Atmospheric mercury speciation in Shanghai, China

Area of Science:

• Environmental Chemistry
• Atmospheric Science
• Mercury Pollution

Background:

• Mercury is a persistent environmental pollutant with significant health implications.
• Understanding mercury speciation and sources is crucial for effective pollution control.

Purpose of the Study:

• To monitor gaseous elemental mercury (GEM), particle-bound mercury (PBM), and gaseous oxidized mercury (GOM) in Shanghai.
• To identify the sources and influencing factors of mercury pollution in a suburban Shanghai environment.

Main Methods:

• Continuous monitoring of GEM, PBM, and GOM from June to December 2014.
• Analysis of diurnal trends and correlations with pollutants like SO2 and NOx.
• Application of the Potential Source Contribution Function (PSCF) model.

Main Results:

• Average GEM, PBM, and GOM concentrations were significantly higher than in European/North American urban sites and Chinese rural areas.
• Mercury concentrations peaked in December, with distinct diurnal patterns for GEM, PBM, and GOM.
• Coal combustion and anthropogenic emissions were identified as major mercury sources, with limited impact from long-range transport.

Conclusions:

• Shanghai's suburban atmosphere experiences substantial mercury pollution, exceeding many international and domestic benchmarks.
• Photochemical reactions significantly influence GOM levels, while coal combustion and direct anthropogenic emissions are key mercury sources.
• Local and regional sources, rather than long-range transport, are the primary drivers of GEM concentrations in Shanghai during summer and autumn.