Maciej Szczotko

Aims: With the ongoing pandemic and increased interest in measures to improve indoor air quality, various indoor air purifiers have become very popular and are widely used. This review presents the advantages and disadvantages of various types of technologies used in air purifiers in terms of reducing microbial contamination. Methods: A literature search was performed using Web of Science, Scopus, and PubMed, as well as technical organizations dealing with indoor air-quality to identify research articles and documents within our defined scope of interest. Relevant sections: The available literature data focus mainly on the efficiency of devices based on tests conducted in laboratory conditions with test chambers, which does not reflect the real dimensions and conditions observed in residential areas. According to a wide range of articles on the topic, the actual effectiveness of air purifiers is significantly lower in real conditions than the values declared by the manufacturers in their marketing materials as well as technical specifications. Conclusions: According to current findings, using indoor air purifiers should not be the only measure to improve indoor air-quality; however, these can play a supporting role if their application is preceded by an appropriate technical and environmental analysis considering the real conditions of its use.

The frequency of respiratory symptoms in workers exposed to water aerosol was evaluated along with the preliminary assessment of microbiological contamination of air and water used in glass processing plants. A questionnaire survey was conducted in 131 workers from 9 glass processing plants. Questions focused on working conditions, respiratory symptoms and smoking habits. A pilot study of air and water microbiological contamination in one glass processing plant was performed. Water samples were tested for Legionella in accordance with EN ISO 11731-2:2008 and for total colony count according to PN-EN ISO 6222:2004. Air samples were tested for total numbers of molds and mildews. During the year preceding the survey acute respiratory symptoms occurred in 28.2% of participants, while chronic symptoms were reported by 29% of respondents. Increased risks of cough and acute symptoms suggestive of pneumonia were found among the respondents working at a distance up to 20 m from the source of water aerosol compared to other workers (OR = 2.7), with no difference in the frequency of other symptoms. A microbiological analysis of water samples from selected glass plant revealed the presence of L. pneumophila, exceeding 1000 cfu/100 ml. The number of bacteria and fungi detected in air samples (above 1000 cfu/m3) suggested that water aerosol at workplaces can be one of the sources of the air microbial contamination. The questionnaire survey revealed an increased risk of cough and acute symptoms suggestive of pneumonia in the group working at a shortest distance form the source of water aerosol.

The presence of parasitic protozoa in drinking water is mostly a result of improperly maintened the water treatment process. Currently, in Poland the testing of Cryptosporidium and Giardia in water as a part of routine monitoring of water is not perform. The aim of this study was the optimization of the method of Cryptosporidium and Giardia detection in water according to the main principles of standard ISO 15553:2006 and using Filta-Max xpress automatic elution station. Preliminary tests were performed on the samples contaminated with oocysts and cysts of reference strains of both parasitic protozoa. Further studies were carried out on environmental samples of surface water sampled directly from the intakes of water (21 samples from Vistula River and 8 samples from Zegrzynski Lake). Filtration process and samples volume reducing were performed using an automatic elution system Filta-Max xpress. Next, samples were purified during immunomagnetic separation process (IMS). Isolated cysts and oocysts were stained with FITC and DAPI and than the microscopic observation using an epifluorescence microscope was carried out. Recovery of parasite protozoa in all contaminated water samples after 9-cycles elution process applied was mean 60.6% for Cryptosporidium oocysts and 36.1% for Giardia cysts. Studies on the environmental surface water samples showed the presence of both parasitic protozoa. Number of detected Giardia cysts ranged from 1.0/10 L up to 4.5/10 L in samples from Zegrzynski Lake and from 1.0/10 L up to 38.9/10 L in samples from Vistula River. Cryptosporidium oocysts were present in 50% of samples from the Zegrzynski Lake and in 47.6% of samples from the Vistula River, and their number in both cases was similar and ranged from 0.5 up to 2.5 oocyst/10 L. The results show that applied procedure is appropriate for detection the presence of parasitic protosoan in water, but when water contains much amount of inorganic matter and suspended solids test method have to be modified like subsamples preparation and filtration process speed reduction. The applied method with the modification using Filta-Max xpress system can be useful for the routine monitoring of water. Detection of Cryptosporidium and Giardia in all samples of water taken from the intakes of surface water shows the possibility oftransfering of the protozoan cysts into the water intended for the consumption, therefore the testing of Cryptosporidium and Giardia should be included into the monitoring of water.

Foregoing research presents results of total number of bacteria and fungi assays carried out in air of operating theatres before, during and directly after planned surgical procedure. Basing on the results obtained in winter and summer the assessment of bacteria and fungi concentration in atmospheric air impact on microbial quality of air inside of operating theatre was elaborated. Investigation of the reason of high concentration of bacteria in air inside of operating rooms was conducted simultaneously. Presented results of microbial air purity collected from atmospheric air in parallel with indoor air demonstrated that air filters applied in air-conditioning system worked correctly and bacterial contamination of air had different reasons.

The aim of this study was to show the influence of air conditioning control for microbial contamination of air inside the operating theatres equipped with correctly working air-conditioning system. This work was based on the results of bacteria and fungi concentration in hospital air obtained since 2001. Assays of microbial air purity conducted on atmospheric air in parallel with indoor air demonstrated that air filters applied in air-conditioning systems worked correctly in every case. To show the problem of fluctuation of bacteria concentration more precisely, every sequences of single results from successive measure series were examined independently.

It's a well-known fact that water-air aerosol can be a result of some dentist's activity during regular dental surgery and can contain broad range of microorganisms from dental plaque, saliva and pus. Assessment of dentist's activity impact on bacteria concentration in air of dentist surgery was a main purpose of this assay. Presented data contains results of four total number of bacteria and fungi in air assays made with fifty minutes intervals. Air samples was taken in dentist's office during regular dental surgery of patients afflicted with oral cavity infection with pus. Due to defective ventilation system, bacteria's concentration in air samples increased from less than thousand cfu/m3 to almost three thousands cfu/m3. Obtained results demonstrated that aerosol containing bacteria is released during regular dental surgery so the concentration of potentially infectious bacteria around patient and dentist can increase up to three thousands cfu/m3.

Main purpose of this paper was to confirm of results obtained by new method based on bioluminescence technique for determination of susceptibility of materials contacting with drinking water were repeatable. Investigation was conducted during 8 weeks in dynamic conditions using continuous flow reactor UPE. Every week swabbes from tested materials were collected and level of ATP was examined. The results obtained from the surface of tested materials were repeatable and clearly approximate to those obtained from the surface of negative control material (stainless steel, low susceptibility for microbial growth). The level of the ATP on the surface of positive control material (paraffin, large susceptibility for microbial growth) was fifty times higher than that observed on other materials. Presented investigation was the main part of validation process, which in short time will serve to initiate system of complete assessment for materials contacting with drinking water according to Council Directives 89/106/EEC and 98/83/EC requirements.

Initial methodological study was conducted to determine the susceptibility to microbial growth of different materials applied in contact with drinking water. The purpose of this assay was to elaborate the method for determining the ability of different materials contacting with drinking water to promote microbial growth and to determine possible correlation of results obtained by two analytic methods: inoculation of microorganisms swabbed from materials surface into a medium and ATP level examination. The assay was conducted during 16 weeks in dynamic conditions using continuous flow reactor. Every two weeks swabbes from examinated materials were collected and the total number of microorganisms was determined after incubation in 22 degrees C for 72 hours and in 37 degrees C for 48 hours respectively. Determination of microorganisms number and ATP level were both examinated in water inlet. Difference in susceptibility to microbial growth of different materials used in contact with drinking water was observed. This was confirmed by both analytic methods. Microbial growth on the surface of negative control materials (glass, poliethylene and stainless steel) was several time less intensive than on positive control material (floor finish not destined for contact with drinking water). Correlation between the quantity of microorganisms and ATP level on the surface of the same kind of materials was confirmed. Usefulness of continous flow reactor was confirmed.

General information about drinking water biofilms containing few steps biofilm forming process, microorganisms' short characterization and potential risk related to microbial presence in water installations has been presented. A part of review concerns European Acceptance Scheme (EAS) basis and current methods applied for assessment of susceptibility of materials contacting with drinking water to microbial growth.