Atmospheric dry and wet deposition of mercury in Toronto

Abstract Atmospheric mercury (Hg) speciation and deposition are critical in understanding the cycling of mercury in the environment. To estimate the dry and wet deposition of mercury in an urban environment, concentrations of gaseous elemental mercury (GEM), gaseous oxidized inorganic mercury (GOIM), mercury associated with particles having size less than 2.5 μm (Hg(p)  The dry deposition rates of GOIM, Hg(p)  −2 month −1 , 0.04–0.32 μg m −2 month −1 and 0.17–1.11 μg m −2 month −1 , respectively, while the wet deposition rates of methyl mercury and total mercury between June 2005–January 2006 and September 2007–March 2008 were 0.01–0.08 μg m −2 month −1 and 0.32–8.48 μg m −2 month −1 , respectively. The total dry deposition (7.66–26.06 μg m −2  a −1 , calculated as the sum of GOIM and THg(p) deposition) and the total wet deposition (= the wet deposition of total mercury = 18.60 μg m −2  a −1 ) contributed proportionally to the total atmospheric Hg deposition in Toronto.