基于分级化学组成的室内外颗粒物来源解析和健康风险评价

In most megacities of China, the persistence and severity of haze events have resulted in widespread public concern of atmospheric particulate matter (PM) pollution. And PM is among the most important pollutants which negatively affect human health. The health risk of PM mainly related to its chemical composition and size distributions, whereas the previous studies mainly focused on single particle fractions (PM2.5 or PM10). Meanwhile, concentrations of PM at outdoor sites were usually used to represent the overall exposure levels. To fill these gaps, the size distributions of chemical species (i.e., water-soluble ions, carbonaceous species and elements) in both indoor and outdoor particles during extreme haze events in different seasons will be investigated by two cascade impactors in urban Beijing. We will compare the size distribution differences of chemical species between indoor and outdoor particles and explore the interaction of them. Exposure levels of particles in different size fractions will be calculated based on both indoor and outdoor data. In order to reduce the health risks of particles, source apportionment of particles in different size fractions will be carried out during haze events. This study will provide a comprehensive and accurate awareness of health risks of particulate matter during haze pollution and will help policy-makers design emission control strategies and can serve as a database for future field measurements and modeling studies.

近些年来，我国城市和区域霾污染频发使颗粒物的健康危害日益受到关注。以往针对颗粒物的健康影响评估主要基于室外观测结果，但居民在室内度过的时间超过80%，忽略室内污染的研究不能全面科学地评估大气颗粒物的健康风险。本研究拟综合评估室内外空气中颗粒物的浓度关系、主要来源和健康风险，在室内外同步采用安德森分级撞击式采样器采集分级颗粒物样品，进行离子、元素碳和有机碳、无机元素和有机物分类的化学分析。在此基础上，（1）利用I/O值分析霾和非霾天气条件下室内外不同粒径段颗粒物及其化学组成的浓度关系特征；（2）利用回归分析评估室外污染物进入室内的渗透系数，结合PMF源解析进行室内颗粒物的定量来源解析；（3）应用人群的时间地点活动模式等信息求得人群对室内外环境加权总暴露值。这将为室内外污染物相关性的数值模拟结果验证和颗粒物的人体健康风险评价提供数据支持，同时为治理污染源和降低人体健康风险提供科学依据。

近些年来，我国城市和区域霾污染频发使颗粒物的健康危害日益受到关注。以往针对颗粒物的健康影响评估主要基于室外观测结果，但居民在室内度过的时间超过80%，忽略室内污染的研究不能全面科学地评估大气颗粒物的健康风险。本研究综合评估了室内外空气中颗粒物的浓度关系、主要来源和健康风险，在室内外同步采用安德森分级撞击式采样器采集分级颗粒物样品，进行离子、元素碳和有机碳、无机元素的化学分析。在此基础上，（1）利用I/O值分析霾和非霾天气条件下室内外不同粒径段颗粒物及其化学组成的浓度关系特征。夏季各化学组成的I/O值变化范围为0.50-1.19，平均值为0.87；EC、SNA、Cr、Co等金属元素的I/O值较低，表明室内颗粒物中的这些化学组成主要来源于室外颗粒物贡献；冬季TSP各化学组成的I/O值变化范围为0.36-1.17，平均值为0.70，低于夏季的I/O值。（2）利用回归分析评估室外污染物进入室内的渗透系数，结合PMF源解析进行颗粒物的定量来源解析；二次无机气溶胶、燃煤、机动车一次排放、生物质燃烧、工业排放和矿物尘，它们对细颗粒物的贡献分别为26.1%、19%、5.9%、8.5%、6.3%和16.1%；对粗颗粒物的贡献分别为9.5%、23.6%、8.0%、2.9%、8.5%和35.1%。六个来源的贡献比例在霾污染天与非霾天存在显著差异，其霾污染天与非霾天贡献比值从高到低依次为二次无机气溶胶 (细颗粒物中为10.7 vs. 粗颗粒物中为7.4)、燃煤 (3.2 vs.1.7)、机动车一次排放 (2.5 vs. 4.1)、生物质燃烧 (2.3 vs. 3.5)、矿物尘(0.7 vs. 1.0) 和工业排放(0.6 vs. 0.6)。（3）应用人群的时间地点活动模式等信息求得人群对室内外环境加权总暴露值。冬季室内、冬季室外、夏季室内、夏季室外四种情况的致癌风险最高值均出现在1.1–2.1μm。而非致癌风险的最高值出现在0.65-1.1μm，其中冬季室内元素的非致癌风险在1.1-2.1μm最高。这将为室内外污染物相关性的数值模拟结果验证和颗粒物的人体健康风险评价提供数据支持，同时为治理污染源和降低人体健康风险提供科学依据。