2012~2013年北京市大气PM2．5浓度与某三级甲等医院急诊人次相关性研究

Study of relationship between atmospheric fine particulate matter concentration and one grade a tertiary hospital emergency room visits during 2012 and 2013 in Beijing

目的分析北京市2012--2013年大气PM2.5，浓度与医院急诊总人次的暴露．反应关系，及PM2.5，重污染对医院门诊急诊人次的影响。方法收集2012年10月1日至2013年12月31日期间北京市每日空气质量监测数据、气象监测数据，并统计该期间就诊于北京市某三级甲等医院的急诊案例。采用广义相加模型，以每日急诊人次为因变量，通过平滑函数控制长期趋势、节假日效应和星期几效应，拟合PM2.5，与每日急诊人次的暴露．反应关系模型，并采用约束性分段线性函数估计相应浓度范围的超额危险度。结果2012年10月1日至2013年12月31日期间大气PM2.5，年均浓度为90．9pg／m2；医院急诊科共接诊患者64260例，其中呼吸系统疾病9849例，循环系统疾病11168例。大气PM10，浓度与PM10、N02、SO2的浓度呈正相关，r值分别为0．87、0．78和0．62（P值均〈0．05）；与相对湿度呈正相关，r值为0．45（P〈0．05）；与温度和风速呈负相关，r值分别为-0．17和-0．32（P〈0．05）。单污染物模型中，大气PM2.5，当日浓度每升高10μg／m3，引起急诊就诊人次的超额危险度为0．25％（95％Ch0．07～0．43）；在双污染物模型PM2.5＋SO2和PM2.5＋NO2中，大气PM2.5，当日浓度每升高10μg／m3,引起急诊就诊人次超额危险度分别为1．07％（95％CI：0．83～1．30）和0．56％（95％CI：0．32—0．80）。5次重污染期大气PM2.5，平均浓度为204．16μg/m3，高于对照期大气PM2.5，平均浓度（85．24pg／H13）。PM2.5重污染天气时，大气PM2.5，浓度升高引起的急诊人次是对照期急诊人次的1．16倍（95％CI：1．09．1．22）。结论大气PM2.5，浓度升高会引起医院急诊人次的增加，尤其是在大气PM2.5，重污染期，大气PM2.5，浓度升高对医院急诊人次的影响更大。

Objective To explore the concentration-response relationship between ambient concentration of PM2.5 and daily total hospital emergency room visits in Beijing during 2012 and 2013. This study also examined the effects of ambient PM2.5 during heavy polluted days on emergency room visits compared with the light polluted days. Methods We collected the daily meteorological factors monitoring data and concentrations of air pollutants in Beijing during October 1, 2012 to December 31, 2013. We also collected the daily emergency room visits from a tertiary hospital in Beijing in the same time period. Generalized additive model was fitted to estimate the association between the ambient PM2.5 and the hospital emergency room visits, by using the smooth function to adjust long term trend of time, public holidays and day of week. In addition, constrained piecewise linear function was then used to estimate the excess risk for different segment of concentration-response function. Results The annual average concentration of PM2.5 was 90.9 μg/m3 during October 1, 2012 and December 31, 2013. There were total 64 260 cases for total emergency room visits, of which respiratory disease had 9 849 cases and cardiovascular disease had 11 168 cases. PM2.5 was positive related with PM10, NO2 and SO2. The corresponding correlation coefficients were 0.87, 0.78 and 0.62, respectively （P〈0.05）. And PM2.5 was positively related with relative humidity, with correlation coefficient 0.45 （P〈0.05）. But PM2.5 was negatively related with mean temperature （r= - 0.17, P〈 0.05） and wind speed （-0.32, P〈0.05）. In the single polluted model, after adjusting the effects of temperature, relative humidity and wind, every 10 μg/m3 increase of concentration of ambient PM2.5, the corresponding excess risk of daily emergency room visits was 0.25% （95% Ch 0.07 - 0.43）. In the two-pollutant model PM2.5＋SO2 and PM2.5＋NO2, every 10 p^g/m3 increase of concentration of ambient PM2.5, the corresponding excess risk of daily emergency room visits were 1.07% （95 %Ch 0.83 - 1.30） and 0.56% （95 %CI： 0.32 - 0.80） respectively, which were higher than the effect in single pollutant model. Average concentration of ambient particulate matters （PM2.5） was 204.16 Ilg/m3 during heavy pollution, higher than control period （85.24 μg/m3）. When PM2.5 as the primary air pollutants during heavy polluted days, we observed a significant increase in emergency room visits, and the odd ratios was 1.16 （95% Ch1.09 - 1.22）. Conclusion There were positive correlation between high concentration of ambient particulate matters （PM2.5） and increasing daily emergency room visits. Especially during the heavy polluted days, the effects of elevated concentration of PM2.5 on hospital emergency room visits were much larger.