中文摘要：

目的探讨兰州市大气气态污染物NO2和SO2对呼吸系统疾病住院的健康效应。方法采用时间序列的半参数广义相加模型（GAM），在控制了时间的长期趋势、“星期几效应”及气象因子等混杂因素的影响后，分析2001-2005年兰州市大气NO2和SO2浓度与呼吸系统疾病入院人数的暴露-反应关系。结果大气NO2和SO，浓度对呼吸系统疾病入院人数具有不同程度的影响。单污染物模型中，NO2和SO2分别以滞后1天和0天对呼吸系统健康的影响最强。滞后1天NO2和无滞后SO2浓度增加一个四分位数间距时，呼吸系统疾病入院人数增加的相对危险度分别为：1．060（95％CI1，1．046-1．074）和1．048（95％CI1．031-1．065）；女性和老年人为易感人群；2种污染物在秋冬季的作用比春夏季更明显。结论兰州市大气NO，和SO，浓度对呼吸系统疾病的日入院人数有影响。

英文摘要：

Objective To evaluate the relationship between exposure to gaseous air pollutants （ NO2 and SO2） and daily hospital admissions for respiratory diseases. Methods After controlling long time trend, the ＂ day of week＂ effect and confounding factors of meteorology, a semi-parametric generalized additive model （GAM） was used to analyze the exposure-effect relationship between gaseous air pollutants and daily respiratory hospital visits from 2001 to 2005 in Lanzhou city. Results Both NO2 and SO2 have positive relationships with residents＇ hospital visits for respiratory complaints. In single- pollutant models, the best fits for NO2 and SO2were one day after （Lagl） and the same day visit （Lag0）. With an IQR concentration increase in NO2 （Lagl） and SO2 （Lag0） , the relative risks of daily hospital admissions for respiratory diseases were 1. 060 （95% CI 1. 046 - 1. 074） and 1. 048 （95% CI 1. 031 - 1. 065） , respectively. The susceptible populations were female and the elderly. The health effect of gaseous air pollution was more obvious in autumn and winter. Conclusion The ambient NO2 and SO2