Rumor: There is a video saying that medical masks will be disinfected with ethylene oxide , and ethylene oxide is a first-class carcinogen that will remain on the mask. Although the residue tested meets national standards, it is still recommended to unpack the mask and swing it in the air for a few times before wearing it, which will help dissipate the ethylene oxide and further reduce the residue.
The truth: Masks that meet national standards have residues within the safe range. Putting aside the dosage and not talking about toxicity, there is no need to wield masks.
from Douyin
It is certain that medical masks purchased from regular channels that meet national standards are safe. Of course, it is okay if anyone likes to swing them twice before wearing them, but the effect is not obvious and there is no need. Why do you say so? Let's start with ethylene oxide. Ethylene oxide, whose chemical formula is C₂H₄O, abbreviation is "EO", is a common and easy-to-use disinfectant. Schematic diagram of the structure of
Ethylene oxide in Baidu Encyclopedia
Ethylene oxide has very active chemical properties and can undergo non-specific alkylation with the proteins and nucleic acids of microorganism , causing them to lose their normal functions, thus achieving the sterilization effect. Moreover, this kind of killing is broad-spectrum, such as bacteria, spores, spores, , viruses, etc., which can be said to be a sterilization expert.
And ethylene oxide has a huge advantage, that is, it can work under "cold and dry" conditions. For example, everyone knows that heating anything to 200 to 300 degrees Celsius will definitely kill germs, but masks and other things will completely break down at this temperature. Although autoclave sterilization pot only needs to be heated to 120-130℃, it will produce a large amount of water vapor and it will have to be dried out after the pot. Many things cannot resist the water and will also be broken.
and ethylene oxide does not have this problem, because ethylene oxide has a low boiling point and a high steam pressure. When disinfecting, it only needs to maintain the temperature at around 50℃, so that it can easily enter any gaps and corners of the items to be disinfected and achieve comprehensive disinfection. Moreover, since ethylene oxide is disinfected in a gaseous state, there will be no damage to the food.
Ethylene oxide will not corrode common materials, such as plastics, paper, cotton, chemical fibers, metals, ceramics, etc. Because of these advantages, ethylene oxide has become one of the most important low-temperature sterilization methods at present. Food packaging, baby diapers, sanitary napkins, etc. can be disinfected with ethylene oxide, of course, medical devices such as masks.
To be honest, like many disinfectants, ethylene oxide does have certain toxicity. If you inhale too much ethylene oxide gas at one time, you will be poisoned on the spot. Frequent exposure to ethylene oxide can also damage your health and increase the risk of cancer. However, only workers in relevant industries need to be prevented from these risk factors, and ordinary people do not need to worry about this.
Moreover, it is precisely because ethylene oxide has a certain toxicity that the country has strict standards for the use of ethylene oxide to disinfect masks. According to the industry standard " Medical Surgical Mask " (YY0469-2011), the residual ethylene oxide of masks after sterilizing by ethylene oxide should not exceed 10μg/g.
In other words, we unpack the packaging and take out a mask, cut out 1 gram of mask fabric, take it to extract and measure, and the ethylene oxide inside should not exceed 10μg. In order to meet this standard, masks disinfected with ethylene oxide need to be dried in a ventilated analysis room for 1-2 weeks before the ethylene oxide dissipates. Then sterile testing will be carried out after 2 weeks before the standards can be met before leaving the factory. Therefore, the ethylene oxide content of the masks we usually use is already very small, and when we wear masks, part of the remaining ethylene oxide will also run into the air, so we actually inhale even less.
Comparing the residual limit of ethylene oxide, you will find that based on a medical mask weighing about 3g, each mask contains up to 30μg of ethylene oxide. According to long-term contact, if the daily dose is ≤0.1mg (1mg=1000μg), must swallow at least 3 masks a day to exceed the standard. premise is that you have to cover it tightly when swallowing, otherwise ethylene oxide will run into the air... (Do not imitate thought experiments)
Data from GB/T 16886.7-2015, ISO 10993-7
Adding ventilation can indeed make ethylene oxide evaporate as soon as possible, but, as mentioned in the video, is it really effective by just waving the mask a few times?
Not to mention, some researchers have done ventilation on the ethylene oxide content in masks. They have disinfected the medical masks that have just been sterilized with ethylene oxide and placed for a few minutes, placed them in the ultra-clean table and blow them with strong wind for different durations, and then measured the ethylene oxide content. The results are as follows.
From the reference at the end of the article
It can be seen that ventilation can indeed reduce the residue of ethylene oxide in the mask. However, it will take several minutes to blow with strong wind to reduce the ethylene oxide content a little, so if you swipe the mask a few times, the effect may not be as obvious as the video says, which may still be needed for further research to confirm.
To sum up, ethylene oxide is a very common disinfectant. As long as the residue is controlled within the safe range, it is safe to use. For qualified masks, there is no need to worry about ethylene oxide threatening health. You should know that there are still sporadic new crown epidemics in various places. In addition to getting vaccine , gather less, wearing masks is considered the most affordable and cheap protective method. Don’t give up on eating because of choking.
Joint production: China Internet Joint Rumor Refutation Platform
References: Zhou Qing, Dong Hualin, Li Li, et al. Improvement of rapid analysis method for medical mask ethylene oxide residues [J]. China Pharmaceutical, 2020, 29(7):3.
This article is produced by "Science Rumor Refutation Platform" (ID: Science_Facts). Please indicate the source when reprinting.
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