Date of Award

2016

Publication Type

Master Thesis

Degree Name

M.A.Sc.

Department

Civil and Environmental Engineering

Supervisor

Xu, Xiaohong

Rights

info:eu-repo/semantics/openAccess

Abstract

The sources and processes affecting ambient speciated mercury concentrations including gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM) and particulate bound mercury (PBM) at Kejimukujik National Park were identified using positive matrix factorization (PMF) model and principal component analysis (PCA). Four factors, Combustion Emission, Industrial Source, Photochemistry and Re-emission of Hg, and Sea Salt, were identified in both 2009 and 2010 by PMF model. The factors Photochemistry and Sea Salt were found to have the largest and smallest impact on ambient speciated mercury concentrations using PMF model, respectively. The components derived from PCA using the same dataset were largely consistent with the factors identified by PMF. A shift of factor impact on mercury concentrations between 2009 and 2010 was observed using both methods. An additional PCA component Gas-particle Partitioning of Hg was identified in 2009 according to the negative relation between GOM and PBM. After including meteorological parameters in the input of PCA, mercury wet deposition, a new factor, was identified in both years. The reproduction of observed GEM concentrations by PMF model was the best among all three mercury forms followed by PBM and GOM. The sensitivity of PMF model to the different treatment to improve the data quality were tested. Imputations and combining or excluding GOM and PBM were found to have no obvious improvement on the model performances. However, increasing the low GOM and PBM concentrations by a scaling factor were effective in improving the model performances. Different treatments of input data had little impacts on factor profiles but factor contributions to Hg were affected to some extent.

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