Status Report on the Role of Ammonia in the San Joaquin Valley December 11, 2003 Air Resources Board California Environmental Protection Agency

Introduction The role of ammonia in particulate formation is complex The Central California Particulate Study and national research programs are providing needed scientific information Results will be used to refine control strategies

Central California Particulate Study Overview Characterize the nature and sources of PM10 and PM2.5 in Central California Most comprehensive particulate matter program in the nation Ongoing research that supports regulatory process

What have we learned to date from the Central California Particulate Study?

Typical Wintertime PM10 Chemical Composition

Formation of Ammonium Nitrate Nitrogen Oxides (NOx) Ammonium Nitrate (NH 4 NO 3 ) Ammonia (NH3) Atmospheric Reactions

SJV Ammonia Emissions Year 2000 estimates prepared for SJV 2003 PM10 SIP <1%

Role of Ammonia Relative abundance of NOx versus ammonia determines amount of ammonium nitrate formed Ammonia more abundant than NOx in the San Joaquin Valley Reducing emissions of least abundant precursor has greatest impact on reducing particulate matter

What’s next from the Central California Particulate Study?

Ongoing Efforts Ambient data analysis Emissions inventory improvements Air quality modeling

Ambient Data Analysis Precursor and particulate composition data collected at over 70 sites Extensive particulate episode captured for assessment Analysis will determine spatial and temporal distribution of ammonium nitrate and precursors

Emissions Inventory Development Improvements to support further data analysis and modeling include: –Activity data –Emission factor development –Spatially resolved data –Temporal allocation Incorporate new research as it becomes available

Air Quality Modeling Modeling objectives include: –Improve modeling methodologies –Refine role of ammonia in particulate matter formation –Use new episode data to reassess effectiveness of ammonia and NOx control strategies throughout the region

Central California Particulate Study Milestones Mid 2004 End 2004 End 2005 Mid 2005 Initiate air quality modelingInitiate air quality modeling Complete ambient data analysisComplete ambient data analysis Refine ammonia inventoryRefine ammonia inventory Integration of ambient analysis and modelingIntegration of ambient analysis and modeling Full evaluation of ammonia control strategies for SJV PM10 SIP UpdateFull evaluation of ammonia control strategies for SJV PM10 SIP Update Complete air quality modelingComplete air quality modeling

Coordination With National Research Efforts Working to implement recommendations by the National Academy of Sciences Compiling and analyzing research on ammonia from motor vehicles Cooperating with U.S. EPA regarding livestock ammonia emissions research Seeking ammonia research applicable to California

Conclusions Central California Particulate Study results are important in refining particulate control strategies in the San Joaquin Valley The Study is on target to be completed over the next two years