Many people may not know that the prototype of the air purifier is just a smoke protection device, so that firefighters can avoid smoke (i.e., particulate pollutants) when putting out fire.
After more than 30 years of development and continuous attempts, it was found that adding charcoal (i.e. activated carbon filter) to the machine can filter harmful and toxic gases.
In the 20th century, in order to enable scientists to breathe clean air in the research of radioactive substances, the HEPA filter came into being.
After the 1980s, the air purifiers were changed from being used in special professional scenes to ordinary commercial and household use. Household air purifiers with functions such as sterilization, formaldehyde removal and allergen filtration have become more and more popular.
Air Purifier History
With the increase of government efforts to control air pollution, the pollution control of haze and PM2.5 that harmful to people has achieved initial success.
On the other hand, with the improvement of living standards, people's pursuit of indoor decoration is gradually diversified. A variety of decorative materials and furniture appear in every corner of the house, followed by formaldehyde, benzene, bacteria and other pollutants seriously exceeding the standard, and indoor pollution control is imminent.
In order to meet the needs of people, the core function of the air purifier has gradually changed from the initial haze and PM2.5 removal to sterilization, formaldehyde removal, etc. The household air purifier has become the mainstream of the air purifier market, and has entered thousands of households as a healthy appliance. The trend of the air purifier market is to be young, high-quality and cost-effective.
Main Filtration Technology
At present, there are three main purification modes of air purifiers in the market, and different purification modes target different pollutants.
1. Activated Carbon Filter
Activated carbon is a porous carbonaceous material. The developed void structure makes it have a large surface area and can effectively contact with toxic and harmful gases. With the strong adsorption capacity, it will actively absorb toxic gas molecules into the carbon pores. Therefore, activated carbon filter is mainly for removing gaseous pollutants.
Activated carbon adsorption technology can be divided into physical adsorption and chemical adsorption.
2. HEPA Filter
HEPA, an acronym for "high efficiency particulate air [filter]", is a type of pleated mechanical air filter.
The standard HEPA filter can absorb 99.7% of the suspended particles with the size of 0.3 microns. HEPA can make the filtered air more fresh and clean. It mainly absorbs chemical smoke, bacteria, dust particles and pollen.
There are 5 levels of HEPA filter according to the precision of the filter.
- H10: Absorbs at least 85% of airborne particles 0.3 microns or larger in diameter.
- H11: Absorbs at least 98% of airborne particles 0.3 microns or larger in diameter.
- H12: Absorbs at least 99.9% of airborne particles 0.3 microns or larger in diameter.
- H13: Absorbs at least 99.97% of airborne particles 0.3 microns or larger in diameter.
- H14: Absorbs at least 99.997% of airborne particles 0.3 microns or larger in diameter.
3. Negative Ion Filter
The negative ion filtration technology has a significant effect on the secondhand smoke pollution. The negative ions can reduce the harm of excessive reactive oxygen species produced by atmospheric pollutants, nitrogen oxides, cigarettes, etc.
Moreover, it can neutralize the settlement of positively charged air dust after lossing electric charge, so that purify the air.
The motor of the air purifier is mainly divided into AC motor and DC motor.
AC motor (AC) can be divided into single-phase motor and three-phase motor.
DC motor (DC) can be divided into brush motor and brushless motor.
Advantages of AC motor are as follows:
- Simple structure.
- Low manufacturing cost.
- Easy to take maintenance and repair.
The main disadvantage of AC motor is that it can not adjust speed automatically, but needs the help of frequency conversion equipment.
Advantages of DC motor are as follows:
- It can adjust speed smoothly.
- It can adjust speed only by changing the input or excitation voltage and current without the help of other equipment.
Disadvantages of DC motor are as follows:
- Complex structure and high manufacturing cost.
- Difficult for maintenance with high maintenance cost.
The mainly use cases of air purifier are as follows:
- Newly decorated or renovated house.
- Families with old people, children, pregnant women and newborns.
- People with asthma, allergic rhinitis and pollen allergy.
- Families with pets.
- Places enclosed or exposed to secondhand smoke.
- Hotels, guesthouses, public places, etc.
- People pursuing high-quality and healthy life.
- Hospitals and other places that need to reduce infection and prevent the spread of disease.
Air purifiers are suitable for the following people:
- Pregnant women: pregnant women will feel unwell in the room with serious air pollution, and suffer from dizziness, sweating, dry throat and tongue, chest tightness and vomiting, which will have adverse effects on the development of the fetus. Children born to pregnant women exposed to air pollution are three times more likely to have heart disease than children born to pregnant women who breathe fresh air.
- Children: children are at the stage of biological development. Their immune system is relatively weak and vulnerable to indoor air pollution, leading to decreased immunity, delayed physical development, and blood diseases. Moreover, air pollution will increase the incidence rate of asthma in children and greatly reduces their intelligence.
- Office workers: the enclosed space with constant temperature is easy to cause bad air quality, leading to dizziness, chest tightness, fatigue, mood swings and other uncomfortable symptoms. In addition, it can cause various diseases, and even cancer in serious cases.
- The elderly: the physical function of the elderly is decreased, and they are often plagued by a variety of chronic diseases. Air pollution will not only cause tracheitis, pharyngitis, pneumonia and other respiratory diseases in the elderly, but induce hypertension, heart disease, cerebral hemorrhage and other cardiovascular diseases.
- Patients with respiratory diseases: living in polluted air for a long time will cause respiratory function decline and aggravation of respiratory symptoms, especially rhinitis, chronic bronchitis, airway asthma, emphysema and other diseases.
- Driver: there is oxygen shortage in the vehicle, and the vehicle exhaust pollution is serious.