Transport and chemical composition of the summer aerosol in the Norwegian Arctic

The chemical composition and transfer routes of the Arctic aerosol during summer have been studied at Ny-Alesund, Bjørnøya, Hopen and Jan Mayen in the period August/September 1983. Samples were also collected on mainland Norway to assess the origin of aerosols transported to the Norwegian Arctic. The concentrations of Si, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Pb, Zn and Cu were measured in samples from a six-stage cascade impactor of Battelle design by particle-induced X-ray emissions (PIXE). The concentrations of Cd, Ni, Pb and Zn were also measured in samples from high-volume samplers by atomic absorption spectrophotometry (AAS).Three interesting periods were identified from the element concentrations. At the beginning of the measurement campaign, the air pollutants measured at Ny-Alesund and Hopen most likely originated in northern America and Greenland. A few days later, very high concentrations of Cd and Zn at Ny-Alesund seemed to be due to air mass transfer from the Soviet Union. During the last episode, observed at Ny-Alesund and Hopen in September, elevated concentrations of several anthropogenic pollutants appeared to be due to emissions in Europe.The results show that anthropogenic emissions from sources in western Europe, Eurasia and northern America may pollute the Arctic air not only in winter but in summer as well. Present levels of air pollutants in the Norwegian Arctic in summer are within the range of levels observed in other remote regions, but are one order of magnitude higher than in Antarctica.     

Observations of Arctic haze during polar flights from Alaska to Norway

Arctic haze observed during polar flights from Anchorage, Alaska, to Thule, Greenland, and Thule to Bodo, Norway, during March 1983, was widespread over the entire Arctic region flown. The distribution of this haze exhibited strong horizontal and vertical variability resulting from the synopticmeteorological situations encountered: e.g. the presence of fronts and haze transport zones. Condensation nuclei concentrations of about 500 cm⁻³ and aerosol scattering extinction values of about 4 × 10⁻⁵m⁻¹ were typical for Arctic haze layers. Intrusions of stratospheric air into the Arctic troposphere through tropopause folds were observed twice, suggesting that these events might occur quite frequently in the springtime Arctic atmosphere.     

The aerosol at Barrow,Alaska: long-term trends and source locations

Aerosol data consisting of condensation nuclei (CN) counts, black carbon (BC) mass, aerosol light scattering (SC), and aerosol optical depth (AOD) measured at Barrow, Alaska from 1977 to 1994 have been analyzed by three-way positive matrix factorization (PMF3) by pooling all of the different data into one large three-way array. The PMF3 analysis identified four factors that indicate four different combinations of aerosol sources active throughout the year in Alaska. Two of the factors (F1, F2) represent Arctic haze. The first Arctic haze have factor F1 is dominant in January–February while the second factor F2 is dominant in March–April. They appear to be material that is generally ascribed to long-range transported anthropogenic particles. A lower ratio of condensation nuclei to scattering coefficient loadings is obtained for F2 indicating larger particles. Factor F3 is related to condensation nuclei. It has an annual cycle with two maxima, March and July–August indicating some involvement of marine biogenic sources. The fourth factor F4 represents the contribution to the stratospheric aerosol from the eruptions of El Chichon and Mt. Pinatubo. No significant long-term trend for F1 was detected while F2 shows a negative trend over the period from 1982 to 1994 but not over the whole measurement period. A positive trend of F3 over the whole period has been observed. This trend may be related to increased biogenic sulfur production caused by reductions in the sea-ice cover in the Arctic and/or an air temperature increase in the vicinity of Barrow. Potential source contribution function (PSCF) analysis showed that in winter and spring during 1989 to 1993 regions in Eurasia and North America are the sources of particles measured at barrow. In contrast to this, large areas in the North Pacific Ocean and the Arctic Ocean was contributed to observed high concentrations of CN in the summer season. Three-way positive matrix factorization was an effective method to extract time-series information contained in the measured quantities. PSCF was useful for the identification possible source areas and the potential pathways for the Barrow aerosol. The effects of long-distance transport, photochemical aerosol production, emissions from biogenic activities in the ocean, volcanic eruptions on the aerosol measurements made at Barrow were extracted using this combined methodology.     

Influence of arctic haze on the solar radiation budget

Comparison of reported measurements of the change in the direct and total hemispheric solar irradiances at Barrow, Alaska between days with and without visible haze with values computed from aerosol models with different imaginary parts of the refractive index leads to the conclusion that the haze is only weakly absorbing. Using the value of the single scattering albedo deduced from the comparison the reduction in the effective local planetary albedo of the Arctic due to Arctic haze is estimated to be about 0.03.     

A study of winter variability in carbon dioxide and Arctic haze aerosols at Barrow,Alaska

Relationships among atmospheric CO₂ concentration, excess sulfate and vanadium, and meteorological analyses for one winter at Barrow, Alaska were investigated. The results provided a basis for understanding the causes of short term CO₂ variability. The study indicated that peaks in CO₂ concentration were related to direct atmospheric transport of industrial pollutants from Eurasia. Evidence that background Arctic concentrations contained a pollution component was also found. Lowest CO₂ concentrations occurred with intrusions of Pacific air above the surface-based polluted Arctic air mass.     

Air mass characteristics in the vicinity oF Barrow,Alaska, 9–19 March 1983

The synoptic conditions over the Alaskan Arctic during the Arctic Gas and Aerosol Sampling Program (AGASP) of March 1983 are described. Air mass characteristics are pictured in terms of meteorological parameters, condensation nuclei, ozone and CO₂ concentrations, aerosol size and number distributions, and aerosol scattering coefficients, as measured at the Barrow Geophysical Monitoring for Climatic Change (GMCC) baseline station and by aircraft Latitude-altitude cross sections of meteorological and aerosol parameters indicated both strong vertical and horizontal variability within the Arctic air mass. Aerosol concentrations aloft were usually higher than those measured at the ground and peak-to-peak variations are greater aloft than at the surface, showing that the stable Arctic boundary layer reduces mixing from aloft to the surface. Thus, surface measurements cannot be extrapolated to higher levels in a straightforward manner. Horizontal variability in the haze, as determined by the aircraft, was found to be abrupt and was not generally due to the presence of strong meteorological fronts. During 9–19 March 1983, at least four different air mass types were present in the Barrow region, each of which was characterized by distinct meteorological, aerosol and trace gas characteristics.     

Aircraft measurements of air pollution in the norwegian arctic

Physical properties, particle size distribution and chemical composition of the Arctic aerosol aloft have been studied to assess the origin of polluted layers of the Arctic air. Four measurement campaigns were made with the NILU aircraft during the period March 1983–JuIy 1984. Evidence of very long range transport of air masses to the Arctic is presented for summer and winter conditions. These polluted air masses are observed at higher altitudes (> 1.5 km). The layers of polluted air at lower altitudes are believed to be due to episodes of air mass transport from emission areas with a temperature similar to that in the Arctic in winter, and from local sources in summer. However, further aircraft measurements are needed to support these preliminary results.     

Estimates of springtime soot and sulfur fluxes entering the Arctic troposphere: Implications to source regions

A box model calculation is used to make preliminary estimates of the springtime fluxes of carbon and sulfur particles into the Arctic troposphere. These fluxes are large and can only be accounted for by major sulfur and soot sources. Comparison of these fluxes with the amount of fuel burned in various latitude bands indicates that the Arctic haze cannot be due to Arctic sources and strongly suggests that the dominant source regions are below 60°N latitude. Comparisons of Arctic sulfur fluxes with sulfur emissions on a regional and global basis indicate that significant fractions enter the Arctic.     

A direct simulation of hemispherical transport of pollutants

The seasonal fate of pollutant emissions from eastern North America, Europe and East Asia during 1974 is examined via 850 mbar forward trajectories of 20 days duration. Simple pure-decay kinetic scenarios are presented for atmospheric residence times of 5 and 10 days to illustrate the spatial extent of the continental plumes. The 20-day cutoff scenario is segregated by source region, indicating mean flow. The simulated potential impact at Barrow, Alaska indicates an annual pattern which resembles measured sulfate and haze patterns, with an anomalous August peak. Apparently European, and especially North American, plumes are unlikely to reach Barrow during May-September, but both appear to contribute to winter haze in the Arctic.     

Anthropogenic pollutants in the Russian Arctic atmosphere: sources and sinks in spring and summer

The 5-day forward and backward trajectories of air mass transport to three Russian Arctic points for each day in April and July over a 10-year period from 1986 to 1995 have been analyzed. The important features and seasonal differences in air exchange processes in various areas of the Arctic have been investigated. Taking into account seasonal variations in aerosol scavenging mechanisms and velocities, the average contributions of large highly industrialized regions of the Russian Arctic air pollution were estimated for April and July. Reasonable correspondence between the calculated mean concentrations for six anthropogenic chemical elements (As, Ni, Pb, V, Zn, Cd) and experimentally determined values have been obtained. The atmospheric pollution transport from the Arctic was studied as yet another way of cleaning the Arctic atmosphere, in addition to the traditionally considered wet and dry depositions onto the surface. The average apportionment of conservative contaminants after passing the observation points was estimated for spring and summer. The air masses passing through the observation points in spring may take about 20–40% of pollutants out of the Arctic. In summer, however, more than 90% of pollutants transported into the Russian Arctic deposit within 5 days onto the surface inside the Arctic region. The monthly average fluxes of six anthropogenic elements onto the surface in the Russian Arctic were estimated for April and July.     

Multi-year measurements of polybrominated diphenyl ethers (PBDEs) in the Arctic atmosphere

Weekly high-volume air samples have been collected in the Canadian High Arctic (Alert, Nunavut) since 1992. Fifteen polybrominated diphenyl ethers (PBDEs) are quantified in 104 samples over the time period of 2002–2004. To our knowledge, this study reports the first continuous multi-year measurements of PBDEs in Arctic air. Average air concentrations (in pg m⁻³) were 7.7 (0.40–47) and 1.6 (0.091–9.8) for 14 PBDEs (excluding BDE-209) and BDE-209, respectively, over the entire sampling period. BDE-28/33, 47, 99, 100, 153, 154, and 209 accounted for 90% (72–97%, n=104) of the 15 PBDEs. Occurrence of BDE-47, 99, and 209 suggests that PBDEs in Alert air were likely associated with the usage of “penta-BDE” and “deca-BDE” technical mixtures worldwide. Natural logarithm of concentrations for less brominated PBDEs correlated significantly with ambient temperatures in the summertime, suggesting importance of volatilization emissions in a local and/or regional scale. On the other hand, episodically elevated concentrations of the less brominated PBDEs in the wintertime and lack of seasonality for the non-volatile BDE-209 indicate potential inputs of particle-bound PBDEs through long-range transport (LRT), especially during the Arctic haze season. Inter-annual trend data further show that concentrations of the eight PBDEs increased inter-annually in 2002–2004 with doubling times of 2–6 years, which were similar to growth rates found in Arctic biotic samples. The results of this study and previous measurements suggest that potential sources of PBDEs in Arctic air include both volatilization emissions and LRT inputs.     

Airborne co2 measurements in the Arctic during spring 1983

A set of flask air samples collected from aircraft in March and April 1983 during the Arctic Gas and Aerosol Sampling Program has been analyzed for CO₂ concentration. The results show CO₂ variations of several ppm in the Arctic troposphere, and qualitative agreement with measurements made on air samples collected at the surface. The CO₂ measurements together with air-mass characteristics determined during the flights show that CO₂ concentrations in the Arctic result from mixing of polluted air transported into the Arctic from lower latitudes with cleaner air of maritime and continental origins. The CO₂ concentration is found to increase or decrease with altitude which is probably dependent on the details of transport and the presence or absence of marine sources and/or sinks.     

Levels and trends of brominated flame retardants in the Arctic

Polybrominated diphenyl ethers (PBDEs) containing two to seven bromines are ubiquitous in Arctic biotic and abiotic samples (from zooplankton to polar bears (Ursus maritimus) and humans; air, soil, sediments). The fully brominated decabromodiphenyl ether (BDE-209), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA) and polybrominated biphenyls (PBBs) are also present in biotic and abiotic samples. Spatial trends of PBDEs and HBCD in top predators are similar to those seen for polychlorinated biphenyls (PCBs) and indicate western Europe and eastern North America as source regions. Concentrations of tetra- to heptaBDEs have increased significantly in North American and Greenlandic Arctic biota and in Greenland freshwater sediments paralleling trends seen further south. For BDE-209, increasing concentrations in Greenlandic peregrine falcons (Falco peregrinus) and in dated lake sediment cores in the Canadian Arctic have been seen during the 1990s. BDE-47, -99, -100 and -153 are observed to biomagnify in Arctic food webs. summation operatorPBDE concentrations in Arctic samples are lower than in similar sample types from more southerly regions and are one or more orders of magnitude lower than summation operatorPCB concentrations except for some levels for air. Air and harbor sediment results for PBDEs indicate that there are local sources near highly populated areas within the Arctic. Findings of PBBs on moss and TBBPA on an air filter, and that both are found in biota at high trophic levels indicates that these compounds may also reach the Arctic by long-range atmospheric transport. Based on the evidence of their presence in the Arctic and indications that most if not all are undergoing long-range transport, these brominated flame retardants (BFRs) have characteristics that qualify them as POPs according to the Stockholm Convention.     

Horizontal inhomogeneities in the particulate carbon component of the Arctic haze

We present results obtained during the ‘AGASP 1983’ Arctic haze aircraft sampling experiment. During this program we operated the aethalometer, an instrument that responds to the aerosol graphitic (‘black’) carbon concentration in real time. Previous results showed strong vertical layering of this component of the Arctic haze. In this paper we present for the first time evidence of horizontal variations of aerosol black carbon concentration. Some of these variations correlate with meteorological parameters, but we also observed horizontal inhomogeneities with a characteristic scale of 50–100 km occurring in the absence of meteorological activity.     

Planetary-wave behavior and Arctic air pollution

An attempt has been made to relate episodes of air pollution at Barrow, Alaska, containing vanadium, to the behavior of planetary waves in middle and high latitudes. A stationarity index for planetary waves is defined as the ratio between amplitudes computed from monthly mean maps and the mean amplitudes computed on a daily basis and averaged over the same month, irrespective of phase angle. Longitude-time sections of 500 mb height anomalies at various latitudes are related to vanadium pollution episodes at Barrow.     

Atmospheric polycyclic aromatic hydrocarbons observed over the North Pacific Ocean and the Arctic area: Spatial distribution and source identification

During the 2003 Chinese Arctic Research Expedition from the Bohai Sea to the high Arctic (37–80°N) aboard the icebreaker Xuelong (Snow Dragon), air samples were collected using a modified high-volume sampler that pulls air through a quartz filter and a polyurethane foam plug (PUF). These filters and PUFs were analyzed for particulate phase and gas phase polycyclic aromatic hydrocarbons (PAHs), respectively, in the North Pacific Ocean and adjacent Arctic region. The ∑PAHs (where ∑=15 compounds) ranged from undetectable level to 4380 pg m⁻³ in the particulate phase and 928–92 600 pg m⁻³ in the gas phase, respectively. A decreasing latitudinal trend was observed for gas-phase PAHs, probably resulting from temperature effects, dilution and decomposition processes; particulate-phase PAHs, however, showed poor latitudinal trends, because the effects of temperature, dilution and photochemistry played different roles in different regions from middle-latitude source areas to the high latitudes. The ratios of PAH isomer pairs, either conservative or sensitive to degradation during long-range transport, were employed to interpret sources and chemical aging of PAHs in ocean air. In this present study the fluoranthene/pyrene and indeno[123-cd]pyrene/benzo[ghi]pyrene isomer pairs, whose ratios are conservative to photo-degradation, implies that biomass or coal burning might be the major sources of PAHs observed over the North Pacific Ocean and the Arctic region in the summer. The isomer ratios of 1,7/(1,7+2,6)-DMP (dimethylphenanthrene) and anthracene/phenanthrene, which are sensitive to aging of air masses, not only imply chemical evolving of PAHs over the North Pacific Ocean were different from those over the Arctic, but reveal that PAHs over the Arctic were mainly related to coal burning, and biomass burning might have a larger contribution to the PAHs over the North pacific ocean.     

Arctic air pollution: An overview of current knowledge

From December to April, the Arctic air mass is polluted by man-made mid-latitudinal emissions from fossil fuel combustion, smelting and industrial processes. In the rest of the year, pollution levels are much lower. This is the outcome of less efficient pollutant removal processes and better south (S) to north (N) transport during winter. In winter, the Arctic air mass covers much of Eurasia and N. America. Meteorological flow fields and the distribution of anthropogenic SO₂ emissions in the northern hemisphere favor northern Eurasia as the main source of visibility reducing haze. Observations of SO₄²⁻ concentrations in the atmosphere throughout the Arctic yield, depending on location and year, a January–April mean of 1.5–3.9 μg m⁻³ in the Norwegian Arctic to 1.2–2.2 μg m⁻³ in the N. American Arctic. An estimate of the mean vertical profile of fine particle aerosol mass during March and April shows that, on average, pollution is concentrated in the lower 5 km of the atmosphere. Not only are anthropogenic particles present in the Arctic atmosphere but also gases such as SO₂, perfluorocarbons and pesticides. The acidic nature and seasonal variation of Arctic pollution is reflected in precipitation, the snowpack and glacier snow in the Arctic. A pH of 4.9–5.2 in winter and ~ 5.6 in summer is expected in the absence of calcareous wind blown soil. Glacial records indicate that Arctic air pollution has undergone a marked increase since the mid 1950s paralleling a marked increase in SO₂ and NO_x emissions in Europe. Effects of Arctic pollution include a reduction in visibility and perturbation of the solar radiation budget in April–June. Potential effects are the acidification and toxification of sensitive ecosystems.     

Organochlorine contaminant and stable isotope profiles in Arctic fox (Alopex lagopus) from the Alaskan and Canadian Arctic

Arctic fox (Alopex lagopus) is a circumpolar species distributed across northern Canada and Alaska. Arctic fox muscle and liver were collected at Barrow, AK, USA (n=18), Holman, NT, Canada (n=20), and Arviat, NU, Canada (n=20) to elucidate the feeding ecology of this species and relate these findings to body residue patterns of organochlorine contaminants (OCs). Stable carbon (delta 13C) and nitrogen (delta 15N) isotope analyses of Arctic fox muscle indicated that trophic position (estimated by delta 15N) is positively correlated with increasing delta 13C values, suggesting that Arctic fox with a predominantly marine-based foraging strategy occupy a higher trophic level than individuals mostly feeding from a terrestrial-based carbon source. At all sites, the rank order for OC groups in muscle was polychlorinated biphenyls (Sigma PCB) > chlordane-related compounds (Sigma CHLOR) > hexachlorocyclohexane (Sigma HCH) > total toxaphene (TOX) > or = chlorobenzenes (Sigma ClBz) > DDT-related isomers (Sigma DDT). In liver, Sigma CHLOR was the most abundant OC group, followed by Sigma PCB > TOX > Sigma HCH > Sigma ClBz > Sigma DDT. The most abundant OC analytes detected from Arctic fox muscle and liver were oxychlordane, PCB-153, and PCB-180. The comparison of delta 15N with OC concentrations indicated that relative trophic position might not accurately predict OC bioaccumulation in Arctic fox. The bioaccumulation pattern of OCs in the Arctic fox is similar to the polar bear. While Sigma PCB concentrations were highly variable, concentrations in the Arctic fox were generally below those associated with the toxicological endpoints for adverse effects on mammalian reproduction. Further research is required to properly elucidate the potential health impacts to this species from exposure to OCs.     

Local Arctic air pollution: Sources and impacts

Local emissions of Arctic air pollutants and their impacts on climate, ecosystems and health are poorly understood. Future increases due to Arctic warming or economic drivers may put additional pressures on the fragile Arctic environment already affected by mid-latitude air pollution. Aircraft data were collected, for the first time, downwind of shipping and petroleum extraction facilities in the European Arctic. Data analysis reveals discrepancies compared to commonly used emission inventories, highlighting missing emissions (e.g. drilling rigs) and the intermittent nature of certain emissions (e.g. flaring, shipping). Present-day shipping/petroleum extraction emissions already appear to be impacting pollutant (ozone, aerosols) levels along the Norwegian coast and are estimated to cool and warm the Arctic climate, respectively. Future increases in shipping may lead to short-term (long-term) warming (cooling) due to reduced sulphur (CO₂) emissions, and be detrimental to regional air quality (ozone). Further quantification of local Arctic emission impacts is needed.     

Sulphur in the Arctic environment (1): results of a catchment-based multi-medium study.

S-concentrations were determined in 9 different sample materials (precipitation (rain and snow), vegetation, O-, E-, B- and C- horizon pf podzols, streams water and ground water) collected in eight small catchments (10-30 km2) at different distances from major SO2 point-source emitters on the Kola Peninsula, Russia. Comparison of the results from these materials, representing different compartments of the ecosystems under varying natural conditions leads to a better understanding of sources, cycling and fate of S in the Arctic environment. More than 300,000 t of SO2 emitted annually from the Kola smelters affect the air quality over a large area. Arctic climatic conditions (cold and dry) and the remote location of the emitters results in considerably lower S-deposition values than those observed in central Europe. The pathways of atmospheric S-deposition in the terrestrial environment vary significantly from summer to winter because different compartments of the ecosystems, with a different capability to accumulate S, are active. The actual S-flux is altered by every component of the ecosystem. When estimating the total S-deposition this effect must be considered.