Burnett R T, Brook J R, Yung W T, Dales R E, Krewski D
Health Canada, Environmental Health Center, Tunney's Pasture, Ottawa, Ontario, Canada.
Environ Res. 1997 Jan;72(1):24-31. doi: 10.1006/enrs.1996.3685.
The effects of tropospheric ozone on lung function and respiratory symptoms have been well documented at relatively high concentrations. However, previous investigations have failed to establish a clear association between tropospheric ozone and respiratory diseases severe enough to require hospitalization after controlling for climate, and with gaseous and particulate air pollution at the lower concentrations typically observed in Canada today. To determine if low levels of tropospheric ozone contribute to hospitalization for respiratory disease, air pollution data were compared to hospital admissions for 16 cities across Canada representing 12.6 million people. During the 3927-day period from April 1, 1981, to December 31, 1991, there were 720,519 admissions for which the principle diagnosis was a respiratory disease. After controlling for sulfur dioxide, nitrogen dioxide, carbon monoxide, soiling index, and dew point temperature, the daily high hour concentration of ozone recorded 1 day previous to the date of admission was positively associated with respiratory admissions in the April to December period but not in the winter months. The relative risk for a 30 ppb increase in ozone varied from 1.043 (P < 0.0001) to 1.024 (P = 0.0258) depending on the selection of covariates in the regression model and subset of cities examined. The association between ozone and respiratory hospitalizations varied among cities, with relative risks ranging from 1.000 to 1.088 after simultaneous covariate adjustment. Particulate matter and carbon monoxide were also positively associated with respiratory hospitalizations. These results suggest that ambient air pollution at the relatively low concentrations observed in this study, including tropospheric ozone, is associated with excess admissions to hospital for respiratory diseases in populations experiencing diverse climates and air pollution profiles.
对流层臭氧在相对高浓度时对肺功能和呼吸道症状的影响已有充分记录。然而，以往的调查未能在控制气候因素后，明确建立起对流层臭氧与严重到需要住院治疗的呼吸道疾病之间的关联，也未能明确其与加拿大现今通常观测到的较低浓度气态和颗粒物空气污染之间的关联。为了确定低水平的对流层臭氧是否会导致呼吸道疾病住院，研究人员将空气污染数据与加拿大16个城市（代表1260万人）的医院入院情况进行了比较。在1981年4月1日至1991年12月31日的3927天期间，共有720519例入院病例，其主要诊断为呼吸道疾病。在控制了二氧化硫、二氧化氮、一氧化碳、污染指数和露点温度后，入院日期前1天记录的臭氧日最高小时浓度在4月至12月期间与呼吸道入院呈正相关，但在冬季月份则不然。臭氧浓度每增加30 ppb的相对风险在1.043（P < 0.0001）至1.024（P = 0.0258）之间，具体取决于回归模型中协变量的选择以及所研究城市的子集。臭氧与呼吸道住院之间的关联在不同城市有所不同，同时进行协变量调整后相对风险范围为1.000至1.088。颗粒物和一氧化碳也与呼吸道住院呈正相关。这些结果表明，本研究中观测到的相对低浓度的环境空气污染，包括对流层臭氧，与经历不同气候和空气污染状况的人群中呼吸道疾病的额外住院情况有关。
