中文摘要：

挥发性羰基化合物（cVOC）是大气光化学反应形成臭氧和灰霾等空气污染现象的重要前体物。超大城市是带动中国城市群快速发展的中心城市，经济发达，人口密集且数量超过1000万。在这些超大城市的大气环境中检出21种cVOC化合物，其总浓度年均值达55．6μg／m3，含量之高惊人。由于机动车尾气、工业排放、有机溶剂大量使用等原因，导致甲醛、乙醛、丙酮等三种健康危险物占据了中国城市大气cVOC总浓度的62．4％。采用日暴露水平、致癌风险和风险商等3种定量评价指标，发现北京、上海和广州大气环境中cVOC含量超标严重，具有较高的健康影响风险。在举办奥运会、亚运会和世博会等大型国际活动期间，中国式的空气质量保障运动仅能起到短期内缓解空气污染的疗效，但是难以长治久安。中国城市大气cVOC的健康风险问题应引起高度重视。

英文摘要：

Carbonyl-containing volatile organic compounds （cVOCs） are important precursors of atmospheric photochemical reactions in the formation of ozone, smog and other air pollutants. China＇s megacities are economically developed and densely populated metropolitan areas, usually with a population over ten million; they drive the rapid growth of surrounding urban clusters. So far, 21 cVOCs have been detected in the atmosphere of these megacities. The average annual total concentration of cVOCs is 55.6 μg/m^3, an alarmingly high level. Vehicle emissions, industrial discharges, excessive use of organic solvents and other factors have led to a situation where hazardous formaldehyde, acetaldehyde and acetone account for 62.4 percent of the total atmospheric concentration of cVOC in Chinese cities. In a quantitative evaluation using daily exposure levels, cancer risk and hazardquotient, we found that the excessive levels of atmospheric cVOCs in Beijing, Shanghai and Guangzhou pose serious health risks to their inhabitants. Air pollution persists, despite the brief improvements in air quality brought about by the air quality campaign undertaken during major intemational events like the 2008 Olympic Games, the 2010 Asian Games, and the 2010 World Expo. The health risks caused by atmospheric cVOCs in Chinese cities require close attention.