Study of Typical Heavy Pollution Events of Atmospheric Mercury in the Yangtze Delta using HYSPLIT4 and PSCF Models

Research Article

Austin Public Health. 2016; 1(1): 1003.

Study of Typical Heavy Pollution Events of Atmospheric Mercury in the Yangtze Delta using HYSPLIT4 and PSCF Models

Jianfeng LI¹*, Zhang X¹ and Diao C²

¹Beijing Municipal Institute of Labor Protections, China

²Department of Chemistry and Environmental Science, Guizhou Minzu University, China

*Corresponding author: Jianfeng LI, Beijing Municipal Institute of Labor Protections, 55# Taoranting Road, Xicheng District, Beijing 100054, China

Received: April 22, 2016; Accepted: June 07, 2016; Published: June 10, 2016


Mercury is a highly toxic heavy metal element that occurs widely in soil, water, and atmosphere. Based on observations of atmospheric mercury in Chongming Island, Shanghai, HYSPLIT4 and the Potential Source Contribution Function (PSCF) models were used to analyze typical pollution events and track the sources of the mercury. Pollution episodes of July 29 to August 1 and October 30 to November 2, 2010 were chosen for the study. Possible reasons for these events were proposed based on results from the HYSPLIT4 simulation, and analysis of the relationship between carbon monoxide and Total Gaseous Mercury (TGM). The PSCF model was used to analyze the long-term distribution and potential emission areas. Results indicate that the pollution event of July 29 to August 1 was influenced mainly by airflow from the southwest, and that the TGM came from urban districts of Shanghai and southern parts of Jiangsu, Zhejiang, Anhui, and Jiangxi. Furthermore, the PSCF simulation identifies the sources most likely contributing TGM to Chongming in different seasons. The objective is to provide an analytical basis for the investigation of periods of high pollution for Shanghai early warning mechanism, to reduce the negative impacts associated with unexpected air pollution events.

Keywords: Atmospheric mercury; Air pollution; Toxic metals; Long-range transport


TGM: Total Gaseous Mercury; GEM: Gaseous Elemental Mercury; RGM: Reactive Gaseous Mercury; PHg: Particulate Mercury; TPM: Total Particulate Mercury; TSP: Total Suspended Particulate; CVAFS: Cold Vapor Atomic Fluorescence Spectrophotometry; HYSPLIT: Hybrid Single-Particle Lagrangian Integrated Trajectory; PSCF: Potential Source Contribution Function



Mercury is a highly toxic heavy metal element that occurs widely in soil, water, and the atmosphere [1]. In the 1980s, high contents of methyl mercury were discovered in fish in remote lakes of Northern Europe and North America. As there were no sources of mercury emission near these areas, it was realized that the atmosphere provided a long-range transport for mercury pollution [2,1]. This was supported subsequently by research using numerical models [3-6].

Atmospheric mercury can be divided into three categories according to its form: Gaseous Elemental Mercury (GEM), Reactive Gaseous Mercury (RGM), Particulate Mercury (PHg). Due to the stable properties, gaseous elemental mercury can remain in the atmosphere for up to six months to two years; moreover, it can be transported for long distances, and involved in the global mercury cycle. Reactive gaseous mercury accounts for about 3% of the total gaseous mercury, and it can be spread to dozens to hundreds of kilometers [7]. Emission sources of atmospheric mercury can be either natural or anthropogenic. Natural sources include topsoil, vegetation, ocean and other water bodies, rocks, volcanoes and geothermal activities, and forest fires [8]. It is complex and difficult to accurately estimate mercury emissions from natural sources. Anthropogenic sources of mercury include the burning of fossil fuels (mostly coal), indigenous methods of gold metallurgy, non-ferrous metallurgy, cement manufacturing, waste incineration, and chlor-alkali manufacturing. Emissions of mercury from anthropogenic sources in total are about 2,503 tons annually [9]. Streets et al., studied the method of mercury emission sources list establishment in China provinces and provided different kinds of emission source and mercury emissions in China provinces in 1999 [10]. Pacyna deemed that global anthropogenic activities emitted 2,190 tons of mercury into the atmosphere in 2000, two-thirds of which is attributed to the burning of fossil fuels [11]. Asian countries contribute 54% of mercury emissions, African countries 18%, and European countries 11%. China’s anthropogenic activities emitted 600 tons of mercury into the atmosphere in 2000, which accounted for 28% of global mercury emissions in 2000. Wu Ye established the list of atmospheric mercury emissions from China’s man-made sources of the years 1995-2003 [12]; during this period, the atmospheric mercury emissions increase at a rate of about 2.9% per year, and the mercury emissions of the year 2003 reached 696 tons; wherein the element mercury emissions are 395 tons, the bivalent mercury emissions are 230 tons, and the particle mercury emissions are 70 tons; the mercury emissions of coal burning and non-ferrous metallurgy account for 80% of total mercury emissions. At present, in addition to the study of atmospheric mercury, many scholars in China and other countries have reported a variety of research concerning the atmospheric pollutants transport. Among them backward trajectory and PSCF (Potential Source Contribution Function) results are the important bases of many researches to track atmospheric pollutants pathways and sources. Alexandru Lupu and Willy Maenhaut used PSCF code to identify several atmospheric aerosol source areas [13]. By studying the PSCF results, Ferhat Karaca, Ismail Anil and Omar Alagha worked out the conclusion that seasonal change of the source of atmospheric aerosol arrived in Istanbul, Turkey [14]. Xiao Hui used a backward trajectory model to study the influence of long distance transmission of continental material to chemical composition of tropical precipitation waters [15]. Zhao Heng used backward trajectory model to study the source of O3, SO2, CO during TRACE-P in Hong Kong [16]. Based on PSCF results, Liu Na revealed the transportation pathways and potential source regions of Lanzhou PM10 pollution in spring [17].

China has become the world’s biggest emitter of mercury. Coal and smelting non-ferrous metal are two main mercury emission sources. Shortcomings in the current literature in China can be summarized as lacking the observations of background levels of atmospheric mercury and the supporting information for unexpected air pollution events serving for local government. Shanghai Chongming Island is located in the Yangtze River Estuary, its atmospheric mercury variation can demonstrate the pattern of eastern coast of China; moreover, Chongming Island that has a clean environment is away from the urban area. So, Chongming Island then was selected for long-term continuous atmospheric mercury monitoring. This study aims (i) to provide observations of background levels of atmospheric mercury in the Yangtze River Delta region; (ii) to reveal potential sources of atmospheric mercury pollution in the Yangtze River Delta region.


Monitoring stations

The atmospheric mercury monitoring station here is located on the roof of the office building of the Chongming Dongtan Birds National Nature Reserve in Shanghai (31°31’20”N, 121°54’30”E; about 11 m height of roof above ground), which is about 5 km from the Dongtan Wetland. The monitoring station is about 50 km from the Shanghai downtown area (People’s Square) and about 30 km from Shanghai suburbs (outer ring expressway). There are no obvious sources of industrial pollution around the monitoring station, and just a small number of residents within a distance of about 5 km Figure 1.