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NH3 Emissions for Regional Air Quality Modeling
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Motivation and QuestionsMotivation
NH3 plays a key role in secondary aerosol formation—impact on health & regional hazeNH3 deposits readily and contributes to N deposition in pristine ecosystems
QuestionsWhat are the major sources of NH3 within the region?For the major sources, what are the uncertainties in the emission factors?For the major sources, how well do we know the activity levels?For the major sources, how do environmental or operating practices affect emission rates?NH3 emissions are uncertain, but how sensitive are model results to these uncertainties? Is near-source NH3 deposition an issue within a grid modeling framework?
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Atmosphere/biosphere Nitrogen Cycle
Anthropogenic Tg NH3 / year
Domesticated animals 21 – 29
Fertilizer 6 - 9
Biomass burning 2 – 6
Fossil fuel 0.3 – 2
Miscellaneous 0 - 7
Total Anthropogenic 30 – 50
Natural 15 – 23
Total 45 - 75
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Source Type NH3 (tons/yr)
Ag Fertilizer Application 12,659
Cattle & calves operations 12,462
Dairy operations 5,718
Other animals 4,957
Biogenic sources 4,082
Waste treatment 2,602
Industrial Processes 1,392
Stationary Fuel Combustion 306
Waste burning 111
Solvent Use 0
WA Total 44,289
NEI NH3 Emissions for Washington
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Fertilizer NH3 emissions factors(Chinkin et al. 2003)
A. NH3---Battye-12(1%)--CMU-1%--Corsi-49(12-121)-EEA-4%
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Beef and dairy cattle NH3 emission factors (lb/head/year; Chinkin et al. 2003)
Dairy 48 to 74 lb/head/yr Beef 29 to 88 lb/head/yr
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Recent Feedlot Emission Results (Flesch et al., 2007)
Spring and summer 0.15 kg/head/day
Extrapolated annual emission factor:
55 kg/head/yr or 120 lb/head/yr
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Recent EI adjustments: Columbia River Gorge Visibility Modeling Analysis (Environ, 2007)
Comparison of 2002 NEI and Environ NH3 GIS EI
(1) Ammonia emissions from confined area feeding operations (CAFO), such as dairies, were understated by factors of 1.5 to approximately 3, depending on the type of manurehandling conducted at each (i.e., flush, scrape, drylot/pasture, or deep-pit);(2) Ammonia emissions from fertilizer application were understated by upwards of a factor of three for anhydrous and aqueous ammonia application sources, and by a factor of 2.5for nitrogen solution fertilizer application sources.
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Tomorrow’s Air Quality: AIRPACT-3 Daily Forecast System
MM5 numerical mesoscalemeteorological model (UW)SMOKE: Sparse Matrix Operating Kernalfor Emissions processing.CMAQ: Community Multi-scale Air Quality model:
O3 & toxics chemistry with 72 species and 214 reactions
Aerosol dynamics & chemistry in Aitken, accumulation, & coarse modes
Deposition of N, S, O3, & Hg species
12 km x 12 km grid cells, 21 layers
Forecast to 64 hours daily
Runs in ~1 hour on 4 nodes of a linuxcluster
PM speciesNitratesSulfatesOrganic aerosolsWind-Blown Dust (soon)PM2.5 total mass
Airpact Terrain ht.
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Daisy-chain Initial Conditions
Dynamic Boundary Conditions: spatial & temporal details
2005 anthropogenic emissions (SMOKE)
Wild and Prescribed Fire Emissions
Gridded Emissions
Updated Biogenic Emission Model (BEIS3)
WSU Dairy NH3 Emissions Module
AIRPACT-3 Dynamic Emissions & IC/BC
MM5/MCIP Meteorology from UW Weather Forecast System
CMAQ
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NH3 Emissions Dairy Module (Rumburg et al., 2006)
• based upon DOAS NH3 & tracer ratio measurements at the WSU dairy
•Housing, lagoon, and slurry application emissions
•Incorporates N balance approach and accounts for wind speed & temperature effects
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Stalls Model SensitivityModel Parameter Avg. Flux Avg. Daily Peak Daily Annual
(mg cow-1 s-1) (kg day-1) (kg day-1) (kg year-1)
Base Case 5.4 20 86 7,000
pH = 8.1 10 40 170 14,000
pH = 7.5 2.7 10 47 3,700
Temperature + 2° C 6.1 24 100 8,500
Temperature - 2° C 4.6 18 80 6,400
Milk Prod. = 50 kg day
6.5 22 97 7,900
Milk Prod. = 35 kg day
4.6 20 86 7,000
Protein = 21% 6.0 23 100 8,300
Protein = 17% 4.7 18 80 6,500
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Dairy Module Input Data Requirements
Column Description Type A FIPS 5-digit Integer B Site-ID 5-digit Integer C Latitude Real D Longitude Real E Number of Milking cow Integer F Number of Dry cow Integer G Number of Heifer Integer H Number of Calves Integer I Lagoon area (m^2) Real J Pit area (m^2) Real K Tank area (m^2) Real L Housing type (Scrape Barn = 1) Integer M Application type (Big Gun = 1) Integer N Application area Real O Site name Text in “quotes”
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Dairy NH3 Emission Module
WA Dairy NH3 (ton/yr)
Housing 8,634
Storage 5,441
Application 4,364
Total 18,439
OR Dairy NH3 (ton/yr)
Housing 9,469
Storage 5,079
Application 3,420
Total 17,967
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Source Type NH3 (tons/yr)
Ag Fertilizer Application 12,659
Cattle & calves operations 12,462
Dairy operations 5,718
Other animals 4,957
Biogenic sources 4,082
Waste treatment 2,602
Industrial Processes 1,392
Stationary Fuel Combustion 306
Waste burning 111
Solvent Use 0
WA Total 44,289
or with WSU dairy module
Dairy operations 18,439
WA Total 57,010
% increase 29%
Airpact NH3 Emissions for Washington
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8
6
4
2
0
Mod
eled
(µ
g/m
3 )
86420
Measured (µg/m3)
EPA_AQS IMPROVE SWCAA
PEC50
40
30
20
10
0
Mod
eled
(µ
g/m
3 )
50403020100
Measured (µg/m3)
EPA_AQS IMPROVE SWCAA
POC
Airpact-3 Evaluation, Aug-Nov 2004 (Chen, 2007)
10
8
6
4
2
0M
odel
ed (
µg/
m3 )
1086420
Measured (µg/m3)
EPA_AQS SWCAA
PNO35
4
3
2
1
0
Mod
eled
(µ
g/m
3 )
543210
Measured (µg/m3)
EPA_AQS SWCAA
PNH420
15
10
5
0
Mod
eled
(µ
g/m
3 )
20151050
Measured (µg/m3)
EPA_AQS SWCAA
PSO4
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Columbia Gorge Visibility Modeling Analyses (Environ, 2007)
Source attribution results for PNH4
Nov. 2004
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Questions remainWhat are the major sources of NH3 within the region?
Fertilizer vs livestock—which is larger? Biogenic natural soil emissions—very few measurements.
For the major sources, what are the uncertainties in the emission factors?
Factor of two or more in available factorsFor the major sources, how well do we know the activity levels?
For the major sources, how do environmental or operating practices affect emission rates?
Seasonal changes, diurnal changesNH3 emissions are uncertain, but how sensitive are model results to these uncertainties--how accurate does an emission inventory need to be?
Is near-source NH3 deposition an issue within a grid modeling framework?
What is required to improve our ability to construct more accurate emission inventories for NH3?
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Animal Ammonia Emissions• Pathways for NH3 emissions from animal
waste• Hydrolysis of urea in urine with urease• Anaerobic biological breakdown • organic nitrogen ® amino acids ® NH3
• Dairy cows have the largest per animal emissions (Bouwmann et al., 1997)• Developed countries ~ 20 kg NH3 cow-1 yr -1
• Developing countries ~ 8 kg NH3 cow-1 yr -1
• European measurements and farming practices• Filters, flasks, and passive samplers
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Housing Emissions Model
• Calculates liquid NH3 concentration based upon cow factors– Uses milk production, dietary Na, K, and N
intake, body weight, and week of lactation -> urinary urea
– Assumes excess of urease from manure– Converts urea to ammonia-N– Partitions ammonia-N between NH3 and NH4+
based upon pH, (pH = 7.8 - lagoon pH)• Calculates volatilization based upon temperature
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Lagoon Emissions Model
• Calculates lagoon ammonia-N concentration based upon temperature
• Partitions ammonia-N between NH3and NH4+ based upon pH, pH = 7.8
• Calculates volatilization based upon temperature
• Uses Gaussian plume model to calculate downwind concentrations
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Lagoon Modeling600
500
400
300
200
100
0
NH
3 M
odel
ed C
once
ntra
tion
(ppb
v)
6005004003002001000
NH3 Measured Concentration (ppbv)
Normalized mean error = 21%
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Stalls Modeled versus Measured Concentrations
2500
2000
1500
1000
500
0
NH
3 M
odel
ed C
once
ntra
tion
(ppb
v)
25002000150010005000
NH3 Measured Concentration (ppbv)
Normalized Mean Error = 30%
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Slurry Application Modeling
600
500
400
300
200
100
0
NH
3 C
once
ntra
tion
[ppb
v]
40302010
Decay Time (Hours)
Measured Concentration Theoretical Model Empirical Model
Theoretical Model Error = 59%Empirical Model Error = 22%
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Lagoon Emissions Model
pH NH3NH4+
Organic N
Bacteria Bacteria
NH3 + NH4+
Organic N
StallsNH3(g)
NH3Free Air StreamConvective Mass Transfer Coefficient hm
Temperature
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Waste Application Model
Theoretical ModelSlurry volatilization from upper layer of soilSlurry infiltration - HYDRUS 1DSlurry adsorption to soil Slurry temperature - radiation & canopy light model
Empirical ModelExponential fit to the data• Useful for air quality models
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Slurry Application
pH NH3NH4+Soil (-)particles
Infiltration
Adsorption
NH3Free Air StreamConvective Mass Transfer Coefficient hm
NH3(g)
Temperature
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Tomorrow’s Air Quality: AIRPACT-3 Daily Forecast System
MM5 numerical mesoscalemeteorological model (UW)SMOKE: Sparse Matrix Operating Kernalfor Emissions processing.CMAQ: Community Multi-scale Air Quality model:
O3 & toxics chemistry with 72 species and 214 reactions
Aerosol dynamics & chemistry in Aitken, accumulation, & coarse modes
Deposition of N, S, O3, & Hg species
12 km x 12 km grid cells, 21 layers
Forecast to 64 hours daily
Runs in ~1 hour on 4 nodes of a linuxcluster
PM speciesNitratesSulfatesOrganic aerosolsWind-Blown Dust (soon)PM2.5 total mass
Airpact Terrain ht.
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Airpact-3 Aerosol Results/
http://www.lar.wsu.edu/airpact-3
http://www.lar.wsu.edu/airpact-3/http://www.lar.wsu.edu/airpact-3
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Modeling sensitivity to NH3 emissions: Columbia Gorge Modeling Analysis (Environ, 2007)
Sensitivity Runs1. Zero PGE Boardman from BART-levelemissions2. Zero ammonia emissions East of Gorge3. Zero on-road mobile emissions inPortland4. Zero major industrial (point) emissionsPortland5. Zero major point emissions in the Gorge
Motivation and QuestionsAtmosphere/biosphere Nitrogen CycleNEI NH3 Emissions for WashingtonFertilizer NH3 emissions factors(Chinkin et al. 2003)Beef and dairy cattle NH3 emission factors (lb/head/year; Chinkin et al. 2003)Recent Feedlot Emission Results (Flesch et al., 2007)Recent EI adjustments: Columbia River Gorge Visibility Modeling Analysis (Environ, 2007)Tomorrow’s Air Quality: AIRPACT-3 Daily Forecast SystemAIRPACT-3 Dynamic Emissions & IC/BCStalls Model SensitivityDairy Module Input Data RequirementsDairy NH3 Emission ModuleAirpact NH3 Emissions for WashingtonAirpact-3 Evaluation, Aug-Nov 2004 (Chen, 2007)Columbia Gorge Visibility Modeling Analyses (Environ, 2007)Questions remainAnimal Ammonia EmissionsHousing Emissions ModelLagoon Emissions ModelLagoon ModelingSlurry Application ModelingLagoon Emissions ModelWaste Application ModelSlurry ApplicationTomorrow’s Air Quality: AIRPACT-3 Daily Forecast SystemAirpact-3 Aerosol Results/Modeling sensitivity to NH3 emissions: Columbia Gorge Modeling Analysis (Environ, 2007)