This investigation studied the concentrations of ambient air total gaseous mercury (TGM) during the rainy periods at the Hung-Kuang traffic sampling site in central Taiwan from May 26 to June 16, 2014. The results were compared with those of a previous study for ambient air TGM during non-rainy daytime and nighttime periods at the Hung-Kuang traffic sampling site, which was conducted during March 21 to July 20, 2012. The observed mean concentration of ambient air TGM was 1.16ng/m(3) during the rainy periods at the Hung-Kuang traffic sampling site. The mean ambient air TGM concentrations were higher in the non-rainy sampling period in daytime than in the rainy sampling period from this study. The mean ratio of non-rainy sampling period in daytime to that of rainy sampling period for ambient air TGM were 3.15. Furthermore, the mean ambient air TGM concentrations were higher in the non-rainy sampling period in nighttime in than in the rainy sampling period for this study. The mean rations for non-rainy sampling period in nighttime to that of the rainy sampling period for ambient air TGM were 2.70. The results obtained in this study also revealed that the ambient air TGM concentrations during the rainy period had the lowest concentrations when compared with the other sampling sites in other world regions.
