update on daqs air quality measurements & mercury studies nc denr/daq mercury/co 2 workshop...
TRANSCRIPT
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