北京地区PM2.5个体暴露水平模拟

Analog calculation of personal PM2.5 exposure levels in Beijing, China

目的模拟计算不同季节不同人群的PM2.5暴露水平。方法结合单人逐日跟踪实验获取的微环境PM2.5实测浓度和北京环境保护监测中心网站所发布的35个监测站点大气PM2.5浓度,建立不同微环境（住宅、办公室、教室等）中PM2.5浓度与大气环境浓度的回归方程,结合问卷调查获得人群日常行为模式,建立模型。通过Matlab软件随机生成大气环境浓度模拟值,计算采暖季和非采暖季、不同年龄段人群PM2.5的暴露水平。最后将模拟结果与跟踪实验实测结果进行比对。结果非采暖季与采暖季的个体日均暴露水平中位数实测结果分别为29.84～40.79和47.71～62.11μg/m3,模型计算结果分别为32.99～37.60和43.10～46.61μg/m3,个体暴露水平与当日大气环境浓度比值大部分介于0.5～0.6之间,实测与模拟计算结果之间具有较好的一致性。模型模拟结果显示,〈18岁人群暴露水平偏高,18～25岁和26～55岁人群暴露水平非常接近。采暖季室内暴露比例（77%～81%）高于非采暖季比例（73%～77%）。18～25岁人群因锻炼所造成的暴露比例（5%）略高于其他年龄组（3%～4%）。结论本研究的建模方法可用于估算目标人群的大气PM2.5暴露水平。采暖季日均暴露水平高于非采暖季,室内暴露占绝大比例,各年龄段人群在暴露水平以及暴露来源分布上具有较高的相似性。

Objective To calculate personal exposure of different age groups in different seasons. Methods Personal exposure to PM2.5 of different age groups were determined directly first and then the regression equation between ambient and various microenvironments concentrations was established and used in microenvironment model based on time-activity questionnaire. Results The median of 24-hour personal exposure concentrations were 29.84-40.79 and 47.71-62.11 μg/m3 in winter and other seasons by direct personal measurement, while the modeling output exposure levels were 32.99-37.60 and 43.10-46.61 μg/m3 in winter and other seasons, with ratio （personal exposure concentration/ambient concentration） from 0.5 to 0.6. The exposure levels were high in under 18 years group, while no significant difference were found between the other two groups. Personal exposure indoors accounted for 77%-81% of total in winter and 73%-77% in other seasons. More physical activities led to higher proportion （about 5%） of total exposure for 18-25 age group, and for the latter, lower exposure was found from commute. Conclusion The model can be used to estimate PM2.5 exposure level of target population. Daily exposure level in winter is higher than in other seasons. Indoor sources dominate the personal exposure, similar pattern is found in exposure levels and source distribution among different profession groups.