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Measurements of speciated atmospheric mercury play a key role in identifying mercury behavior in the atmosphere. In this study, we measured speciated atmospheric mercury, including gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and particulate bound mercury (PBM) (2.5 μm), in 2015 and 2016 at an urban site in Beijing, China. The mean concentrations of GEM, RGM, and PBM were 4.70 ± 3.53 ng m

Airborne particulate pollution is a critical environmental problem affecting human health and sustainable development. Understanding of the sources of aerosol particles is of extreme importance for regional air pollution control. Here we show that natural Si isotopic signature can be used as a new tool to elucidate the sources of fine particulate matter (PM2.5). Through the analysis of Si isotopic composition (δ30Si) of PM2.5 and its primary sources collected in a typical pollution region – Beijing, we recognized the direct source tracing ability of Si isotopes for PM2.5. The different primary sources of PM2.5 had different Si isotopic signatures. The δ30Si value of PM2.5 ranged from −1.99‰ to −0.01‰ and showed a distinct seasonal trend (isotopically lighter in spring/winter and heavier in summer/autumn). The variations in δ30Si of PM2.5 revealed that Si-isotopically light sources were important sources for Beijing’s severe haze pollution and that coal burning was a major cause for the aggregating haze we...

Dissolved gaseous mercury (DGM, largely Hg(0)) in coastal seawater and gaseous elemental mercury (GEM or Hg(0)) in the atmosphere were simultaneously measured on the coast of the Yellow Sea, China in four different seasons (2008–09). Mean concentrations (±SD) of DGM and GEM over the study period were 34.0 ± 26.1 pg L −1 and 2.55 ± 0.98 ng m −3 , respectively. DGM concentrations and the degree of DGM saturation ( S a ) exhibited distinct seasonal variation with the order of summer (DGM: 69.0 ± 23.3 pg L −1 , S a : 11.00 ± 5.92) > fall (27.0 ± 16.4 pg L −1 , 3.50 ± 2.60) > spring (23.0 ± 8.7 pg L −1 , 2.00 ± 0.98) > winter (16.0 ± 6.0 pg L −1 , 0.96 ± 0.39). Under typical meteorological condition with low wind speed and intensive solar radiation in warm seasons, DGM usually exhibited the clear diurnal variation with elevated levels around noon and low levels in morning and afternoon. The diurnal and seasonal variation of DGM indicated the importance of photochemical DGM formation in the seawater. A consistent low DGM levels in high wind speed condition suggested that the biological activity probably influenced the DGM formation. There was no significant correlation between DGM and total mercury (THg), reactive mercury (RHg), dissolved organic carbon (DOC) in the seawater, indicating that THg/RHg and DOC might be not the controlling factors for the DGM formation in our study region. Based on the data of DGM and GEM and a two-layer gas exchange model, Hg(0) fluxes (in the unit of ng m −2 h −1 ) at air–sea interface were 0.51 ± 1.29 over the entire study period with 0.89 ± 1.84 in fall, 0.88 ± 1.38 in summer, 0.32 ± 0.71 in spring, and −0.06 ± 0.64, a slightly net Hg(0) deposition rate, in winter, respectively.

Mercury concentrations in size fractions of airborne particulate matter obtained from urban and suburban sites in Beijing in 2003 and 2004 are presented in this paper. The average concentrations of total particulate mercury were 1.18 +/- 0.82 ng m(-3) with a range of 0.18-3.51 ng m(-3) at the urban site and 0.68 +/- 0.62 ng m(-3) with a range of 0.13-2.40 ng m(-3) at the suburban site. This is much higher than what is found in Europe and Northern America. The results implie that significant anthropogenic sources in Beijing contribute to the concentration of particulate mercury in air and therefore, to the mercury deposition in this region. There are clear seasonal variations in concentration of particulate mercury with highest concentrations in winter at urban and suburban sites. This illustrates the important contribution from coal burning to particulate mercury during the heating season. The mercury concentration in each size fraction of airborne particulates was closely related to its size range. The highest mercury concentration was found in the size fraction less than 1.1 mu m with average concentrations of 0.59 +/- 0.50 and 0.29 +/- 0.26 ng m(-3) at the urban and suburban sites, respectively. The mercury in this size fraction accounts for 45.7 +/- 9.5% and 41.9 +/- 8.2% of the total particulate mercury, respectively. This implies that a large fraction of the particulate mercury in this area can be transported long range before it becomes deposited. Based on the concentrations of size-fraction a ted particulate mercury in ambient air, the dry deposition fluxes of mercury were estimated to 407 mu g m(-2) a(-1) at the urban site and 270 mu g m(-2) a(-1) at the suburban site. More than 90% of the deposition flux came from particles larger than 1.1 mu m despite a substantial fraction of the Hg found in particles less than 1.1 mu m. (c) 2006 Elsevier Ltd. All rights reserved.

Rapid industrialization has put citizens and ecosystems at risk. Acid rain emerged as an important environmental problem in China in the late 1970s. Many years of record economic growth has been accompanied by increased energy demand, greater coal combustion, and larger emission of pollutants. As a result of significant emissions and subsequent deposition of sulfur, widepsread acid rain is observed in southern and southwestern China. In fact, the deposition of sulfur is in some places higher than what was reported from the back triangle in central Europe in the early 1980s. In addition, nitrogen is emitted from agriculture, power production, and a rapidly increasing number of cars. As a result, considerable deposition of pollutants occurs in forested areas previously thought to be pristine. Little is known about the effects of acid deposition on terrestrial and aquatic ecosystems in China. In this article, we present the current situation and what to expect in the future, largely on the basis of results from a five-year Chinese-Norwegian cooperative project. In the years ahead, new environmental challenges must be expected if proper countermeasures are not put into place.

Mercury (Hg) emission from coal combustion in China is estimated in this study and its deposition calculated using the Models-3 Community Multi-scale Air Quality (CMAQ-Hg) modeling system with meteorological fields calculated by MM5. Three kinds of Hg speciation were included in the models: particle-bound mercury (PHg), gaseous elemental mercury (GEM) and gas oxidized mercury (RGM). Much of the Hg was released as RGM from coal combustion in China, accounting for 58.4 - 66.8% of total emissions. The large proportion of RGM in overall Hg emission also led to large Hg deposition. Based on simulations, Hg deposition originating from coal combustion reaches as high as 2 - 6 mu g m(-2) month(-1) in southwestern China (particularly Guizhou Province), the industrialized and populated regions of east central and coastal China, and Liaoning Province in the northeast.