Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON K1A 0K9, Canada.
Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON K1H 8L6, Canada.
Int J Environ Res Public Health. 2018 Sep 17;15(9):2029. doi: 10.3390/ijerph15092029.
: An oil refinery in Oakville, Canada, closed over 2004⁻2005, providing an opportunity for a natural experiment to examine the effects on oil refinery-related air pollution and residents' health. : Environmental and health data were collected for the 16 years around the refinery closure. Toronto (2.5 million persons) and the Greater Toronto Area (GTA, 6.3 million persons) were used as control and reference populations, respectively, for Oakville (160,000 persons). We compared sulfur dioxide and age- and season-standardized hospitalizations, considering potential factors such as changes in demographics, socio-economics, drug prescriptions, and environmental variables. : The closure of the refinery eliminated 6000 tons/year of SO₂ emissions, with an observed reduction of 20% in wind direction-adjusted ambient concentrations in Oakville. After accounting for trends, a decrease in cold-season peak-centered respiratory hospitalizations was observed for Oakville (reduction of 2.2 cases/1000 persons per year, p = 0.0006 ) but not in Toronto = 0.856) and the GTA = 0.334). The reduction of respiratory hospitalizations in Oakville post closure appeared to have no observed link to known confounders or effect modifiers. : The refinery closure allowed an assessment of the change in community health. This natural experiment provides evidence that a reduction in emissions was associated with improvements in population health. This study design addresses the impact of a removed source of air pollution.
加拿大奥克维尔的一家炼油厂于 2004-2005 年关闭，为一项自然实验提供了机会，以检验炼油厂相关空气污染对居民健康的影响。
在炼油厂关闭前后的 16 年中收集了环境和健康数据。多伦多（250 万人）和大多伦多地区（630 万人）分别作为奥克维尔（16 万人）的对照和参考人群。我们比较了二氧化硫和按年龄和季节标准化的住院率，考虑了人口变化、社会经济、药物处方和环境变量等潜在因素。
炼油厂关闭消除了每年 6000 吨的二氧化硫排放，奥克维尔风向调整后的环境浓度观察到了 20%的下降。在考虑到趋势后，奥克维尔的冬季高峰中心呼吸道住院率下降（每 1000 人每年减少 2.2 例，p = 0.0006），但多伦多（p = 0.856）和大多伦多地区（p = 0.334）没有。关闭炼油厂后奥克维尔呼吸道住院率的下降似乎与已知的混杂因素或效应修饰剂无关。
炼油厂关闭使我们能够评估社区健康的变化。这项自然实验提供了证据，表明减少排放与改善人口健康有关。这种研究设计解决了去除空气污染源对健康的影响。
