电场

Electric 字段 are created around appliances and wires wherever a 电压存在. You can think of electric voltage as the pressure of water in a garden hose – the more voltage, the higher the electric field 强度. Electric 字段 are present when an electrical appliance is 即使关机也能插上电源. Electric 字段 diminish rapidly with distance from the source and can be shielded by objects such as 树木或建筑物的墙壁.

磁场

Magnetic 字段 are created whenever there is a flow of electric current. This can be thought of as the flow of water in a garden hose. As the amount of current flowing increases, so does the magnetic field. Magnetic 字段 are present when there is a flow of electricity, such as when an electrical appliance is operating. Magnetic 字段 are measured in milligauss (mG), and diminish rapidly with distance from the source, but are not shielded by objects such as trees or buildings. The level of magnetic 字段 from electrical appliances in homes can be as high as or higher than the magnetic 字段 people may experience under power lines. Magnetic field 强度 from power lines depend on many factors, 包括线路的设计, the amount of current the line carries, 以及到直线的距离.

Earth's magnetic field (direct current)^*

250 - 650 mG

Video display terminals (VSTs) (distance 1')^*

5 mG

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电范围(距离1')

8 mG

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洗碗机(距离1')

10 mG

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复印机(距离1')

20 mG

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真空吸尘器(距离1')

60 mG

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电动剃须刀(距离6英寸)

100 mG

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吹风机(距离6英寸)

300 mG

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¹ NIEHS, EMF Questions and Answers, 2002年6月

Magnetic 字段 decrease as distance from 电力来源增加

^{*levels shown above are examples only, not predictions of actual EMF from PSE lines
Source: 国家 Institute of Environmental Health Sciences (NIEHS), EMF Questions and Answers. 2002年6月.}

电动势研究

For over 40 years, there have been many scientific studies conducted on power frequency EMF. Extensive reviews and research conducted by leading public health agencies – such as the World Health Organization (WHO) and the U.S. 国家 Cancer Institute (NCI) (one of the U.S. 国家 Institutes of Health) – have not established that power frequency EMF cause any adverse effects in 人或动物.

²世卫组织EMF规划网站: www.谁.int/news-room/q-a-detail/radiation-electromagnetic-字段

Similarly, the 美国国家癌症研究所 has concluded that, “Numerous epidemiologic studies and comprehensive reviews of the scientific literature have evaluated possible associations between exposure to non-ionizing EMFs and risk of 癌症 in children. 没有一致的证据证明 association between any source of non-ionizing EMF and 癌症 has been found.”

NCI Fact Sheet "Electromagnetic Fields and Cancer" - www.癌症.gov/about-癌症/causes-prevention/ risk/radiation/electromagnetic-字段-fact-sheet

Exceedance of these safety standards requires that a person be exposed to EMF levels higher than those listed above for any duration of time. There are no time restrictions for exposures below the threshold.