Estimating Ammonia Emissions in California Dr. Michael T. Benjamin California Air Resources Board LADCO Workshop on Fine Particle Emission Inventories Des Plaines, IL September 28, 2000

Presentation Overview Air quality in CaliforniaAir quality in California NH3 emission inventory methodologyNH3 emission inventory methodology NH3 emission inventory resultsNH3 emission inventory results Current research projectsCurrent research projects Future prioritiesFuture priorities Conclusions and recommendationsConclusions and recommendations

Air Quality in California Most areas are in nonattainment for O 3 and PMMost areas are in nonattainment for O 3 and PM Serious PM 10 exceedancesSerious PM 10 exceedances Increasing concern about PM 2.5 and hazeIncreasing concern about PM 2.5 and haze Major regional and seasonal variations in air quality exceedancesMajor regional and seasonal variations in air quality exceedances

California PM 10 Nonattainment Areas

California PM 2.5 Extensive study of PM2.5 in CAExtensive study of PM2.5 in CA –CRPAQS –IMPROVE monitoring study California PM2.5 is nitrate-dominatedCalifornia PM2.5 is nitrate-dominated Emissions are extremely variable by:Emissions are extremely variable by: –By season –By location –By day

secondaryemissions primary, direct emissions From ammonia and combustion exhaust San Joaquin Valley Wintertime PM 2.5

Source Data and Methodology Activity and Population DataActivity and Population Data –Primarily government agencies –Industry groups when possible Emission Rate DataEmission Rate Data –California-specific where possible –Peer-review literature Inventory MethodologyInventory Methodology –Statewide inventory is tabular (Excel) –County- and gridded inventories will be GIS-based

Current Ammonia Emission Inventory Statewide spatial resolutionStatewide spatial resolution Average annual dayAverage annual day By source categoryBy source category –Anthropogenic: 13 major categories –Biogenic: 4 major categories

ARB Ammonia Emission Inventory Sample Output

Summary of California Ammonia Emissions

California Ammonia Emissions by Source Data Source: ARB (2000)

Spatial Allocation of Cattle Emissions

Ammonia Emission Inventory Comparisons

Issues in Comparing Ammonia Emission Inventories Inconsistencies in basic assumptions (e.g. natural soils)Inconsistencies in basic assumptions (e.g. natural soils) Large variations in the emissions rate data (e.g. dairy cattle emissions)Large variations in the emissions rate data (e.g. dairy cattle emissions) Domain scale strongly influences source significance (e.g. motor vehicles)Domain scale strongly influences source significance (e.g. motor vehicles)

Livestock Emission Factor Comparison (lbs/head/yr) * The Battye emission factors are based on population weighted composites of animals in the category.

Ammonia Inventory Research Avoid literature reviews or comprehensive needs assessmentsAvoid literature reviews or comprehensive needs assessments Focus on concrete improvementsFocus on concrete improvements Improve emissions rate informationImprove emissions rate information Collect activity dataCollect activity data

Evaluate Inventory Priorities What sources need the most effort?What sources need the most effort? CriteriaCriteria –Source importance –Source magnitude –Emission factor quality –Activity data quality –Temporal & spatial data Weight criteria to prioritize sourcesWeight criteria to prioritize sources Priority Sources >Soils >Beef & dairy >Other livestock >Fertilizer use >Biomass burning >Motor vehicles >Industrial sources -POTW, NO x control, NH 3 & fertilizer mfg. >Urban sources -human, pets, etc.

Current Ammonia Research Projects Natural and Fertilized SoilsNatural and Fertilized Soils –Flux measurements in agricultural fields (CSUF) –Development of biophysical model (NASA-Ames) –Fertilizer application calendar (King) Beef & DairyBeef & Dairy –Emission estimation methodology (ARB) –Emission factor development (UC-Davis) –Waste lagoon buffering (CSUF)

Cal-CASA Soil NH 3 Model Inputs and Outputs

Current Ammonia Research Projects (continued) Emission Inventory DevelopmentEmission Inventory Development –Southern California inventory (SCAQMD) –GIS-based statewide inventory (ARB) –GLOBEIS-based statewide inventory (CRPAQS) Inventory Validation ToolsInventory Validation Tools –Ambient and source testing using LIDAR (NOAA)

Improve emission factor and activity data for significant sources and pollutants (e.g. natural soils, livestock, motor vehicles)Improve emission factor and activity data for significant sources and pollutants (e.g. natural soils, livestock, motor vehicles) Develop process-specific emission factors where necessary (e.g. dairies)Develop process-specific emission factors where necessary (e.g. dairies) Future Priorities – Input Data

Future Priorities - Modeling Improved understanding of scaling of facility level emissions and processes to regional levelImproved understanding of scaling of facility level emissions and processes to regional level Net effect models (emission and deposition)Net effect models (emission and deposition) Develop environmentally responsive GIS- based models (e.g. CAL-CASA) that incorporate temp., humidity, soils, etc.Develop environmentally responsive GIS- based models (e.g. CAL-CASA) that incorporate temp., humidity, soils, etc. Refine inventory validation tools (e.g. NOAA lidar)Refine inventory validation tools (e.g. NOAA lidar)

Conclusions Most significant California NH 3 sources:Most significant California NH 3 sources: –Livestock (38%) –Natural soils and vegetation (38%) –Fertilizer application (7%) –Burning (5%) –On-road mobile sources (4%) Source contributions vary locallySource contributions vary locally Air quality modeling needed to assess actual contribution to PM 2.5 formationAir quality modeling needed to assess actual contribution to PM 2.5 formation

Recommendations Develop an ammonia inventory appropriate to area needsDevelop an ammonia inventory appropriate to area needs Maximize resources through interagency and industry cooperative research effortsMaximize resources through interagency and industry cooperative research efforts Involve stakeholders early and oftenInvolve stakeholders early and often

California Ammonia Emission Inventory Information Michael Benjamin

Population and Emissions Population (head) Statewide SJV Statewide SJV Beef1,993, ,527 Beef1,993, ,527 Dairy2,605,9871,783,959 Dairy2,605,9871,783,959 Total4,599,3672,237,486 Total4,599,3672,237,486 Emissions (tons/yr) Statewide SJV Statewide SJV Beef 18,983 4,318 Beef 18,983 4,318 Dairy 38,805 26,564 Dairy 38,805 26,564 Total 57,788 30,882 Total 57,788 30,882