Caldwell J C, Woodruff T J, Morello-Frosch R, Axelrad D A
U.S. Environmental Protection Agency Office of Air and Radiation, Research Triangle Park, North Carolina 27711, USA
Toxicol Ind Health. 1998 May-Jun;14(3):429-54. doi: 10.1177/074823379801400304.
Relatively little is known about the spectrum of health effects, and the scope and level of ambient air concentrations of those pollutants regulated under the Clean Air Act as "hazardous air pollutants". The U.S. Environmental Protection Agency's (USEPA) Cumulative Exposure Project uses currently available emissions inventories, from a variety of source types, and an atmospheric dispersion model to provide estimates of ambient concentrations for 148 hazardous air pollutants (HAPs) in over 60,000 census tracts for the year 1990. This paper uses currently available hazard information for those pollutants and provides a database of potential regulatory threshold concentrations of concern, or "benchmark concentrations," and a methodology for prioritizing and characterizing the quality of the data. In order to demonstrate application of the database and prioritization scheme to outputs from the Cumulative Exposure Project, comparisons were made with the maximum modeled concentration of each individual hazardous air pollutant across the census tracts. Of the 197 benchmark concentrations for cancer and non-cancer (long- and short-term exposures) effects compiled for the study, approximately one half were exceeded with a predominance of exceedance of cancer benchmarks. While the number of benchmark concentrations available to fully characterize potential health effects of these pollutants was limited (approximately 80 percent of HAPs identified as cancer concerns had benchmark concentrations for cancer and 50 percent of all HAPs had non-cancer benchmark concentrations) and there was greater uncertainty in derivation of maximum modeled air concentrations than other levels, the comparison between the two was a useful approach for providing an indication of public health concern from hazardous air pollutants.
对于健康影响的范围，以及《清洁空气法》规定为“有害空气污染物”的那些污染物的环境空气浓度范围和水平，人们了解得相对较少。美国环境保护局（USEPA）的累积暴露项目利用目前可得的来自各种源类型的排放清单以及大气扩散模型，来估算1990年60000多个普查区中148种有害空气污染物（HAPs）的环境浓度。本文利用了目前可得的这些污染物的危害信息，提供了一个潜在的关注监管阈值浓度（即“基准浓度”）数据库，以及一种对数据质量进行排序和表征的方法。为了展示该数据库和排序方案在累积暴露项目输出结果中的应用，对各个普查区中每种有害空气污染物的最大模拟浓度进行了比较。在为该研究汇编的197个癌症和非癌症（长期和短期暴露）影响的基准浓度中，大约有一半被超过，其中超过癌症基准的情况占主导。虽然可用于全面表征这些污染物潜在健康影响的基准浓度数量有限（被确定为癌症关注对象的HAPs中约80%有癌症基准浓度，所有HAPs中有50%有非癌症基准浓度），并且最大模拟空气浓度的推导比其他水平存在更大的不确定性，但两者之间的比较是一种有用的方法，可用于表明有害空气污染物对公众健康的影响。
