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首页> 外文期刊>Atmospheric environment >Variability of concentrations of polybrominated diphenyl ethers and polychlorinated biphenyls in air: implications for monitoring, modeling and control
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Variability of concentrations of polybrominated diphenyl ethers and polychlorinated biphenyls in air: implications for monitoring, modeling and control

机译：空气中多溴联苯醚和多氯联苯浓度的变化：对监测，建模和控制的意义

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摘要

Monitoring data indicate that organic compounds with high octanol-air partition coefficients (K_(OA)), such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) exhibit seasonally variable air concentrations, especially during early spring, shortly after snow melt and before bud-burst when levels are elevated. This variability can complicate the interpretation of monitoring data designed to assess year-to-year changes. It is suggested that relatively simple dynamic multimedia mass balance models can assist interpretation by "factoring out" variability attributable to temperature and other seasonal effects as well as identifying likely contaminant sources. To illustrate this approach, high-volume air samples were collected from January to June, 2002 at a rural location in southern Ontario. Gas-phase concentrations for both ∑PBDE and ∑PCB rose from below the detection limit during the winter to 19 and 110pgm~(-3), respectively, in early spring, only to decrease again following bud-burst. Passive air samples (PAS), deployed at seven urban, rural and remote sites for two one-month periods prior and following bud-burst, indicate a strong urban-rural gradient for both the PBDEs and PCBs. Calculated air concentrations from the PAS are shown to agree favorably with the high-volume air sampling data, with concentrations ranging 6-85 pg m~(-3) and 6-360 pg m~(-3) for ∑PBDE and ∑PCB, respectively. Concentrations in urban areas are typically 5 times greater than in rural locations. These data were interpreted using simulation results from a fate model including a seasonally variable forest canopy and snow pack, suggesting that the primary source is urban and that the "spring pulse" is the result of several interacting factors. Such contaminants are believed to be efficiently deposited in winter, accumulate in the snow pack and are released to terrestrial surfaces upon snow melt in spring. Warmer temperatures cause volatilization and a rise in air concentrations until uptake in emerging foliage leads to a decline in late spring. Implications for monitoring are discussed.
机译：监测数据表明，具有高辛醇-空气分配系数（K_（OA））的有机化合物，例如多溴联苯醚（PBDEs）和多氯联苯（PCBs），表现出季节性变化的空气浓度，尤其是在早春期间，融雪后不久和在发芽前，当水平升高时。这种可变性会使旨在评估逐年变化的监视数据的解释变得复杂。建议相对简单的动态多媒体质量平衡模型可以通过“排除”可归因于温度和其他季节性影响的可变性以及识别可能的污染源来辅助解释。为了说明这种方法，2002年1月至2002年6月在安大略省南部的农村地区收集了大量空气样本。 ∑PBDE和∑PCB的气相浓度从冬季的检测极限以下分别上升到早春的19和110pgm〜（-3），仅在芽爆发后才降低。被动空气样本（PAS）在爆发前和爆发后的两个月内部署在七个城市，农村和偏远地区，这表明多溴二苯醚和多氯联苯均具有很强的城乡梯度。结果表明，通过PAS计算出的空气浓度与高容量空气采样数据吻合良好，其中∑PBDE和∑PCB的浓度范围为6-85 pg m〜（-3）和6-360 pg m〜（-3）。 ， 分别。城市地区的浓度通常是农村地区的5倍。这些数据是使用命运模型的模拟结果解释的，该模型包括季节性变化的森林冠层和积雪，表明主要来源是城市，而“春季脉冲”是几个相互作用因素的结果。据信这种污染物在冬天有效地沉积，积聚在积雪中，并在春季融雪时释放到地面。温暖的温度会导致挥发，空气中的浓度会升高，直到新叶的吸收导致春末下降。讨论了监视的含义。

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