Increasing evidence suggests that ambient air pollution is a major risk factor for both acute and chronic respiratory disease exacerbations and emergencies. The objective of this study was to determine the association between ambient air pollutants and emergency department (ED) visits for respiratory conditions in nine districts across the province of Ontario in Canada. Health, air pollutant (PM_2.5, NO₂, O₃, and SO₂), and meteorological data were retrieved from April 2004 to December 2011. Respiratory diseases were categorized as: chronic obstructive pulmonary disease (COPD, including bronchiectasis) and acute upper respiratory diseases. A case-crossover design was used to test the associations between ED visits and ambient air pollutants, stratified by sex and season. For COPD among males, positive results were observed for NO₂ with lags of 3–6 days, for PM_2.5 with lags 1–8, and for SO₂ with lags of 4–8 days. For COPD among females, positive results were observed for O₃ with lags 2–4 days, and for SO₂ among lags of 3–6 days. For upper respiratory disease emergencies among males, positive results were observed for NO₂ (lags 5–8 days), for O₃, (lags 0–6 days), PM_2.5 (all lags), and SO₂ (lag 8), and among females, positive results were observed for NO₂ for lag 8 days, for O₃, PM_2.5 among all lags. Our study provides evidence of the associations between short-term exposure to air pollution and increased risk of ED visits for upper and lower respiratory diseases in an environment where air pollutant concentrations are relatively low.

越来越多的证据表明，环境空气污染是急性和慢性呼吸系统疾病恶化和紧急情况的主要危险因素。这项研究的目的是确定加拿大安大略省9个地区的环境空气污染物与急诊室（ED）的呼吸状况之间的联系。健康，空气污染物（PM _2.5，NO ₂，O ₃和SO ₂），并从2004年4月至2011年12月检索了气象数据。呼吸系统疾病分类为：慢性阻塞性肺疾病（COPD，包括支气管扩张）和急性上呼吸道疾病。案例交叉设计用于测试按性别和季节分层的急诊就诊与周围空气污染物之间的关联。对于男性中的COPD，NO ₂滞后3-6天，PM _2.5滞后1-8，SO ₂滞后4-8天，观察到阳性结果。对于女性中的COPD，O ₃滞后2-4天观察到阳性结果，而SO ₂在3-6天滞后观察到阳性结果。对于男性中的上呼吸道疾病紧急情况，未观察到阳性结果₂（滞后5-8天），O ₃（滞后0-6天），PM _2.5（所有滞后）和SO ₂（滞后8），在女性中，滞后8的NO ₂观察到阳性结果天，对于O ₃，PM _2.5在所有滞后中。我们的研究提供了证据，表明在空气污染物浓度相对较低的环境中，短期暴露于空气污染与上，下呼吸道疾病的急诊就​​诊风险增加之间存在关联。