Woodruff T J, Axelrad D A, Caldwell J, Morello-Frosch R, Rosenbaum A
U.S. Environmental Protection Agency, Washington, DC 20460, USA.
Environ Health Perspect. 1998 May;106(5):245-51. doi: 10.1289/ehp.98106245.
Occupational and toxicological studies have demonstrated adverse health effects from exposure to toxic air contaminants. Data on outdoor levels of toxic air contaminants have not been available for most communities in the United States, making it difficult to assess the potential for adverse human health effects from general population exposures. Emissions data from stationary and mobile sources are used in an atmospheric dispersion model to estimate outdoor concentrations of 148 toxic air contaminants for each of the 60,803 census tracts in the contiguous United States for 1990. Outdoor concentrations of air toxics were compared to previously defined benchmark concentrations for cancer and noncancer health effects. Benchmark concentrations are based on standard toxicological references and represent air toxic levels above which health risks may occur. The number of benchmark concentrations exceeded by modeled concentrations ranged from 8 to 32 per census tract, with a mean of 14. Estimated concentrations of benzene, formaldehyde, and 1,3-butadiene were greater than cancer benchmark concentrations in over 90% of the census tracts. Approximately 10% of all census tracts had estimated concentrations of one or more carcinogenic HAPs greater than a 1-in-10,000 risk level. Twenty-two pollutants with chronic toxicity benchmark concentrations had modeled concentrations in excess of these benchmarks, and approximately 200 census tracts had a modeled concentration 100 times the benchmark for at least one of these pollutants. This comprehensive assessment of air toxics concentrations across the United States indicates hazardous air pollutants may pose a potential public health problem.
职业和毒理学研究表明，接触有毒空气污染物会对健康产生不利影响。美国大多数社区都没有关于有毒空气污染物室外水平的数据，因此难以评估一般人群接触这些污染物对人类健康产生不利影响的可能性。利用固定源和移动源的排放数据，通过大气扩散模型估算了1990年美国本土60803个人口普查区中148种有毒空气污染物的室外浓度。将空气有毒物质的室外浓度与先前确定的癌症和非癌症健康影响的基准浓度进行了比较。基准浓度基于标准毒理学参考值，代表可能产生健康风险的空气有毒物质水平。每个普查区超过基准浓度的数量在8至32之间，平均为14。在超过90%的普查区中，苯、甲醛和1,3 - 丁二烯的估计浓度高于癌症基准浓度。所有普查区中约10%的区域，一种或多种致癌性有害空气污染物的估计浓度超过了万分之一的风险水平。22种具有慢性毒性基准浓度的污染物，其模型浓度超过了这些基准，约200个人口普查区至少有一种此类污染物的模型浓度是基准浓度的100倍。这项对美国空气有毒物质浓度的全面评估表明，有害空气污染物可能构成潜在的公共卫生问题。
