In 2011 the International Agency for Research on Cancer classified radiofrequency electromagnetic fields (RF EMF) from cell phones as possibly carcinogenic to humans. The National Toxicology Program and the Ramazzini Institute have both reported that RF EMF exposures significantly increase gliomas and Schwannomas of the heart in rodent studies. Recent studies indicate that RF EMF exposures from cell phones have negative impacts on animal cells and cognitive and/or behavioral development in children. Case-control epidemiological studies have found evidence for cell phone use and increased risk for glioma and localization of the glioma associated with the consistent exposure site of regular cell phone use. Understanding the exposure level, or power density, from RF EMF emitted by cell phones under real-world usage and signal reception conditions, as distinct from the published measurements of maximum Specific Absorption Rate values, may help cell phone users decide whether to take behavioral steps to reduce RF EMF exposure. Exposure measurements were conducted on phone models from four major mobile network operators (MNOs) in the USA for calls received under strong and weak reception signal conditions, near the phone face and at several distances up to 48 cm. RF EMF exposure from all phones was found to be greater under weak (1-2 display bars) than under strong (4-5 display bars) reception signal conditions by up to four orders of magnitude. Notably, RF EMF exposure levels under weak reception signal conditions at a distance of 48 cm from the phone were similar to or greater than those detected under strong reception signal conditions at a distance of 4 cm. Under weak reception signal conditions, power density reductions of up to 90% occurred at 16 cm typical for speaker phone or texting over the 4 cm near-ear exposure. The results of this investigation of second-generation (2G) technology suggest that reduced and precautionary use of cell phones under weak signal conditions could lower a user's RF EMF exposure by up to several orders of magnitude. Bluetooth headset power density exposures were 10-400 times lower than those of the cell phones to which they were connected and dependent on the headset rather than the connected phone. The results of this study informed the development of public health guidance regarding cell phone use.

中文翻译：

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现实世界中手机的射频电磁场辐射。

2011年，国际癌症研究机构将手机的射频电磁场（RF EMF）分类为可能对人类致癌的物质。美国国家毒理学计划和Ramazzini研究所都报告说，在啮齿类动物研究中，RF EMF暴露会显着增加心脏的神经胶质瘤和神经鞘瘤。最近的研究表明，手机暴露的RF EMF对动物细胞以及儿童的认知和/或行为发展有负面影响。病例对照的流行病学研究发现了使用手机的证据，并且胶质瘤和胶质瘤本地化的风险与定期使用手机的持续暴露部位有关，从而增加了风险。了解在实际使用情况和信号接收条件下，手机发出的RF EMF的暴露水平或功率密度，与已发布的最大比吸收率值测量结果不同，它可以帮助手机用户决定是否采取行为步骤来减少RF EMF暴露。在来自美国四个主要移动网络运营商（MNO）的电话型号上进行了曝光测量，以测量在强接收信号和弱接收信号条件下，靠近电话脸部以及在48厘米处的几个距离处所接收到的呼叫。发现所有电话的RF EMF暴露在弱（1-2个显示条）条件下比强（4-5个显示条）条件下的接收信号要大四个数量级。值得注意的是，在距离手机48厘米的弱接收信号条件下，RF EMF暴露水平与在距离4 cm的强接收信号条件下检测到的RF EMF暴露水平相似或更高。在弱接收信号条件下，扬声器电话或发短信在近距离4 cm的情况下，典型的16 cm处功率密度降低高达90％。第二代（2G）技术研究的结果表明，在弱信号条件下减少和预防性使用手机可以将用户的RF EMF暴露降低几个数量级。蓝牙耳机的功率密度暴露比其所连接的手机低10-400倍，并且取决于耳机而不是所连接的手机。这项研究的结果为有关手机使用的公共卫生指南的制定提供了信息。第二代（2G）技术研究的结果表明，在弱信号条件下减少和预防性使用手机可以将用户的RF EMF暴露降低几个数量级。蓝牙耳机的功率密度暴露比其所连接的手机低10-400倍，并且取决于耳机而不是所连接的手机。这项研究的结果为有关手机使用的公共卫生指南的制定提供了信息。第二代（2G）技术研究的结果表明，在弱信号条件下减少和预防性使用手机可以将用户的RF EMF暴露降低几个数量级。蓝牙耳机的功率密度暴露比其所连接的手机低10-400倍，并且取决于耳机而不是所连接的手机。这项研究的结果为有关手机使用的公共卫生指南的制定提供了信息。蓝牙耳机的功率密度暴露比其所连接的手机低10-400倍，并且取决于耳机而不是所连接的手机。这项研究的结果为有关手机使用的公共卫生指南的制定提供了信息。蓝牙耳机的功率密度暴露比其所连接的手机低10-400倍，并且取决于耳机而不是所连接的手机。这项研究的结果为有关手机使用的公共卫生指南的制定提供了信息。