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During the 2003 Chinese Arctic Research Expedition (CHINARE2003) from the Bohai Sea to the high Arctic (37°N-80°N), filter-based particle samples were collected and analyzed for tracers of primary and secondary organic aerosols (SOA) as well as water-soluble organic carbon (WSOC). Biomass burning (BB) tracer levoglucosan had comparatively much higher summertime average levels (476 ± 367pg/m3) during our cruise due to the influence of intense forest fires then in Siberia. On the basis of 5-day back trajectories, samples with air masses passing through Siberia had organic tracers 1.3-4.4 times of those with air masses transporting only over the oceans, suggesting substantial contribution of continental emissions to organic aerosols in the marine atmosphere. SOA tracers from anthropogenic aromatics were negligible or not detected, while those from biogenic terpenenoids were ubiquitously observed with the sum of SOA tracers from isoprene (623 ± 414pg/m3) 1 order of magnitude higher than that from monoterpenes (63 ± 49 pg/m3). 2-Methylglyceric acid as a product of isoprene oxidation under high-NOx conditions was dominant among SOA tracers, implying that these BSOA tracers were not formed over the oceans but mainly transported from the adjacent Siberia where a high-NOx environment could be induced by intense forest fires. The carbon fractions shared by biogenic SOA tracers and levoglucosan in WSOC in our ocean samples were 1-2 orders of magnitude lower than those previously reported in continental samples, BB emissions or chamber simulation samples, largely due to the chemical evolution of organic tracers during transport. As a result of the much faster decline in levels of organic tracers than that of WSOC during transport, the trace-based approach, which could well reconstruct WSOC using biogenic SOA and BB tracers for continental samples, only explained ~4% of measured WSOC during our expedition if the same tracer-WSOC or tracer-SOC relationships were applied. [ABSTRACT FROM AUTHOR]

During the 2003 Chinese Arctic Research Expedition (CHINARE2003) from the Bohai Sea to the high Arctic (37° N to 80° N) aboard the icebreaker Xuelong (Snow Dragon), air samples were collected for the analysis of hexachlorocyclohexanes (HCHs) in the North Pacific Ocean and adjacent Arctic region. The ΣHCHs (α-HCH + γ-HCH) ranged from 2.3 to 95.1 pg/m³ with the highest levels observed in Far East Asia (32.5 pg/m³), followed by the North Pacific Ocean (17.0 pg/m³) and the Arctic (7.3 pg/m³). Compared to previous studies in the same areas in 1990s, our measurements were approximately 1 order of magnitude lower. Because of disproportionate chemical reduction and physical fractioning during long-range transport, the ratios of α-HCH to γ-HCH (α/γ-HCH) showed a significant increasing trend from low to high latitudes, suggesting that the α/γ-HCH range of 4-7 could not be used to identify sources of technical HCHs especially in remote areas. The ratios of (+)-α-HCH to the sum of (+)-α-HCH and (-)-α-HCH were on average much more biased from 0.5 compared to previous observations in mid-1990s, indicating the exchange of atmospheric α-HCH with those in the oceans, where (+)-α-HCH was selectively depleted in biological degradation processes. Estimated fugacity ratios based on available data for both α-HCH and γ-HCH further implied their net volatilization from seawater to air in the Arctic Ocean. [ABSTRACT FROM AUTHOR]

In July to September 2003, particulates in the oceanic atmosphere from the Bohai Sea to the high Arctic (37 °N to 80 °N) were collected aboard a research expedition icebreaker, Xuelong(Snow Dragon), under the 2003 Chinese Arctic Research Expedition Program (CHINARE 2003). These samples were analyzed to elucidate the atmospheric distributions of polybrominated diphenyl ethers (PBDEs) in the North Pacific Ocean and adjacent Arctic region. The levels of 11 PBDE congeners (BDE-28, -47, -66, -100, -99, -85, -154, -153, -138, -183, and -209; the sum was defined as Σ11PBDE) in the oceanic atmosphere of Far East Asia (34- 48 °N/122-148 °E) ranged from 2.25 to 198.9 pg/m³ with a mean of 58.3 pg/m³. BDE-47, -99, -100, and -209 were the dominant congeners in all the samples, suggesting that the widely used commercial penta- and deca-BDE products were the original sources. The PBDE levels exhibited a decreasing trend from the mid- to high-latitudinal regions of the North Pacific Ocean, probably resulting from dilution, deposition, and decomposition of PBDEs during long- range transport of air masses. On the other hand, no apparent geographical pattern of PBDE distribution was observed within the Arctic, attributable to unstable air circulation and strong air mixing. Correlations among the PBDE congeners suggested that air masses collected from the North Pacific Ocean were relatively fresh, whereas those from the Arctic were aged as a result of photode- composition. The higher average level (17.3 pg/m³) of PBDE congeners in the Arctic than those in the adjacent North Pacific Ocean (12.8 pg/m³) or other remote areas reported in the literature was attributed to the impact of the North American continent and temperature effects, which was consistent with the hypotheses of global fractionation. [ABSTRACT FROM AUTHOR]