There is disinfectant in the air. Where does it come from? It is formed spontaneously

Hydrogen peroxide, if this name sounds unfamiliar to you, then its other name must be very familiar to you, that is, hydrogen peroxide.

Hydrogen peroxide is a disinfectant. Its disinfecting effect is mainly achieved through its strong oxidizing property. The pyogenic cocci and various intestinal pathogenic bacteria we are familiar with can be easily killed by hydrogen peroxide. Therefore, hydrogen peroxide is widely used in environmental disinfection and wound disinfection. In addition to the medical field, it is also used in many places in industrial production and daily life.

Although hydrogen peroxide has a wide range of uses, it is not very easy to prepare. The production of hydrogen peroxide requires voltage and a catalyst. Commonly used methods include electrolysis, isopropyl alcohol method, anthraquinone method, etc. The anthraquinone method is commonly used in my country.

Hydrogen peroxide has a wide range of uses and is in great demand, so people around the world have been researching new methods for producing hydrogen peroxide. While studying this issue, a research team at Stanford University unexpectedly discovered a phenomenon: hydrogen peroxide can be formed spontaneously.

The research team found that water molecules in the air can be spontaneously converted into hydrogen peroxide. This sounds like nothing, because water is H2O, and hydrogen peroxide is H2O2, and the only difference between the two is an oxygen atom. It seems easy to complete the conversion, but in fact it is not that easy. Although there is only one oxygen atom difference between water and hydrogen peroxide, if you want to make up for this atom, it means that you must break an existing covalent bond before you can add an oxygen atom. How can this covalent bond be broken without the participation of voltage and catalysts?

There is a condition for the spontaneous conversion of water molecules in the air into hydrogen peroxide, and that condition is that the volume of the water droplets must be small enough.

Research has found that when the diameter of water droplets in the air reaches less than 20 microns, water can spontaneously turn into hydrogen peroxide. What is the concept of 20 microns? The smallest unit of length we can use in daily life is millimeter, and 1 micron is equal to one thousandth of a millimeter, which is so small. Now the question is, why can water droplets be spontaneously turned into hydrogen peroxide when they are small enough? This is due to a phenomenon called "contact electrification". When micro-water droplets collide with solids, the charge will "jump" between the liquid and the solid, thus generating unstable molecular fragments, which are reactive oxygen species.

Among the unstable molecular fragments produced by these collisions are hydroxyl radicals, which are three-electron reduction products that can combine to form hydrogen peroxide when they form pairs.

Water droplets collide with solids? Where do the solids come from? The air is full of various dust particles, which are solid particles. The collision of water droplets in the air with solids happens all the time, so hydrogen peroxide is naturally generated, but the amount of naturally generated hydrogen peroxide is very small. The research report of the Stanford University research team has aroused doubts as soon as it came out. For example, some people questioned that potassium permanganate must be used to detect hydrogen peroxide in the air. However, the team later explained that they used mass spectrometry to detect hydrogen peroxide in the air.

There is spontaneously formed hydrogen peroxide in the air. What does this have to do with our lives? It has a lot to do with it.

As we all know, in the cold winter, people are always more likely to suffer from respiratory diseases such as colds. Why is this? Because of the cold weather? These diseases are essentially caused by bacterial or viral infections and have no direct relationship with cold or heat. Moreover, even if you stay at home all the time, you are still more likely to catch a cold in winter than in summer. Now we seem to have a more reasonable explanation for this problem, that is, the number of bacteria and viruses in the air in winter is higher than in summer, and the reason lies in the spontaneous formation of hydrogen peroxide. The air is dry in winter, and the number of micro-droplets in the air is less, which reduces the amount of spontaneously formed hydrogen peroxide, reduces the disinfection effect, and naturally increases the number of germs.

In winter, due to the use of heating equipment, the indoor air is drier, and the content of water droplets and hydrogen peroxide in the air is even less. If you do not pay attention to ventilation, bacteria will inevitably breed.

The above is the conclusion drawn by the Stanford University research team, which explains part of the relationship between seasons and respiratory diseases to a certain extent, which makes me think of another question, that is, life expectancy. It is well known that the average life expectancy of people living in dry and cold areas is significantly longer than that of people living in humid and hot areas. This may also be related to the content of hydrogen peroxide in the air, because hydrogen peroxide is a strong oxidant, and the aging process of human beings is essentially an oxidation process, so the high content of hydrogen peroxide in the air may accelerate the aging of the human body to a certain extent.

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