People allergic to plant pollen, animal hair, and other organic irritants are advised to install air purifiers indoors. Also, household appliances are useful for residents of cities whose houses are located near industrial zones and busy highways. Modern models protect the user from dust, harmful aerosols and unpleasant odors. How to choose an air purifier for a city apartment - read on.
Ways to clean room air
Effective air purification involves two operations:
- removal of the smallest particles and impurities;
- deactivation of harmful microorganisms.
There are several methods for solving these problems. Let us consider in detail those that have found application in home air purifiers.
Mechanical particle capture (HEPA filters)
It is carried out by means of fibrous materials working on the principle of a sieve. HEPA is the designation of all such filters, adopted in the West (regardless of the degree of purification) and has recently gained distribution in the territory of the former USSR. Previously, such elements were known under the name “Petryanov’s fabric”.
HEPA is an abbreviation for the term High Efficiency Particulate Arrestance, in Russian - "high-performance particle capture."
Filters of this type used in home air purifiers look like a sheet folded with an accordion made of a material resembling paper. This is the most effective means of delaying solids:
- possesses a meager slip coefficient (the ratio of the dust content of the air at the filter outlet to the contamination of the inlet stream);
- traps particles up to 0.3 microns in size (for example, hair thickness is 80 ... 120 microns, flower pollen - 10 ... 250 microns).
The filtering ability of an element is periodically restored by a vacuum cleaner; at the end of its useful life, the "accordion" is changed. If this is not done, the filter from the dust cleaner turns into a pollutant, since it saturates the air with particles that have fallen on it earlier.
Disadvantages:
- High aerodynamic drag is the flip side of efficiency. The HEPA dust collector needs a fan to create powerful airflow.
- Special disposal is required: pathogens are likely to breed on the filter. Bactericidal traps are less dangerous.
- The element does not trap chemical gaseous impurities. These include substances recorded by the sense of smell as unpleasant odors.
Adsorption-catalytic method (carbon filters)
By special treatment, coal is converted into activated carbon containing many micropores. Due to the small size of the pores, they easily capture molecules of foreign gases, allow only air to pass through. The carbon filter purifies the room atmosphere from unpleasant odors, tobacco smoke, car exhaust and emissions from nearby industries.
Purifiers of this type, like HEPA, after running out of resources pollute the air with accumulated material, therefore they require timely replacement.
Attention! Coal absorbers do not tolerate high humidity: under such conditions, the filter material "sinter" and ceases to perform its functions.
Electrostatic elements
An electrostatic filter (aka a plasma ionizer) is a set of plates with metallic threads installed between them. A potential difference is applied to the indicated elements, an electric field is formed around, and a corona discharge is formed on the threads themselves. The latter causes ionic current between the conductors and the plates.Dust in the passing air stream is ionized (magnetized), then, under the influence of an electric field, it is attracted to the plates.
Note. The filter must be cleaned of accumulated dirt 1-2 times a week.
Photocatalytic Purification
This filter contains two components:
- catalyst plates, usually made of titanium dioxide;
- Ultraviolet lamp.
Under the influence of ultraviolet radiation, all organic substances that have fallen on the catalyst enter into a photochemical reaction with oxygen contained in titanium oxide. As a result of oxidation, they decompose into carbon dioxide and water. Microorganisms are also chemically “burned,” so the photocatalytic filter also has an antibacterial effect.
Minus element: to capture inorganic impurities, for example, building dust, such a device is incapable.
Hydrofiltration
Water filters are available in two versions:
- Conical. The device is equipped with a cone, which creates a moist mist due to rotation in the water tank. The air blown through this suspension is saturated with moisture, and the mechanical impurities contained in it become wet, heavier and settle.
- Disk devices differ from the previous type in the principle of action: instead of a water curtain, a rotating cassette of plates installed with a gap is used. Flat parts are arranged vertically and half recessed in a container of water.
Explanation. As a result of rotation of the cartridge, the plates are constantly wetted. Air is blown through the gaps between them, making most mechanical impurities remain on a wet surface. The adhering dirt is washed off the next time the “blade” is immersed in water.
Air washers are positioned as two-in-one devices: they combine the functions of humidification and air purification. This is undoubtedly a plus. But the hydraulic filter, in the first place, is precisely a humidifier - it cleans the atmosphere of a home very mediocre. Only large particles are retained and far from all; cone models are powerless against soaks that are not susceptible to wetting. Such a device will not help a sensitive allergy sufferer.
Features:
- The water in the tank is periodically changed - dirt accumulates in it. Ideally, daily maintenance is required.
- Poorly purified water in the sink "blooms", especially with prolonged downtime of a household appliance. It is not recommended to fill the cartridge with tap water - you need distilled.
- The increased humidity in the device causes the intensive development of colonies of microorganisms, therefore it is highly advisable to do disinfection (disinfection). Often, UV lamps are built into air washers.
Tip. With high purity requirements, it is more reasonable to purchase a high-quality air purifier and a separate humidifier, for example, an ultrasonic one. Or spend money on a climate complex, consisting of a full-fledged air purifier and a humidifier with cold evaporation.
Disinfection
Destruction of harmful microorganisms is carried out using ultraviolet lamps. They also die, as already mentioned, on the catalyst of the photocatalytic filter.
Recently, some manufacturers began to use ozone for disinfection. Oxygen molecules are converted into it during an electric discharge (ozone formula - O3). This gas is a strong oxidizing agent, at a certain concentration destructive for all living things. At the outlet of the purifier, it is neutralized by a special adsorption-catalytic filter.
Criteria for choosing a household appliance
When considering how to choose an air purifier for the home, you should pay attention to the following points:
- purification method;
- device performance;
- power consumption;
- noise level and functionality.
The cleaning methods involved
The best air purifiers contain several filters of different types (multi-stage cleaning). It is important that there is an effective HEPA filter among them.Today they actively advertise the so-called filterless climate systems that do not burden the user with the need to periodically buy replacement filters. HEPA and coal dirt traps are absent in them, but only:
- ionizer (see below);
- photocatalytic and electrostatic unit.
Such devices are ineffective by definition, because the listed traps are elements of auxiliary air treatment, and here's why:
- Photocatalytic decomposition takes time, and airborne contaminants travel too fast. Note: not all organics lend themselves to such splitting.
- Electrostatic filters are effective for large plate sizes. Household models are distinguished by small blocks, therefore they are unable to purify air from all impurities.
- An ionizer acts on dust like an electrostatic unit and, for the same reasons, cannot delay it completely.
By the way, the term “HEPA filter” does not mean high-quality filtering. This is a common name for all fabric dust collectors. For the right choice, it is worth specifying the product class. The European standard EN 1822 identifies 17 such classes - from G1 to U17.
Reference. Each category of tissue elements corresponds to the MPPS (Most Penetrating Particle Size) - the largest size of the transmitted particles. Filters of the highest category retain particles with MPPS = 0.3 μm.
Filter classes are grouped:
- rough - G1 ... G4;
- fine cleaning - F5 ... F9;
- high efficiency filters - H10 ... H14;
- ultra high efficiency - U15 ... U.
The best cleaners must have a charcoal filter and three HEPA filters of different classes - coarse, medium and fine cleaning (the latter is not lower than H11). A good addition will be antibacterial impregnation of the filter surface.
Note. For rooms with strong unpleasant odors, manufacturers produce activated carbon filters.
Productivity
Typically, the characteristics of the device indicate the maximum area of the room for which it is designed. But this is a relative indicator. It’s more correct to take the air performance and correlate it with the volume of the room for which the device is selected. Under normal conditions, a single air exchange is required (1 room volume per hour). For allergy sufferers - three times.
Calculation example. For a room of 50 m² with a ceiling height of 2.5 m, an ordinary person needs a cleaner with a capacity of 50 x 2.5 = 125 m³ / h, for allergy sufferers - 50 x 2.5 x 3 = 375 m³ / h.
Noise level
All air purifiers are noisy “thanks” to the built-in fan and, since the devices work for a long time, the sound level is important. The model is selected taking into account the installation location. For example, in an office, even a noisy system of discomfort will not cause, but for a bedroom, quieter equipment is required.
According to medical standards, the maximum noise level during a night's sleep is 30 dB. There are air purifiers so quiet that the user has to visually check if the device is working.
Installation options
Household air cleaning systems are available in three versions:
- desktop (low-power models);
- wall mounted;
- outdoor.
Tip. The choice in favor of the desktop version should be done with caution for those who have a small child in the family. It is undesirable for him to have access to the device.
Floor models win in comparison with wall models in mobility - if necessary, the device can be temporarily transferred, for example, to the kitchen. But such cleaners occupy more useful space, especially since they can not be placed close to the walls. The minimum allowable distance for different models is from 15 to 50 cm.
Additional functions
Some models of air purifiers are supplemented with useful functions:
- Aromatization. The device mixes in the air stream a pair of aromatic oil contained in a special cartridge, that is, it works as a freshener.The function is useless in appliances equipped with a carbon filter that removes odors.
- A mixture of fresh air from the outside. In addition to the standard recirculation mode, the cleaner works as a supply unit. That is, the outside air enters the room already clean, which minimizes the risk of allergies and other diseases. Some models are equipped with an air flow heater. Such stations are called ventilators or breathers.
- Filter pollution indicator. Convenient feature that saves money: filters change when it is really needed.
- Automation functions: control of dust / gas pollution, timer.
- Night mode. When activated, the device works much quieter, but at the same time performance decreases.
- Ionization.
In part, the ionizer helps filter the air, acting on the dust like a magnet - impurities are electrified and then attracted to a horizontal surface (it is periodically wiped). But the main work of the device is to saturate the air with positive and negative ions.
Marketers position the ion module as absolutely necessary - according to their assurances, the air after filtration loses charged particles and becomes dead. Indeed, ions are important for the normal functioning of the body and their number is even regulated by the normative document SanPiN 2.2.4.1294-03 "Hygienic requirements for the aeroionic composition of the air", but with regard to ionizers, experts state the following:
- the benefits of artificial ions are not confirmed in any way;
- the ionizer can exceed the concentration of charged particles in excess of the permissible (in the mentioned document not only the minimum, but also the maximum quantity is specified);
- this module can produce ozone, and when it exceeds MPC, it has a toxic effect on the body.
For reference. Ozone in acceptable amounts by sense of smell is not recognized. If the smell of "freshness" or "as after a thunderstorm" is felt, then the maximum concentration limit is exceeded and the room needs to be ventilated urgently.
The question of the appropriateness of using ionizers is still controversial. One way or another, many experts recommend abandoning this option.
Browse Popular Models
A potential buyer should pay attention to several proven air purification systems. Consider 4 models from various companies.
Daikin is a Japanese manufacturer of household and semi-professional air purifier options (Daikin Siesta and Daikin MC704VM).
Features Daikin MC70LVM:
- number of cleaning steps: 5 standard + in-house development - Flash Streamer technology for combating unpleasant odors and formaldehyde fumes;
- power consumption - 65 W;
- air productivity - 55–420 m³ / h;
- optimum served area - 46 m²;
- noise level - 16 dB;
- control - remote control.
The inexpensive Ballu AP-430F7 air purifier with the following characteristics:
- the number of stages of filtration - 7;
- power consumption - 91 W;
- room area - up to 50 m²;
- productivity - up to 270 m³ / h;
- noise level - 53 dB;
- the number of operating modes - 3;
- management - touch screen.
The Chinese device Xiaomi Mi Air Purifier 2 is equipped with two filters:
- external: the grid and HEPA pleated are installed in it. Their task is to retain solid suspensions;
- internal: filled with activated carbon made from coconut shells. Gaseous impurities and odors are adsorbed here.
Up to 518 thousand particles of 0.3-0.5 microns in size remain in a cubic meter of purified air. You can control the operating mode, monitor the degree of air pollution using a smartphone.
Reference. The performance of Xiaomi Mi Air Purifier 2 is about 300 m³ / h. This model can clean air in an area of 23 m² in 600 seconds.
Climatic complex Panasonic F-VXK70R classic version has three stages of cleaning + humidification:
- The carbon filter absorbs odor and gaseous impurities.
- With allergens and fine dust the HEPA filter copes.
- A layer of green tea extract reduces the activity of viruses.
For an hour of operation, the device cleans 402 cubic meters of air. This is enough to clean a room of 52 m2 from dust. According to the results of many tests, the Panasonic F-VXK70R confidently takes the 1st place among the considered plants for processing indoor air.
User reviews
Artem, Tula.
In our apartment, the air humidity is only 10-15%. And you can open only the casement windows (window leaves for some reason are missing). Heating works like at the north pole - the heat is immense! In general, we decided to buy an air purifier with a humidification function. And now for a day he faithfully performs his tasks. It’s too early to talk about the results, but now the smell of clean linen has “settled” in the house. And breathing easier.
Arseny, the city of Kaluga.
My wife rebelled, demanded to remove the air purifier. He says he is tired of washing white plaque from surfaces close to the device. Although knowledgeable people claim that this inconvenience occurs when filling the apparatus with tap water. The amount of chlorine in it is so great that it is not able to delay its device. So he settles on the surrounding objects.
Vitaliy, a practical engineer.
Ionizers can be harmful: the standards set the maximum permissible value of the emitter voltage - 25 kV. Models of 30 kV and above are not worth buying. In addition, some powerful devices simultaneously ozonize the air. Fortunately, the smell of ozone is already felt at a concentration of 0.05 mg / l, so you are aware of the danger. This device is better not to use.
Arina, Kuznetsk.
I have been using a humidified air purifier for two years now. I must say right away: with hot batteries this function is useless. But the air in the room is clean. I do not turn off the device at night, I only reduce power so that it does not make much noise. A lot of dirt forms on the walls of the water tank. If it is not removed, an unpleasant odor appears.