Characterization of atmospheric mercury concentrations along an urban–rural gradient using a newly developed passive sampler

Due to the high costs and deployment difficulties associated with automated sampling technologies, few investigations have been published on atmospheric mercury in typical urban and rural areas in developing countries. In this study, a novel passive sampler for gaseous elemental mercury was developed and applied to characterize trends in atmospheric mercury levels across an urban–rural transect. The sampling transect originated in the city of Beijing and extended ∼150 km southward into a rural region. Field deployment was conducted during September–October (autumn) and November–December (winter) in 2010. The mercury concentrations in air obtained using the passive sampler were consistent with synchronous automated measurements performed during the field deployment. The results demonstrated that atmospheric mercury concentrations increased along the urban–rural gradient in the following order in both of the two periods: urban > suburban > rural (populated) > rural (farmland).