Speciated Mercury Measurements in Rochester New York: Concentrations and Sources

Jiaoyan Huang1, Hyun-Deok Choi1, Philip K. Hopke2 and Thomas M. Holsen1

A Tekran mercury (Hg) speciation system (Models 1130, 1135, and 2537) has been operated at an urban site (Rochester, New York) since Dec 2007. Ozone (O3), sulfur dioxide (SO2), carbon monoxide (CO), and PM2.5 and meteorological data including temperature (Temp), barometric pressure (BP), relative humidity (RH), wind direction (WD), wind speed (WS), and precipitation (precip) are also being measured. These data were examined using principle component analysis (PCA) to identify mercury sources for this site. A melting factor was also included to account for Hg release from melting snow.

PCA of 3886 observations identified 8 factors. Melting snow was a source of Hg0 during both winters. Conversion of Hg0 to RGM in the presence of O3 was found to be important in spring and summer 2008, and spring 2009. A factor in which RGM concentrations increased simultaneously with SO2 when the winds came from northwest where local coal fired utilities are located was also found. A factor characterized as a combustion source based on the relationship among Hg0, RGM, and CO was found to be important for most seasons. Conditional probability function (CPF) analysis found the factors were associated with different wind directions and suggests that the three species of mercury often come from different directions. Seasonal Hg0 concentrations in winter 2007 and spring 2008 were significantly higher than the following seasons when Hg0 concentrations were relatively constant. These differences may be attributed to the closing of the Russell coal fired power plant, located to the northwest of site in spring 2008

1 Department of Civil and Environmental Engineering, Clarkson University, 8 Clarkson Ave. Potsdam, NY, 13699-5712
2 Center for Air Resource Engineering and Science, Clarkson University, Potsdam, New York 13699-5708 Phone: 315-268-3979, Email: