With the popularity of Bluetooth headsets, many people are increasingly worried about the risk of using Bluetooth headsets. Recently, an article titled "Are Airpods and Other Bluetooth Headsets Safe?" said that 250 scientists from 40 countries around the world sent a letter to the World Health Organization, warning that the radiation of wireless headphones may cause cancer. How does a Bluetooth headset work? Does Bluetooth headset cause cancer? People's Daily Science Popularization China interviewed Zhou Hongzhi, associate professor of School of Applied Mathematics and Science of Beijing University of Technology, and Yan Zhanfeng, director of otorhinolaryngology department of Dongzhimen Hospital of Beijing University of Traditional Chinese Medicine.
How does a Bluetooth headset work?
Zhou Hongzhi explained that although people often think of Bluetooth as a device, in fact, Bluetooth is a wireless communication technology protocol, which uses 2.4GHZ-2.485GHZ radio waves, and can realize short distance digital communication exchange between fixed devices, mobile devices, and buildings.
Zhou Hongzhi introduced that Bluetooth can be divided into three types according to its power: the power of Bluetooth Group 1 is about 1/20 of that of mobile phones (currently the standard peak power of mobile phone SAR is below 2W/KG, that is, the electromagnetic radiation energy absorbed by each kilogram of brain tissue within 6 minutes should not exceed 2W), and the communication distance is about 100 meters; The power of Bluetooth group 2 is about 1/1000 of that of mobile phones, and the communication distance is about 20 meters; The power of Bluetooth group 3 is about 1/2000 of that of mobile phones, and the communication distance is about 10 meters. "If the requirements for the working range are relatively small, it is generally OK to choose the one with short distance and low power", Zhou Hongzhi said, "For example, the Bluetooth headset is usually not far away from our transmission source, so it is sufficient to use two sets of standards of 20 meters of Bluetooth. For the wireless mouse, the range of using it is basically about 1 meter, using the three sets of standards of Bluetooth."
So, how does Bluetooth headset work? Zhou Hongzhi explained that the Bluetooth headset mainly uses wireless module, digital module and audio amplifier when working. "The wireless module is to complete the wireless communication between two devices, just like the communication between two mobile phones. The wireless module wirelessly transmits the digital signal transmitted from one device to the device at the other end, and the other end receives the signal. The wireless module completes its work." After receiving the signal, the digital module decodes the signal, Then the code is transmitted to the processing chip, and the code is converted into an audio signal, which is processed by the audio amplifier to make people hear the sound.
Does Bluetooth headset cause cancer?
In response to the statement that "the use of Bluetooth headsets causes cancer by radiation", Yan Zhanfeng told the People's Daily Online Science Popularization China that according to the conclusion of a research article published in the journal Environmental Research in September 2018, the radiation generated by the use of Bluetooth headsets on the human body is much lower than the use of mobile phones, and will not increase the risk of human cancer. "It can be said that the risk of cancer caused by Bluetooth headsets is very low, and there are no clinical cases of cancer caused by the use of Bluetooth devices at present. It is exaggerated to think that 'cancer caused by the use of Bluetooth headsets', and consumers need not worry about cancer."
Zhou Hongzhi also believes that the statement of "radiation carcinogenesis caused by Bluetooth headset" is exaggerated, and it is unscientific to talk about harm without dose. "The wireless communication equipment artificially adds an electromagnetic field around us, and people naturally think that it will interfere with the electromagnetic field of the human body itself, but if it interferes with the human body, the electromagnetic field must be strong enough, because the electromagnetic field of our body itself is also very 'stubborn'." So, how strong is the electromagnetic field that can affect the human body? Zhou Hongzhi explained that, for example, if a radio station's transmission power is 10 kilowatts, then its transmission power needs to be increased to 100 megawatts, that is, to the fourth power of 10, or the current mobile phone power needs to be increased to the sixth power of 10 to the eighth power to have an impact on the surrounding environment and people.
In addition, Zhou Hongzhi also said that all Bluetooth devices on the market need to follow international and national standards. "If the product cannot achieve low radiation and is not controlled within the range of harmless to human body, it is not allowed to be marketed."
What should I pay attention to when using headphones?
Experts remind that although the risk of cancer caused by using Bluetooth headsets is extremely low, other problems caused by improper use of Bluetooth headsets should not be underestimated. "For in ear Bluetooth earphones, if the shape of the earphone does not match the shape of the ear canal, it will cause ear canal inflammation, eczema and other problems; in addition, if the earphone is used for more than 60 minutes at a time and the volume exceeds 60% of the maximum volume, it may lead to apoptosis of auditory nerve cells, which may lead to irreversible damage such as hearing loss and even deafness. Some patients use earphones with high intensity, and their hearing will be damaged within one to two weeks. " Yan Zhanfeng said that the probability of hearing loss caused by improper use of earphones is as high as 50%, or even 80%, "which is much higher than the risk of cancer caused by Bluetooth earphones."
So, what problems should we pay attention to when using earphones in our daily life? Yan Zhanfeng made the following suggestions:
1. Avoid answering and making calls when the mobile phone signal is poor. If possible, it is better to use the handsfree function of the mobile phone to reduce the use of headphones.
2. If you want to use earphones, try to use earphones instead of earphones.
3. Follow the principle of "two 60's", that is, the time of each use of the headset should not exceed 60 minutes, and the volume of the headset should not exceed 60% of the maximum volume. In addition, the total time of using headphones every day should be controlled within 3-4 hours.
Zhou Hongzhi also reminded us to pay attention to the surrounding environment when using earphones to avoid falls and collisions.
