Total Particulate Mercury Concentrations Research Articles

Characteristics and source appointment of atmospheric particulate mercury over East China Sea: Implication on the deposition of atmospheric particulate mercury in marine environment

Total Suspended Particulate (TSP) samples were collected at Huaniao Island in northern East China Sea (ECS) from March 2012 to January 2013. Chemical analysis were conducted to measure the concentration of total particulate mercury (TPM) and speciated particulate mercury including HCl-soluble particulate mercury (HPM), elemental particulate mercury (EPM) and residual particulate mercury (RPM). The bromine (Br) and iodine (I) on particles were also detected. The mean concentration of TPM during the study period was 0.23 ± 0.15 ng m−3, while the obviously seasonal variation was found that the concentrations of TPM in spring, summer, fall and winter were 0.34 ± 0.20 ng m−3, 0.15 ± 0.03 ng m−3, 0.15 ± 0.05 ng m−3 and 0.27 ± 0.26 ng m−3, respectively. The statistically strong correlation of bromine and iodine to HPM was only found in spring with r = 0.81 and 0.77 (p < 0.01), respectively. While the strongest correlations between EPM and bromine and iodine were found in winter with r = 0.92 (Br) and 0.96 (I) (p < 0.01), respectively. The clustered 72-h backward trajectories of different seasons and the whole sampling period were categorized into 4 groups. In spring, the clusters passed a long distance across the East China Sea and brought about low concentration of mercury due to the deposition of mercury over the sea. The cluster of air mass across the sea had low concentration of HPM in winter, which suggested that the oxidation of mercury in winter might be related to other oxidants. During the whole sampling period, the air mass from the north of China contributed to the higher concentration of TPM in Huaniao Island.

Characterization of atmospheric mercury at a suburban site of central China from wintertime to springtime

Atmospheric mercury exits primarily as gaseous mercury and particulate mercury (PHg). Change in the species of atmospheric mercury will pose significant impact on the biogeochemical process of mercury. Here total gaseous mercury (TGM) and total particulate mercury (TPM) were measured from heating season in wintertime to springtime with frequent dust storm during February to May 2009 in the suburban of Hefei, central China, where atmospheric mercury measurements were completely absent. The average concentrations of TGM and TPM were 2.57±1.37ng/m3 and 0.32±0.10ng/m3, respectively. Variations in the TGM were affected by both emissions and meteorological parameters. In the heating period (February), due to coal combustion TGM concentrations were significantly higher than those in the spring (March, April and May). A clear different diurnal variation in TGM concentration was also observed both in late winter and in spring, accompanying with the advance of sunrise. The percentage of total particulate mercury (TPM) in total atmospheric Hg ranged from 5.8%–19.2%, with relatively high levels appeared in March and April. PHg was mainly derived from direct emissions by coal combustion in February and May, while it was dominated by transformation from gaseous Hg on particles in March and April due to dust storms, which may result in more deposition of mercury to ecosystem.

Total particulate and reactive gaseous mercury in ambient air on the eastern slope of the Mt. Gongga area, China

Total particulate mercury (TPM) and reactive gaseous mercury (RGM) concentrations in ambient air on the eastern slope of the Mt. Gongga area, Sichuan Province, Southwestern China were monitored from 25 May, 2005 to 29 April, 2006. Simultaneously, Hg concentrations in rain samples were measured from January to December, 2006. The average TPM and RGM concentrations in the study site were 30.7 and 6.2 pg m(-3), which are comparable to values observed in remote areas in Northern America and Europe, but much lower than those reported in some urban areas in China. The mean seasonal RGM concentration was slightly higher in spring (8.0 pg m(-3)) while the minimum mean concentration was observed in winter (4.0 pg m(-3)). TPM concentrations ranged across two orders of magnitude from 5.2 to 135.7 Pg m(-3) and had a clear seasonal variation: winter (74.1 pg m(-3)), autumn (22.5 Pg m(-3)), spring (15.3 Pg m(-3)) and summer (10.8 Pg m(-3)), listed in decreasing order. The annual wet deposition was 9.1 mu g m(-2) and wet deposition in the rainy season (May-October) represented over 80% of the annual total. The temporal distribution of TPM and RGM suggested distinguishable dispersion characteristics of these Hg species on a regional scale. Elevated TPM concentration in winter was probably due to regional and local enhanced coal burning and low wet deposition velocity. The RGM distribution pattern is closely related to daily variation in UV radiation observed during the winter sampling period indicating that photo-oxidation processes and diurnal changes in meteorology play an important role in RGM generation. (c) 2007 Elsevier Ltd. All rights reserved.

Intercomparison study of atmospheric mercury models: 1. Comparison of models with short-term measurements

Five regional scale models with a horizontal domain covering the European continent and its surrounding seas, one hemispheric and one global scale model participated in an atmospheric mercury modelling intercomparison study. Model-predicted concentrations in ambient air were compared against mercury species observed at four monitoring stations in Central and Northern Europe and a station on the Irish west coast. The modelled concentrations of total particulate mercury (TPM) were generally consistent with the measurements at all sites. The models exhibited significant ability to simulate concentrations of gaseous elemental mercury (GEM), but some of the short-duration peaks at the Central European stations could not be consistently reproduced. Possible reasons for these discrepancies include (1) errors in the anthropogenic emissions inventory utilized; (2) coarse spatial resolution of the models; and (3) uncertainty of natural and re-emitted mercury sources. The largest discrepancies between measurements and modelled concentrations were found for reactive gaseous mercury (RGM). For these models, the uncertainty in predicting short-term (two-week episode) variations of mercury species in air can be characterized by the following overall statistics: 90% of the results for TGM are within a factor of 1.35 of the measurements; for TPM, 90% are within a factor of 2.5; and for RGM, 90% are within a factor of 10.

Gaseous and particulate atmospheric mercury concentrations in the Campinas Metropolitan Region (São Paulo State, Brazil)

The concentrations of Total Gaseous Mercury (TGM) and Total Particulate Mercury (TPM) were monitored during the 2002-2003 rainy and dry seasons at two sampling points (industrial and residential areas) of the Campinas Metropolitan Region. No significant difference was observed between the concentrations found at the two sampling areas and the mean values were 7.0 ± 5.8 ng m-3 (TGM) and 0.4 ± 0.3 ng m-3 (TPM). The analysis of the diel variability showed higher TGM concentrations during the day, which could be related to more intense anthropogenic activity during the day. Atmospheric dispersion processes could also explain some seasonal variation observed in TGM concentrations. For TPM concentrations a decreasing trend was observed during the rainy season, which could be explained by the removal of particles by wet deposition. The concentrations of TGM and TPM found in this study were of the same order of magnitude of those recorded in some highly industrialized regions of the northern hemisphere. These data show that emissions from the most industrialized Brazilian regions, and probably from similar regions in other countries of the southern hemisphere, should also be assessed and integrated into the global anthropogenic mercury emission assessment.

Mercury concentrations in size-fractionated airborne particles at urban and suburban sites in Beijing, China

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 −3at 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 μm 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-fractionated particulate mercury in ambient air, the dry deposition fluxes of mercury were estimated to 407 μg m −2 a −1 at the urban site and 270 μg m −2 a −1 at the suburban site. More than 90% of the deposition flux came from particles larger than 1.1 μm despite a substantial fraction of the Hg found in particles less than 1.1 μm.

Seasonal mercury concentrations measured in rural air in Southern Poland: Contribution from local and regional coal combustion

The concentration of total atmospheric gaseous mercury (TGM) and total particulate mercury (TPM) have been measured during one summer campaign (19–29 August 2003) and one winter campaign (26 January–3 February 2004) at a rural site in Poland. Mercury deposition was also measured using bulk samplers. The measurement campaigns were performed in a typical agricultural area of Southern Poland where 85% of the houses use low capacity domestic heating units (DHUs) fuelled with hard coal during the cold season. An average TGM value of 1.63 ± 0.35 ng m - 3 was obtained in the summer campaign, whereas a 2.5 times higher TGM concentration was found during winter. The mean TPM concentration during summer was 0.11 ± 0.05 ng m - 3 while 10 times higher values were obtained during the winter campaign. The mercury deposition was also found to be much higher during winter in comparison to summer. The summer TGM values are at the same level as the annual average TGM at background locations in most West European countries including Scandinavia. The higher TGM values in winter are most likely due to the use of DHUs in the local area. However, both summer and winter TPM concentrations and mercury deposition fluxes are much higher than in most neighbouring West European countries. This probably reflects the regional use of coal combustion for electric energy production and in low-capacity DHUs.

Atmospheric mercury distribution in Northern Europe and in the Mediterranean region

Mercury species in air have been measured at five sites in Northwest Europe and at five coastal sites in the Mediterranean region during measurements at four seasons. Observed concentrations of total gaseous mercury (TGM), total particulate mercury (TPM) and reactive gaseous mercury (RGM) were generally slightly higher in the Mediterranean region than in Northwest Europe. Incoming clean Atlantic air seems to be enriched in TGM in comparison to air in Scandinavia. Trajectory analysis of events where high concentrations of TPM simultaneously were observed at sites in North Europe indicate source areas in Central Europe and provide evidence of transport of mercury on particles on a regional scale.

A Device for Sampling and Determination of Total Particulate Mercury in Ambient Air

A miniaturized device, which serves as both particulate trap and pyrolyzer for airborne particulate mercury species, is described. It has been used in combination with amalgamation/thermal desorption/cold vapor atomic fluorescence spectrometry detection for the determination of total particulate mercury (TPM) associated with atmospheric aerosols. A standard reference material (SRM 1633b, NIST) has been used for validating of the pyrolysis technique, and a relative error smaller than 3% has been obtained. Contrary to most methods currently employed, this new technique does not require any sample preparation (e.g., extraction/digestion), no manual sample transfer or sample handling, and no addition of chemicals or reagents. Hence the risk of contamination is low. The time for complete analysis is less than 10 min per sample. The concentrations of TPM determined in metropolitan Toronto ranged from 3 to 91 pg m(-)(3) with standard deviations of <±2 pg m(-)(3) for simultaneous sets of four samples. These atmospheric TPM concentration values fall within the range reported in the literature. Good agreement was obtained by the three methods compared in a field study at Ny-Ålesund (78°54'N, 11°53'E), Svalbard. The elevated values of TPM concentrations obtained using the method developed in this work may arise from the Arctic springtime conversion of atmospheric mercury from gas-phase to particulate-phase Hg species.