Indoor air pollution is a serious problem. According to the Environmental Protection Agency (EPA), air pollution levels are two to five times higher indoors. In some buildings with a lack of proper ventilation, the indoor air may be 100 times more polluted than the air outside! This is because modern buildings are constructed with energy efficiency in mind. However, the tight seals that make a home energy-efficient also trap pollutants inside. On top of that, the average American takes nine out of ten breaths indoors, so it's imperative to make sure that your indoor air is free of allergens and other impurities. Máy lọc không khí tạo ẩm Daikin MCK55TVM6

Air purifiers eliminate allergens, toxic chemicals, and other dangerous pollutants. This article explains why people use air purifiers, how they work, which air purifiers you should avoid, and how to select the best air purifier for your needs.

Common Indoor Air Pollutants

What is the source of indoor air pollution? In terms of organic pollutants, mold and dust mites are everywhere - and they are the two most common causes of year-round allergic rhinitis (hay fever). Pollen is also a pervasive allergen that always finds its way into your home since it is so small and sticky. If you have pets, they will surely spread their dander to every nook and cranny of your home. Many viruses and bacteria are also airborne.

Even though they are not organic allergens, Volatile Organic Compounds (VOCs) cause many people to experience allergic reactions and other health problems. VOCs include formaldehyde, fragrances, pesticides, solvents, and cleaning agents. VOCs can enter the air through chemical off-gassing from furniture, new carpets, adhesives, plastics, and various building materials. Furthermore, many VOCs are known carcinogens (cancer-causing agents).

Environmental contaminants like cigarette smoke, carbon dioxide, carbon monoxide, and nitrogen dioxide may also be present in your indoor air, as well as toxic heavy metals like airborne lead, mercury vapor, and radon.

How Air Purifiers Work

HEPA air purifiers use a HEPA air filter, which was developed by the Atomic Energy Commission in the 1940s as a way to filter radioactive contaminants. HEPA filters set the standard for air purifiers: to be classified as HEPA, a filter must capture a minimum of 99.97% of pollutants at 0.3 microns or larger. Top-selling HEPA air purifiers include the Austin Air purifier, available with a HEGA (High Efficiency Gas Adsoprtion) filter, along with air purifiers from IQAir, Allerair, Blueair, and Honeywell.

Activated carbon filters remove gases, odors, and chemical toxins. The carbon is "activated" when it is treated with oxygen, which opens up millions of tiny pores to attract and adsorb chemicals. Impregnated carbon filters have been treated with an additional chemical, normally either potassium iodide or potassium permanganate; these chemicals, known as chemisorbents, improve the carbon filter's ability to trap VOCs and other chemically reactive gases.

Electrostatic filters use an electrostatic charge to attract pollutants and trap them on collector plates. These filters are great for people who don't want to have to worry about changing HEPA filters, but if the collection plates are not cleaned frequently, they quickly lose efficiency. Also, beware that some electrostatic filters emit ozone, which is known to be a powerful lung irritant and can be very irritating to some people with asthma or allergies. The Friedrich air purifier is, by far, the best electrostatic air purifier, as well as the overall top-ranked air purifier in previous Consumer Reports rankings.

Charged media filters give pollutants an electrostatic charge before collecting them in a traditional filter. Charged media filters are typically quite effective, but like electrostatic filters, they lose efficiency rapidly-and they may require frequent and expensive filter changes. Some charged media air filter units also emit ozone. The advantage of charged media filters is that they are quieter and more energy-efficient than HEPA air purifiers. The Blueair air purifier is the best charged media filter, and it does not emit ozone.