中文摘要：

大气细颗粒物暴露与肺癌和心血管疾病及其死亡率增加的因果关系，已经在过去几十年欧美国家所开展的长期研究中得到确认．但是，细颗粒物是空气动力学直径小于或等于2．5pm的所有颗粒的统称，包括对消光、致霾贡献很大的亚微米颗粒物和纳米级的小颗粒物（〈100nm，超细颗粒物）．以质量浓度（即颗粒物的重量）测量，细颗粒物中微米尺度颗粒物的浓度最大；但以颗粒物数浓度（即颗粒物的数目）测量，超细颗粒物的浓度最大．与大尺寸的颗粒物相比，超细颗粒物具有不同的吸附能力、表面化学反应能力、分散与团聚能力等．长期以来，由于缺乏有效的研究手段和方法，科学家们只能推测雾霾中的超细颗粒物有可能是雾霾健康损害的主要贡献者．近年来，伴随着纳米科技的迅速发展，纳米毒理学得以兴起并受到广泛关注．尽管大气超细颗粒物的成分、尺寸等远比人造纳米颗粒复杂，但是，纳米毒理学所建立的实验技术和方法学可以在二者的研究中共享．本文根据过去15年发展起来的纳米毒理学的研究方法和获得的知识，从毒理学研究角度针对雾霾超细（纳米级）颗粒物在肺部的沉积和吸收、呼吸系统急性毒性反应、清除、炎症反应等健康效应，以及心血管系统对超细颗粒物的急性毒性反应等进行了分析和讨论，并针对我国雾霾特征提出了开展雾霾超细颗粒物健康效应系统研究的优先方向．

英文摘要：

Recently, the heavy haze weather frequently attacked the majority of Chinese cities throughout the country. Research results have shown clear associations between short-term or long-term exposure to ambient fine particles （FPs, PM2.5） and the increased incidence and mortality of cardiovascular or respiratory diseases. However, the ambient ultrafine particles （UFPs, PM0.1） are dominant contributors to particle number in haze weather. Compared with FPs, UFPs could be inhaled and deposited more deeply into the lung, and may carry more toxicants and poses larger interface with biological systems. So, it has been proposed that UFPs are more harmful to human health than bigger ones, and their health effects warrant further comprehensive assessment. In the last decade, nanotoxicology has been developed quickly. By taking advantage of new conception, new knowledge and methodology from nanotoxicology studies, we here discuss comprehensively the UFPs＇ health effects on respiratory and cardiovascular systems. We also try to identify the further research priorities and provide suggestions when studying health effects of ambient UFP in China： （1） systematic study of associations between physicochemical characteristics of ambient UFPs （such as resources, components, structures, sizes, surface, interface, et al.） and health effects, especially associations among chemical conversion, biological behavior, toxicological response and underlying mechanisms; （2） systematic appreciation of small-size-effects, surface effects, interface effects, multi- component synergistic effects and effects of multiple weak interactions for ambient UFPs; （3） systematic assessment of health effects of ambient UFPs on potential susceptible populations （for example, children, the elderly and patients with cardiovascular and pulmonary diseases） and relevant triggering mechanisms; （4） systematic establishment of analytical methods and technologies for health effects studies, especially development of integrated source