Record high peaks in PCB concentrations in the Arctic atmosphere due to long-range transport of biomass burning emissions
Record high peaks in PCB concentrations in the Arctic atmosphere due to long-range transport of biomass burning emissions
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DOI：
10.5194/acp-7-4527-2007
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发表时间：
2007-01-01
影响因子：
6.3
通讯作者：
Stohl, A.
中科院分区：
文献类型：
--
作者：
Eckhardt, S.;Breivik, K.;Stohl, A.
北半球北方地区的土壤和森林被认为具有储存空气传播的持久性有机污染物（POPs）的巨大能力，例如多氯联苯（pcb）。在各种遗留持久性有机污染物的初次排放减少之后，人们对持久性有机污染物大气水平的二次再排放的相对重要性越来越感兴趣和争论。2006年春季，东欧农业火灾产生的生物质燃烧排放物被运送到斯瓦尔巴群岛的齐柏林站，那里记录了许多空气污染物的创纪录高水平（Stohl等人，2007年）。在此，我们报告了在此期间测量到的极高浓度的多氯联苯。32个多氯联苯同系物中有21个比长期平均浓度增加了两个标准差以上。2004年7月，北美约580万公顷的北方森林被烧毁，排放出的污染羽流经过3-4周的旅行时间到达齐柏林站（Stohl et al., 2006）。同样，12种多氯联苯同系物比长期平均值高出两个标准差以上，氯化程度较低的同系物受到的影响最大。我们认为这些异常高浓度是由生物质燃烧排放引起的。根据与一氧化碳的增强比和该物种已知的排放因子，我们估计每千克干物质燃烧分别释放130和66 μ g多氯联苯。据我们所知，这是第一次将大气多氯联苯增强与生物质燃烧联系起来的研究。对远离污染源的观测浓度的强烈影响表明，生物质燃烧是大气中多氯联苯的一个重要来源。
Soils and forests in the boreal region of the Northern Hemisphere are recognised as having a large capacity for storing air-borne Persistent Organic Pollutants (POPs), such as the polychlorinated biphenyls (PCBs). Following reductions of primary emissions of various legacy POPs, there is an increasing interest and debate about the relative importance of secondary re-emissions on the atmospheric levels of POPs. In spring of 2006, biomass burning emissions from agricultural fires in Eastern Europe were transported to the Zeppelin station on Svalbard, where record-high levels of many air pollutants were recorded (Stohl et al., 2007). Here we report on the extremely high concentrations of PCBs that were also measured during this period. 21 out of 32 PCB congeners were enhanced by more than two standard deviations above the long-term mean concentrations. In July 2004, about 5.8 million hectare of boreal forest burned in North America, emitting a pollution plume which reached the Zeppelin station after a travel time of 3-4 weeks (Stohl et al., 2006). Again, 12 PCB congeners were elevated above the long-term mean by more than two standard deviations, with the less chlorinated congeners being most strongly affected. We propose that these abnormally high concentrations were caused by biomass burning emissions. Based on enhancement ratios with carbon monoxide and known emissions factors for this species, we estimate that 130 and 66 mu g PCBs were released per kilogram dry matter burned, respectively. To our knowledge, this is the first study relating atmospheric PCB enhancements with biomass burning. The strong effects on observed concentrations far away from the sources, suggest that biomass burning is an important source of PCBs for the atmosphere.