Total gaseous mercury in the atmosphere of Guiyang, PR China

Four measurement campaigns were carried out to monitor total gaseous mercury (TGM) at one site in Guiyang City, PR China in the following periods: April 19–30, 2000; February 26–March 14, 2001; June 26–July 20, 2001; and October 9–November 22, 2001, respectively. High temporal resolved data were obtained by using automated mercury analyzers Gardis 1A and Tekran 2537A. TGM data from all measurement periods followed the typical log normal distribution pattern. The geometric mean of TGM from different seasons were 8.56, 7.45, 5.20 and 8.33 ng m−3 in spring 2000, winter 2001, summer 2001 and autumn 2001, respectively. The overall average TGM covering the sampling periods was 7.39 ng m−3, which is significantly elevated comparing to global background of approximately 1.5–2.0 ng m−3. The major anthropogenic atmospheric mercury emission sources differed significantly among seasons, which caused the seasonal variability of TGM level. Distinct daily variability of TGM was observed among seasons. The daytime TGM concentrations were larger than that of nighttime in spring and winter seasons, while in summer and autumn the opposite daily TGM distribution pattern was observed.