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Can those "negative ion" purifiers on the market really purify the air

Recently, as soon as the weather in various cities is reported to be seriously polluted, the market has begun to pay attention to the control of the weather and the purification of the air. More and more people in the market are selling air purifiers. Does it really work?

There is an air purifier manufacturer to introduce the principle of their products: "air molecules capture electrons, will become negative ions. It is very beneficial to people's health, known as the & lsquo; vitamin in the air;. Negative air ions can enhance human metabolism and immunity. It is particularly high in forests, waterfalls, lakes, oceans and other natural environments, so people will feel fresh and breathe freely in these places. Negative air ions can reduce formaldehyde, cigarettes and other air pollutants, kill bacteria, neutralize positively charged air dust, and purify the air?

Is there any negative ion in nature

The original source of the negative ion may be Japan. Some creative businessmen invented the concept of 'negative ion' and concocted various research evidences to advocate the health effects of 'negative ions'. What's the truth? First, let's take a look at what can be charged in nature.

In a dry environment, wearing and taking off clothes will be hit by static electricity. We know that solid can be charged. Lightning and thunder are generated by the discharge between rain clouds. We know that liquid droplets can also be charged. These charged solids and liquids do exist in nature for a long time.

But unlike gas molecules, they have difficulty catching electrons. To make a gas negative, high temperature, strong electric field or high-energy photons are needed to ionize the gas and release enough electrons. Some gas molecules, such as oxygen, water, sulfur hexafluoride, which are easy to absorb electrons, will be negatively charged in this ionization environment. But this state is unstable. Once the ionization source is removed, the density of electrons will be reduced, and these gases will soon lose their electrons and return to the uncharged state. Therefore, the negative ion gas molecules cannot exist stably in nature. Only thunderstorms may produce some negative ions temporarily, while forests and waterfalls do not have ionization sources, so it is impossible to have high concentrations of negative ions.

So, even if there are no stable 'anion' gases in nature, we can produce them by artificially ionizing air. But are you sure this charged air is what you want?

What's the use of negative ions

When ionizing air, the negative ions, i.e. negatively charged oxygen molecules, can be converted into superoxide ion radicals with strong oxidation capacity. They can be used to collect positively charged dust, react with some harmful gases and kill pathogenic microorganisms. But it can't distinguish between normal human cells and harmful microorganisms. If you encounter cells, you'd rather kill them by mistake than let them go. Ozone is also produced in the process of ionizing air. Ozone also has a strong oxidation capacity and burns the respiratory tract. It is the main pollutant in the city in summer. Its lethality is not weaker than PM2.5. It may cause lung burns, headache, eye pain and asthma attack.

It is not reliable to eliminate particulate matter pollution by negative ions. If electrons are constantly released into the air, small particles of solid and liquid in the air will be charged. Charged particles are easy to be absorbed by door and window furniture, so that they are covered with a layer of ash. It is conceivable that if these particles enter the respiratory tract, they will be more easily adsorbed to the respiratory wall than when they are not charged. Of course, if a positive electrode is set near the negative electrode, these negatively charged particles can be adsorbed, but in this case, there is no negative ion in the air, which is far from the propaganda of the manufacturer.

In 2003, a consumer report of a nonprofit organization in the United States issued a report that the product of using negative ions to purify air is suck. A producer of anion air purifiers was in a hurry and took the report's publisher, the Consumer Association, to court. The court said after investigation, the report is right, negative ion purifying air is suck. In 2005, the California District Court ruled that the company lost the lawsuit and asked the company to pay 525000 dollars of litigation costs to the Consumer Association.

Therefore, the anion can be sterilized and suck dust, but it is not effective for air purification. It is far less effective than the propaganda of the manufacturer.