Preece A W, Grainger P, Golding J, Kaune W
Department of Medical Physics and Bioengineering, Bristol Oncology Centre, UK.
Phys Med Biol. 1996 Jan;41(1):71-81. doi: 10.1088/0031-9155/41/1/006.
To define a protocol for surrogate measurement of magnetic field exposure by questionnaire, a series of spot and 24-hour measurements was made at 50 houses in Avon, UK. Measurements were made with Emdex II equipment in the centres of rooms with the house power encountered at the start of the visit, and then with all power to the house isolated at the main switch. The mean spot magnetic field averaged over the 50 homes for each room varied between 0.011 and 0.023 microT with an overall mean (0.017 +/- 0.003) microT with the power 'on', and between 0.008 and 0.015 microT, giving an overall mean (0.012 +/- 0.002) microT with power 'off'. Measurements over 24 h in the three main occupancy rooms showed a distinct diurnal variation in the overall mean magnetic field of the 50 homes by a factor of three, giving a 24-hour mean of (0.044 +/- 0.06) microT; at the same time mean recorded personal exposure for the occupants monitored was (0.067 +/- 0.08) microT. These values appear low compared with, for example, USA domestic levels of magnetic field exposure demonstrated in several studies, but also show a wide variation in individual values, which could not be predicted from spot measurements.
为通过问卷调查确定替代测量磁场暴露的方案，在英国埃文的50所房屋中进行了一系列即时测量和24小时测量。使用Emdex II设备在房间中央进行测量，测量时在访问开始时接通房屋电源，然后在主开关处切断房屋所有电源。50所房屋中每个房间的即时磁场平均强度在0.011至0.023微特斯拉之间变化，通电时总体平均值为（0.017±0.003）微特斯拉，断电时在0.008至0.015微特斯拉之间，总体平均值为（0.012±0.002）微特斯拉。在三个主要居住房间进行的24小时测量显示，50所房屋的总体平均磁场存在明显的昼夜变化，变化系数为三倍，24小时平均值为（0.044±0.06）微特斯拉；与此同时，监测到的居住者的个人暴露平均记录值为（0.067±0.08）微特斯拉。与例如几项研究中显示的美国国内磁场暴露水平相比，这些值似乎较低，但也显示出个体值的广泛差异，而即时测量无法预测这些差异。
