Spatial and temporal PAH concentrations in Zaragoza,Spain

The concentration of seven polycyclic aromatic hydrocarbons (PAH) associated with the atmospheric solid phase was measured in the Zaragoza (North-East of Spain) atmosphere using fluorescence spectroscopy in the synchronous mode (FS). The PAH results were reported for four different urban and suburban places, located within the city and during the period October 1999-September 2001. The PAH data obtained indicated the importance of local sources generated from urban/industrial areas. Although the PAH total concentration was quite similar in all the sampling sites, the main differences were due to Benzo[a]pyrene (BaP) and Coronene (Cor) concentrations, reaching the highest values in the sites associated with heavy traffic (trucks, lorries, etc.). The temporal evolution of atmospheric solid phase PAH concentrations indicated a seasonal trend. Higher PAH concentrations were found during colder seasons for the four sampling sites. The influence of environmental parameters such as temperature, rain, relative humidity, wind speed and direction on the PAH emissions was analyzed observing a positive correlation between the total PAH concentration and the relative humidity and a negative one with the temperature. With regard to the wind direction, higher PAH emissions were detected when wind was coming from an east and north-east direction. Wind from a north-westerly direction showed lower PAH emissions associated with the cierzo wind which provided cleaner air.     

Sources and chemical reactivity of polynuclear aromatic hydrocarbons in the atmosphere — A critical review

This paper reviews critically studies on the sources and chemical reactivity of Polynuclear Aromatic Hydrocarbons (PAH) in the atmosphere. In the case of the sources the PAH emission conditions and their effects on the PAH atmospheric pollution level, the source sample chemical compounds structure, some representative atmospheric concentrations and the source comparison problems of the automobile, industrial, working environment, domestic heating, refuse burning and tobacco-smoking emissions are reviewed.In the case of chemical reactivity: the reaction mechanism, the products and their human health effects and the reaction conditions of the PAH photooxidation, thermal decomposition, NO_x action, O₃ action, SO₂ action, one-electron oxidation and oxidants action are reviewed.     

Atmospheric concentrations and air-soil gas exchange of polycyclic aromatic hydrocarbons (PAHs) in remote, rural village and urban areas of Beijing-Tianjin region, North China

Forty passive air samplers were deployed to study the occurrence of gas and particulate phase PAHs in remote, rural village and urban areas of Beijing-Tianjin region, North China for four seasons (spring, summer, fall and winter) from 2007 to 2008. The influence of emissions on the spatial distribution pattern of air PAH concentrations was addressed. In addition, the air-soil gas exchange of PAHs was studied using fugacity calculations. The median gaseous and particulate phase PAH concentrations were 222 ng/m³ and 114 ng/m³, respectively, with a median total PAH concentration of 349 ng/m³. Higher PAH concentrations were measured in winter than in other seasons. Air PAH concentrations measured at the rural villages and urban sites in the northern mountain region were significantly lower than those measured at sites in the southern plain during all seasons. However, there was no significant difference in PAH concentrations between the rural villages and urban sites in the northern and southern areas. This urban-rural PAH distribution pattern was related to the location of PAH emission sources and the population distribution. The location of PAH emission sources explained 56%-77% of the spatial variation in ambient air PAH concentrations. The annual median air-soil gas exchange flux of PAHs was 42.2 ng/m²/day from soil to air. Among the 15 PAHs measured, acenaphthylene (ACY) and acenaphthene (ACE) contributed to more than half of the total exchange flux. Furthermore, the air-soil gas exchange fluxes of PAHs at the urban sites were higher than those at the remote and rural sites. In summer, more gaseous PAHs volatilized from soil to air because of higher temperatures and increased rainfall. However, in winter, more gaseous PAHs deposited from air to soil due to higher PAH emissions and lower temperatures. The soil TOC concentration had no significant influence on the air-soil gas exchange of PAHs.     

2,3,7,8-TCDD equivalence and mutagenic activity associated with PM10 from three urban locations in New Zealand

Ambient particulate matter (PM(10)) in urban centres varies depending on emission sources, geography, demography, and meteorology. Hence physical (PM(10), wind speed, rainfall, temperature), chemical (polycyclic aromatic hydrocarbons, PAH), and toxicological (Ames Test, H4IIE EROD Assay) analyses were done on daily PM(10) (approximately 1640 m(3)/day) collected from three New Zealand urban sites where winter emissions were predominantly due to domestic home heating. Daily PM(10) levels ranged between 9.7 and 20.8 in summer and between 21.8 and 61.0 microg/m(3) in winter. Daily PAH concentrations were 0.5, 0.45, and 1.5 ng/m(3) in summer and 52.1, 128.9, and 5.8 ng/m(3) in winter at sites Christchurch, Alexandra and Dunedin, respectively. During winter, 74% of PM(10) extracts from all three sites showed significant mutagenicity in the Ames Test (TA 98, -S9), whereas approximately 25% of the daily PM(10) was mutagenic in summer. Benzo[a]pyrene and BaP carcinogenic equivalence concentrations during winter were strongly correlated to both mutagenicity and TCDD-like activity at two sites. Daily levels of TCDD toxicity equivalence concentrations ranged from 0.5 to 3.6 pg TCDD/m(3) air in summer and from 0.3 to 4009 pg TCDD/m(3) air in winter. Chemically and biologically derived TCDD toxicity equivalent concentrations were significantly correlated in all study locations indicating that PAH may represent most of the TCDD-like activity present in the PM(10).     

Exploratory investigation of the chemical characteristics and relative toxicity of ambient air particulates from two New Zealand cities

We examined the chemical composition and biological response associated with particulate emissions from the two largest cities in New Zealand, Auckland and Christchurch. The organic and water-soluble fractions were isolated from the particulate matter (PM). The organic fraction was examined for PAH content, direct mutagenicity, CYP1A1 induction, and cytotoxicity and TNF-α release in RAW264.7 macrophages. The water-soluble fraction was examined for metal content, and cytotoxicity and TNF-α release in RAW264.7 macrophages.Particulate, PAH and water-soluble metal concentrations were all higher in PM collected from Christchurch, being highest in May-July when woodburners for home heating are widely in use. In contrast, PM from Auckland showed the highest concentrations in March, but PAH and metal concentrations were highest in July. We found marked differences in the biological response elicited by ambient air PM: the organic extracts of Christchurch PM_2.5 and PM₁₀ showed higher mutagenicity and CYP1A1 induction compared with PM₁₀ from Auckland. In contrast, water-soluble extracts of Auckland PM were more cytotoxic and resulted in greater TNF-α release than those from Christchurch PM, although they had a lower metal content. The organic fraction of PM from both cities did not induce any cytokine release, and the organic extract from Auckland samples showed no cytotoxicity; smaller PM mass was available for testing for these samples. Biological responses typically occurred at lower doses of the organic extract, indicating that organic components may be more important in eliciting effects than water-soluble components.Preliminary apportionment of the biological responses to the dominant sources of PM in both cities-woodburners and vehicles-was undertaken. This indicated that for both cities, vehicles have a greater contribution to the direct mutagenic activity of ambient PM than woodsmoke, despite a lower contribution to ambient PM. In contrast, woodsmoke is estimated to have a greater contribution to CYP1A1 induction of ambient PM. The calculated activity forms only a small proportion of the activity observed in extracts of ambient PM from Christchurch, particularly for mutagenicity, and may indicate a significant influence of atmospheric transformation processes on biological response. Only data for mutagenicity and CYP1A1 activity could be used for apportionment as low and/or variable cytotoxicity or TNF-α release response were obtained for either the individual source or ambient PM at the doses tested. Further, in the case of the water-soluble extracts from Auckland, additional components are suggested to have a role in the observed activity.     

A source inventory and budget for chlorinated dioxins and furans in the United Kingdom environment.

Polychlorinated dibenzo-p-dioxins (PCDDs) and -furans (PCDFs) are ubiquitous in the environment. This paper estimates the present UK environmental loading of PCDD/Fs in soils, vegetation, air, water and sediments. Greater than 95% of the estimated total PCDD/F loading of 5.7 t in the UK environment is present in surface soils. Annual emissions from known primary sources of PCDDs and PCDFs are estimated. The most important of these include: municipal waste incinerator stack emissions (10.9 kg sigma PCDD/F per annum); industrial (7.7 kg/year) and domestic (5.1 kg/year) combustion of coal; clinical waste incinerators (1.7 kg/year); volatilisation from chlorophenol-treated substrates (1.7 kg/year) and combustion of leaded petrol by motor vehicles (0.7 kg/year). These sources are generally easy to define and reasonably reliable national estimates can be obtained. More difficult to quantify are secondary releases from the large UK stock of pentachlorophenol (PCP) and PCP-treated products, which may represent quantitatively one of the most important sources of total PCDD/Fs to the environment. Estimates of homologue-specific emissions indicate that combustion processes represent a far more significant source of tetra and penta CDD/Fs than do chlorophenols, which in turn constitute a greater source of hepta- and octachlorinated congeners. Direct emission of PCDD/Fs into the atmosphere from combustion processes facilitates their atmospheric transport to remote locations. This, coupled with the diffuse nature of combustion processes, means that the effects of PCDD/F contamination originating from anthropogenic combustion are more widespread than those from the use and disposal of chlorophenols. Contamination from chlorophenols will be more localised, owing to the insignificance of direct atmospheric release pathways for this source. Although there is reasonable agreement between the estimated current annual flux and the present UK environmental loading of PCDDs and PCDFs, a large discrepancy exists between the sum of the annual contributions from primary sources and this annual flux. Whilst the existence of an as yet unidentified source or sources or gross underestimates of known sources cannot be excluded, it is proposed that much of this discrepancy may be accounted for by secondary releases from the use and disposal of chlorophenols and the long-range transport, continued remobilisation and subsequent redeposition of PCDDs and PCDFs already present in the environment. Despite limited evidence for a modest decline in levels of PCDDs and PCDFs in some environmental compartments over the last 20 years, the environmental persistence of these chemicals means that they will remain in the UK environment for the foreseeable future despite recent action to curb primary emissions.     

The distribution and origin of mutagens in airborne particulates, detected by the salmonella/microsome assay in relation to levels of lead, vanadium and PAH

At three stations in central Copenhagen, Denmark, samples of particulate matter were collected simultaneously with different contributions from automobile exhaust products. Samples were obtained at street level, 22 m above street level and within a hospital zone; 32 samples were analysed for levels of polycyclic aromatic hydrocarbons (PAH) and elements, as well as for mutagenicity towards S. typhimurium TA1538. Two classes of mutagens were quantified: a non-polar extract rich in PAH and, other promutagens, and a polar extract containing direct acting mutagens (not requiring microsomal activation). Covariances between lead and mutagenicity, and the varying distribution of the polar and non-polar mutagens at the stations, indicate that at all stations the mutagenicity of the non-polar extract is dominated by automobile exhaust products. The polar extract is relatively less influenced by primary traffic emissions; a considerable part of the activity of this extract is attributed to secondary emissions, transformed by atmospheric reactions, and primary emissions from stationary sources.     

Vertical distributions of SO(2) and NO(2) in the lower atmosphere in Beijing urban areas, China

Measurements of SO(2) and NO(2) were conducted from January to March 2001 and August 2003 at a 325 m meteorological tower in Beijing. The concentrations of SO(2) and NO(2) observed by passive samplers at ten heights showed complex vertical distributions in winter and summer. The vertical profiles of pollutants were influenced by source emissions, meteorological conditions, urban canopy and other factors. The comparison analysis of winter and summer pollutant concentrations suggests that the decrease in SO(2) concentration was significant in summer, and the reduction of NO(2) was relatively not distinctive. Domestic heating and industrial sources were major sources of SO(2) in urban areas of Beijing. Differing from SO(2,) urban NO(2) was closely related to traffic emission. Meteorological evidence suggests that strong temperature inversions influence vertical distribution of air pollutants over urban Beijing. The high levels of SO(2) and NO(2) concentrations were due to the accumulation of pollutants resulting from the stable atmosphere prevalent during the measurement period. The vertical distributions of air pollutants were controlled and affected by atmospheric dynamical characteristics.     

Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Huangpu River, Shanghai, China

We applied cluster analysis and principal component analysis (PCA) with multivariate linear regression (MLR) to apportion sources of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Huangpu River in Shanghai, China, based on the measured PAH concentrations of 32 samples collected at eight sites in four seasons in 2006. The results indicate that petrogenic and pyrogenic sources are the important sources of PAHs. Further analysis shows that the contributions of coal combustion, traffic-related pollution and spills of oil products (petrogenic) are 40%, 36% and 24% using PCA/MLR, respectively. Pyrogenic sources (coal combustion and traffic related pollution) contribute 76% of anthropogenic PAHs to sediments, which indicates that energy consumption is a predominant factor of PAH pollution in Shanghai. Rainfall, the monsoon and temperature play important roles in the distinct seasonal variation of PAH pollution, such that the contamination level of PAHs in spring is significantly higher than in the other seasons.

Brief

We apportion PAHs in surface sediments of the Huangpu River and show that coal combustion, traffic-related pollution, and petroleum spillage are the major sources.     

Mass balance for polycyclic aromatic hydrocarbons in the urban watershed of Le Havre (France): transport and fate of PAHs from the atmosphere to the outlet

Polycyclic aromatic hydrocarbon (PAH) concentrations have been monitored simultaneously in ambient air, bulk atmospheric deposition and runoff waters during one year in a small urban watershed of the Seine river basin (France). PAH fluxes from the atmosphere to the outlet of the urban watershed have been calculated to establish a mass balance for PAHs. PAH flux in runoff waters was 5.2 kg km(-2) yr(-1) while PAH atmospheric deposition was 0.21 kg km(-2) yr(-1). The comparison between atmospheric input and output by runoff has shown the importance of street deposits that appeared to be the most important source of PAHs for surface waters in urban areas. PAH profiles in the various compartments showed the fate of PAHs in the air-water system: proportion of carcinogenic PAHs was more important in runoff waters (35%) than in bulk atmospheric deposition (22%) and air (6%).     

The importance of source configuration in quantifying footprints of regional atmospheric sulphur deposition

An atmospheric transport-chemistry model is applied to investigate the effects of source configuration in simulating regional sulphur deposition footprints from elevated point sources. Dry and wet depositions of sulphur are calculated for each of the 69 largest point sources in the UK. Deposition contributions for each point source are calculated for 2003, as well as for a 2010 emissions scenario. The 2010 emissions scenario has been chosen to simulate the Gothenburg protocol emission scenario. Point source location is found to be a major driver of the dry/wet deposition ratio for each deposition footprint, with increased precipitation scavenging of SO_x in hill areas resulting in a larger fraction of the emitted sulphur being deposited within the UK for sources located near these areas. This reduces exported transboundary pollution, but, associated with the occurrence of sensitive soils in hill areas, increases the domestic threat of soil acidification. The simulation of plume rise using individual stack parameters for each point source demonstrates a high sensitivity of SO₂ surface concentration to effective source height. This emphasises the importance of using site-specific information for each major stack, which is rarely included in regional atmospheric pollution models, due to the difficulty in obtaining the required input data. The simulations quantify how the fraction of emitted SO_x exported from the UK increases with source magnitude, effective source height and easterly location. The modelled reduction in SO_x emissions, between 2003 and 2010 resulted in a smaller fraction being exported, with the result that the reductions in SO_x deposition to the UK are less than proportionate to the emission reduction. This non-linearity is associated with a relatively larger fraction of the SO₂ being converted to sulphate aerosol for the 2010 scenario, in the presence of ammonia. The effect results in less-than-proportional UK benefits of reducing in SO₂ emissions, together with greater-than-proportional benefits in reducing export of UK SO₂ emissions.     

Polycyclic aromatic hydrocarbon (PAH) concentrations in ambient airborne particles from local traffic and distant sources; variation of the PAH profile

The temporal and spatial dependence of the PAH profile, i.e. the relative concentrations of polycyclic aromatic hydrocarbons, was investigated for ambient airborne particles during a period with moderate photochemical air pollution. The concentrations of 14 PAH were measured; they differed in volatility, sensitivity to atmospheric chemical conversion and contributing sources. Multivariate analysis (principal-component analysis and factor analysis) revealed that temporal dependence was predominantly determined by five factors clearly linked with volatility, reactivity and sources of the PAH, the first being by far the most important. The results, therefore, indicate that volatilization, conversion and a varying contribution of local sources were the major causes of the variation of the profile with time. The contribution of local sources was investigated by comparison of samples that were taken simultaneously at three different sites, one a background site and two sites downwind of traffic. A marked site dependence was found. The comparison suggested that the differences were not only determined by sources, but also by volatilization and/or conversion during residence of the particles in the air.     

The potential for methane emissions from groundwaters of the UK

Methane (CH4) is only a trace constituent of the atmosphere but an important greenhouse gas. Although groundwater is unlikely to be a major source of atmospheric CH4, its contribution to the CH4 budget of the UK has up to now been poorly characterised. Groundwater CH4 concentrations have been measured on 85 samples from water-supply boreholes and a further eight from other miscellaneous water sources. Concentrations in abstracted groundwaters ranged from <0.05-42.9 microg/l for Chalk, <0.05-22 microg/l for the Lower Greensand, 0.05-21.2 microg/l for the Lincolnshire Limestone and from <0.05-465 microg/l for the Triassic sandstone. Having the largest abstraction volume, the Chalk is likely to be the main UK groundwater contributor to global CH4 emissions. A calculation to estimate the total emissions of CH4 from water-supply groundwater sources based on the median and the maximum CH4 concentrations gave values of 2.2x10(-6) and 3.3x10(-4) Tg/year. Estimates show groundwater contributes a maximum of 0.05% of all UK CH4 emissions and a further two orders of magnitude less in terms of the global CH4 budget. Other groundwater sources such as inflows to tunnels may have significantly higher CH4 concentrations, but the volume of water discharged is much lower and the overall amount of CH4 outgassed is likely to be of the same order as the aquifer release. The generally low concentrations of CH4 in groundwater supplies suggest no threat of explosion, although groundwater released by excavations remains a hazard.     

Measurement and source identification of polycyclic aromatic hydrocarbons (PAHs) in the aerosol in Xi'an, China, by using automated column chromatography and applying positive matrix factorization (PMF)

In this study, we measured polycyclic aromatic hydrocarbons (PAHs) in aerosols in Xi'an, China from 2005 to 2007, by using a modified Soxhlet extraction followed by a clean-up procedure using automated column chromatography followed by HPLC/fluorescence detection. The sources of PAHs were apportioned by using the positive matrix factorization (PMF) method. The PM₁₀ concentration in winter (161.1 ± 66.4 μg m^− 3, n = 242) was 1.5 times higher than that in summer (110.9 ± 34.7 μg m^− 3, n = 248). ΣPAH concentrations, which are the sum of the concentrations of all detected PAHs, in winter (344.2 ± 149.7 ng m^− 3, n = 45) was 2.5 times higher than that in summer (136.7 ± 56.7 ng m^− 3, n = 24) in this study. These strong seasonal variations in atmospheric PAH concentration are possibly due to coal combustion for residential heating. According to the source apportionment with PMF method in this study, the major sources of PAHs in Xi'an are categorized as (1) mobile sources such as vehicle exhaust that constantly contribute to PAH pollution, and (2) stationary sources such as coal combustion that have a large contribution to PAH pollution in winter.     

A comparison of the UK Standard Assessment Procedure and detailed simulation of solar energy systems for dwellings

The drive to reduce worldwide carbon emissions that are directly associated with dwellings and to achieve a zero carbon home dictates that renewable energy technologies will have an increasingly large role in the built environment. The Standard Assessment Procedure (SAP), formulated by the Building Research Establishment (BRE), is the UK Government's approved methodology for assessing the energy ratings of dwellings. This article presents an evaluation of the advantage given to SAP ratings by the domestic installation of typical photovoltaic (PV) and solar domestic hot-water (SDHW) systems in the UK. Comparable PV and SDHW systems will also be simulated with more detailed modelling packages. Results suggest that calculation variances can exist between the SAP methodology and detailed simulation methods, especially for higher performance systems that deviate from the default efficiency parameters.     

Source apportionment of PAHs in sediments using factor analysis by time records: application to Lake Michigan, USA

Apportionment of sources of polycyclic aromatic hydrocarbons (PAHs) by a factor analysis model based on time records for seven sediment cores from central Lake Michigan is reconsidered to provide a more quantitative treatment, and one additional factor (source). The effect of mixing depth was observed on the unmixed fluxes, and a computer program was developed for estimation of the average PAH fluxes from the reconstructed PAH records. The new factor analysis model with nonnegative constraints includes not only scaling but also back scaling which improved the source apportionment significantly. One core, CLM-A, was an outlier and was omitted from the analysis. Wood burning was identified as a third major source of PAHs in the area (20% of the total PAH flux). The other two sources petroleum (traffic), 45%, and coal (coke oven emissions), 35%, became more apparent, where the contributions are based on the sum of concentrations of 16 PAH compounds. A reduced mixing depth (1.0-1.5cm) was found to be more appropriate than the originally estimated mixing depth (1.5-2.0cm).     

The sedimentary fluxes of polycyclic aromatic hydrocarbons in the Yangtze River Estuary coastal sea for the past century

Polycyclic aromatic hydrocarbons (PAHs) in two (210)Pb dated sediment cores from the coastal East China Sea, strongly influenced by the discharge from the Yangtze River, were determined to help to reconstruct the economic development over the past century in East China. The variations in PAH concentrations and fluxes in the sediment cores were primarily due to energy structure change, severe floods and dam construction activities. The impact on PAHs by the river discharge overwhelmed the atmospheric depositions. The profiles of PAH fluxes and concentrations as well as compositions in the cores revealed the transformation from an agricultural economy to an industrial one especially after the 1990s' in the region. PAHs in the study area were dominated by pyrolytic sources.     

Variations in vanadium, nickel and lanthanoid element concentrations in urban air

The emission of trace metal pollutants by industry and transport takes place on a scale large enough to alter atmospheric chemistry and results in measurable differences between the urban background of inhalable particulate matter (PM) in different towns. This is particularly well demonstrated by the technogenic release into the atmosphere of V, Ni, and lanthanoid elements. We compare PM concentrations of these metals in large datasets from five industrial towns in Spain variously influenced by emissions from refinery, power station, shipping, stainless steel, ceramic tiles and brick-making. Increased La/Ce values in urban background inhalable PM, due to La-contamination from refineries and their residual products (fuel oils and petcoke), contrast with Ce-rich emissions from the ceramic related industry, and clearly demonstrate the value of this ratio as a sensitive and reliable tracer for many point source emissions. Similarly, anomalously high V/Ni values (> 4) can detect the influence of nearby high-V petcoke and fuel oil combustion, although the use of this ratio in urban background PM is limited by overlapping values in natural and anthropogenic materials. Geochemical characterisation of urban background PM is a valuable compliment to the physical monitoring of aerosols widely employed in urban areas, especially given the relevance of trace metal inhalation to urban health issues.     

Organic compounds of PM2.5 in Mexico Valley: spatial and temporal patterns, behavior and sources

A longitudinal study on spatial and temporal behavior of particles less than 2.5 μm (PM_2.5), solvent extracted organic matter (SEOM), polycyclic aromatic hydrocarbons (PAH), n-alkanes and nitro-PAH was carried out for a full year in 2006, at five sites simultaneously around the Metropolitan Zone of Mexico Valley (MZMV). There is rather uniform distribution of PM_2.5 and SEOM in the MZMV regarding gravimetric mass concentration, while some specific organic chemical components showed mass heterogeneity. The highest mass concentrations of target compounds occurred in the dry seasons with respect to the rainy season. Bonfires and fireworks are probably responsible for extreme values of PM_2.5, SEOM and PAH (≥ 228 g mol^− 1). Benzo[ghi]perylene was the most abundant PAH, with C₂₄-C₂₆ the most abundant n-alkanes and 2-nitrofluoranthene and 9-nitroanthracene the most abundant nitro-PAH. The northeast zone was the area with the greatest presence of sources of incomplete diesel combustion, while the central for gasoline combustion. In the southwest, the biogenic sources were more abundant over the anthropogenic sources. This was opposite to the other sites. Factor analysis allowed us to relate different compounds to emitting sources. Three main factors were associated with combustion, pyrolysis and biogenic primary sources while the other factors were associated with secondary organic aerosol formation and industry. Correlation analyses indicated that SEOM originates from different primary emission sources or is formed by different processes than the other variables, except in southwest. Associations among variables suggest that PM_2.5 in the northwest and in the southeast originated mainly from primary emissions or consisted of primary organic compounds. PM_2.5 in the northeast, central and southwest contains a greater proportion of secondary organic compounds, with the less oxidized organic aerosols in the northeast and the most aged organic aerosol in the southwest. This follows the trends in the prevailing wind directions in MZMV during 2006.     

Atmospheric mercury in Norway: contributions from different sources

The environmental loadings of national Norwegian mercury emissions compared to the loadings of atmospheric long range transported mercury have been estimated using national emission data and EMEP model data. The results indicate that atmospheric long-range transport to Norway is somewhat larger than the national Norwegian emissions of mercury. Atmospheric deposition of mercury has been studied using data from Norwegian monitoring programs on mercury in precipitation, mosses, natural surface soils, and lake sediments. Precipitation data show no significant time trend during 1990-2002, whereas moss samples show similar concentrations from 1985 to 1995, but a 30% decrease from 1995 to 2000. Concentrations of mercury in peat cores and reference sediments indicate that the current mercury levels measured in surface sediments, surface soils and mosses at background sites in Norway are substantially affected by long-range atmospheric transport.