辽东湾大气中多环芳烃的含量组成及气粒分配

2016年5月和8月对辽东湾大气环境中气相和颗粒相样品进行了走航和定点采集，并对24种PAHs在气相和颗粒相中的含量和组成进行探讨，对15种PAHs的气粒分配过程进行了分析.结果表明：5月和8月辽东湾大气气相和颗粒相中∑₂₄PAHs总平均含量分别为28.8 ng·m^-3和24.0 ng·m^-3，气相中∑₂₄PAHs含量5月小于8月，颗粒态∑₂₄PAHs含量5月大于8月，低分子量PAHs主要分布在气相中，高分子量PAHs组分主要分布在颗粒相，中等分子量PAHs的气粒分配更容易受到气温等环境条件影响；气粒分配系数K_p随着PAHs分子量增加而增加；lgK_p-lgP_L模型和lgK_p-lgK_OA模型的斜率m分别为-0.35和0.37，偏离平衡态m为-1或+1，辽东湾气粒分配未达到平衡；假设达到平衡态时的lgK_p-lgK_OA模型、lgK_p-lgP_L模型和碳黑-空气模型均表明，5环PAHs的模型预测结果与实际测定结果之间的吻合程度较好，15种PAHs的碳黑-空气模型能够更好地接近野外实际测定值，低分子量和中等分子量PAHs的气粒分配受到碳黑影响较大.

Occurrence and Gas-particle Partitioning of Polycyclic Aromatic Hydrocarbons in the Air of Liaodong Bay

The gas-and particle-phase polycyclic aromatic hydrocarbons (PAHs) were collected from the air of Liaodong Bay in May and August to investigate their occurrence and gas/particle distribution. The 24 PAHs were analyzed for gas-and particle-phase samples, and the concentrations of total gas-and particle-phase PAHs were found to be 28.8 ng·m^-3 and 24.0 ng·m^-3, respectively. The concentrations of the gas-phase PAHs were higher in August than in May, and the concentrations of the particle-phase PAHs were higher in May than in August. The low molecular weight PAHs were mainly distributed in the gas-phase, and the high molecular weight PAHs were mainly distributed in the particle-phase; the medium molecular weight PAHs were more easily affected by the environmental conditions than the low and high molecular weight PAHs. The value of K_p increased with an increase in the molecular weight. The slopes m for regressed lgK_p-lgP_L and lgK_p-lgK_OA plots were -0.35 and 0.37, deviated from -1 and+1 for the equilibrium states of gas/particle partitioning. The equilibrium states of the lgK_p-lgK_OA, lgK_p-lgP_L, and soot-air models were applied; the predicted results of the 5-ring PAHs fitted well with the field measure results. The predicted results of the soot-air model were much closer to the field measure results than the results of the lgK_P-lgK_OA and lgK_P-lgP_L models; compared to their heavier counterparts, the low and medium molecular weight PAHs were influenced to a greater extent by soot.