elevated levels of NOx and reactive VOCs lead to rapid formation of high O3 levels. Models using inventoried emissions of VOCs fail.
Evaluation of Emissions from Texas Petrochemical Facilities
(Ryerson et.al., JGR, 108, 4249, doi:10.1029/2002JD003070, 2003)
PM2.5 source apportionment from chemical mass balance compared to the emission inventory in Denver, CO
Showed nearly twice the fractional contribution from fugitive dust emissions. Did not include cold start gasoline vehicle exhaust, which makes a substantial contribution in the CMB analysis. Underrepresented high emitter (i.e. poorly-maintained) gasoline vehicles.
Compared to emission inventory, CMB showed:
Inverse modeling application to
ammonia emission inventory
Showed 40% lower average annual emissions with strong seasonal cycle. Dramatic improvement in aerosol nitrate simulation (not included in inverse optimization)
Compared to emission inventory, inverse modeling showed:
Conclusions
Recommendations
Challenge inventories with ambient measurements.
Increase interaction and feedback between inventory and measurement folks.
(Appropriate sites, measurement techniques, data analysis.)
“Top down” tests do provide valuable evaluations of current inventories.
It is not yet possible to develop “bottom up” inventories that are accurate enough for many scientific uses without support of direct measurements (e.g. CEMS)
Still, “bottom up” inventories are indispensable
Global CO Emissions Inventory Enigmas:
Compared to U.S., Western Europe emits factor of 2 less with 40% more population. Lifestyle!
Western Europe emissions decreasing significantly while U.S. emissions nearly constant?
Road transportation emissions in U.S.: ≈ 2/3 of total. Really increasing?
4
3
2
1
020001995199019851980
U.S. Western Europe
Total
RoadTransport
+0.5 %/year(1990-1995)
-1.8 %/year(1980-1995)
+2.0 %/year(1990-1995)
+0.2 %/year(1990-1995)
-2.3 %/year(1990-1995)
+0.2 %/year(1980-1995)
Total
RoadTransport
EDGAR 2.0
EDGAR 3.2CO Emissions
“Everyone knows” that CO emissions have decreased dramatically over the last couple of decades
“National Vehicle Emissions Policies and Practices and Declining US Carbon Monoxide-Related Mortality”, J.A. Mott et al., J. Amer. Med.
Assoc., 288, 988-995, 2002. ≈ 12,000 deaths avoided in U.S.
≈ 86% increase in vehicle miles traveled 1975-1998
Death rates from CO Poisoning
140
120
100
80
60
40
20
0200019951990198519801975
NAPAP (1989)1990 Trends report1995 Trends report2000 Trends report2003 Trends report
U.S. National CO Emissions Inventory Enigmas:
U.S. EPA emissions estimates have changed drastically. Danger Sign!!
Looking at history of current estimates gives impression of increasing emissions.
(Road Transport Sources)
140
120
100
80
60
40
20
0200019951990198519801975
NAPAP (1989)1990 Trends report1995 Trends report2000 Trends report2003 Trends report
U.S. National CO Emissions Inventory Enigmas:
U.S. EPA emissions estimates have changed drastically. Danger Sign!!
Looking at history of current estimates gives impression of increasing emissions.
EDGAR
EDGAR inventory may be affected by this changing of models (Road Transport Sources)
CO to NOx Ratio in Urban Vehicle Exhaust
1200
1000
800
600
400
200
012:00 AM7/7/99
6:00 PM
150
100
50
0
6:00 - 8:30
(5 min averages)
Ambient CO and NOy correlate well during morning rush hour.
Ambient measurements characterize CO/NOy emission ratio in vehicle exhaust.
CO to NOx automotive exhaust
emission ratios
3000
2000
1000
0 16012080400NOy (ppbv)
Year Slope r2 1989 18.9 ± 2.70.95 1991 15.7 ± 2.30.94 1996 12.7 ± 2.00.87 1998 8.9 ± 1.30.94
6:00 - 10:00Boulder, CO(5 min averages)
2500
2000
1500
1000
500
0 200150100500NOy (ppbv)
Year Slope r2
1994 10.2 ± 1.50.97 1995 8.5 ± 1.30.90 1999 6.3 ± 0.90.95
6:00 - 8:30Nashville, TN(5 min averages)
• Ratio of CO to NOx in vehicle exhaust has decreased dramatically at these two sites from 1989 to 1999.
2000199619921988
Nashville-8.8% / yr
Boulder-6.7% / yr
U.S. Inventory-3.4% / yr
L.A. Boulder-DenverInventory-7.1% / yr
5
7
10
15
20
Comparison to Emission Inventories
• VOC emissions parallel CO emissions.
• The character of urban photochemistry must have changed as well.
• National inventory does not accurately reflect observed decrease.
2000199619921988
Nashville-8.8% / yr
Boulder-6.7% / yr
U.S. Inventory-3.4% / yr
L.A. Boulder-DenverInventory-7.1% / yr
5
7
10
15
20
(National Air Pollutant Emission Trends, 2000)
• Colorado inventory does reflect Boulder decrease.
2000199619921988
Nashville-8.8% / yr
Boulder-6.7% / yr
U.S. Inventory-3.4% / yr
L.A. Boulder-DenverInventory-7.1% / yr
5
7
10
15
20
(Colorado Department of Public Health and Environment)
CO
to
NO
x R
atio
Emissions ratios: from near-field aircraft transects in mixed layer
32.0
31.9
31.8
31.7
31.6
31.5
31.4
Latitude
-96.6 -96.5 -96.4 -96.3 -96.2
Longitude
wind
Limestone PP
10
8
6
4
2
0
NOy, ppbv
TX
385
380
375
370
365
CO2
, ppmv
5:54:00 PM9/10/00
5:55:00 PM 5:56:00 PM
Time, GMT
25
20
15
10
5
0
NOy
and SO2, ppbv
CO2SO2NOy
Emissions ratios: from near-field aircraft transects in mixed layer
32.0
31.9
31.8
31.7
31.6
31.5
31.4
Latitude
-96.6 -96.5 -96.4 -96.3 -96.2
Longitude
wind
Limestone PP
10
8
6
4
2
0
NOy, ppbv
TX
40
30
20
10
0
SO2, ppbv
384382380378376374372370
CO2, ppmv
16
14
12
10
8
6
4
2
0
NOy, ppbv
Emissions ratios: from near-field aircraft transects in mixed layer
32.0
31.9
31.8
31.7
31.6
31.5
31.4
Latitude
-96.6 -96.5 -96.4 -96.3 -96.2
Longitude
wind
Limestone PP
10
8
6
4
2
0
NOy, ppbv
TX
40
30
20
10
0
SO2, ppbv
384382380378376374372370
CO2, ppmv
16
14
12
10
8
6
4
2
0
NOy, ppbv
Obs. CEMS NOx/CO2 1.2±0.1 1.4±0.1 SO2/CO2 1.8±0.2 1.9±0.2
Emissions ratios: from near-field aircraft transects in mixed layerslopes from multiple transects vary by ±2%combined instrumental uncertainties typ. ± 10%
provides an exacting test of inventory ratios
32.0
31.9
31.8
31.7
31.6
31.5
31.4
Latitude
-96.6 -96.5 -96.4 -96.3 -96.2
Longitude
wind
Limestone PP
10
8
6
4
2
0
NOy, ppbv
TX
40
30
20
10
0
SO2, ppbv
384382380378376374372370
CO2, ppmv
16
14
12
10
8
6
4
2
0
NOy, ppbv
Obs. CEMS NOx/CO2 1.2±0.1 1.4±0.1 SO2/CO2 1.8±0.2 1.9±0.2
Absolute emission rates: calculate flux across plume transect
White et al., Science, 194, 187-189, 1976.
Absolute emission rates: calculate flux across plume transect365
360
355
350
34520:287/7/99
20:29 20:30
20
10
0
60
50
40
30
20
10
0
Species Calculated Tabulated Flux Emissions
NOy 1.27 x 1025 1.24 x 1025
SO2 6.0 x 1024 5.6 x 1024
CO2 4.0 x 1027 4.3 x 1027
units: molec / s
Thomas Hill plantRandolph County, MO
July 7, 1999
20 km/1.5 hrs downwind
Estimated uncertainty of±20% in flux calculationunder optimal conditions
Application to CO emissions from power plants:
400
350
300
250
200
150
100
806040200
NOy, ppbv
440420400380360
CO2, ppmv
D
9/3/009/13/00
400
350
300
250
200
150
100
806040200
NOy, ppbv
440420400380360
CO2, ppmv
C
9/3/009/13/00
Power plant combustion is carefully monitored for maximum efficiency;most power plants emit undetectable amounts of CO, most of the time
Martin Lake (TX) Monticello (TX)
Three out of four lignite-coal-fueled power plants showed substantiallyenhanced CO emissions, up to factors of 30 greater than inventory values;also observed in bituminous- and gas-fired electric utility power plants.
J. Environ. Monit., 5, 35-39 (2003)
expectedslopes, frominventoryratios
Application to petrochemical industrial emissions: Houston, TX
Compare measured (alkene/NOx) to inventory (alkene/NOx) • Electra NOx and VOC measurements accurate to ±10%• 2000 PSDB inventory NOx data are accurate to ± 30%• any larger discrepancies in (alkene/NOx) comparison attributed to errors in the alkene emissions inventory
25
20
15
10
5
0NOx
,
ethene,
and
propene,
ppbv
12:52 PM8/27/00
12:56 PM 1:00 PM 1:04 PM
70
60
50
40
30
20
10
Ozone, ppbv
Sweeny FreeportChocolateBayou
Ethene
Propene
NOxavg
Isobutane
Application to petrochemical industrial emissions: Houston, TX
25
20
15
10
5
0NOx
,
ethene,
and
propene,
ppbv
12:52 PM8/27/00
12:56 PM 1:00 PM 1:04 PM
70
60
50
40
30
20
10
Ozone, ppbv
Sweeny FreeportChocolateBayou
Ethene
Propene
NOxavg
Isobutane
Inventory alkene emissions are low by the following factors:Sweeny Freeport Choc. Bayou
Ethene: 72 60 25Propene 67 70 40 (JGR, 108(D8), 4249, doi:10.1029/2002JD003070, 2003)
Nashville and Boulder are representative
199819961994199219903
4
5
6
7
8
Boulder-6.3 ± 1.5% / yr
r2 = 0.89
Nashville-4.8 ± 2.4% / yr
r2 = 0.63
U.S. medianambient levels-5.2 ± 0.8% / yr
r2 = 0.95