Mohamed Mahmoud F, Kang Daiwen, Aneja Viney P
Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh 27695-8208, USA.
Chemosphere. 2002 Jun;47(8):863-82. doi: 10.1016/s0045-6535(02)00107-8.
Volatile organic compounds (VOCs) have been determined to be human risk factors in urban environments, as well as primary contributors to the formation of photochemical oxidants. Ambient air quality measurements of 54 VOCs including hydrocarbons, halogenated hydrocarbons and carbonyls were conducted in or near 13 urban locations in the United States during September 1996 to August 1997. Air samples were collected and analyzed in accordance with US Environmental Protection Agency-approved methods. The target compounds most commonly found were benzene, toluene, xylene and ethylbenzene. These aromatic compounds were highly correlated and proportionally related in a manner suggesting that the primary contributors were mobile sources in all the urban locations studied. Concentrations of total hydrocarbons ranged between 1.39 and 11.93 parts per billion, by volume (ppbv). Ambient air levels of halogenated hydrocarbons appeared to exhibit unique spatial variations, and no single factor seemed to explain trends for this group of compounds. The highest halogenated hydrocarbon concentrations ranged from 0.24 ppbv for methylene chloride to 1.22 ppbv for chloromethane. At participating urban locations for the year of data considered, levels of carbonyls were higher than the level of the other organic compound groups, suggesting that emissions from motor vehicles and photochemical reactions strongly influence ambient air concentrations of carbonyls. Of the most prevalent carbonyls, formaldehyde and acetaldehyde were the dominant compounds, ranging from 1.5-7.4 ppbv for formaldehyde, to 0.8-2.7 ppbv for acetaldehyde.
挥发性有机化合物（VOCs）已被确定为城市环境中的人类风险因素，也是光化学氧化剂形成的主要促成因素。1996年9月至1997年8月期间，在美国13个城市地点或其附近对包括碳氢化合物、卤代烃和羰基化合物在内的54种挥发性有机化合物进行了环境空气质量测量。空气样本按照美国环境保护局批准的方法进行采集和分析。最常检测到的目标化合物是苯、甲苯、二甲苯和乙苯。这些芳香族化合物高度相关且成比例关系，这表明在所研究的所有城市地点，主要来源是移动源。总碳氢化合物浓度范围为每十亿体积份1.39至11.93份（ppbv）。卤代烃的环境空气水平似乎呈现出独特的空间变化，而且似乎没有单一因素能够解释这组化合物的趋势。卤代烃最高浓度范围从二氯甲烷的0.24 ppbv到氯甲烷的1.22 ppbv。在所考虑数据年份的参与城市地点，羰基化合物水平高于其他有机化合物组的水平，这表明机动车排放和光化学反应对羰基化合物的环境空气浓度有强烈影响。在最普遍的羰基化合物中，甲醛和乙醛是主要化合物，甲醛浓度范围为1.5 - 7.4 ppbv，乙醛浓度范围为0.8 - 2.7 ppbv。
