Lewtas J, Lewis C, Zweidinger R, Stevens R, Cupitt L
US Environmental Protection Agency, Research Triangle Park, NC 27711.
Pharmacogenetics. 1992 Dec;2(6):288-96. doi: 10.1097/00008571-199212000-00007.
Products of incomplete combustion are identified as a major source of carcinogenic risk in urban areas, especially those from small non-industrial sources. The major ubiquitous emission sources outdoors in populated areas are residential home heating and motor vehicles. Indoors the major combustion source is environmental tobacco smoke. Polycyclic organic matter adsorbed onto the particles emitted from incomplete combustion are estimated to make the largest contribution to human genotoxic and cancer risk. Mutagenic emission factors combined with dispersion modelling indicated that automobiles and heating sources were major sources of mutagens. Ambient air studies to apportion the sources of mutagens in non-industrial areas confirmed this prediction. To apportion and estimate the cancer risk of ambient organic matter from particles in vivo animal tumour data, receptor modelling and human exposure data were combined. Tumourigenicity studies of the source apportioned ambient organic matter provided the relative tumour potencies of two ambient samples of different source composition. The human cancer unit risks were developed based on the comparative potency method using tumour data from these ambient samples. Residential wood combustion accounted for 75% of the exposure to particle associated organics, but only 20% of the estimated cancer risk. The remaining 80% of the risk appears to be associated with the mobile source component and atmospheric transformation products from these source emissions.
不完全燃烧产物被认定为城市地区致癌风险的主要来源，尤其是来自小型非工业源的产物。人口密集地区户外主要的普遍排放源是家庭取暖和机动车。室内主要的燃烧源是环境烟草烟雾。据估计，吸附在不完全燃烧排放颗粒上的多环有机物质对人类基因毒性和癌症风险的贡献最大。致突变排放因子与扩散模型表明，汽车和热源是诱变剂的主要来源。在非工业地区进行的环境空气研究，以确定诱变剂的来源，证实了这一预测。为了在体内动物肿瘤数据中分配和估计环境有机物质颗粒的癌症风险，结合了受体模型和人类暴露数据。对来源已确定的环境有机物质的致瘤性研究，提供了两个不同来源组成的环境样品的相对肿瘤效力。基于比较效力法，利用这些环境样品的肿瘤数据，得出了人类癌症单位风险。住宅木材燃烧占与颗粒相关有机物暴露量的75%，但仅占估计癌症风险的20%。其余80%的风险似乎与移动源成分以及这些源排放的大气转化产物有关。
