Safe? Effective? - Pregnant Women'S Radiation Protection Clothing Test Data Released.

Recently, the "anti radiation door" incident, which has been bubbled up by the media, has made many famous brands of radiation protection clothing deeply trapped in the whirlpool. Is it a "secret war" or a commercial speculation? The focus of the debate is all about the core issue of whether radiation protection clothing is effective. "Seeking truth" and "data" have become the most urgent demands of the public and the media. In response to these problems, this newspaper interviewed "GB/T 23463-2009 protection". clothing Dr Shi Meiwu, the draftsman of microwave radiation protective clothing, has a clear truth about the radiation research and precise testing of the public for many years.

It is not realistic to expect radiation protection clothing to be protected.

In order to prove whether the radiation protection clothing is effective, how about the shielding effectiveness of the brand's radiation protection clothing? In December 31, 2011, Shi Mei Wu carried the team's 19 pieces of 8 brands, such as moon Mommy, Chi Ni, plus plus, which were well sold to the market at Beijing University of Technology. Radiation protection Samples are tested, and the conclusion is that the radiation protection clothing has certain radiation protection effect. However, because the radiation protection clothing can not completely wrap up the human body, it is unrealistic to expect the radiation protection clothing to protect the environment which has strong electromagnetic radiation.

According to Shi Meiwu, the test uses the QJ2809-1996 "plane". Shield The shielding effectiveness of materials is measured. The standard coaxial spanmission line method of flange is used to test the three kinds of materials, such as nylon, silver, metal fiber and metal coating, such as sling, vest, dresses, trousers and so on. The test is based on the "GB/T 23463-2009 protective clothing microwave protective clothing" standard. The test frequency is divided into low frequency band 30 to 1000MHz (MHz) and high frequency band 1 to 18GHz (GHz). The protective effect of the radiation protection clothing in these two bands is measured by two sets of spanmitting and receiving system respectively, and the test power is 20.00dBm (decibel milli volt).

In the shielding effectiveness test of the radiation shielding clothing, the detection personnel placed two heads of the dummy in the head, chest and abdomen, respectively, receiving high-frequency and low-frequency electromagnetic waves of two frequency sensors. First, the electromagnetic field strength at the bottom of the low frequency band and the high frequency band is measured. Then the electromagnetic field intensity of the dummy wearing the radiation protection clothing is measured. The shielding effectiveness of the clothing is calculated according to the formula of GB/T 23463.

Through rigorous testing, the testing data of the public and media are most concerned: electromagnetic shielding material made of metal fiber, chemical fiber plating metal or fabric plated metal can shield electromagnetic field and attenuate the intensity of electromagnetic field. The radiation shielding clothing is more tightly shielded to the human body, and the protective effect is better. The electromagnetic field of the direct shielding part of the electromagnetic radiation, which is exposed to positive radiation, has larger exposed structure such as waistcoat and suspenders, to a certain extent. The measurement results also show that the electromagnetic shielding effectiveness of unprocessed shielding materials is much higher than that of the radiation shielding clothing made of the same shielding materials, especially the radiation protection clothing with a small coverage area. For example, the shielding effectiveness of material 8 is about 30dB (decibel), while the shielding effectiveness of clothing is about 10 to 20dB (equivalent to the attenuation of electromagnetic radiation energy by 90%~99%). The shielding effectiveness of the 18 and 19 samples is about 60dB, the shielding effectiveness of the coat is about 6 to 20dB (equivalent to the energy of electromagnetic radiation is reduced by 75%~99%), and the basic shielding efficiency is 20 to 40dB (equivalent to the energy of electromagnetic radiation is attenuated 99%~99.99%). Because electromagnetic shielding materials usually have higher shielding ability to high frequency than low frequency, shielding effectiveness of electromagnetic shielding materials or radiant protective clothing is larger than that of low frequency shielding. The higher the shielding effectiveness is, the better the electromagnetic shielding effectiveness is.

Shi Meiwu said that the shielding effectiveness of radiation shielding clothing varies with different frequencies under different frequencies due to the different results of multiple reflection of electromagnetic waves at different frequencies. The peak value at high position indicates that the shielding effectiveness is high, and the protective effect is good. In addition, if the position of the sensor is changed, the shielding effectiveness will also change.

Regarding the difference between the shielding test of dummy and real person, Shi Mei Wu explained that when using dummy material, electromagnetic wave spanparent material was basically not absorbed by the dummy test. For real people, electromagnetic waves entered the human body, and most of them consumed on the epidermal tissue. Because the epidermal tissue is relatively insensitive to electromagnetic waves, it is not as easy to cause diseases as the organs which are sensitive to electromagnetic waves, such as heart and brain.

Compared with the actual situation of wearing protective clothing, the use of dummy to measure radiation protection clothing, because of the neglect of the absorption of electromagnetic waves by the skin, the result should be more conservative.

Popularizing scientific knowledge is the best gift for a prospective mother.

Shi Meiwu summed up the test results when he talked about his personal view: electromagnetic radiation protective clothing is for professionals working in a strong electromagnetic environment, such as missiles, radar debugger, communication base station maintenance personnel, and so on, and should not be worn by the public. Shi Meiwu said: "at present, our electromagnetic environment has not deteriorated to the extent that individuals need to protect themselves. According to the data of the German Federal Radiation Safety Office on the electromagnetic environment, the intensity of the magnetic field measured at 30cm (CM) is only 60v/m (volt per meter), far below the standard of international 5000v/m2 (volt per square meter), according to the data of the German Federal Radiation Safety Office.

In fact, even if the nuclear leakage accident occurred in the world's most serious Chernobyl nuclear power plant, only 28 people actually died of nuclear radiation, together with 30 other deaths. According to Pan Ziqiang, member of the main Committee of the International Radiation Protection Committee and academician of the Chinese Academy of engineering, "14 years after the accident, follow-up studies show that no increase in the incidence or mortality of various cancers attributable to ionizing radiation has been observed except for the increase in thyroid cancer after exposure to childhood. The risk of leukemia is not showing an increasing trend, nor is there any evidence that other non malignant diseases are related to ionizing radiation. But the psychological impact of accidents is widespread. This is mainly due to fear of radiation, rather than the actual dose of radiation. "

Based on this, Shi Mei Wu believes that popularizing scientific knowledge is the best gift for mothers.