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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 California NH3 emission inventory methodology
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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 California • NH3 emission inventory methodology • NH3 emission inventory results • Current research projects • Future priorities • Conclusions and recommendations
Air Quality in California • Most areas are in nonattainment for O3 and PM • Serious PM10 exceedances • Increasing concern about PM2.5 and haze • Major regional and seasonal variations in air quality exceedances
California PM2.5 • Extensive study of PM2.5 in CA • CRPAQS • IMPROVE monitoring study • California PM2.5 is nitrate-dominated • Emissions are extremely variable by: • By season • By location • By day
San Joaquin Valley Wintertime PM2.5 primary, direct emissions secondary emissions From ammonia and combustion exhaust
Source Data and Methodology • Activity and Population Data • Primarily government agencies • Industry groups when possible • Emission Rate Data • California-specific where possible • Peer-review literature • Inventory Methodology • Statewide inventory is tabular (Excel) • County- and gridded inventories will be GIS-based
Current Ammonia Emission Inventory • Statewide spatial resolution • Average annual day • By source category • Anthropogenic: 13 major categories • Biogenic: 4 major categories
California Ammonia Emissions by Source Data Source: ARB (2000)
Issues in Comparing Ammonia Emission Inventories • Inconsistencies in basic assumptions (e.g. natural soils) • Large variations in the emissions rate data (e.g. dairy cattle emissions) • 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 assessments • Focus on concreteimprovements • Improve emissions rateinformation • Collect activity data
Evaluate Inventory Priorities Priority Sources • Soils • Beef & dairy • Other livestock • Fertilizer use • Biomass burning • Motor vehicles • Industrial sources • POTW, NOx control, NH3 & fertilizer mfg. • Urban sources • human, pets, etc. • What sources needthe most effort? • Criteria • Source importance • Source magnitude • Emission factor quality • Activity data quality • Temporal & spatial data • Weight criteria toprioritize sources
Current Ammonia Research Projects • Natural and Fertilized Soils • Flux measurements in agricultural fields (CSUF) • Development of biophysical model (NASA-Ames) • Fertilizer application calendar (King) • Beef & Dairy • Emission estimation methodology (ARB) • Emission factor development (UC-Davis) • Waste lagoon buffering (CSUF)
Current Ammonia Research Projects (continued) • Emission Inventory Development • Southern California inventory (SCAQMD) • GIS-based statewide inventory (ARB) • GLOBEIS-based statewide inventory (CRPAQS) • Inventory Validation Tools • Ambient and source testing using LIDAR (NOAA)
Future Priorities – Input Data • 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)
Future Priorities - Modeling • Improved understanding of scaling of facility level emissions and processes to regional level • Net effect models (emission and deposition) • Develop environmentally responsive GIS-based models (e.g. CAL-CASA) that incorporate temp., humidity, soils, etc. • Refine inventory validation tools (e.g. NOAA lidar)
Conclusions • Most significant California NH3 sources: • Livestock (38%) • Natural soils and vegetation (38%) • Fertilizer application (7%) • Burning (5%) • On-road mobile sources (4%) • Source contributions vary locally • Air quality modeling needed to assess actual contribution to PM2.5 formation
Recommendations Develop an ammonia inventory appropriate to area needs Maximize resources through interagency and industry cooperative research efforts Involve stakeholders early and often
California Ammonia EmissionInventory Information http://arbis.arb.ca.gov/emisinv/pmnh3/pmnh3.htmMichael Benjamin mbenjami@arb.ca.gov
Population and Emissions Population (head) StatewideSJV Beef 1,993,380 453,527 Dairy 2,605,987 1,783,959 Total 4,599,367 2,237,486 Emissions(tons/yr) StatewideSJV Beef 18,983 4,318 Dairy 38,805 26,564 Total 57,788 30,882