The most core function of an air purifier is to filter out the dirt in the air. For instance, particulate matter such as PM2.5, pollen and dust can be intercepted by HEPA filters (high-efficiency air filters). Harmful gases such as formaldehyde and benzene produced during decoration can be adsorbed by activated carbon filters. High-end models will also use decomposition technology (such as amino decomposition) to turn formaldehyde into harmless water and carbon dioxide. If there are people with allergic constitutions at home or if you have cats or dogs that shed a lot of hair, an air purifier can reduce allergens in the air and relieve symptoms such as sneezing and runny nose.

For instance, my friend's home was just renovated last year. When the formaldehyde level in the living room was tested, it exceeded the standard by more than twice. She bought a purifier with formaldehyde decomposition function. After running it for a week and testing again, the value dropped to a safe range. She said the most obvious feeling was that before, when she entered the house, she could smell the pungent "renovation smell", but now it's basically gone.

In addition, air purifiers are also effective against second-hand smoke and cooking fumes. For instance, if someone smokes at home or there is a lot of cooking fumes, an air purifier can quickly adsorb the odor molecules, making the air fresher. This is especially practical for small-sized apartments when ventilation is poor.

One more point is often overlooked - sterilization and disinfection. Nowadays, many air purifiers are equipped with ultraviolet lamps or plasma generators, which can inactivate bacteria and viruses in the air. For instance, during the flu season, if there are elderly people or children at home, turning on a purifier can reduce the risk of cross-infection.