Neubauer Georg, Cecil Stefan, Giczi Wolfram, Petric Benjamin, Preiner Patrick, Fröhlich Jürg, Röösli Martin
Seibersdorf Laboratories, Seibersdorf, Austria.
Bioelectromagnetics. 2010 Oct;31(7):535-45. doi: 10.1002/bem.20587.
The selection of an adequate exposure assessment approach is imperative for the quality of epidemiological studies. The use of personal exposimeters turned out to be a reasonable approach to determine exposure profiles, however, certain limitations regarding the absolute values delivered by the devices have to be considered. Apart from the limited dynamic range, it has to be taken into account that these devices give only an approximation of the exposure due to the influence of the body of the person carrying the exposimeter, the receiver characteristics of the exposimeter, as well as the dependence of the measured value on frequency band, channel, slot configuration, and communication traffic. In this study, the relationship between the field strength measured close to the human body at the location of the exposimeter and the exposure, that is, the field strength at the location of the human body without the human body present, is investigated by numerical means using the Visible Human model as an anatomical phantom. Two different scenarios were chosen: (1) For FM, GSM, and UMTS an urban outdoor scenario was examined that included a transmitting antenna mounted on the roof of one of four buildings at a street crossing, (2) For WLAN an indoor scenario was investigated. For GSM the average degree of underestimation by the exposimeter (relation of the average field levels at the location of the exposimeter to the field level averaged over the volume of the human body without the body present) was 0.76, and for UMTS 0.87; for FM no underestimation was found, the ratio was 1. In the case of WLAN the degree of underestimation was more pronounced, the ratio was 0.64. This study clearly suggests that a careful evaluation of correction factors for different scenarios is needed prior to the definition of the study protocol. It has to be noted that the reference scenario used in this study does not allow for final conclusions on general correction factors.
选择合适的暴露评估方法对流行病学研究的质量至关重要。事实证明，使用个人暴露计是确定暴露情况的合理方法，然而，必须考虑到这些设备所提供绝对值的某些局限性。除了动态范围有限外，还必须考虑到由于携带暴露计的人的身体影响、暴露计的接收特性以及测量值对频段、信道、时隙配置和通信流量的依赖性，这些设备只能给出近似的暴露情况。在本研究中，利用可视人体模型作为解剖模型，通过数值方法研究了在暴露计所在位置靠近人体处测量的场强与暴露之间的关系，即不存在人体时人体所在位置的场强。选择了两种不同的场景：(1)对于调频(FM)、全球移动通信系统(GSM)和通用移动通信系统(UMTS)，研究了城市室外场景，该场景包括在一个十字路口的四栋建筑物之一的屋顶上安装一个发射天线；(2)对于无线局域网(WLAN)，研究了室内场景。对于GSM，暴露计的平均低估程度(暴露计所在位置的平均场强与不存在人体时人体体积平均场强的关系)为0.76，对于UMTS为0.87；对于FM，未发现低估情况，比值为1。在WLAN的情况下，低估程度更为明显，比值为0.64。本研究清楚地表明，在确定研究方案之前，需要仔细评估不同场景的校正因子。必须指出，本研究中使用的参考场景无法得出关于一般校正因子的最终结论。
