1. UPDATE ON DAQS AIR QUALITY MEASUREMENTS & MERCURY STUDIES NC DENR/DAQ Mercury/CO 2 Workshop Raleigh, NC April 19, 2004 Steve Schliesser Todd Crawford NC Division of Air Quality

2. Presentation Summary n DAQ Hg studies in Eastern NC - Waccamaw Study - Hg from Wet Deposition - Ambient Air Hg near Chlor-alkali Plant n Charlotte-Mecklenburg Air Hg Study - Four locations in 2002 & 2003 n Summary / Conclusions & Plans

3. Drivers for DAQ Hg Studies in Eastern NC n Blackwaters sensitive to Hg n 1970 – Cited Hg in Cape Fear River fish n Hg in Fish up to 1.5 ppm n Hg in H2O 10X Safe Drinking Level n Hg in Humans - 3.4 ppm in Blood of Fish Eaters, 10X > Non Fisheaters - 34 ppm in Hair of Fish Eaters - Some of Highest Levels Recorded in US n Discovery of more widespread Hg issues

4. Mercury Deposition Network (MDN) in Eastern NC n 2 MDN Sites in Eastern NC for Wet Deposition and Ambient Air Monitoring Starting in 1996 n Annual Wet Deposition Data from 9,000-19,000 ng/m3 n Noticeable Reduction Trend from 1998- 2002

5. Eastern NC Mercury Emission Sources

6. MDN US Network in 1999 ( NC08 = Lake Waccamaw site, NC42 = Pettigrew State Park site.)

7. MDN Wet Deposition Collection System

8. Annual Cumulative Hg Wet Deposition

9. Mercury Wet Deposition, as Volume- Weighted Avg Concentration (ng/L) by Season, Site & Year..

10. Mercury in Ambient Air near Waccamaw MDN Site n Total and Speciated Hg Air Monitoring - TGM up to 300 ng/m 3 –5 min Avg - TGM Annual Avg 2.3 ng/m 3 - TGM Background < 2 ng/m 3 - RGM up to 300 pg/m 3 – 2 hr Avg - RGM background < 2 pg/m 3 n Air with Met Data Argued Chlor-Alkali Plant Main Contributor, Leading to Plant Closing in 1999

11. Total Gaseous Mercury Measured at Riegelwood Flynn Site in 1999

12. Riegelwood Ballpark, TGM vs. Wind Direction, 1999

13. Observed Relationships between Reactive Gaseous Mercury, Elemental Mercury, & Meteorology VariableReactive Gaseous Mercury (RGM) Elemental Mercury (Hg 0 ) Time of DayElevated readings primarily in daylight hours No clear pattern; high levels in day and night HumidityInverse proportional trend; RGM suppressed by high humidity conditions. No clear pattern; high and low levels across all humidity levels TemperatureNone

14. Comparison of Hg Deposition & Eastern NC Regional Emissions

15. Mecklenburg / Charlotte Ambient Mercury Study in 2002-2003 n EPA NATA Study Predicted Mecklenburg County Atmospheric Mercury Levels in Top 5% of US Counties n Charlotte Surrounded by Mercury Emission Sources: Electric Utilities, Medical Waste Incinerator, Large Industrial Boilers n Given No Prior Data, DAQ Initiated Ambient Air Mercury Monitoring Study for TGM, RGM, Hg 0 n Setup 4 Sites around Charlotte - One Near Downtown - Other 3 in Suburbia n Completed Data Collection – Reported in 2004

16. 1996 US Estimated County Median Ambient Mercury Concentrations

17. 1996 Estimated County Median Ambient Mercury Concentrations – NC Counties

18. Location and Size of NC Electric Utility Plants

19. Summary & Conclusions n NC has / had relatively high Hg, well above US average, in terms of: - Emissions into ambient air - Measurements in specific ambient airsheds - Modeling in specific ambient airsheds - Wet deposition levels - Fish of selected species - People who eat selected fish species n NC data suggests high humidity could reduce ambient RGM, while promoting wet deposition

20. Future Plans n Finalize Charlotte Area Ambient Mercury Monitoring Study Report n Consider Arrangements for New Hg Study in Piedmont, including: - MDN Site(s) for wet deposition, - Ambient Air Hg and Meteorological Monitoring - Assessing Relationship Between Hg Emissions, Wet Deposition, Meteorology, & Ambient Air Levels