Brunekreef B, Dockery D W, Krzyzanowski M
Department of Epidemiology and Public Health, University of Wageningen, Netherlands.
Environ Health Perspect. 1995 Mar;103 Suppl 2(Suppl 2):3-13. doi: 10.1289/ehp.95103s23.
Since the development of the World Health Organization (WHO) Air Quality Guidelines for Europe, a large number of epidemiologic studies have been published documenting effects of major air pollutants on health at concentrations below existing guidelines and standards. In this review, recent studies are discussed that permit some evaluation of short-term health effects observed at exposure levels lower than the current WHO Guidelines or U.S. Environmental Protection Agency (U.S. EPA) standards. Some studies have been conducted at concentration levels that never exceeded existing guidelines or standards. Other studies have been conducted at exposure levels sometimes exceeding current guidelines or standards. The published analyses of several of these studies permit evaluation of low-level health effects either because analyses were restricted to levels not exceeding the guidelines or graphic analyses were reported suggesting effects at these low levels. For ambient ozone, effects on lung function of subjects exercising outdoors have now been documented at 1-hr maximum levels not exceeding 120 micrograms/m3, i.e., half the current U.S. EPA standard. One study even suggests that such effects occur at levels below 100 micrograms/m3. Several studies are now available documenting effects of particulate air pollution on health in the virtual absence of SO2. Effects on mortality and hospital admissions for asthma have been documented at levels not exceeding 100 micrograms/m3, expressed as 24-hr average inhalable particles PM10 concentration. Effects on lung function, acute respiratory symptoms, and medication use have been found at 24-hr average PM10 levels not exceeding 115 micrograms/m3. When the WHO Air Quality Guidelines and the U.S. EPA standard for PM10 were developed, there were no studies available on health effects of PM10. In this review, we include nine studies documenting health effects of measured PM10 at low levels of exposure, indicating that there is now an entirely new epidemiologic database that can be evaluated in the process of revising current guidelines and standards. The low levels of exposure at which effects on health were seen underscore the urgent need for such reevaluations.
自世界卫生组织（WHO）欧洲空气质量指南发布以来，大量流行病学研究相继发表，记录了主要空气污染物在低于现有指南和标准的浓度下对健康的影响。在本综述中，将讨论近期的研究，这些研究使得对低于当前WHO指南或美国环境保护局（U.S. EPA）标准的暴露水平下观察到的短期健康影响进行某种评估成为可能。一些研究是在从未超过现有指南或标准的浓度水平下开展的。其他研究则是在有时超过当前指南或标准的暴露水平下进行的。对其中几项研究已发表的分析使得对低水平健康影响的评估成为可能，这要么是因为分析仅限于不超过指南的水平，要么是因为报告了图表分析表明在这些低水平存在影响。对于环境臭氧，现已证明在1小时最大水平不超过120微克/立方米（即当前美国EPA标准的一半）时，对户外锻炼的受试者的肺功能有影响。一项研究甚至表明，在低于100微克/立方米的水平时就会出现这种影响。现在有几项研究记录了在几乎不存在二氧化硫的情况下，颗粒物空气污染对健康的影响。已证明在不超过100微克/立方米（以24小时平均可吸入颗粒物PM10浓度表示）的水平时，对死亡率和哮喘住院率有影响。在24小时平均PM10水平不超过115微克/立方米时，发现对肺功能、急性呼吸道症状和药物使用有影响。在制定WHO空气质量指南和美国EPA的PM10标准时，尚无关于PM10对健康影响的研究。在本综述中，我们纳入了九项记录低暴露水平下实测PM10对健康影响的研究，这表明现在有了一个全新的流行病学数据库，可在修订当前指南和标准的过程中进行评估。观察到对健康有影响的低暴露水平凸显了进行此类重新评估的迫切需求。
