多环芳烃及其杂原子衍生物源解析中的气/颗粒分配影响与校正

Polycyclic aromatic hydrocarbons and their alkyl-, N-, O- and S- substituted derivatives (polycyclic aromatic compounds, PACs) are major toxic organic compounds in the atmosphere. Accurate source apportionment of PACs and their toxicity is of great importance for protecting public health. As semi-volatile compounds (SVOCs), appreciable concentations and toxicities of PACs exist in the gas phase. The gas/particle partitioning of PACs and organic molecular marker (MM) is a crucial factor influencing the accuracy of the source apportionment of PACs and their toxicity. In this study, a typical urban area in the southern China will be selected as the receptor site. Based on extensive collection of or utilizing measured domestic gas and particle phase source profiles and screening of effective MM and diagnostic ratios, as well as systematic measurement of gas and particle phase concentrations of PACs and organic MM in different atmospheric conditions, the characteristics of and main influencing factors on the gas/particle partitiong of each SVOCs will be investigated. Applicable partitioning models for nonpolar, weak polar and polar SVOCs will be screened from various single- or polyparameter linear free energy relationships models. After comparison of three solutions, i.e. measured particle, measured particle+measured gas (real value) and measured particle+predicted gas (corrected value) by recepor models (PMF and CMB), and respective results coupled with toxic equivalency factors of PACs, the impact of gas/particle partitioning on the source apportionment of PACs and their toxicity and the correction effectiveness of each partitioning model will be explored.

多环芳烃及其烷基、含N、O和S衍生物（PACs）是大气主要毒害有机物。准确解析其来源对保护公众健康至关重要。作为半挥发有机物（SVOCs），PACs有可观的含量和毒性存在于气相中。PACs和有机分子标志物（MM）的气/颗粒分配是影响PACs及其毒性源解析准确性的关键因素。本项目拟选取我国南方典型城区作为受体点，在重点收集或利用实测国内气/颗粒两相源谱并筛选有效MM及其比值的基础上，通过对不同大气环境条件下PACs和有机MM气/颗粒两相浓度的实测，研究各SVOCs的分配特征及主要影响因素；从多种单/多参数线性自由能关系模型中筛选适合模拟非极性、弱极性和极性SVOCs气相浓度的分配模型；对比颗粒相、颗粒+实测气相（真实值）和颗粒+模拟气相（校正值）三种方案PACs受体模型（PMF和CMB）源解析结果及其与毒性当量因子的耦合结果，探讨两相分配对PACs及其毒性源解析的影响和各分配模型的校正效果。

多环芳烃及其衍生物（PACs）是大气典型毒害有机物，对公众健康具有重要影响。然而当前PACs源解析主要依赖于颗粒相数据，而忽略半挥发有机物（SVOCs）气/颗粒分配的影响，使得估算各类源对PACs及其毒性的贡献存在不同程度的偏差。本项目在目标SVOCs筛选、两相SVOCs分析测试方法优化、SVOCs两相分配及其影响因素、SVOCs两相分配对PACs及其毒性源解析的影响和分配模型校正效果评估方面开展研究。主要结果如下：.1. 通过对比大量生物质燃烧、燃煤、机动车、烹饪、烟草烟气源谱中PACs组成及诊断比值的差异，揭示了烷基化PACs增强源区分度的潜力。综合考虑SVOCs气/颗粒浓度、毒性因子、主要来源，确定了目标物。.2. 经过实验条件优化，建立了一套气/颗粒两相多种非极性/极性SVOCs同步分析方法，并应用于目标物实测。.3. 观测期间，2-3环PACs气相占比较大，5环以上PACs颗粒相占比较大，而4环PACs气相和颗粒相占比接近；SVOCs气/颗粒分配受其自身物理化学性质、颗粒物组分、大气环境状况重要影响；对于PACs，吸收作用可能比吸附作用更重要；分配模型模拟效果对比显示吸收模型更适合模拟PACs的气/颗粒分配。.4. 气/颗粒分配对PACs毒性评估以及定性和定量源解析均有较大影响。基于实测数据估算的PACs毒性当量浓度（BaPeq）和呼吸致癌风险（ICR）在气相和颗粒相中具有相近的数值。只考虑颗粒相的PACs及其毒性源解析显著低估生物质燃烧的贡献，而高估燃煤和机动车的贡献。经吸附模型和吸收模型校正的PACs源贡献与实测值校正的结果均较为接近，但相比吸附模型，吸收模型校正的BaPeq源贡献与实测值校正结果更为接近。