UPDATE ON DAQ’S AIR QUALITY MEASUREMENTS & MERCURY

STUDIES

NC DENR/DAQ

Mercury/CO2 Workshop

Raleigh, NCApril 19, 2004

Steve Schliesser

Todd Crawford

NC Division of Air Quality

Presentation Summary

DAQ Hg studies in Eastern NC

- Waccamaw Study

- Hg from Wet Deposition

- Ambient Air Hg near Chlor-alkali Plant Charlotte-Mecklenburg Air Hg Study

- Four locations in 2002 & 2003 Summary / Conclusions & Plans

Drivers for DAQ Hg Studies in Eastern NC

Blackwaters sensitive to Hg 1970 – Cited Hg in Cape Fear River fish Hg in Fish up to 1.5 ppm Hg in H2O 10X Safe Drinking Level 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

Discovery of more widespread Hg issues

Mercury Deposition Network (MDN) in Eastern NC

2 MDN Sites in Eastern NC for Wet Deposition and Ambient Air Monitoring Starting in 1996

Annual Wet Deposition Data

from 9,000-19,000 ng/m3 Noticeable Reduction Trend from 1998-

2002

Eastern NC Mercury Emission Sources

MDN US Network in 1999 (NC08 = Lake Waccamaw site,

NC42 = Pettigrew State Park site.)

MDN Wet Deposition Collection System

Annual Cumulative Hg Wet Deposition

Mercury Wet Deposition, as Volume-Weighted Avg Concentration (ng/L) by

Season, Site & Year.

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

site and year

vol-w

eig

hte

d a

vera

ge

Hg

co

nce

ntr

atio

n (n

g/L

)

October-March

April-September

October-March 5.14 5.84 4.73 5.68 5.83 6.16 6.78 6.82 5.46 6.40

April-September 12.28 12.32 9.54 7.02 9.22 14.56 13.87 15.25 8.69 11.45

phelps 96 phelps 97 phelps 98 phelps 99 phelps 00 wac96 wac 97 wac 98 wac 99 wac 00

.

Mercury in Ambient Air near Waccamaw MDN Site

Total and Speciated Hg Air Monitoring

- TGM up to 300 ng/m3 –5 min Avg

- TGM Annual Avg 2.3 ng/m3

- TGM Background < 2 ng/m3

- RGM up to 300 pg/m3 – 2 hr Avg

- RGM background < 2 pg/m3

Air with Met Data Argued Chlor-Alkali Plant Main Contributor, Leading to Plant Closing in 1999

Total Gaseous Mercury Measured at Riegelwood Flynn Site in 1999

Riegelwood Flynn, March - June 1999

0

40

80

120

160

200

240

280

320

360

Date

TG

M (

5-m

inu

te a

ve

rag

e, n

g/m

3)

Riegelwood Ballpark, TGM vs. Wind Direction, 1999

Observed Relationships between Reactive Gaseous Mercury, Elemental

Mercury, & Meteorology

Variable Reactive Gaseous Mercury (RGM)

Elemental Mercury (Hg0)

Time of Day Elevated readings primarily in daylight hours

No clear pattern; high levels in day and night

Humidity Inverse proportional trend; RGM suppressed by high humidity conditions.

No clear pattern; high and low levels across all humidity levels

Temperature None None

Comparison of Hg Deposition & Eastern NC Regional Emissions

Comparison of Deposition Rate and Regional Emissions

0

500

1000

1500

2000

2500

3000

Calendar Year

Hg A

nnua

l Em

issi

ons,

lb/yr

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

Wet

Dep

ositi

on, n

g/m

2

Hg Emissions 2716 1285 497 460 679

NC08 18811 17362 12193 9083 10213

NC42 10027 7907 10829 6097 7777

1998 1999 2000 2001 2002

Mecklenburg / Charlotte Ambient Mercury Study in 2002-2003

EPA NATA Study Predicted Mecklenburg County Atmospheric Mercury Levels in Top 5% of US Counties

Charlotte Surrounded by Mercury Emission Sources: Electric Utilities, Medical Waste Incinerator, Large Industrial Boilers

Given No Prior Data, DAQ Initiated Ambient Air Mercury Monitoring Study for TGM, RGM, Hg0

Setup 4 Sites around Charlotte

- One Near Downtown

- Other 3 in Suburbia Completed Data Collection – Reported in 2004

1996 US Estimated County Median Ambient Mercury Concentrations

1996 Estimated County Median Ambient Mercury Concentrations

– NC Counties

Location and Size of NC Electric Utility Plants

Summary & Conclusions 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 NC data suggests high humidity could reduce

ambient RGM, while promoting wet deposition

Future Plans Finalize Charlotte Area Ambient

Mercury Monitoring Study Report 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