Dörre W H
Universitätsklinikum Charité, Institut für Mikrobiologie und Hygiene, Medizinische Fakultät, Humboldt-Universität zu Berlin, Germany.
J Expo Anal Environ Epidemiol. 1997 Oct-Dec;7(4):471-91.
In preparation for large-scale investigations, we have conducted some methodological studies with small groups in order to determine patterns of stay and time activity patterns in various microenvironments at different times of the day. A diary technique was used. This paper reports some results of this methodological study: In one study we investigated a group of toddlers (n = 52, aged 2-3 years) attending a nursery school, and in a second study we compared two groups of medical students (n = 79 and 54, respectively). The reported data was analyzed by descriptive statistical methods. The toddlers spent an average of 87.6% of their time indoors (66.2% at home, 20.4% at nursery schools, 1% at other indoor areas), 11.2% of their time outdoors, and 1.2% of their time using various means of enclosed transportation. In the student study, time budgets of the two student groups differ only slightly. The students spent about 87% of their time indoors (about 66% at home, 14% in rooms connected with their study, 7% in other indoor areas), about 6% of their time using various means of enclosed transportation, and about 7% of their time outdoors. In order to describe the physical activity, the students were asked to evaluate their physical activity according to a low, medium or high physical strain. These evaluations were used to calculate a "mean activity coefficient" for each microenvironment and each hour of day. Not every individual in a group spent time in every given microenvironment during the period of investigation. Therefore, the mean over all the individuals of the group (the "group mean") and the mean over the individuals who in fact did spend time in any given microenvironment (the "actual doers mean") may be very different. There are two kinds of frequency distributions of time spent in various microenvironments: (1) The distribution of the individual's mean time spent in the microenvironment across the entire investigation period (distribution of the individual means) and (2) the distribution of the duration of time spent in the microenvironment for all participants at all days (distribution of the person-days). Both types of frequency distributions should be determined for the purpose of exposure and risk estimation for pollutants.
为开展大规模调查做准备，我们对小群体进行了一些方法学研究，以确定一天中不同时间在各种微环境中的停留模式和时间活动模式。采用了日记法。本文报告了这项方法学研究的一些结果：在一项研究中，我们调查了一组就读于幼儿园的幼儿（n = 52，年龄2 - 3岁），在另一项研究中，我们比较了两组医学生（分别为n = 79和54）。所报告的数据采用描述性统计方法进行分析。幼儿平均87.6%的时间待在室内（66.2%在家中，20.4%在幼儿园，1%在其他室内区域），11.2%的时间待在户外，1.2%的时间使用各种封闭式交通工具。在学生研究中，两组学生的时间分配仅有轻微差异。学生们约87%的时间待在室内（约66%在家中，14%在与学习相关的房间，7%在其他室内区域），约6%的时间使用各种封闭式交通工具，约7%的时间待在户外。为描述身体活动情况，要求学生根据低、中、高身体负荷来评估他们的身体活动。这些评估用于计算每个微环境和每天每小时的“平均活动系数”。在调查期间，并非每个群体中的个体都在每个给定的微环境中度过时间。因此，该群体所有个体的平均值（“群体均值”）与实际上在任何给定微环境中度过时间的个体的平均值（“实际参与者均值”）可能会有很大差异。在各种微环境中度过的时间有两种频率分布：（1）个体在整个调查期间在微环境中度过的平均时间分布（个体均值分布）和（2）所有参与者在所有日子里在微环境中度过的时间持续分布（人日分布）。为了对污染物进行暴露和风险估计，应确定这两种频率分布。
