表征室外人体暴露的监测网络设计(续完)

Monitoring Network Design on Representation Outdoor Human Exposure

对悬浮颗粒物室外人体暴露的测定一直受到可用资源的限制,设计有效的网络就要求对测定方法的选择、采样点的数量、采样时间、采样频率等进行调整。采样位置要求能表征因周围污染源对附近地区和城市最小影响的空间数值。虽然大多数判定PM是否达标的测定方法是每第3天至第6天的24 h监测,但是室外人体暴露的评价要求连续监测一整天,最好有1 h或更短时间的监测时段。更详细的粒径大小和化学性质数据也很有必要,因为较小的颗粒及其特殊的化学物质要比总的样品质量更有助于反映对健康的不良影响。

Measurments of outdoor human expceure to suspended particulate matter （PM） are always constrained by available resources . An effective network design requires tradecffs between variables measured , the number of sampling locations , sample duration, and sampling frequency . Sampling sites are needed to represent neighborhood and urban spatial scales with minimal influences from nearby sources. Although most PM measurements for deterrmining compliance with standards are taken over 24 h periods every third to sixth day , outdoor human exposure assessment requires measurements taken continuously throughout the day, preferably over durations of 1h or less . More detailed panicle size and chemistry data are also desirable , as smaller size fi＇actions and specific chemicals may be better indicators of adverse health effects than total mass samples.