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Semi-continental monitoring of gaseous elemental mercury (GEM), particulate mercury (Hg p ), and reactive gaseous mercury (RGM) was conducted in the Institute of Urban Environment, CAS in Xiamen, China from March 2012 to February 2013. The average concentrations and relative standard deviations (RSD) were 3.50 (34.6%) ng m −3 , 174.41 (160.9%) pg m −3 , and 61.05 (113.7%) pg m −3 for GEM, Hg p , and RGM, respectively. The higher concentrations of GEM and Hg p were observed in spring and winter months, indicating the combustion source, while RGM showed the different seasonal variation with highest concentration in spring and the minimum value in winter. The concentrations of Hg species were generally elevated in nighttime and low in daytime to reflect the diurnal changes in meteorology, especially the mixing condition of the air masses. The high Hg concentrations were observed in SWW–NW sectors due to calm wind while the low levels in NE–SE due to high speed wind, and the amplitude was much larger for Hg p and RGM. Backward trajectories calculation indicated that summer air masses were much more from ocean with lower Hg while the air masses were mainly from inland area in other seasons. Principal component analysis suggested that combustion and road traffic emissions were the dominant anthropogenic mercury sources for the study area, and the temporal distribution of atmospheric mercury was mainly the result of climatological change. [ABSTRACT FROM AUTHOR]

Daily precipitation samples were collected from June 2012 to May 2013 at four observation sites in Xiamen, a coastal city of Southeast China. Concentrations of Total mercury (THg) and methyl mercury (MeHg) in precipitation were rigorously treated and determined. The annual volume-weighted mean concentrations of THg and MeHg at four sites were 12.3 and 0.053 ng L −1 , and wet deposition fluxes of THg and MeHg were 14.04 μg m −2 yr −1 and 58.2 ng m −2 yr −1 , respectively. MeHg could account for 0.43% of THg, and dissolved Hg contributed 55.4% to THg. There was no significant difference in THg concentration between monsoon and non-monsoon seasons, which was consistent with neither the general seasonal pattern of inland cities of China nor the report from the Gulf coast. Higher wet deposition flux of THg in monsoon season was a function of intense rainfall, whereas higher MeHg flux in non-monsoon season could attribute to increased MeHg concentration. Atmospheric Hg was more efficiently scavenged during the earlier period of the rain event. Positive correlations between precipitation depth and wet deposition fluxes suggested that rainfall played an important role in scavenging atmospheric Hg rather than diluting concentrations. Pearson correlation analysis combined with ions ratios implied that sea salt aerosols had an important impact on rainwater, but coal combustion and traffic emission could be the dominant factors influencing THg in precipitation. [ABSTRACT FROM AUTHOR]