You may be keeping your home as clean as possible. It may also look very clean and dust-free. But the reality is different. Every cubic foot of air in the average home is loaded with about 3 million dust particles. Most of these dust particles are invisible to human eyes but they are harmful to health.

Air cleaners (also called air filters or air purifiers) can help reduce the problem by filtering out the microscopic dust particles caused by smoking, fireplaces, pets, molds, pollen, and other sources of indoor pollution.

Wide range of air purifiers / air filters are available.  Different technologies are used by these air cleaners to clean the air. There are air purifiers that can be installed to filter air in a single room of can be connected to the air conditioning or heating system of the house to filter air in the entire house.

Let us now understand the different types of air cleaners available and how they work.

Several technologies are there to remove dust from air and make it clean but the most common of them all involve cycling the air through or past a filter that traps or attracts dust particles to withdraw them from the air.

Most small tabletop and room air cleaners send air through an array of filters – The first air filter is foam pre-filter to screen out large particles. The second air filters to catch smaller dust particles. Third is a carbon filter to remove odors and some gases, and fourth one is a post-filter for final air filtration.

There are different types of air filters to purify air. Let us understand them one-by-one:

HEPA stands for High Efficiency Particulate Accumulation. These are highly effective filters designed for removing radioactive particles from air. Today, HEPA filters are made from finely woven glass particles formed into a pleated filter with a very large surface area. HEPA filters remove 99.97 % dust from air. It can revove dust of size as small as .3 micron.

ULPA stands for Ultra Low Penetrating Air. These are used mail in “clean room areas” such as hospitals and manufacturing places that are very sensitive to dust. These are available in self-contained home air cleaners. These air filters are made of micro-fibers that traps 99.99 percent of tiny dust particles of size .1 micron.

An electret, or electrostatic air filter attract dust particles using static charge. An electrostatic filter blocks between 10% and 35% of microscopic particles.

A negative-ion generator or ionizer purifier uses tiny charged wires to create ions with a negative charge that latch onto airborne particles. Some ionizers have a fan that improves the cleaning and distribution of air. Ionizers make lots of noise but are more effective than other types of air purifiers without a fan. This air cleaner forces airborne dust particles to stick to walls, floors, tables, and other surfaces near the unit.

An electronic air cleaner draws dust particles in by a fan and charges them with a series of high-voltage wires. A precipitating cell that carries the opposite electrical charge attracts the particles as they pass by. These air purifiers are quite effective and remove about 90-95% of bulk dirt and 80-85% of microscopic dust particles.