Air filters: filter out the excess?

The main detail in the air purifier, of course, is the air filter, which catches and neutralizes everything. And then again there is the problem of choice: filters are not only different brands, but also quite different in principle. Which one is more efficient?? Which one lasts longer?? And there are those that are the best – both in price and quality of cleaning of the air in the apartment? So what do we have??

Mechanical strainers pre-filters

Traps coarse, visible debris: downy poplar, animal hair, coarse dust particle size 100 microns and above . Many air ionizers do not have them.

Operating principle: coarse dust remains on the filter screen.

Design: consists of a regular fine mesh, made of high quality plastic.

Efficiency: no data.

Special features: protect not only people but also the inside of the appliance itself from dust. If not used or it does not remove particles effectively enough, it can lead to premature wear and tear of the activated charcoal or HEPA filter.

Lifetime: reusable, do not need to be replaced.

Care: can be cleaned and washed.

Electrostatic plasma

These are fine filters that remove particles with a diameter of 0.01 microns from the air.

Principle of operation: attraction of electric charges of different signs.

Design: a wire or sawtooth electrode is stretched between parallel metal plates. Potential difference is created between the plates and the electrode. Dust that passes through the filter gets electrified and settles on the plates.

Efficiency: about 95 percent.

Special features: air is ionized as it passes through the filter.

Service life: 10 years.

Care: It must be cleaned once in 10 days.

Photocatalytic

Good at removing not only organic pollutants but also formaldehyde, carbon monoxide and nitrogen oxides. In one minute the filter removes 85% of the cigarette smoke, ammonia, acetaldehyde and other toxic gases.

How it works: it doesn’t keep harmful impurities out of the air, but decomposes them on the surface of a photocatalyst titanium dioxide under the action of ultraviolet light wavelength over 300 nm . Reactions take place at room temperature and organic impurities are not accumulated, but are broken down into harmless components water and carbon dioxide .

Design: The filter includes a porous carrier with a TiO2-photocatalyst, which is irradiated with light and through which the air is blown.

Efficiency: about 80 percent.

Features: efficiency does not diminish in the process. Slow cleaning speed.

Service life: unlimited filter life.

Maintenance: not required.

Water

Usually used in climate complexes “air washers”.

Working principle: the air is purified with water.

Construction: the separator, made of high-strength materials, rotates at high speed, creating a real water storm in the purification chamber. The dust particles receive a certain charge and are fed into the humidifying discs, which have an opposite charge. Dust is attracted to the wetted discs, deposited on them and washed away with water.

Efficiency: the degree of air purification is not regulated.

Features: do not require replacement and purchase of additional consumables.

Service life: equal to the life of the appliance.

Care: Must be periodically rinsed with water.

Carbon carbon

Eliminate volatile and semi-volatile organic compounds with a rather large molecular weight.

Operating principle: absorb gas molecules.

Design: may be finely dispersed activated carbon pellets or larger pellets. In the first case, there is more air resistance, in the second – the movement of air through the filter is facilitated. Corrugated shape of the filter increases the filtering surface of the carbon, which in turn increases the efficiency of gas removal the larger the surface, the greater the efficiency of absorption .

Efficiency: the amount of filter material is an important determinant of its efficiency. Obviously, the more micropores there are in the coal, the more gas and odors can be eliminated and the longer its service life.

Special features: these filters are not very efficient in high humidity environments and do not remove gases with lower molecular weight, such as formaldehyde, sulfur anhydride and nitrogen dioxide. Additives such as aluminum oxide, aluminum silicate and potassium permanganate are used for their elimination.

Lifetime: short, up to 4-6 months.

Care: Must be changed regularly.

Zeolite

They are adsorptive filters that remove harmful gas compounds and odors.

Operating principle: absorb gas molecules.

Design: Zeolite is a special porous mineral with a large number of voids and branched channels inside, which account for up to half of its volume. This structure allows the zeolite to efficiently absorb molecules of a variety of volatile compounds.

Efficiency: no data.

Special features: Only used in some brands of air purifiers.

Service life: up to 5 years.

Care: some of the zeolite filters can be washed with water, so such filters are reusable.

HEPA also called Nano filters

More than 99% of all particles with a size of 0.3 microns and larger, i.e. most allergens pollen, fungal spores, animal hair and dander, dust mite allergens, etc. are retained in the filter. .

Operating principle: The air is forced through the filter by a fan, thus freeing the dust particles.

Design: made mostly of borosilicate fibers of varying sizes, compressed to form a lattice structure with holes large enough for air to pass through, but too small for most microparticles.

Efficiency: according to the adopted international classification there are five classes of HEPA-filters: H10, H11, H12, H13 and H14. The higher the class, the better the quality of the air filtration – so, HEPA filters H13 or TRUE HEPA are able to trap particles up to 0,3 micron in size with an efficiency up to 99,975%. But once a filter has reached 20-25% of its lifetime, its efficiency is reduced to 80%.

Features: the larger the filter size, the more particles are trapped each time they pass through the filter. The pleating of the HEPA filter must be continuous to ensure equal filtration efficiency. If the folds fit too tightly together, it restricts airflow and reduces airflow.

Service life: need to be replaced at least once a year.

Care: Not required.