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Horses stay in different types of stables; especially during the cold season, they stay inside for most of the day. A stable is also a place where many people spend quite a lot of time either as employees who care for and train horses or as equine enthusiasts. Keeping horses in stables causes their constant exposure to high concentrations of particulate matter (PM) and molds in the air inside these facilities. The study was conducted in Udórz Stud Farm located in the southern region of Poland. It was carried out in two different types of stables: three runners and two box stables. The study continued for 2 years; samples were collected in each season of the year. The following devices were used: a six-stage Andersen-Graseby cascade impactor, the DustTrak™ II Aerosol Monitor 8530. The obtained results allowed for the conclusion that horses kept in box stables are exposed to lower concentrations of molds and yeasts than those kept in runners. Molds dominated in the stable air during humid periods—spring and autumn—while yeasts were more prominent during summer and winter. It was observed that cleaning stables reduces the morphotic elements of fungi in the air, even though it results in a higher level of particulate matter in the stable air. It should be noted that microclimate conditions were optimal for horses practically throughout the whole year. Key points: • In stables, there is a high level of air intoxication, both by yeast and by mold fungi • The concentrations of fungi in the air depend on the season and the stable cleaning procedure • The PM concentrations depend on the type of stable [ABSTRACT FROM AUTHOR]

This study aimed to assess the markers of chemical and microbiological contamination of the air at sport centers (e.g., the fitness center in Poland) including the determination of particulate matter, CO2, formaldehyde (DustTrak™ DRX Aerosol Monitor; Multi-functional Air Quality Detector), volatile organic compound (VOC) concentration (headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry), the number of microorganisms in the air (culture methods), and microbial biodiversity (high-throughput sequencing on the Illumina platform). Additionally the number of microorganisms and the presence of SARS-CoV-2 (PCR) on the surfaces was determined. Total particle concentration varied between 0.0445 mg m−3 and 0.0841 mg m−3 with the dominance (99.65–99.99%) of the PM2.5 fraction. The CO2 concentration ranged from 800 ppm to 2198 ppm, while the formaldehyde concentration was from 0.005 mg/m3 to 0.049 mg m−3. A total of 84 VOCs were identified in the air collected from the gym. Phenol, D-limonene, toluene, and 2-ethyl-1-hexanol dominated in the air at the tested facilities. The average daily number of bacteria was 7.17 × 102 CFU m−3–1.68 × 103 CFU m−3, while the number of fungi was 3.03 × 103 CFU m−3–7.34 × 103 CFU m−3. In total, 422 genera of bacteria and 408 genera of fungi representing 21 and 11 phyla, respectively, were detected in the gym. The most abundant bacteria and fungi (>1%) that belonged to the second and third groups of health hazards were: Escherichia-Shigella, Corynebacterium, Bacillus, Staphylococcus, Cladosporium, Aspergillus, and Penicillium. In addition, other species that may be allergenic (Epicoccum) or infectious (Acinetobacter, Sphingomonas, Sporobolomyces) were present in the air. Moreover, the SARS-CoV-2 virus was detected on surfaces in the gym. The monitoring proposal for the assessment of the air quality at a sport center includes the following markers: total particle concentration with the PM2.5 fraction, CO2 concentration, VOCs (phenol, toluene, and 2-ethyl-1-hexanol), and the number of bacteria and fungi. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess bacterial aerosols in a herbal processing plant in Poland. Bioaerosol measurements of indoor and outdoor air of the herbal processing plant were performed in four measurement rounds, in a seasonal cycle—in spring, summer, autumn, and winter—using a six-stage Andersen's cascade air sampler. At each measuring point, during the bioaerosol sampling, the values of relative humidity and air temperature were simultaneously measured using the Kestrel 4000 device, and the concentration of particulate matter (fractions 1.0 μm, 2.5 μm, 4.0 µm, and 10.0 µm) using a DustTrak II dust analyzer. The results showed that the production process affects the bacterial aerosol concentrations in the tested plant. There were statistically significant differences in the concentrations of bacterial aerosol between indoor and outdoor air, and between production rooms, taking into account the seasons of the year. The concentrations of bacterial aerosol in the production rooms did not exceed 7.6 ×·103 cfu·m−3 and were lower than the permissible concentration values proposed for production rooms contaminated with organic dust. The calculations showed a significant correlation between the concentration of bacterial aerosol and air temperature. Qualitative analysis of microorganisms isolated from the air of production rooms showed the dominance of Gram-positive cocci of the genus Micrococcus and spore-forming rods of the Bacillus genus. The study confirmed that herbal processing plants may be related to exposure to microbiological agents. [ABSTRACT FROM AUTHOR]

The results of the study on the characteristics of the viable (culturable) and total bacterial particles in the ambient air in Gliwice, Poland, are presented. The concentration of viable bacteria in the air ranged from 57 CFU m−3 (Colony Forming Units per cubic meter) during winter to 305 CFU m−3 in spring, while the concentration of all bacteria (live and dead) in the air, measured in selected days, ranged from 298 cells m−3 in winter to over 25 thousand per m3 in autumn. A field study was also carried out to find out the level of the sterilization rate (k) for airborne bacteria. The obtained value of k for viable bacteria exposed to UV solar radiation in Gliwice was approximately 10 cm2 W−1s−1. The patterns of the size distributions of viable bacteria found in three seasons, spring, summer, and autumn, were similar, showing a peak in the range of 3.3–4.7 µm. In the winter season, the main peak was shifted into the smaller particles with an aerodynamic diameter ranging from 2.1 to 4.7 µm. The dominant group of culturable bacteria within the studied period was Gram-positive rods-forming endospores (34–55%), while the least frequent were Gram-negative rods (2%). This research can be used to assess the health effects of exposure to bacterial aerosols in people living in this area. [ABSTRACT FROM AUTHOR]

The study's primary focus lies in examining the relationship between respiratory and deposition doses of bacterial aerosols in urban kindergarten, providing valuable insights into the specific doses absorbed by individuals in different sections of their respiratory systems based on the aerodynamic diameter of bacterial particles. Samples were collected twice a week, using by an Andersen cascade impactor during autumn and winter seasons 2018/2019 resulting in a total of 1152 Petri dishes analyzed. The highest average concentration of bacterial aerosol was observed during autumn (1698 ± 663 CFU/m3) in comparison to winter months (723 ± 134 CFU/m3). Respirable doses for children and staff were 2945 and 2441 CFU/day during winter and 5988 and 4964 CFU/day during autumn, respectively. Deposition doses incorporated from empirical models for regional deposition in the respiratory tract showed that children in kindergarten absorb 33% less of bacteria into alveolar region if breath by nose instead of mouth. Additionally, risk assessment results indicate that the hazard indices for children attending kindergartens for 3 years and for staff working 25 years are below 1, suggesting minor risks associated with the inhalation of bioaerosols during autumn and winter. HI was <1, so the non-carcinogenic effects are on an acceptable level, but the indoor/outdoor ratio were 3.5 and 2.4 for autumn and winter, respectively, indicating children's and adult's exposure to bacterial aerosol should be reduced. [Display omitted] • Concentration and daily dose of bacteria were measured in Polish kindergarten. • The highest concentration of bacterial aerosol in indoor was 1698 CFU/m3. • The bacterial aerosol in indoor was relatively fresh and mostly of human origin. • The highest inhaled dose of respirable bacteria was observed during autumn. • Health risk from the exposure to bacterial aerosol is on acceptable level. [ABSTRACT FROM AUTHOR]

Objectives: This study was aimed to assess the concentration of microbial aerosol and species composition of airborne staphylococci in 10 healthcare facilities in southern Poland including primary healthcare units and hospital wards; and to assess whether the selected components of microbial aerosol pose a threat of severe infections to either patients or the personnel.Methods: The study was conducted at monthly intervals over a period of one year. Air samples were collected by MAS-100 sampler. The number of mesophilic bacteria, mould fungi, actinomycetes and staphylococci was determined on general and selective media. The species identification of staphylococci was conducted using API tests for strains that were pre-selected based on macroscopic and microscopic observations.Results: A total number of 1,584 samples were collected during the sampling period. The numbers of airborne microorganisms varied between the examined premises and between the seasons of the year. The observed differences were statistically significant with one exception for actinomycetes and their differences between the examined premises. The concentrations of mesophilic bacteria varied from 5 to 297 CFU/m3 of air, for Staphylococcus the values ranged from 1 to 96 CFU/m3, for fungi - from 1 to 100 CFU/m3, and the number of actinomycetes ranged from 7 to 321 CFU/m3. Ten species of coagulase-negative staphylococci (CoNS) were identified among 55 isolates with S. saprophyticus and S. warneri being the most frequently detected (n = 14 and 13, respectively). S. haemolyticus, which is one of the most common causal agents of nosocomial infections was observed in four facilities (n = 5).Conclusions: The microbial concentrations varied both between the seasons of the year and between the examined facilities. The highest bioaerosol concentrations were observed in most crowded premises. The identified species of staphylococci, although not typically associated with human infections, are common causal agents of nosocomial infections and infections in immunocompromised people. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the types of changes - depending on season and tourist traffic - occur in the array of fungi in selected adits in Lower Silesia (Ciechanowice, Rozdroże Izerskie or Izera Crossroads, Kletno - Sztolnia Wiejąca or Windy Adit, and Kletno - Sztolnia Turystyczna or Tourist Adit). Air samples were collected by impact method in 2015-16. The dominant fungi in the adit air were the ones of the genus Penicillium and of the species Cladosporium cladosporiodes. The mycobiota of each adit varied to a certain extent; the differences, however, were more pronounced between the adits, which are inaccessible to the public and the Tourist Adit in Kletno. It was demonstrated that the presence of tourists exerts a marked influence on species composition and the number of fungi and spores in caves and underground facilities. This may greatly affect the biological and historical maintenance and stability of these sites. [ABSTRACT FROM AUTHOR]

Objectives: To date, the scientific source materials usually focus on microbial contamination of the museum or library collections themselves, while the exposure of persons who professionally deal with this type of objects in cultural heritage conservation laboratories is ignored.Material and Methods: The study was carried out in 9 naturally ventilated conservation laboratories with no history of water damage. Viable (understood as culturable) bioaerosol stationary samples were collected in both outdoor and indoor environments using 6-stage Andersen impactor. Simultaneously, stationary and personal indoor bioaerosol measurements were carried out using both Gesamtstaubprobenahme an der Person (GSP) and Button filter samplers. These measurements were complemented by evaluation of microbial content in the dust settled on conserved works of art. All impactor, filter, and settled dust samples were quantitatively examined to obtain viable and total concentrations of bacteria and fungi. All isolated microbial strains were taxonomically identified.Results: At workplaces, the concentrations of viable microorganisms in air were below 2000 cfu/m3 and accounted for not more than 5.5% of total microbiota. The study showed that quantitative assessment of viable bioaerosol can be made with an Andersen impactor as well as by using Button and GSP filter samplers, irrespective of whether they are applied for personal or stationary measurements. Compared to the impactor, however, the use of filter samplers for microbial contamination monitoring substantially limits the scope of qualitative information which can be obtained. Size distribution analysis revealed that the largest "load" of microorganisms can penetrate into the respiratory tract between the trachea and terminal bronchi, and thereby may be responsible for allergic inflammations in exposed workers.Conclusions: The precise assessment of microbial hazards in conservation laboratories should comprise control of both viable and total particle counts. The hermetization of such workplaces and control of relative humidity should be implemented and maintained to assure proper hygienic conditions. [ABSTRACT FROM AUTHOR]

Even though biological hazards in the work environments related to waste management were the subject of many scientific works, the knowledge of the topic is not extensive. This study aimed to conduct a comprehensive assessment of microbiological and toxicological hazards at the workstations in a waste sorting plant and develop guidelines for selecting filtering respiratory protective devices that would consider specific workplace conditions. The research included the assessment of quantity (culture method), diversity (high-throughput sequencing), and metabolites (endotoxin - gas chromatography-mass spectrometry; secondary metabolites - liquid chromatography tandem-mass spectrometry) of microorganisms occurring in the air and settled dust. Moreover, cytotoxicity of settled dust against a human epithelial lung cell line was determined with an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The research was performed in a waste sorting plant (Poland; 240,000 tons waste/year) at six workstations: two feeders, two pre-sorting cabins, secondary raw material press and organic fraction waste feeder for composting. The total dust concentration at tested workstations varied from 0.128 mg m−3 to 5.443 mg m−3. The number of microorganisms was between 9.23 × 104 CFU m−3 and 1.38 × 105 CFU m−3 for bacteria and between 1.43 × 105 CFU m−3 and 1.65 × 105 CFU m−3 for fungi, which suggests high microbial contamination of the sorting facility. The numbers of microorganisms in the air correlated very strongly (R2 from 0.70 to 0.94) with those observed in settled dust. Microorganisms representing Group 2 biological agents (acc. to Directive, 2000/54/EC), including Corynebacterium spp., Pseudomonas aeruginosa , Staphylococcus aureus , and others potentially hazardous to human health, were identified. The endotoxins concentration in settled dust ranged from 0.013 nmol LPS mg−1 to 0.048 nmol LPS mg−1. Seventeen (air) and 91 (settled dust) secondary metabolites characteristic, e.g., for moulds, bacteria, lichens, and plants were identified. All dust samples were cytotoxic (IC 50 values of 8.66 and 56.15 mg ml−1 after 72 h). A flowchart of respiratory protective devices selection for biological hazards at the workstations in the waste sorting plant was proposed based on the completed tests to help determine the right type and use duration of the equipment. [Display omitted] • Microbiological and toxicological hazards in a waste sorting plant were assessed. • High microbiological contamination of the air was demonstrated. • 17 metabolites in the air and 91 in the settled dust were detected. • All tested dust samples were cytotoxic for A-549 cells of human lung epithelium. • Respiratory protective devices selection rules for biological hazards were proposed. [ABSTRACT FROM AUTHOR]

This study aimed to assess the physicochemical, microbiological and toxicological hazards at an illegal landfill in central Poland. The research included the analysis of airborne dust (laser photometer), the number of microorganisms in the air, soil and leachate (culture method) and the microbial diversity in the landfill environment (high-throughput sequencing on the Illumina Miseq); the cytotoxicity ( PrestoBlue ) and genotoxicity (alkaline comet assay) of soil and leachate were tested. Moreover, an analysis of UHPLC-Q-ToF-UHRMS (ultra-high-performance liquid chromatography-quadrupole-time-of-flight ultrahigh-resolution mass spectrometry) was performed to determine the toxic compounds and microbial metabolites. The PM 1 dust fraction constituted 99.89% and 99.99% of total dust and exceeded the threshold of 0.025 mg m -3 at the tested locations. In the air, the total number of bacteria was 9.33 × 10 1 -1.11 × 10 3 CFU m -3 , while fungi ranged from 1.17 × 10 2 to 4.73 × 10 2 CFU m -3 . Psychrophilic bacteria were detected in the largest number in leachates (3.3 × 10 4 to 2.69 × 10 6 CFU mL -1 ) and in soil samples (8.53 × 10 5 to 1.28 × 10 6 CFU g -1 ). Bacteria belonging to Proteobacteria (42-64.7%), Bacteroidetes (4.2-23.7%), Actinobacteria (3.4-19.8%) and Firmicutes (0.7-6.3%) dominated. In the case of fungi, Basidiomycota (23.3-27.7%), Ascomycota (5.6-46.3%) and Mortierellomycota (3.1%) have the highest abundance. Bacteria ( Bacillus , Clostridium , Cellulosimicrobium , Escherichia , Pseudomonas ) and fungi ( Microascus , Chrysosporium , Candida , Malassezia , Aspergillus , Alternaria , Fusarium , Stachybotrys , Cladosporium , Didymella ) that are potentially hazardous to human health were detected in samples collected from the landfill. Tested leachates and soils were characterised by varied cyto/genotoxins. Common pesticides (carbamazepine, prometryn, terbutryn, permethrin, carbanilide, pyrethrin, carbaryl and prallethrin), quaternary ammonium compounds (benzalkonium chlorides), chemicals and/or polymer degradation products (melamine, triphenylphosphate, diphenylphtalate, insect repellent diethyltoluamide, and drugs (ketoprofen)) were found in soil and leachate samples. It has been proven that the tested landfill is the source of the emission of particulate matter; microorganisms (including potential pathogens) and cyto/genotoxic compounds.

The main goal of this study was to assess the levels of concentration of biological air pollutants in biomass processing power plants, based on the measurements taken in a plant located in Southern Poland. This work shows problems related to the co-combustion of biomass and indicates the health risks to which employees of positions closely related to the processing and combustion of biomass are exposed. Bacterial and fungal aerosol samples were collected using a six-stage Andersen cascade impactor with aerodynamic cut-off diameters of 7.0, 4.7, 3.3, 2.1, 1.1 and 0.65 µm (Tisch Environmental, USA). The highest average concentration level of micro-organisms was recorded in the air in the biomass analysis laboratory, where there was no constant airflow. It was found that the concentration levels of biological agents were below the Polish proposals for threshold limit values in the work environment polluted with organic dust. However, it was observed that the share of the respirable fraction (RF) of bacterial aerosol (particles less than 3.3 µm) in workplaces was equal to or higher than 50% of the total concentration, which may cause increased potentially adverse health effects and problems with concentration among power plant employees. Therefore, to ensure adequate air quality in the tested object, it is necessary to properly ventilate. This preliminary research could be the important starting point for a complete and precise assessment of bioaerosol exposures in biomass processing power plants in order to protect workers' health. [ABSTRACT FROM AUTHOR]

Air pollution, a by-product of economic growth, generates an enormous environmental cost in Poland. The issue of healthy living spaces and indoor air quality (IAQ) is a global concern because people spend approximately 90% of their time indoors. An increasingly popular method to improve IAQ is to use air purifiers (APs). Indoor air is often polluted by bioaerosols (e.g., viruses, bacteria, fungi), which are a major concern for public health. This work presents research on culturable bacterial aerosol (CBA) samples collected from dwellings with or without active APs during the 2019 summer season. The CBA samples were collected using a six-stage Andersen cascade impactor (ACI). The CBA concentrations were expressed as Colony Forming Units (CFU) per cubic metre of air. The average concentration of CBA in dwellings when the AP was active was 450–570 CFU/m3, whereas the average concentration when the AP was not active was 920–1000 CFU/m3. IAQ, when the APs were active, was on average almost 50% better than in cases where there were no procedures to decrease the concentration of air pollutants. Moreover, the obtained results of the particle size distribution (PSD) of CBA indicate that the use of APs reduced the proportion of the respirable fraction (the particles < 3.3 µm) by about 16%. Life cycle assessment (LCA) was used to assess the ecological cost of air purification. Our conceptual approach addresses the impact of indoor air pollution on human health and estimates the ecological cost of APs and air pollution prevention policies. [ABSTRACT FROM AUTHOR]

Introduction: Money is the most common item with which we have daily contact. Circulated banknotes and coins can become microbiologically contaminated and act as both a source and a means of spreading such pollutants., Material and Methods: The study was carried out in three money sorting facilities in Poland. Bioaerosol samples were collected using a 6-stage Andersen impactor, and microorganisms deposited on tabletop surfaces were sampled using the swab method. Bacterial and fungal concentrations were calculated and all isolated species were taxonomically identified., Results: The study confirmed that means of payment are active sources of microbial emission in money sorting facilities. The bioaerosol concentrations did not exceed the threshold limit values proposed for this type of office premises. It confirms that ventilation systems in these facilities worked efficiently, protecting them from the migration of microbial contaminants present in both indoor and outdoor (atmospheric) background air. On the other hand, the average concentrations of bacteria and fungi on tabletop surfaces in banknote and coin sorting rooms were above the proposed purity levels for indoor surfaces and should be treated as microbiologically contaminated. Microbiota isolated from the air and surfaces were very diverse and among those strains were bacterial and fungal pathogens that can pose a health threat to exposed individuals., Conclusions: The results showed that employees in money sorting facilities were exposed to microorganisms that may contribute to the development of adverse health outcomes. To protect them, highly efficient hygienic measures should be introduced in this working environment, to prevent both unwanted pollution and subsequent secondary emission of microbial contaminants from sorted means of payment and tabletop surfaces.

Background: The aim of the study was to assess the occupational exposure to Staphylococcus aureus bacteria, including methicillin- resistant S. aureus (MRSA) and other antibiotic-resistant strains in the municipal wastewater treatment plants (WWTPs) environment., Material and Methods: In 16 WWTPs in Poland, 33 wastewater and 253 air samples were collected in the spring-summer season. The microbiological analysis was carried out using a chromogenic medium. Species identification was carried out using the matrix assisted laser desorption ionization time-of-flight method, while the antibiotic-resistance analysis was performed with an automatic method., Results: Among 2805 bacterial isolates from the air and wastewater, 574 were identified as S. aureus species (20.5%). The presence of S. aureus species was found in 11 WWTPs (69%), among them in 11 WWTPs in raw wastewater and in 1 WWTP additionally in treated wastewater. The concentrations of S. aureus in wastewater ranged 2-1215 colony-forming units per milliliter (CFU/ml). In the air, 2 S. aureus isolates were identified in concentrations of 5 and 10 CFU/m 3 ; both samples were collected at the stage of mechanical wastewater treatment. The results revealed the following trend: the higher the outdoor temperature, the bigger the number of WWTPs with confirmed S. aureus presence. Among 149 S. aureus isolates (2 from the air and 147 from wastewater, including 2 MRSA), 100 isolates were resistant only to penicillin, while 34 isolates showed multi-antibiotic resistance (to penicillin and other drugs). It was found that isolated bacteria were resistant almost strictly to critical and highly important antibiotics in veterinary medicine., Conclusions: In general, WWTPs workers are occupationally exposed to S. aureus , including MRSA, and other antibiotic- and multi-antibiotic-resistant strains. The highest risk of infection concerns the activities carried out in direct contact with wastewater or devices through which wastewater flows, particularly at the stage of mechanical treatment. A significant source of S. aureus seems to be intensive livestock farming located in the area of the WWTPs under analysis. The study confirms the necessity to disinfect the wastewater discharging into WWTPs. Med Pr. 2020;71(3):265-78., (This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.)

Introduction: Workers of pellet production facilities (WPPF) are exposed to high concentrations of wood dust and microbial pollutants. Such stimulation may lead to numerous allergic and toxic reactions, infections, and other non-specific syndromes., Objective: To check the influence of individual traits of workers and characteristic features / factors of their living and working environments on the probability of adverse outcomes' appearance., Material and Methods: The questionnaire study assessing adverse health effects resulting from individual exposure was conducted among 28 workers of 10 Polish WPPF. The logistic regression (for dichotomous variables) was used to determine the appearance probability (given as odds ratio) of adverse symptoms or diseases., Results and Conclusions: WPPF workers may have an increased risk of developing work-related adverse health outcomes. Both the individual traits and environmental exposure factors significantly influence the probability of their occurrence.

Bioaerosol monitoring is a rapidly emerging area in the context of work environments because microbial pollution is a key element of indoor air pollution and plays an important role in certain infectious diseases and allergies. However, as yet, relatively little is known about inhaled doses of microorganisms in workplaces. Today, the important issue of social concern is due to waste management, transport, sorting, and processing of wastes and their environmental impact and effects on public health. In fact, waste management activities can have numerous adverse effects on human wellbeing. Health effects are generally linked to exposure (EX), defined as the concentration of a contaminant and the length of time a person is exposed to this concentration. Dose is an effective tool for evaluating the quantity of a contaminant that actually crosses the body's boundaries and influences the goal tissue. This document presents an analysis of the fungal waste-sorting plant EX dose (FWSPED) inhaled by workers in a waste-sorting plant (WSP) in Poland in March 2019. The main purpose of this research was to assess FWSPED inhaled by workers in two cabins at the WSP: the preliminary manual sorting cabin (PSP) and the purification manual sorting cabin (quality control; QSP). It was found that the FWSPED inhaled by workers was 193 CFU/kg in the PSP and 185 CFU/kg in the QSP. Fungal particles were quantitatively evaluated and qualitatively identified by the GEN III Biolog system. During the research, it was found that isolates belonging to the Aspergilus flavus and Penicillum chrysogenum strains were detected most frequently in the WSP. The total elimination of many anthropogenic sources is not possible, but the important findings of this research can be used to develop realistic management policies and methods to improve the biological air quality of WSPs for effective protection of WSP workers., Competing Interests: The author declares no conflict of interest.

The aims of this article are to characterize: the quantity of culturable bacterial aerosol (QCBA) and the quality of culturable bacterial aerosol (QlCBA) in an office building in Southern Poland during the spring. The average concentration of culturable bacterial aerosol (CCBA) in this building ranged from 424 CFU m -3 to 821 CFU m -3 , below Polish proposals for threshold limit values. Size distributions were unimodal, with a peak of particle bacterial aerodynamic diameters less than 3.3 μm, increasing potentially adverse health effects due to their inhalation. The spring office exposure dose (SPED) of bacterial aerosol was estimated. The highest value of SPED was in April (218 CFU kg -1 ), whereas the lowest was in June (113 CFU kg -1 ). Analysis was undertaken to determine the antibiotic resistance of isolated strains and their ability to form biofilms, which may facilitate the spread of antibiotic resistance genes. In the course of the study, it was found that Staphylococcus xylosus had the greatest ability to form biofilms, while the strains with the highest antibiotic resistance were Micrococcus luteus D and Macrococcus equipercicus . Given that mainly antibiotic-sensitive bacteria from bioaerosol were isolated, which transfers resistance genes to their plasmids, this shows the need for increased monitoring of indoor air quality in workplaces.

Background: Cleaning services are carried out in almost all sectors and branches of industry. Due to the above, cleaners are exposed to various harmful biological agents, depending on the tasks performed and the commercial sector involved. The aim of this study was to assess the exposure of cleaning workers to biological agents based on quantitative and qualitative characteristics of airborne microflora., Material and Methods: A six-stage Andersen sampler was used to collect bioaerosols during the cleaning activities in different workplaces, including schools, offices, car services, healthy services and shops. Standard Petri dishes filled with blood trypticase soy agar and malt extract agar were used for bacterial and fungal sampling, respectively., Results: The bioaerosol concentration values obtained during testing of selected workposts of cleaners were lower than the Polish recommended threshold limit values for microorganisms concentrations in public service. The most prevalent bacterial species in studied places were Gram-positive cocci (mainly of genera Micrococcus, Staphylococcus) and endospore-forming Gram-positive rods (mainly of genera Bacillus). Among the most common fungal species were those from genera Penicillium and Aspergillus. The size distribution analysis revealed that bioaerosols present in the air of workposts at shops, schools and car services may be responsible for nose and eye mucosa irritation and allergic reactions in the form of asthma or allergic inflammation in the cleaning workers., Conclusions: The study shows that occupational activities of cleaning workers are associated with exposure to airborne biological agents classified into risk groups, 1. and 2., according to their level of infection risk, posing respiratory hazard., (This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.)