Air purifiers: about those who could defeat smog

Indoors we especially lack fresh air, which is what is most important for human life. No matter how much pollution there is in the outside air, there is even more of it indoors, because to street dirt easily seeping through ventilation systems and cracks in windows and doors is added a no less long list of “homemade.

And the consequences of breathing poisoned air are well known: allergies and asthma, infections, colds, lung and heart diseases..

Children, whose immune system has not yet been fully developed, as well as the sick and the elderly, are at particular risk. And the ever increasing flow of cars and the use of new toxic materials every year are increasingly affecting the deterioration of air quality and as a consequence, human health.

The only solution is to clean the air in our homes, and very easy to use and economical devices – air cleaners do it perfectly.

Pros and cons of different air purification technologies

There are different types of air purifiers, differing primarily in the type of pollutants they are designed for. Conditionally, the impurities in the air can be divided into 3 groups: aerosols, which are constantly floating solid microparticles, toxic organic compounds and harmful or unpleasant odors.

The so-called “dusty” air cleaners, which purify the air from aerosols, use filters that work like a sieve with very fine cells.

Made of a special fibrous fabric, these filters have such a complex structure that virtually all particles larger than 0.3 microns get stuck in them which is the size characteristic of the most common allergens .

After some time the filter cells will get clogged with traces of particles and as a result the air does not pass through the filter, therefore the “dust” filter should be changed regularly. This leads to very significant operating costs and one should realize that air purifiers with “dust” filters are powerless against organics and unpleasant odors.

To absorb volatile impurities activated carbon is used, which has a good absorption capacity and is used not only in air purifiers, but also in water filters and we ourselves sometimes, if something is wrong with digestion, ingest “black” pills.

No doubt, the coal is an excellent adsorbent, but with two essential reservations: it does not absorb organic compounds with a molecular weight less than 40 atomic units and is saturated very quickly as D.I. Meyer found out as early as 1976 . i. Mendeleev, coal can only absorb up to 20% of its weight .

The first means that coal does not work against such typical urban air pollutants as carbon monoxide and nitrogen oxides contained in exhaust gases. And the second – that it must be changed every 3-4 months, and it’s very important to do it in time, otherwise the carbon not only ceases to absorb, but also itself becomes a source of pollution.

Nor can the harmful organic compounds most typical of the air in city houses be controlled by electrofilters. The advantage of this type of air purifiers is their high efficiency of cleaning from the smallest particles up to 0,1 micron in whole and up to 0,01 micron in part aerosol particles, having been charged while passing through the ionization chamber, are collected on the plate with an opposite charge.

In addition, electrofilters kill virtually all bacteria and viruses in the air. However, due to high-voltage fields, ESP operation is accompanied by formation of other toxic substances – very toxic ozone gas and nitrogen oxides.

The only filters that can get rid of most of the harmful organic compounds in your home are photocatalytic filters. based on a phenomenon discovered just 20 years ago, it is recognized worldwide as the most effective in cleaning closed spaces from harmful organic compounds.

The processes that occur in photocatalytic filters, in fact, repeat the natural photochemical processes that occur in nature. This method of molecular cleaning consists in the destruction of the organic impurities on the surface of the catalysts and this destruction occurs by oxidation caused by the action of ultraviolet radiation.

In the process of such oxidation organic impurities are decomposed into harmless components – carbon dioxide and water, and, moreover, viruses are deactivated and cell membranes of microbes are destroyed.

Who could defeat coal?

Among the organic compounds destroyed by photocatalysis are the very same carbon monoxide and nitrogen oxides that no other methods can cope with. It means that the street smog – the disease of all big cities – is not a problem if you have a photocatalytic air purifier at home.

This is especially urgent for our country, and not so much because of the ever-increasing flow of cars in other countries they are not less , but because of the lack of good roads, as a result of which cars are not so much driving as standing in traffic jams. so many exhaust fumes are produced that residents of houses near highways have to keep their windows shut at all times.

Naturally for these citizens the photocatalytic filters are a real salvation, especially that the purification efficiency remains constant regardless of how high the concentration of exhaust gases is and how long the filter works.

The photocatalytic filter has this remarkable ability due to the “waste-free” technology: impurities are not accumulated, but destroyed, and the harmless gaseous components and moisture vapor remaining as a result of oxidation are simply carried away by the air stream.

Equally successful with the help of photocatalysis is the purification of the air from such toxic compounds as phenol and formaldehyde, the source of which is particleboard furniture.

Passive smokers” can also breathe in easily: in a few minutes there is no trace of tobacco odor. Other unpleasant odors are also completely eliminated, which is not surprising: the smell molecule is nothing but an organic compound.

Combine!

What photocatalytic filters can’t do is keep dust and other particulate matter out of the air. Including allergens, which are easily absorbed by dust and electrostatic air purifiers. So if you combine different technologies in one device, you can get an air purifier capable of purifying the air from all kinds of impurities.

Actually, this is how it is done: quite a few air purifiers, which use several technologies, have recently appeared. And what’s interesting: with the right combination of these, the cleaning efficiency of each technology increases!