监测频率对PM_(2.5)暴露水平的影响研究

Effects of monitoring frequency on PM_(2.5) personal exposure level

目的探讨不同采样频率下PM_(2.5)个体暴露监测结果的差异性,为PM_(2.5)健康效应研究中暴露测量仪器的科学选择提供理论依据。方法开展在职人员的PM_(2.5)个体暴露水平监测,采用线性拟合及变异率(以10 s为基准)计算的方法,探讨不同时间-活动模式特征、不同微环境(办公室,家,交通)及不同采样频率下(30 s,1、5、10、30、60 min)暴露水平的差异。结果各微环境中不同采样频率下监测结果与10 s采样频率下监测结果的线性拟合r^2均在0.98以上;办公室中变异率为-31.91%~24.03%,家中变异率为-14.60%~4.69%,交通微环境中变异率为-26.61%~32.37%。30 s^10 min采样频率下监测结果的变异率<15%。结论通常情况下使用10 min的采样频率进行采样可以满足需求,但在调查对象处于特殊微环境下或具有特殊活动模式时需要采用1 min或更精确的采样频率进行采样。

Objective To understand the differences of exposure monitoring results at different sampling frequencies and to provide theoretical basis for the scientific selection of exposure monitoring instruments used in population health research.Methods Personal PM2.5 exposure levels of serving officers were monitored. The differences of exposure levels between respondents with different time-activity patterns, different microenvironments and different sampling frequencies（30 s, 1 min,5 min, 10 min, 30 min, 60 min） were investigated,the linear regression model was fitted, and variance rate, reflecting the difference in the personal PM2.5 exposure levels at different sampling frequencies mentioned above compared with that at sampling frequency of 10 s, was calculated. Results The R^2 of linear regression model in each microenvironment was above 0.98. The variance rates were-31.91%-24.03%,-14.60%-4.69%,-26.61%-32.37% in offices, home and traffic microenvironment. The variance rates at sampling frequencies of 30 s, 1 min, 5 min, 10 min were less than 15%. Conclusion Normally, a sampling frequency of 10 min or more accurate can be used, but a sampling frequency of 1 min or more accurate should be required when the subject is in a special microenvironment or has a special activity mode.