Infectious diseases caused by airborne bacteria and viruses are a major problem for both social and economic reasons. The significance of this phenomenon is particularly noticeable during the time of the coronavirus pandemic. One of the consequences is the increased interest in the air purifier (AP) market, which resulted in a significant increase in sales of these devices. In this study, we tested the efficiency of APs in removing bacterial air contamination in the educational context in the Upper Silesia region of Poland during the “cold season” of 2018/2019. During the 6 months of measuring microbiological air quality, an 18% decrease in the concentration of microbiological pollutants as a result of the action of the APs was recorded. Additionally, the results of the particle size distribution of the bacterial aerosols showed a reduction in the share of the respirable fraction (particles with an aerodynamic diameter below 3.3 µm) by an average of 20%. The dominance of gram-positive cocci in the indoor environment indicates that humans are the main source of most of the bacteria present in the building. We conclude that the use of APs may significantly decrease the level of concentration of microbiological air pollutants and reduce the negative health effects of indoor bioaerosols; however, further work that documents this phenomenon is needed.

There is also limited evidence that these decreases result in improved cardiorespiratory health (Fisk, 2013; Morishita et al., 2015). APs usage has been associated with decreased blood pressure, reduced oxidative stress, reduced systemic inflammation, and enhanced lung function in a number of studies (Kelly and Fussell, 2019).

The COVID-19 pandemic has forced a significant focus on indoor disinfection and air purification options. The most frequent applications are the local control of the source of pollution, disinfection of rooms and surfaces, and ventilation. The use of APs can be considered an additional complementary and preventive action in the spread of biological contamination. Adequate IAQ can be achieved mainly by reducing and constantly controlling the concentrations of harmful microorganisms in the air.

The limited data on IAQ in Polish educational institutions and the lack of generalized standards for bioaerosol levels are the reason why the presented studies can increase awareness and focus more attention on IAQ issues.

According to the Air Quality in Europe 2020 report published by the European Environment Agency (EEA), Poland has the European Union’s most polluted air. The report found that the concentration of both PM10 and PM2.5—two types of harmful airborne participate matter—was higher in Poland than in any other European Union (EU) country. The collected data can be used to assess the exposure of children and kindergarten staff in southern Silesia, which is one of the most polluted areas in the EU. The specific aims include (i) the evaluation of the impact of APs on the microbial IAQ, (ii) investigation of the concentration levels of culturable bacteria, (iii) determination of the size distributions with particular attention to the respirable fraction of bacterial aerosols, and (iv) examination of the bacterial community structure.

Materials and Methods

Sampling Sites

The study was carried out in a kindergarten located in Gliwice (50.324,666 N, 18.711,405 E). Gliwice is a typical example of a city located in the industrial region of Upper Silesia, Poland, with 178.186 thousand occupants. The surrounding area of the measurement point is characterized by compact building development. Buildings, roads, asphalt, etc., cover most of the surfaces in this part of the city. More detailed information about the main characteristics of the studied kindergarten in Gliwice is provided in Table 1.

Air sampling was conducted during the “cold season,” from September 2018 to February 2019. The sampling was performed two times each week, with one sample taken outside the building and two indoors, one when the APs were turned off and the other after 60 min from turning the APs on (Table 2). Two sets of measurements were performed with the APs turned on. Samples were collected between 10:00 and 12:00 local time, in order to check the efficiency of the tested device. The kindergarten had natural ventilation and was insulated and windows were kept closed during the sampling.

Epidemiologic studies indicate that indoor air pollution is correlated with morbidity caused by allergic diseases. We evaluated the effectiveness of reducing the levels of indoor fine particulate matter 2.5 micrometer diameter (PM2.5) in Fresno, California using air purifiers on health outcomes in children with asthma and/or allergic rhinitis. Methods: The active group (with air purifiers) and the control group consisted of eight houses each. Air purifiers were installed in the living rooms and bedrooms of the subjects in the active group during the entire 12-week study duration. Childhood asthma control test, peak flow rate monitoring, and nasal symptom scores were evaluated at weeks 0, 6, and 12. Results: At 12 weeks, the active group showed a trend toward an improvement of childhood asthma control test scores and mean evening peak flow rates, whereas the control group showed deterioration in the same measures. Total and daytime nasal symptoms scores significantly reduced in the active group (p = 0.001 and p = 0.011, respectively). The average indoor PM2.5 concentrations reduced by 43% (7.42 to 4.28 μg/m3) in the active group (p = 0.001). Conclusions: Intervention with electrostatic precipitator air purifier reduces indoor PM2.5 levels with significant improvements in nasal symptoms in children with allergic rhinitis in Fresno.

The current health situation, consequent to the Covid-19 pandemic in the world, has brought air purifiers to the forefront. NatéoSanté, specialising in indoor air quality since 2009, has extensive experience of and insight into these devices’ evolution. Reinforcing the fight against the coronavirus, especially in hospitals, schools or companies, our EOLIS Air Manager models are at the forefront of innovation and technology. Their function: to filter and purify the air. Here is a general presentation of these devices and focus on the particularities of the brand.

An indoor air purifier ensures the filtration of air within an enclosed/closed place, which is processed then released as purified air. It operates as a complement to natural ventilation where it is possible to open windows.

It is vital to distinguish a professional model from a consumer device: they do not both guarantee identical air treatment or comparable overall performance.

A professional air purifier, equipped with a HEPA 13 or 14 filter, will operate effectively on pollens, fine particles PM2.5 and PM10, VOCs (Volatile Organic Compounds), viruses and bacteria.

Finally, the device’s benign operation is key: that is to say the ozone generator air purifier itself does not generate any secondary pollutants.

This official position on air purifiers has evolved since the spring of 2020. Previously, a negative opinion from the French Agency for Food, Environmental and Occupational Health Safety (ANSES) was the accepted reference viewpoint. In November 2020, a publication of the INRS (National Institute for Research and Safety) and then in May 2021, a second contribution from the HCSP (High Council for Public Health) set the standard: only equipment with a high efficiency filter against airborne particles were considered effective. Remember that in the case of Covid-19, they play a role in the fight against possible aerosol transmission, in addition to barrier gestures, wearing masks … This is particularly important in enclosed places lacking ventilation. They can be combined with a CO2 sensor which acts as a containment measure and will warn an area’s occupants when the 0.08% threshold limit is exceeded (see the HCSP recommendations on this topic).

What are the objectives of an air purifier?

To limit the diffusion of harmful residues, allergens or even viral elements; prevent asthma or allergy problems linked to poor indoor air quality to people at risk (children, elderly or sensitive people).

An air purifier, not to be confused with an air ioniser or air humidifier, can be used as a preventative and/or therapeutic measure: at home, in enclosed offices, open spaces or coworking sites, shops, hairdressing salons, hotels or restaurants, medical and paramedical offices… By extension, as Covid-19 is obliging us, it is assuming an expanding rôle in schools, hospitals, medical and paramedical sectors, services…

It concerns people and\or companies wanting, through preventative measures, to protect their health and\or that of their group or employees. In the latter case, for example, in the case of an activity’s resumption or continuation. The indoor air purifier is, in this sense, in alignment with current air quality health and social issues. This is both with regard to fine particle pollution PM2.5 and the risks related to viral propagation by air or aerosol(s).

A purifier filters indoor air and purifies it thereby removing various sources of pollution and pollutants.

This air purification goes through several stages. First of all, the purifier sucks in ambient air present in the room in order to capture particles. The air then passes through various filters that further permit the retention of different types of pollutants present in the air.

Dependent on your air purifier’s performance, it will be able to treat different air volumes related to room size (bedroom, living room, dining room), offices, shared spaces, open spaces…

For optimal performance, it is essential to install one portable uvc air purifier per room: we are always speaking in terms of partitioned areas.

What are the targets of an air purifier’s pre-filter?

The pre-filter captures macro-particles such as large dust particles, animal hair, etc. Placed directly between the device’s hood and the other filters, it is the initial filtration system: operating as soon as air enters the unit. This filter, which is generally washable, extends the life of the other filters by filtering macro-particles upstream.

Is the medical grade HEPA filter effective against viruses?

The HEPA filter of a professional air purifier like EOLIS Air Manager can retain more than 99% of particles larger than 0.3 µm. This filter is of medical quality. It is also called an absolute filter.

It is composed of a layer of very fine fibre. It permits, thanks to its tight weave, the retention of dust mites, pollens, moulds, fungi, pesticides, bacteria, viruses, fine dust, animal hair, or even diesel particles.

The activated carbon filter is primarily used for the elimination of bad odours present in a room. It is a filter containing activated carbon beads which filter and eliminate toxic gases such as benzene, hydrogen sulphide, formaldehyde, ammonia vapours, bleach, bad odours… Activated carbon filters, used by NatéoSanté for its wall mounted uv air purifier, also make it possible to eliminate excessive ozone present in your room’s environment.

How does oxidation/UV-C air filtration work?

Polluting particles are absorbed thanks to an oxidation and reduction reaction between the catalyst and UV-C radiation. This process converts the VOCs into H2O and CO2. This is a switchable On\Off function on our models.

What is the purpose of the Active Oxygen Generator?

The active oxygen function treats indoor air thoroughly. This function, to be activated when you are not present in the room or at your workplace, eliminates deep-seated odours (sheets, textiles, carpets) and also treats the space against mites and mould. This feature is available as an option on the EOLIS Air Manager professional indoor air purifier. It is also On\Off switchable on our various models.