AIR QUALITY MODELING FOR MERCURY TMDL

UPDATE

Laura Boothe

Attainment Planning Branch Supervisor

January 11, 2012

BACKGROUND INFORMATION

Used EPA’s modeling files 2005 mercury air emission files 2005 meteorology files EPA’s version of the Community Multiscale

Air Quality (CMAQ) model used for mercury deposition modeling

Zeroed out North Carolina’s mercury air emissions to understand the impact of North Carolina’s air emission sources on North Carolina

Ran model with clean boundary conditions to understand impact of the global air emissions on North Carolina

NATIONAL BREAKDOWN OF MERCURY AIR EMISSIONS

Electric Generating Sources

49%

Other Point Sources44%

Area Sources5%

On Road Mobile1%

Non Road Mobile1%

National Breakdown of Mercury Emissions

Based on EPA’s 2005 Data

12-KM MODELING DOMAIN

AIR QUALITY MODELING RESULTS

Zero out run indicated ~16% of the mercury deposition in North Carolina is coming from air emission sources in North Carolina

Clean boundary conditions indicate that 70% of the mercury deposition in North Carolina comes from outside of the 12-km modeling domain

EXPECTED REDUCTIONS IN NC’s MERCURY AIR EMISSIONS

Source Type

2002 lbs/year

2010 lbs/year

2016* lbs/year

2003-2016

Reduction

Electric Generating

3,500 963 700 80%

Other Point 1,800 881 800 56%

Total 5,300 1,844 1,500 72%

*2016 projected emission include EPA’s proposed Electric Generating Units and Boiler Maximum Achievable Control Technology (MACT) Rules and planned shutdowns/fuel conversions

NEXT STEPS DWQ is developing a Mercury Total Maximum

Daily Load (TMDL) for North Carolina based in part on air quality modeling

January 2012 Final draft TMDL completed Draft Implementation

February 2012 Final draft TMDL available to public Request feedback

March 2012 EMC informational item Stakeholder meetings