NILU - Norwegian Institute for Air Research, the FRAM Centre, P.O. Box 6606, Langnes, NO-9296 Tromsø, Norway; UiT - the Arctic University of Norway, P.O. Box 6050, Langnes, NO-9037 Tromsø, Norway.
NILU - Norwegian Institute for Air Research, P.O. Box 100, NO-2027 Kjeller, Norway.
Sci Total Environ. 2018 Jan 15;612:129-137. doi: 10.1016/j.scitotenv.2017.08.217. Epub 2017 Sep 1.
Ambient air is a core medium for monitoring of persistent organic pollutants (POPs) under the Stockholm Convention and is used in studies of global transports of POPs and their atmospheric sources and source regions. Still, data based on active air sampling remain scarce in many regions. The primary objectives of this study were to (i) monitor concentrations of selected POPs in air outside West Africa, and (ii) to evaluate potential atmospheric processes and source regions affecting measured concentrations. For this purpose, an active high-volume air sampler was installed on the Cape Verde Atmospheric Observatory at Cape Verde outside the coast of West Africa. Sampling commenced in May 2012 and 43 samples (24h sampling) were collected until June 2013. The samples were analyzed for selected polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB) and chlordanes. The concentrations of these POPs at Cape Verde were generally low and comparable to remote sites in the Arctic for several compounds. Seasonal trends varied between compounds and concentrations exhibited strong temperature dependence for chlordanes. Our results indicate net volatilization from the Atlantic Ocean north of Cape Verde as sources of these POPs. Air mass back trajectories demonstrated that air masses measured at Cape Verde were generally transported from the Atlantic Ocean or the North African continent. Overall, the low concentrations in air at Cape Verde were likely explained by absence of major emissions in areas from which the air masses originated combined with depletion during long-range atmospheric transport due to enhanced degradation under tropical conditions (high temperatures and concentrations of hydroxyl radicals).
大气环境是《斯德哥尔摩公约》下监测持久性有机污染物（POPs）的核心介质，用于研究 POPs 的全球传输及其大气来源和源区。然而，在许多地区，基于主动空气采样的数据仍然很少。本研究的主要目的是：(i)监测西非以外地区空气中选定 POPs 的浓度，(ii)评估影响测量浓度的潜在大气过程和源区。为此，在西非海岸外的佛得角大气观测站安装了一个主动式大容量空气采样器。采样于 2012 年 5 月开始，至 2013 年 6 月共采集了 43 个样本（24 小时采样）。这些样本用于分析选定的多氯联苯（PCBs）、多溴二苯醚（PBDEs）、六氯苯（HCB）和氯丹。佛得角的这些 POPs 浓度通常较低，与北极的偏远地区相比，几种化合物的浓度相当。几种化合物的季节性趋势不同，氯丹的浓度与温度有很强的相关性。我们的结果表明，北大西洋佛得角北部的大气团处于净挥发状态，是这些 POPs 的来源。大气团后向轨迹表明，在佛得角测量的大气团通常是从大西洋或北非大陆输送过来的。总的来说，佛得角空气中的低浓度可能是由于大气团起源地区没有主要排放源，以及在热带条件下（高温和羟基自由基浓度高），长距离大气传输过程中由于增强的降解作用而导致的损耗所致。
