Exploratory investigation on spatiotemporal variation and source identification of atmospheric speciated mercury surrounding the Taiwan Strait

This pioneering study explored the spatiotemporal variation, gas-solid partition, and potential sources of atmospheric speciated mercury surrounding the Taiwan Strait. Total gaseous mercury (TGM) and particle bound mercury (Hgp) were sampled simultaneously at six coastal and island sites located on both sides and in the middle of the Taiwan Strait. Field measurement results showed that the campaign average concentrations of TGM and Hgp at all sites were 4.56 +/- 0.35 and 0.17 +/- 0.02 ng/m(3), with the range of 3.22-5.84 and 0.06-0.25 ng/m(3), indicating that TGM and Hgp partitioned as 96.09-97.02% and 2.98-3.91%, respectively, The spatial distribution results showed that the highest and lowest TGM and Hgp concentrations were mostly observed at Xiang-An site in the suburban of Xiamen City and at Sandiaojiao site in the remote coast of New Taipei City, respectively. The seasonal variation of TGM at six sampling sites was in the order as: spring > winter > fall > summer, while that of Hgp was in the order as: winter > spring > fall > summer. Regarding the levels of TGM and Hgp, they increased gradually and consistantly from late fall to early spring when polluted air masses were transported from the Northeast Asia to the Taiwan Strait by Asian Northeastern Monsoons (ANEMs). On the contrary, the lowest concentrations of TGM and Hgp were observed commonly in summer as clean marine air masses transported from the seas toward the Taiwan Strait. It was inferred that atmospheric speciated mercury surrounding the Taiwan Strait was mainly attributed from both local sources and long-range trasport (LRT) from the Northeast Asia.

Automated summary

This study investigated the speciated mercury in the atmosphere surrounding the Taiwan Strait, finding that the mercury primarily came from local sources and long-range transport from Northeast Asia. Seasonal variations were influenced by the Asian Northeastern Monsoons and clean marine air masses during different seasons.