Air purifiers
An air purifier or building site air purifier is a unit for filtering indoor air by retaining harmful particles in the room. Indoor air can be up to five times more polluted than outdoor air, for example with dust, fungi, bacteria or allergens. Air purifiers counteract this and ensure clean and purified indoor air. They enable fine dust, germs or contaminated aerosols as well as unpleasant odours to be filtered out of the air in a wide variety of environments. This ensures improved air quality and fewer health hazards for people present. An air purifier can be used on building sites, in industry and in handicraft environments, as well as in medical practices, offices or meeting rooms.
The functions of an air purifier
Air purifiers massively reduce pollution on building sites and in rooms. Their filter system removes dust, spores, virus-laden aerosols, bacteria and pollen from the air. On the building site, air purifiers also filter inhalable fine dusts from the air to protect the tradesman.
(Air purifiers with filter system draw in the polluted indoor air via a fan and direct it into the interior of the air purifier. A larger fan ensures that a greater amount of air is taken in while it rotates slowly. This keeps the noise level lower than air purifiers with a smaller fan. The air drawn in is directed through the built-in filter system and passes through several filters. In this process, dust and larger particles are first collected and the smallest particles are then filtered out of the air. Fine dust, aerosols and other pollutants are collected and the air purifier releases the purified, clean air back into the room via an outlet).
Filter systems
A building air purifier needs more than just one type of filter in order to remove as many pollutants as possible from the indoor air. This is why most air purifiers contain several air filters, each of which filters a specific type of pollutant such as fine dust or viruses.
As a rule, there is a pre-filter mat in the air purifier at the beginning. This retains coarse particles and protects the filter cartridge. The coarse filter that follows, also referred to as a pre-filter, already retains 90 % of the dust particles, as well as hairs or small insects. The pre-filter consists of a grille or a fleece and works like a sieve. Unpleasant odours in the room can also be filtered with an activated carbon filter. This activated carbon-based filter retains around 70 % of the dust particles. A fine dust filter retains up to 80 % of the fine dust particles that are usually present on building sites.
HEPA filters, as they are known, have the greatest effect. The abbreviation HEPA stands for "High Efficiency Particulate Air". These air filters are made of synthetic filter fibres and work by means of the barrier, inertia and diffusion effect. In the barrier effect, small particles that follow the airflow due to their low mass are attracted to the fibres when they get too close and then stick to them. The inertia effect affects larger particles. Due to their greater mass, these maintain their direction unchanged even when the airflow changes direction, causing them to hit the fibres to which they likewise stick. The diffusion effect affects the smallest particles, the movement of which is influenced by collision with other gas molecules. As a result, the particles do not follow the air flow evenly, but instead are constantly deflected and thus hit the filter material to which they stick. HEPA filters are available in two classes, HEPA13 and HEPA14. The HEPA H13 filter retains 99.99% of particles, and the HEPA H14 filter retains as much as 99.995% of particles.
Replacing filters
Depending on the type of filter, the air filters must be replaced sooner or later. This depends on the environment in which the air purifier is used and which model. On a building site, the filters usually last for less time than in an office for example, because more dust and dirt need to be absorbed during air purification there. HEPA filters last for about three months on a building site, whereas in an office they can be used for as long as one year. Pre-filters and activated carbon filters should be changed more frequently, depending on the amount of dust they are required to absorb during air purification.
Uses of an air purifier
Office air purifier
If an air purifier is installed in the office, attention should be paid to the ratio of room size and room structure to the performance of the air purifier. The air purifier should convey the all of the indoor air through the filters at least six times per hour. This means that in a larger room, there is greater demand on the unit than in a smaller room. The air purifier's required capacity can be determined by multiplying the indoor volume by six. Noise volume should also be taken into account when installing an air purifier in an office. This should be kept as low as possible so as not to unpleasantly disturb the working atmosphere. Along with easy handling, care and maintenance should also be considered.
By installing air purifiers, companies protect their employees against contagions and their lungs being exposed to dust. Allergy sufferers in particular benefit from the air purification performed by these units. Allergens such as pollen and household dust or air pollutants are automatically filtered out of the air. The air purifier also benefits people who are sensitive to odours, because odours in the office are also filtered out with the aid of the activated carbon filter.
An air purifier is particularly useful in offices where adequate ventilation is not possible, or in large cities where ventilation may increase the level of pollutants.
Building site air purifiers
On a building site, such as during construction work or refurbishment, special conditions apply with regard to indoor air. Compared with such places as schools, kitchens or domestic settings, dust exposure regulations exist for indoor settings on building sites. These must be strictly adhered to in order to protect tradesmen, which is why an air purifier is usually essential on a building site. For building site air purifiers, the fine dust filters and HEPA filters are particularly important as these capture the inhalable and harmful dusts and filter them out of the air. In addition, other harmful substances are produced in the air on building sites and the removal of such things as odours, gases, germs or mould is also done by the air purifier. On a building site, the air purifier captures construction dust and pollutants, and releases the purified air into the room.
Air purifiers in businesses
Private premises, offices or building sites aren't the only places where air purifiers ensure clean air. Industrial air purifiers can also be used in businesses. As in other environments, these units suck in viruses, bacteria, pollen and other air pollutants and filter them out of the air. Depending on the setting, unpleasant odours often arise in businesses and these can be easily neutralised or eliminated with an activated carbon filter inside an air purifier. More dust is also created, which is why a HEPA filter is also useful in commercial applications. An industrial air purifier ensures improved overall well-being at the workplace. Air purifiers have different cubic metre performance levels per hour, which is why care must also be taken to ensure that the filter is right for the room size in the business.
How appropriate are air purifiers?
Air purifiers have been proven to improve air quality. However, they are no substitute for regular ventilation. But they are particularly useful in rooms where regular ventilation isn't always possible for a particular reason. However, air purifiers in a room are only helpful in terms of air quality if their performance is tailored to the size of the room and the number of people in it. For example, a small air purifier used to remove odours in a small kitchen is of no use on a large building site.
If the right air purifier is chosen, the unit will significantly improve the quality of the air. An air purifier is therefore appropriate in many different areas. The amount of pollutants and very small particles is massively reduced, allergy sufferers can reduce their suffering by filtering out allergens such as pollen and dust, the risk of infection by viruses and bacteria is reduced and health problems caused by inhalable fine dust is prevented.
What are the benefits of an air purifier against coronavirus?
The importance of an air purifier to support clean and virus-free air became particularly clear with respect to the coronavirus pandemic of the past two years. While ventilation is still essential for indoor air quality and reducing the risk of covid infection, air purifiers can effectively filter contaminated aerosols and coronaviruses through the air filters. With a HEPA filter, which comes in two different classes, air purifiers can filter not only dust, odours and allergens but also coronaviruses. The HEPA filter is available as HEPA 13 filter, which retains 99.99% of particles from the air, and as HEPA 14 filter, which can filter 99.995% of particles from the air.
Buying an air purifier
Price isn't the only factor to be considered when buying an air purifier. Because even if the cheaper item seems more attractive, there are other details about air purifiers that are more important when it comes to making a purchase. Decisive purchase factors should include filter effectiveness and power consumption. The effectiveness of the filters is indicated for example in the removal of odours and allergens as well as dust and pollen.