1. Update on CASTNET Modernization Air Monitoring Steering Committee Meeting May 4, 2006 Larry Kertcher Office of Atmospheric Programs (OAP)

2. Background Purchased three MARGA systems Conducted intensive study at Beltsville, MD in July-August 2005 2 systems in Beltsville - 10 months operation 1 system in RTP (Burden’s Creek) – 3 months operation

3. CASTNET Modernization: Status, Project Value, Progress Status: Value: Initial system testing and development with US EPA funding. Major equipment upgrades made, installed, and tested. More to come. Development of contract to purchase upgraded equipment underway. RFP expected June. Once successfully completed, real-time continuous air quality data will be available to EPA and States. Data available within hour of measurement. Data includes major aerosol species and PM precursor gases Data can be used to improve air quality models States rely upon for attainment planning. Providing real-time data on aerosols and precursor gases as they move across the country can improve air quality forecast systems.

4. CASTNET Modernization: Status, Project Value, Progress (Continued) Progress: Good correlation with thermo SO 2 trace gas analyzer (R 2 =.86) Precision very good for ammonia gas even at low concentrations Achieved good precision between 2 MARGA instruments for SO 4 Denuder performance very consistent for gases Successfully corrected certain operational and equipment problems, still working on solutions for others

5. Problems Instrument Currently on version 3 of particle collector Column suppressor failure (enhances signal to noise ratio) Lack of independent calibration standards Software support for production chromotography Drive motor failures Steam Jet Aerosol Collector

6. Problems Operational Consistency is key to successful operation Making solutions correctly and of sufficient purity Bacterial contamination Predicting consumption of liquids Infrastructure –Data communication –Electricity –Baking at 140F –Freezing solid

7. Schedule: Equipment Testing and Development Phase I Initial version installation and testing System modifications/ Upgrades Installed Test redesign of particle collectors Install upgraded software Replace particle collectors and return to stable operations Intensive Study Phase II 1-Year pilot operation Phase III Broader deployment Completed September 2005 Completed February 2006 May-June 2006 June 2006 July-Aug 2006 Aug-Sept 2006 Oct 2006 – Sept 2007 2007 - 2010

8. Schedule: Equipment Testing and Development Jan – June Develop design and performance specifications Drafted Mar – May Notice of Capabilities Request/Evaluation Completed Jun - Oct Procurement contract for a continuous gaseous sampling system June- Proposal to FR July- Bids Aug - Sept- Evaluation October-Nov - Selection and Award * Procurement is contingent on Demonstration of Product Performance FY07-10 Exercise of Options – contingent on acceptable product performance

9. Participation and Help Suggestions for Consideration Quarterly status reports to Steering Committee – by conference calls when no scheduled meeting Evaluate and contribute to procurement specifications Review and evaluate performance when sufficient data is available

10. Criteria for Next Generation Instruments 7 day unattended operation 1 hour measurements of major nitrogen and sulfur species Detection Limit < 0.1 ug/m3 for all species Relative percent difference from standard methods < 20% Consumable liquids < 10 gallons/week (IC based instruments) Non-hazardous waste liquids or by-products Data available within 24 hours of sampling Reasonably sized (fit within existing CASTNET shelter) Internal, automated quality assurance checks Does not require specialized instrument training of field technician Remote data availability Sampling height between 4 and 10 m Periodic External Calibration

11. Data and Results Data Completeness (2/15/06 to 3/21/06) A relatively stable period after startup of MARGA in RTP and the instrument upgrades February 1 st. Subsequent operational and design problems caused both increased downtime and invalid data after March 25 for all three instruments and are not included in this data analysis.

12. Data and Results Comparison with Thermo SO2 Trace-gas analyzer at RTP site (2/15/06-3/1/06) (-4 designate invalid hours; -8 designate missing data)

13. MARGA Results Poor collection efficiency with one instrument was corrected by adjustment of the particle collector temperature. Precision between the two instruments was very good during this period for SO 4 All R 2 are calculated for valid hours only R 2 =.94 Data correctly identified as suspect by software

14. MARGA Results Denuder performance was very consistent between the two instruments for gases Relative percent difference for gases has typically been less than 20%

15. MARGA Results Precision was very good for ammonia gas even at concentrations of less than 1 ug/m 3 R 2 =.95 … although particulate ammonium was not. Software and equipment problems both contributed to performance problems. R 2 =.46 Data incorrectly identified as valid by software

16. MARGA Results Comparison of MARGA to: Thermo SO2 Trace-gas analyzer (right) is collocated at Beltsville R 2 =.72 R 2 =.86 MARGA Thermo SO 2 Trace-gas analyzer (left) is collocated at RTP/Burdens Creek MARGA R 2 =.80 Data provided by Lewis Weinstock (EPA/OAQPS)

17. MARGA Results Comparison of MARGA to: Thermo Particle Sulfate monitor is from the Maryland Department of Environment site ~4 mi away. It is unknown if differences are due to siting factors or measurement differences. R 2 =.72 MARGA Data provided by David Krask and George Allen