PM2.5 still can't handle it: Inventory of in-car air purification technologies

    In the past two days, people in many parts of China have been in a state of "virtue carries fog, self-improvement does not inhale". This is not the poetic fog, but the haze containing pathogenic particles (especially the famous PM2.5). The air quality index at many monitoring points in Beijing once exceeded 500, which is "off the charts". For these pollutants, can modern cars filter them out? Let's take a look at the current mainstream in-car air purification technology.

Car air conditioning filter

Main functions: filter dust particles and absorb odors

    The "pollen filter" function is currently equipped on many car models. It mainly filters out large particles of dust, pollen and other harmful substances in the air entering the car from the outside through the car's air filter. Some cheap car models do not have air conditioning filters, so they do not have this function.

Inventory of vehicle air purification technologies

    The air conditioning filter is equipped with electrostatic filter cotton to absorb particles in the air, and is made into a corrugated shape to increase the contact area with the air. At the same time, some models of filters also have activated carbon. Since activated carbon has many tiny holes, it is also a good material for purifying the air (activated carbon can not only absorb particles, but also eliminate odors. Many charcoal bags placed on new cars are activated carbon, which is also a long-term air purification method).

Inventory of vehicle air purification technologies

Air conditioning plasma generator

Main functions: Kill bacteria and mold, decompose harmful gases

    In fact, the plasma purification function is also used in ordinary household air conditioners. Its main principle is to generate plasma through high-voltage circuits, and destroy the protein film on the surface of bacteria through positive and negative ions, thereby killing bacteria and mold in the air. At the same time, the plasma generator can also partially decompose gases such as styrene to purify the air.

Inventory of vehicle air purification technologies

Inventory of vehicle air purification technologies

Inventory of vehicle air purification technologies

In-car negative ion generator

Main function: eliminate static electricity and make the air fresher

    The principle of negative ion generator is similar to that of plasma, which is realized by high-voltage circuit combined with tip discharge. It is now mainly used in household air conditioners. The role of negative ions is different from that of plasma. The former mainly eliminates static electricity and makes the air in the car fresher. You can even feel like you are in a big forest (the air in the forest, after rain, etc. is rich in negative ions, which makes people feel very fresh).

Inventory of vehicle air purification technologies

    Negative ion generators also have their own disadvantages, that is, while producing negative ions, they are also prone to produce excessive ozone. Therefore, for car air conditioners, the negative ion generator should not be used for too long, and attention should be paid to internal and external ventilation.

Photocatalyst purification

Main function: decompose harmful substances such as formaldehyde and benzene

    Photocatalyst is a new technology that has emerged in recent years in air conditioning and vehicle air purification. It is actually to install a solid catalyst in the air conditioner or car, and under the action of light (including visible light and ultraviolet light), it decomposes harmful substances such as formaldehyde, benzene, xylene in the room or car into harmless substances such as carbon dioxide, nitrogen and water. Some car series, such as the new Camry, have integrated photocatalyst purification devices in the air conditioning system.

Inventory of vehicle air purification technologies

Is the existing in-car air purification technology effective against PM2.5?

Conclusion: Limited effect, does not solve the fundamental problem

    PM2.5 is one of the hottest terms at present. It refers to particulate matter in the atmosphere with a diameter of less than or equal to 2.5 microns. Because it contains a large number of toxic and harmful substances and is not easily eliminated by the human body, it is very harmful to the human body, so it has become the "air killer" in everyone's mind. In contrast, the size of pollen ranges from a few microns to thousands of microns, usually tens of microns. It is difficult for the filter of the car air conditioner to completely filter out PM2.5 particles.

Inventory of vehicle air purification technologies

Inventory of vehicle air purification technologies

    In addition, plasma and negative ion purification equipment can only partially decompose PM2.5 particles, and it is difficult to completely remove them. As for photocatalysts, they are basically ineffective against PM2.5. Therefore, for PM2.5, these current purification measures in the car are difficult to solve the problem. If it is really impossible, you can only wear a PM2.5 filter mask when traveling. If you don't wear a mask, the only thing you can do is to calm down as much as possible and don't breathe in more air. That's all.

Inventory of vehicle air purification technologies

summary

    Facts have proved that the air purification equipment in the car can indeed deal with fine dust such as pollen, which is still very useful for passengers who are prone to allergies or have diseases such as asthma. However, faced with PM2.5, which is rising faster than the stock market, these technologies are currently unable to fundamentally solve the problem. Therefore, we also hope that automobile manufacturers will make more efforts in technology, at least to give consumers more choices and care.