Mercury Wet Deposition and Speciated Air Concentrations from Two Urban Sites in New York State: Temporal Patterns and Regional Context

ABSTRACT

Since 2008, ambient speciated mercury (Hg) concentrations and weekly Hg wet deposition have been measured at two urban locations in New York – Rochester and New York City (borough of Bronx). These measurements were initiated to establish ambient Hg baselines ahead of anticipated emissions reductions, as well as characterize air concentrations and deposition at two different urban settings. In this paper seasonal and regional patterns in Hg wet deposition are presented, as well as seasonal, day of week and diurnal patterns in ambient Hg species at these two sites. The mean (and median) Hg concentration in precipitation was 9.56 ng/L (8.37 ng/L) at the Bronx site, and 9.95 ng/L (8.30 ng/L) at Rochester. Mean ambient air concentrations of gaseous elemental Hg (GEM), reactive gaseous Hg (RGM), and particle-bound Hg (PBM) at the Bronx and Rochester sites were 1.52 and 1.40 ng/m³, 6.26 and 8.24 pg/m³, and 7.96 and 13.48 pg/m³, respectively. Conditional probability function analysis was used to examine potential source regions impacting these two sites. Using these data we were able to examine monthly and diurnal patterns in speciated ambient Hg; however, more research is needed to more fully characterize potential emission sources that impact these sites.