Sagar Sanjay, Struchen Benjamin, Finta Viktoria, Eeftens Marloes, Röösli Martin
Swiss Tropical and Public Health Institute, Department of Epidemiology and Public Health, Socinstrasse 57, Basel 4051, Switzerland; University of Basel, Petersplatz 1, Basel 4051, Switzerland.
Eötvös Lorand University, Faculty of Science, Center of Environmental Studies, Pázmány Péter Sétány 1/A, H-1117 Budapest, Hungary.
Environ Res. 2016 Oct;150:289-298. doi: 10.1016/j.envres.2016.06.020. Epub 2016 Jun 20.
Spatial and temporal distribution of radiofrequency electromagnetic field (RF-EMF) levels in the environment is highly heterogeneous. It is thus not entirely clear how to monitor spatial variability and temporal trends of RF-EMF exposure levels in the environment in a representative and efficient manner. The aim of this study was to test a monitoring protocol for RF-EMF measurements in public areas using portable devices.
Using the ExpoM-RF devices mounted on a backpack, we have conducted RF-EMF measurements by walking through 51 different outdoor microenvironments from 20 different municipalities in Switzerland: 5 different city centers, 5 central residential areas, 5 non-central residential areas, 15 rural residential areas, 15 rural centers and 6 industrial areas. Measurements in public transport (buses, trains, trams) were collected when traveling between the areas. Measurements were conducted between 25th March and 11th July 2014. In order to evaluate spatial representativity within one microenvironment, we measured two crossing paths of about 1km in length in each microenvironment. To evaluate repeatability, measurements in each microenvironment were repeated after two to four months on the same paths.
Mean RF-EMF exposure (sum of 15 main frequency bands between 87.5 and 5,875MHz) was 0.53V/m in industrial zones, 0.47V/m in city centers, 0.32V/m in central residential areas, 0.25V/m non-central residential areas, 0.23V/m in rural centers and rural residential areas, 0.69V/m in trams, 0.46V/m in trains and 0.39V/m in buses. Major exposure contribution at outdoor locations was from mobile phone base stations (>80% for all outdoor areas with respect to the power density scale). Temporal correlation between first and second measurement of each area was high: 0.89 for total RF-EMF, 0.90 for all five mobile phone downlink bands combined, 0.51 for all five uplink bands combined and 0.79 for broadcasting. Spearman correlation between arithmetic mean values of the first path compared to arithmetic mean of the second path within the same microenvironment was 0.75 for total RF-EMF, 0.76 for all five mobile phone downlink bands combined, 0.55 for all five uplink bands combined and 0.85 for broadcasting (FM and DVB-T).
This study demonstrates that microenvironmental surveys using a portable device yields highly repeatable measurements, which allows monitoring time trends of RF-EMF exposure over an extended time period of several years and to compare exposure levels between different types of microenvironments.
环境中射频电磁场（RF - EMF）水平的时空分布高度不均一。因此，目前尚不完全清楚如何以具有代表性且高效的方式监测环境中RF - EMF暴露水平的空间变异性和时间趋势。本研究的目的是测试一种使用便携式设备在公共场所进行RF - EMF测量的监测方案。
我们使用安装在背包上的ExpoM - RF设备，在瑞士20个不同城市的51个不同室外微环境中进行了RF - EMF测量：5个不同的市中心、5个中央住宅区、5个非中央住宅区、15个农村住宅区、15个农村中心和6个工业区。在不同区域之间出行时收集公共交通工具（公交车、火车、电车）上的测量数据。测量于2014年3月25日至7月11日进行。为了评估一个微环境内的空间代表性，我们在每个微环境中测量了两条长度约为1公里的交叉路径。为了评估可重复性，在两到四个月后在相同路径上对每个微环境进行重复测量。
工业区域的平均RF - EMF暴露（87.5至5875MHz之间15个主要频段的总和）为0.53V/m，市中心为0.47V/m，中央住宅区为0.32V/m，非中央住宅区为0.25V/m，农村中心和农村住宅区为0.23V/m，电车中为0.69V/m，火车中为0.46V/m，公交车中为0.39V/m。室外场所的主要暴露源是移动电话基站（相对于功率密度尺度，所有室外区域均超过80%）。每个区域第一次和第二次测量之间的时间相关性很高：总RF - EMF为0.89，所有五个移动电话下行链路频段总和为0.90，所有五个上行链路频段总和为0.51，广播为0.79。在同一微环境中，第一条路径的算术平均值与第二条路径的算术平均值之间的Spearman相关性，总RF - EMF为0.75，所有五个移动电话下行链路频段总和为0.76，所有五个上行链路频段总和为0.55，广播（调频和数字视频广播 - T）为0.85。
本研究表明，使用便携式设备进行微环境调查可获得高度可重复的测量结果，这使得能够在数年的较长时间段内监测RF - EMF暴露的时间趋势，并比较不同类型微环境之间的暴露水平。
