APPLICATION OF THE CMAQ PARTICLE AND PRECURSOR TAGGING METHODOLOGY (PPTM) TO SUPPORT WATER QUALITY PLANNING FOR THE VIRGINIA MERCURY STUDY

CMAQ is being applied in this study to assess the contribution of mercury sources within Virginia and surrounding states to impaired waterways. A key component of this study is the use of the CMAQ Particle and Precursor Tagging Methodology (PPTM) which allows one to track the emission, dispersion, chemical reaction, and deposition of mercury from particular sources, source categories, or source regions throughout the simulation. The PPTM technique is being used to quantify the contributions of individual sources and source categories for a base year of 2001 and several future years. The modeling will be used to evaluate the effectiveness of emissions reductions expected as part of the Clean Air Mercury Rule (CAMR) and whether additional control measures will be needed in Virginia to meet applicable water quality criteria. Another important objective of the modeling analysis is to provide information that will enable VDEQ to conduct Total Maximum Daily Load (TMDL) studies for mercury of various Virginia waterways.