Simultaneous monitoring of total gaseous mercury at four urban monitoring stations in Seoul, Korea

The monitoring of total gaseous mercury (TGM) concentrations together with other trace gases and meteorological parameters was made at hourly intervals over 2-year period (1 January 2010 to 31 December 2011) at four urban monitoring sites: Guro-gu (G), Nowon-gu (N), Songpa-gu (S), and Yongsan-gu (Y) in Seoul, Korea. The mean concentrations of TGM at these sites were found to span the range of 3.28 (Y) to 3.47 ng m− 3 (N). Inspection of the seasonal patterns indicates that the maximum concentrations (ng m− 3) occur at different times of year across the four sites: winter at N (3.67 ± 1.77), fall at S (3.64 ± 1.12), summer at G (3.61 ± 1.51), and spring at Y (3.40 ± 1.26). The long-term trend in Hg concentrations, when also considering data sets from previous studies, suggests modest reductions in concentrations at all four sites, from 2.89 to 4.49 ng m− 3 in 2004 and from 2.49 to 3.42 ng m− 3 in 2011.