中文摘要：

目的以过早死亡风险为指标评估北京、上海、广州和西安2013年1月雾霾天气事件的健康风险。方法收集2013年1月我国4个区域代表性城市：北京、上海、广州和西安环境空气中粒径≤2．5μm的颗粒物（PM2.5）日均浓度，分析4个城市的PM2.5的污染水平和浓度特征；收集2010年为标准年的这4个城市人口学资料及死亡率，参考环境保护部科技标准司的《我国五城市大气细颗粒物（PM。）污染与居民死亡关系研究报告》的暴露-反应关系系数，并基于Possion回归的比例风险模型计算过早死亡人数。结果2013年1月，北京、上海、广州和西安PM2.5 24h平均浓度分别为（240±165）、（83±27）、（94±49）和（210±98）μg/3，均超过我国《环境空气质量标准》（GB3095．2012）二级标准（75μg／m3），北京和西安整体高于上海和广州，北京、上海、广州和西安超标率分别为86．4％（19／22），58．1％（18／31），54．8％（17／31）和93．5％（29／31）；计算得出2013年1月雾霾天气事件过早死亡人数：北京为725（95％CI：457～977）人，上海为296（95％CI：96—502）人，广州为310（95％CI：189—434）人，西安为85（95％CI：21～141）人。结论2013年1月雾霾天气事件PM2.5污染严重，增加了人群健康风险。

英文摘要：

Objective To evaluate the human health risks （premature death risk as an indicator） in Beijing, Shanghai, Guangzhou and Xi＇an during extreme haze in January 2013. Methods The daily average particulate matter ≤2.5μm in aerodynamic diameter （PM2.5 ） concentrations of Beijing, Shanghai, Guangzhou and Xi＇an in January 2013 were collected and their characteristics explored. The populations and mortality rate of four cities in 2010 were collected from the statistical yearbook, the exposure-response relationships selected from the reference and then the premature death calculated according to the proportion risk model of Poisson regression. Results In January 2013, the 24 h mean concentrations of PM2,5 in Beijing, Shanghai, Guangzhou and Xi＇an were （240±165）、（83±27）、（94±49）和（210±98）μg/3 respectively and they were all above the secondary level of Ambient Air Quality Standards （ GB 3095-2012）. The 24 h mean concentrations of PMz5 in Beijing and Xi＇an were much higher than those in Shanghai and Guangzhou. Approximately 86.4% （19/22） ,58. 1% （ 18/31 ） ,54. 8% （ 17/31 ） and 93.5% （29/31） of 24 h mean PM2.5 concentrations in Beijing, Shanghai, Guangzhou and Xi＇an respectively exceeded the secondary level of Ambient Air Quality Standards （ GB 3095-2012）. The number of premature death due to the exposure to haze were 725 （95% CI： 457 -977） for Beijing, 296 （95% CI： 96 -502） for Shanghai, 310 （95% CI： 189 -434） for Guangzhou and 85 （95% CI： 21 - 141 ） for Xi＇an respectively in January 2013. Conclusion The PM2.5 pollutions of four cities in January 2013 were serious enough to pose elevated risks of human health.