ABSTRACT

Ambient ozone measurements are often used as surrogates for personal exposures. Due to the limited number of central ozone monitors and varying personal behavioral patterns, some level of variability between ambient and personal exposures is expected. Low-cost sensors and different ways to capture personal activity patterns are being developed as an effort to improve the accuracy of exposure assessment. However, it is still most common to use the traditional approach of using unadjusted ambient concentrations as surrogates for personal exposures. To our knowledge, there has not been a meta-analysis that summarizes the findings from studies that investigated the differences between personal and ambient ozone. We conducted a literature search in PubMed and Science Direct for peer-reviewed studies reporting at least one of the following in a numeric format: 1) personal-ambient measurements, 2) personal-ambient slopes, or 3) personal-ambient correlations to identify and summarize existing studies that investigated personal and ambient ozone concentrations. Twenty-two articles met inclusion criteria and were included in our review. Ambient concentrations almost always overestimated personal exposures. A meta-analysis of slopes showed an overall personal-ambient slope of 0.21 (95% CI: 0.15, 0.27) with high heterogeneity (97%) across studies. The correlations between personal and ambient ozone varied dramatically across subjects from a strong positive (0.77) to a moderate negative correlation (−0.43). Our study found that ambient measurements are not accurate representations of personal exposure, while the magnitude of exposure measurement error varied across studies. Different sources of ozone and how they contribute to true exposure levels for individuals in complementary ways need to be better addressed. The effort to better understand the impact of traditional exposure assessment on the risk estimates must be emphasized along with efforts to improve the current exposure assessment approaches to provide context for interpreting the results from ozone epidemiological studies.

Implications: The traditional approach of using ambient ozone measurements as surrogates for personal exposures is likely to result in exposure misclassification, which is a well-recognized source of bias in epidemiological studies. There are efforts to characterize the differences between ambient and personal ozone measurements, though, to our knowledge, there has not been a meta-analysis that summarizes the findings of different studies. Better understanding of the pattern and magnitude of exposure error for ambient and personal ozone can provide directions for future studies and context for interpreting the results from ozone epidemiological studies.

摘要

环境臭氧测量通常用作个人暴露的替代指标。由于中央臭氧监测仪数量有限和个人行为模式不同，预计环境和个人暴露之间存在一定程度的可变性。低成本传感器和捕捉个人活动模式的不同方法正在开发中，以提高暴露评估的准确性。然而，使用未经调整的环境浓度作为个人暴露的替代品的传统方法仍然是最常见的。据我们所知，还没有一项荟萃分析总结调查个人和环境臭氧之间差异的研究结果。我们在 PubMed 和 Science Direct 中进行了文献检索，以查找以数字格式报告至少以下一项的同行评审研究：1) 个人环境测量，2) 个人环境斜率，或 3) 个人环境相关性以识别并总结调查个人和环境臭氧浓度的现有研究。22 篇文章符合纳入标准，并被纳入我们的审查。环境浓度几乎总是高估个人暴露。对斜率的荟萃分析显示，总体个人环境斜率为 0.21（95% CI：0.15, 0.27），研究间的异质性很高（97%）。个人和环境臭氧之间的相关性在受试者之间变化很大，从强正相关（0.77）到中等负相关（-0.43）。我们的研究发现，环境测量并不能准确代表个人暴露，而暴露测量误差的幅度因研究而异。需要更好地解决不同的臭氧来源以及它们如何以互补的方式对个人的真实暴露水平做出贡献。必须强调努力更好地理解传统暴露评估对风险估计的影响，同时努力改进当前的暴露评估方法，为解释臭氧流行病学研究结果提供背景。

影响：使用环境臭氧测量作为个人暴露替代物的传统方法可能会导致暴露错误分类，这是流行病学研究中公认的偏差来源。有人努力描述环境和个人臭氧测量之间的差异，但据我们所知，还没有荟萃分析总结不同研究的结果。更好地了解环境和个人臭氧暴露误差的模式和幅度可以为未来的研究和解释臭氧流行病学研究结果的背景提供方向。