中文摘要：

目的研究PM_（2.5）个体暴露浓度与固定站点监测浓度的关系,以及在不同空气PM_（2.5）浓度下,个体暴露浓度与固定站点浓度比值的变化规律。方法于2014年12月—2015年1月使用PM_（2.5）个体暴露采样器对两名高校学生在19个工作日进行跟踪采样,同时收集个体跟踪采样时间段内距离学校最近的北京市空气质量监测固定站点的PM_（2.5）浓度小时值,利用所得数据分别计算每位研究对象个体暴露日均值和相应的固定站点日均值,并计算个体暴露浓度与固定站点浓度日均值的比值,并与固定站点浓度进行拟合。结果研究期间的个体暴露浓度均值（98μg/m3）高于固定站点浓度均值（80μg/m3）。个体暴露浓度与固定站点浓度的比值（y）与固定站点PM_（2.5）浓度的常用对数（lgx）呈负相关（y=-1.186lgx-5.464,R2=0.47,P〈0.000 1）,且当固定站点浓度较低（〈10μg/m3）时,比值波动较大（2.5～12.7）。结论当PM_（2.5）固定站点监测浓度较低时,固定站点浓度与个体暴露水平差异较大,如在人群健康研究中使用PM_（2.5）固定站点监测浓度作为研究对象的暴露浓度,则有可能明显低估其真实的暴露水平。

英文摘要：

Objective To explore the relationship between personal exposure and fixed-site concentration of PM_（2.5）, and the disparity of ratios of personal exposure concentration to fixed-site concentration under different concentration levels of ambient PM_（2.5）. Methods Two students from a university were involved in PM_（2.5） personal exposure assays which lasted 19 workdays.During the period of personal exposure sampling, hourly data of PM_（2.5） concentrations in two nearby fixed-sites were also collected. Then the daily average concentration of personal exposure of each object and the corresponding fixed-site concentration were calculated. Finally, the ratio of personal exposure to fixed-site ambient measurements was calculated and the relationship between the ratio and fixed-site concentration was fitted. Results The average of personal exposure concentrations of PM_（2.5）（98 μg/m3） was higher than the average of fixed-site concentrations（80 μg/m3）. The ratio of personal exposure concentration to fixed-site concentration（y） decreased with the increase of common logarithm of the ambient PM_（2.5） concentrations（lgx）（y=-1.186lgx-5.464, R2=0.47, P〈0.000 1）. The ratios（2.5-12.7） fluctuated significantly when the fixed-site concentration was under a relatively low level（〈10 μg/m3）. Conclusion When the ambient PM_（2.5） concentration is lower, the personal exposure concentration may be significantly different from the fixed-site concentration. Hence, in the study of environmental human health, taking fixed-site concentration as personal exposure level, will lead to the underestimation of real personal exposure level.