From the Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA.
Epidemiology. 2018 Mar;29(2):165-174. doi: 10.1097/EDE.0000000000000777.
Despite dramatic air quality improvement in the United States over the past decades, recent years have brought renewed scrutiny and uncertainty surrounding the effectiveness of specific regulatory programs for continuing to improve air quality and public health outcomes.
We employ causal inference methods and a spatial hierarchical regression model to characterize the extent to which a designation of "nonattainment" with the 1997 National Ambient Air Quality Standard for ambient fine particulate matter (PM2.5) in 2005 causally affected ambient PM2.5 and health outcomes among over 10 million Medicare beneficiaries in the Eastern United States in 2009-2012.
We found that, on average across all retained study locations, reductions in ambient PM2.5 and Medicare health outcomes could not be conclusively attributed to the nonattainment designations against the backdrop of other regional strategies that impacted the entire Eastern United States. A more targeted principal stratification analysis indicates substantial health impacts of the nonattainment designations among the subset of areas where the designations are estimated to have actually reduced ambient PM2.5 beyond levels achieved by regional measures, with noteworthy reductions in all-cause mortality, chronic obstructive pulmonary disorder, heart failure, ischemic heart disease, and respiratory tract infections.
These findings provide targeted evidence of the effectiveness of local control measures after nonattainment designations for the 1997 PM2.5 air quality standard.
尽管美国在过去几十年里空气质量有了显著改善，但近年来，针对特定监管计划继续改善空气质量和公共卫生成果的有效性，人们重新进行了审查并产生了不确定性。
我们采用因果推理方法和空间层次回归模型，来描述 2005 年美国 1997 年国家环境空气质量标准（NAAQS）对细颗粒物（PM2.5）不达标的指定，在多大程度上对 2009 年至 2012 年间美国东部超过 1000 万医疗保险受益人的环境 PM2.5 和健康结果产生了因果影响。
我们发现，在所有保留的研究地点中，平均而言，在考虑到影响整个美国东部的其他区域策略的背景下，环境 PM2.5 和医疗保险健康结果的减少，不能归因于不达标的指定。更有针对性的主要分层分析表明，在指定区域估计实际降低了环境 PM2.5 水平，超出了区域措施所达到的水平的地区中，不达标的指定对健康有重大影响，所有原因死亡率、慢性阻塞性肺疾病、心力衰竭、缺血性心脏病和呼吸道感染均有显著减少。
这些发现为 1997 年 PM2.5 空气质量标准不达标的指定后地方控制措施的有效性提供了有针对性的证据。
