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Combining wideband integrated bioaerosol sensors and DNA-staining techniques, online and offline shipboard observations of fluorescent aerosol particles in the atmosphere were carried out over the central Pacific Ocean during March 2019 to identify bioaerosols and determine their spatiotemporal distribution. To understand the origins of and processes associated with bioaerosols, we conducted correlation analyses of fluorescent particle number concentration, wind speed, and a variety of chemical and biological indicators, including concentrations of chlorophyll a, bacteria, and marine organic gel particles such as transparent exopolymer particles (TEPs) and Coomassie stainable particles (CSPs). Five-day backward trajectory analysis indicated that oceanic air masses were dominant between 6 and 18 March, after which the influence of long-range transport from the continent of Asia was prominent. For the first period, we identified certain types of fluorescent particles as bioaerosols with marine origins, because their number concentrations were highly correlated with concentrations of TEPs and bacteria (R: 0.80–0.92) after considering the wind speed effect. For the second period, there was strong correlation between another type of fluorescent particles and CSPs irrespective of wind speed, implying that the fluorescent particles advected from land were mixed with those of marine origins. From the results of our correlation analysis, we developed equations to derive atmospheric bioaerosol number density in the marine atmosphere over the central Pacific Ocean from a combination of biogenic proxy quantities (chlorophyll a, TEPs, and bacteria) and wind speed. We conclude that it is likely that TEPs were transported from the sea surface to the atmosphere together with bacteria to form fluorescent bioaerosols.

Understanding the atmospheric concentration of pollen (which is one of the most common vectors of allergens) is necessary to determine the atmospheric allergen level. Airborne pollen concentrations were predominantly evaluated using volumetric and gravitational particle samplers. However, no previous studies have successfully shown whether these sampling methods can be used to evaluate actual airborne pollen concentrations. In this study, the relationship between wind speed and sampling efficiency was investigated to determine whether the influence of ambient wind speed on sampling efficiency was significant. To this end, the influence of wind speed was analyzed by comparing a volumetric sampler and a gravitational sampler. The experimental results indicate that an increase in the wind speed results in an increase in the sampling efficiency of the gravitational sampler because of fluctuations in the turbulence. Our simulation shows that when pollen is entrained in the turbulence, the changes in the wind speed, turbulence amplitude, and turbulence length influence the deposition rate of pollen on the gravitational sampler. These influences can be explained by the turbulence vibration model. These results show the inadequacy of existing evaluation methods, not only for pollen deposition data, but also for all types of bioaerosol deposition data.

Landfill sites are regarded as prominent sources of bioaerosols for the surrounding atmosphere. The present study focused on the emission of airborne bacteria and fungi in four seasons of a sanitary landfill site. The main species found in bioaerosols were assayed using high-throughput sequencing. The SourceTracker method was utilized to identify the sources of the bioaerosols present at the boundary of the landfill site. Furthermore, the health consequences of the exposure to bioaerosols were evaluated based on the average daily dose rates. Results showed that the concentrations of airborne bacteria in the operation area (OPA) and the leakage treatment area (LTA) were in the range of (4684 ± 477)-(10883 ± 1395) CFU/m3 and (3179 ± 453)-(9051 ± 738) CFU/m3, respectively. The average emission levels of fungal aerosols were 4026 CFU/m3 for OPA and 1295 CFU/m3 for LTA. The landfill site received the maximum bioaerosol load during summer and the minimum during winter. Approximately 41.39%- 86.24% of the airborne bacteria had a particle size of 1.1 to 4.7 µm, whereas 48.27%- 66.45% of the airborne fungi had a particle size of more than 4.7 µm. Bacillus sp., Brevibacillus sp., and Paenibacillus sp. were abundant in the bacterial population, whereas Penicillium sp. and Aspergillus sp. dominated the fungal population. Bioaerosols released from the working area and treatment of leachate were the two main sources that emerged in the surrounding air of the landfill site boundary. The exposure risks during summer and autumn were higher than those in spring and winter.

Real-time onsite monitoring of indoor airborne microbes in a residential property in central Tokyo was carried out in 2020 and 2021, following the onset of the COVID-19 pandemic. A microbial sensor utilizing fluorescence emitted by microorganisms was used to measure bioaerosol concentrations in the living room and children’s bedroom as well as on the balcony. Indoor PM2.5 was also monitored simultaneously at certain time points using a PM2.5 sensor. The behavior of the residents was also recorded during some monitoring periods. The average number concentration of microbes as fungi in the living room was 15,100, 58,800, and 10,600 counts m-3 in spring, summer, and winter, respectively, increasing in summer when the outside temperature was high. Microbial number concentrations were closely related to human behavior, increasing rapidly during periods of physical activity, but decreasing again within 20-30 min of the activity ending. There was no clear correlation between indoor microbial number concentrations and PM2.5 concentrations, suggesting that indoor microorganisms are concentrated in coarse particles, such as dust, which are quickly removed via gravitational settling. The concentration of indoor airborne microorganisms decreased significantly after ventilation, and although an occasional increase was observed immediately after ventilation, concentrations decreased again rapidly within 10-20 min. These results suggest that even a short period of ventilation can significantly reduce the indoor bioaerosol © 2021 by Asian Association for Atmospheric Environment

Limiting infection transmission is central to the safety of all in dentistry, particularly during the current SARS-CoV-2 pandemic. Aerosol-generating procedures (AGPs) are crucial to the practise of dentistry; it is imperative to understand the inherent risks of viral dispersion associated with AGPs and the efficacy of available mitigation strategies.In a dental surgery setting, crown preparation and root canal access procedures were performed with an air turbine or electric speed-controlled hand-piece, with mitigation via rubber dam or high-volume aspiration and a no mitigation control. A phantom head was used with a 1.5 mL flow of artificial saliva infected with Φ6 bacteriophage (a surrogate virus for SARS-CoV-2) at ∼108plaque forming units mL-1, reflecting the upper limits of reported salivary SARS-CoV-2 levels. Bioaerosol dispersal was measured using agar settle plates lawned with the bacteriophage’s host,Pseudomonas syringae. Viral air concentrations were assessed using MicroBio MB2 air sampling, and particle quantities using Kanomax 3889 GEOα particle counters.Compared to an air turbine, the electric hand-piece reduced settled bioaerosols by 99.72%, 100.00% and 100.00% for no mitigation, aspiration and rubber dam, respectively. Bacteriophage concentrations in the air were reduced by 99.98%, 100.00% and 100.00%, with the same mitigation strategies. Use of the electric hand-piece with high-volume aspiration, resulted in no detectable bacteriophage, both on settle plates and in air samples taken 6-10-minutes post-procedure.To our knowledge, this study is the first to report the aerosolization of active virus as a marker for risk determination in the dental setting. Whilst this model represents a worst-case scenario for possible SARS-CoV-2 dispersal, these data showed that the use of electric hand-pieces can vastly reduce the risk of viral aerosolization, and therefore remove the need for clinic fallow time. Furthermore, our findings indicate that the use of particle analysis alone cannot provide sufficient insight to understand bioaerosol infection risk.

Respiratory bioaerosol deposition in public transport cabins is critical for risk analysis and control of contact transmission. In this work, we built a two‐row four‐seat setup and an air duct system to simulate a cabin environment. A thermal manikin on the rear left‐hand seat was taken as the infected passenger (IP) and “coughed” three times through a cough generator. The deposited viruses and droplets on nearby seats were measured by a cultivation method and microscope, respectively. The effects of seat backrest and overhead gasper jet were studied. Results showed that the number of deposited virus on the front seat was one order of magnitude higher than that on other seats which only contained droplets smaller than 10 µm in diameter. When the backrest was 15 cm higher than the cough, the deposited number of viruses was reduced to 5% of that with the backrest at the same height with the cough. The gasper jet above the IP with a velocity of 1.5 m/s can reduce the deposited viruses to 4% of that with gasper off. It indicates that both the gasper jet and backrest can work as mitigation measures to block the cough jet and protect the nearby passengers.

Anaerobic digestion is an emerging technology producing energy from renewable resources or food waste. Exposure screenings, comprising hazardous substances and biological agents, at different workplaces are necessary for a comprehensive overview of potential hazards in order to assess the risk of employees in biogas plants. In order to analyse these parameters, workplace measurements were conducted in seven full-scale anaerobic digesters. Personal and stationary sampling was performed for inhalable and respirable particles, volatile organic compounds, ammonia, hydrogen sulphide, carbon monoxide, and carbon dioxide. Furthermore, concentrations of the total cell count, endotoxins, and fungi—down to species level—were determined in comparison to windward air. Sequencing of the 16S rRNA genes was utilized for the determination of the bacterial composition inside the biogas plants. Measurements of hazardous substances show hardly values reaching the specific occupational exposure limit value, except ammonia. An approximate 5-fold increase in the median of the total cell count, 15-fold in endotoxins, and 4-fold in fungi was monitored in the biogas plants compared with windward air. Specifying the comparison to selected workplaces showed the highest concentrations of these parameters for workplaces related to delivery and cleaning. Strikingly, the fungal composition drastically changed between windward air and burdened workplaces with an increase of Aspergillus species up to 250-fold and Penicillium species up to 400-fold. Sequence analyses of 16S rRNA genes revealed that many workplaces are dominated by the order of Bacillales or Lactobacillales, but many sequences were not assignable to known bacteria. Although significant changes inside the biogas plant compared with windward air were identified, that increase does not suggest stricter occupational safety measures at least when applying German policies. However, exposure to biological agents revealed wide ranges and specific workplace measurements should be conducted for risk assessment.

Although numerous bioaerosol samplers for counting and identifying airborne microorganisms are available, the considerably high purchase and maintenance costs for the sampler often prevent broad monitoring campaigns for occupational or environmental surveillance of bioaerosols. We present here a newly developed simple adapter and filter system (TOP filter system) designed to collect bioaerosol particles from a defined air volume using conventional vacuum cleaners as air pumps. We characterized the physical properties of the system using air flow measurements and validated the biological performance. The culture-based detection capacities for airborne fungal species were compared to a standard impaction sampler (MAS-100 NT) under controlled conditions in a bioaerosol chamber (using Trichoderma spores as the test organism) as well as in the field. In the chamber, an overall equivalent detection capacity between all tested filters was recorded, although a significant underrepresentation of the TOP filter system for Trichoderma spores were seen in comparison to the MAS-100 NT. In a comparative field study (n = 345), the system showed similar biological sampling efficiencies compared to the MAS-100 NT impactor, only the diversity of identified fungal communities was slightly lower on the filters. Thus, the system is suitable for large-scale environmental sampling operations where many samples have to be taken in parallel at a given time at distant locations. This system would allow endeavors such as antibiotics resistance monitoring or hygiene surveys in agricultural or occupational settings.

Exposure of microbial agents in the air of indoor dwellings is associated with effects on respiratory and general health. The current study was conducted in the urban area of Delhi Metropolis for the seasonal quantitative assessment of viable microbial indoor air quality. Bioaerosol measurement was conducted by using Anderson six stage impactor with cut-off diameters of 7.0, 4.7, 3.3, 2.1, 1.1, and 0.65 µm) throughout the all the seasons (April 2019 to March 2020). Meteorological parameters such as temperature and relative humidity were measured to check their effect on microbial survival. Air quality index data of the sampling area were recorded by DPCC air quality monitoring system, Ashok Vihar, Delhi. The highest (1654 ± 876.87 CFU/m3) and lowest (738 ± 443.59 CFU/m3) mean bacterial concentration in houses was recorded in August and December, respectively. Similarly, the highest fungal concentration (1275 ± 645.22 CFU/m3) was found in August and the lowest in (776 ± 462.46 CFU/m3) in January. Bacterial respirable fraction shows an irregular pattern in different seasons. In the case of fungi, the respirable fraction of 2.1 and 1.1 contributes more than 60% of total culturable bioaerosols in all seasons. Bacterial genera including Staphylococcus, Micrococcus, and Streptobacillus were most dominant, and Cladosporium, Aspergillus, Penicillium, and Alternaria were the most dominant fungal genera observed indoors. The results of this study suggest that higher respirable fungal fraction might penetrate deeper into the lungs and cause various health effects. A higher concentration of bioaerosols in outdoor areas than indoor shows that the source of indoor bioaerosols is outdoor air. Supplementary Information The online version contains supplementary material available at 10.1007/s10453-021-09718-3.

Summarization: This study presents for the first time comprehensive measurements of the particle number size distribution (10 nm to 10 μm) together with next-generation sequencing analysis of airborne bacteria inside a dental clinic. A substantial enrichment of the indoor environment with new particles in all size classes was identified by both activities to background and indoor/outdoor (I/O) ratios. Grinding and drilling were the principal dental activities to produce new particles in the air, closely followed by polishing. Illumina MiSeq sequencing of 16S rRNA of bioaerosol collected indoors revealed the presence of 86 bacterial genera, 26 of them previously characterized as potential human pathogens. Bacterial species richness and concentration determined both by qPCR, and culture-dependent analysis were significantly higher in the treatment room. Bacterial load of the treatment room impacted in the nearby waiting room where no dental procedures took place. I/O ratio of bacterial concentration in the treatment room followed the fluctuation of I/O ratio of airborne particles in the biology-relevant size classes of 1–2.5, 2.5–5, and 5–10 μm. Exposure analysis revealed increased inhaled number of particles and microorganisms during dental procedures. These findings provide a detailed insight on airborne particles of both biotic and abiotic origin in a dental clinic. Presented on: Indoor Air

Large amounts of bioaerosols are generated during the treatment of landfill leachate, which poses potential threat to public health safety. In this study, the concentrations, particle size distribution, and microbial community of bioaerosols emitted from the low-pH biofilter (LPB) and neutral-pH biofilter (NPB) used to treat the odors from landfill leachate, as well as the effect of the inlet flow rate (IFR) and water-containing rate (WCR) were investigated. The results showed that the removal efficiency of the LPB for heterotrophic bacteria and the NPB for fungi were higher when the IFR was higher. The outlet concentrations (OCs) of heterotrophic bacteria, neutral sulfur bacteria, ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, NO2−, and NO3− were negatively correlated with the IFR in the LPB, whereas those of fungi and acidophilic sulfur bacteria were positively correlated with the IFR. Inverse correlation between the OCs and IFR was exhibited in the NPB. The proportions of dominant microorganisms with large particle size (> 3.3 μm) reduced significantly after both the LPB and NPB, which was aggravated under higher WCR. The analysis of microbial community illustrated that the dominant heterotrophic bacteria were different, while the dominant fungi were similar in the bioaerosols between the LPB and NPB, respectively. Due to the different emission characteristics, bioaerosols in the LPB and NPB outlet should be distinguished and taken seriously.

Due to a large concentration of animals living in a relatively small area, air on pig farms can be contaminated by microorganisms which can have an adverse effect on the health of pigs and farm workers. There is also a possibility of spreading bioaerosol from the farm to the surrounding area which can become a problem for the surrounding populace. Since the concentration of microorganisms in the air around and on the farm can be increased, a microbiological control of indoor and outdoor air is necessary. If the standard values are exceeded, measures of contamination suppression must be taken. To ascertain the microbiological air quality on a pig farm in Slavonia, as well as the changes in the microbiological air quality when moving away from the farm, five samples were taken from the pig farm (nursing ground, feeding ground 1, feeding ground 2, breeding ground, farrowing ground) and four samples were taken 1.5, 5, 10 and 15 meters away from the farm. The sampling was done by impaction, using the SAS SUPER 90 in four iterations (n=36). At the same time, the FLUKE 975V AirMeter device was used to measure the temperature and relative humidity. All air samples were analyzed on a Sabouraud dextrose agar for mold cultivation, as well as on a blood agar for cultivation of aerobic mesophilic bacteria (AMB), and these CFU/m3 values were compared to the standard values ("Diario da Republica n.° 235/2013, 1° Suplemento, Serie I de 2013-12-04"). The number of airborne aerobic mesophilic bacteria on all five farm locations was over the referential value prescribed by the common standards. By moving away from the farm, a drop in the number of airborne AMB was noted. The overall number of indoor air AMB was significantly higher (p>0.05) than in outdoor air. The amount of molds on two farm locations (nursing ground and feeding ground 1) also did not meet the criteria prescribed by the common standards. Just like AMB, a drop in the amount of mold was noted when moving away from the farm. However, there were no notable differences (p>0.05) in their number when comparing indoor and outdoor air.

This study investigated the air quality improvement in terms of bacterial and fungal contamination in an exercise room of a fitness center under normal operating conditions. Environmental conditions including air conditioning, ventilation, moisture, CO2, particulate matters, and total number of users were also recorded. In addition, fungal and bacterial load were assessed and disinfection on sports equipment surface was also examined. Background bacteria and fungi densities in bioaerosols were in the range of 249 ± 65 to 812 ± 111 CFU/m3 and 226 ± 39 to 837 ± 838 CFU/m3 in the exercise room of the fitness center and 370 ± 86 to 953 ± 136 CFU/m3 and 465 ± 108 to 1734 ± 580 CFU/m3 in the outdoor air, respectively. Chlorine dioxide and weak acid hypochlorous water aerosols could remove both bacteria and fungi much better than water scrubbing. Contact time of 15 min was sufficient to control both bacteria and fungi to comply with the official air quality standards. User density and carbon dioxide deteriorated both bacteria and fungi disinfection performance whereas temperature was only statistically significant on fungi disinfection. Other factors including relative humidity, airflow velocity, and particulate matters did not have any statistically significant effect on microbial inactivation. Apart from bioaerosol disinfection, inactivation of microorganisms on surfaces of sports equipment was also conducted using chlorine dioxide, zinc oxide, weak acid hypochlorous water, and commercial disinfectant. The surfaces of bicycle handle, dumbbell, and sit-up bench were found to be contaminated with bacteria. Overall bacterial load was 390 to 3720 CFU/cm2 with Escherichia coli specifically 550 to 1080 CFU/cm2. Chlorine dioxide and zinc oxide were noticeably better than weak acid hypochlorous water and commercial disinfectant in terms of bacteria inactivation whereas all tested disinfectants had comparable effectiveness on E. coli disinfection. Targeted microorganisms on the sports equipment surface were sufficiently inactivated within 2 min after the application of disinfectant.

The present study was carried out to estimate the spatiotemporal variation of fungal bioaerosols, in and around a landfill site in Delhi. The sites were deep in the landfill to nearby residential areas. Fungal bioaerosol sampling was done with the help of Anderson six stage viable cascade impactor on monthly basis for one year from June 2015 to May 2016 at seven different sites in and around the landfill site. The entire sampling period was classified in five different seasons, viz., winter, spring, summer, monsoon and autumn, characteristic of Delhi. It was observed in monsoon season concentration was maximum at most of the sites while lowest during autumn season. Contrary to this, it was also found that concentrations of fine fraction of bioaerosols were significantly high even during autumn at sites deep in the landfill while low in the residential areas near landfill. As such no significant pattern was observed with the coarse fraction of fungal bioaerosols. Typical relations of fungal concentration with the meteorological parameters were also observed. It was noticed that concentration was directly related to temperature and wind speed while inversely related to humidity. Fine and coarse fractions of bioaerosols showed a very good and positive relationship with each other. Among the eight fungal genera identified from the samples of Okhla landfill sites, Penicillium, Aspergillus and Rhizopus were found in abundance at all the seven sites in all the five seasons. Alternaria and Fusarium were found in abundance in spring, summer and winter seasons whereas Cladosporium in autumn and winter. Aspergillussps was present in all the five seasons.

Bioaerosols, including bacteria and fungi, are ubiquitous and have been shown to impact various organisms as well as biogeochemical cycles and human health. However, sample collection poses a challenge for aeromicrobiologists and can determine the success of a study. Establishing a standard collection procedure for bioaerosol sampling could help advance the field. We tested the efficiency (number of organisms collected and DNA yield per unit time) of three sampling devices: a membrane filtration device, a liquid impinger, and a portable electrostatic precipitator bioaerosol collector. We compared the efficiency of these three devices for both culture-dependent studies, by enumerating colony forming units (CFUs), and culture-independent studies, by extracting and quantifying total DNA. Our results show that the electrostatic precipitator collected microorganisms significantly more efficiently than the membrane filtration and liquid impingement in both types of studies over the same time interval. This is due to the high flow rate of the device. This work is important and timely because aeromicrobiology is currently restricted by long sampling times and risk of evaporation, desiccation, or freezing during sample, which increases with sampling times. Fieldwork convenience and portability of instruments are an additional challenge for sampling. Using a sampler that can overcome these technical hurdles can accelerate the advancement of the field, and the use of a lightweight, battery-powered, inexpensive, and portable bioaerosol collection device could address these limitations.

Thermal caves represent an environment characterized by unique chemical/physical properties, often used for treatment and care of musculoskeletal, respiratory, and skin diseases. However, these environments are poorly characterized for their physical and microbiological characteristics; furthermore, the recent pandemic caused by COVID-19 has highlighted the need to investigate the potential transmission scenario of SARS-CoV-2 virus in indoor environments where an in-depth analysis of the aerosol concentrations and dimensional distributions are essential to monitor the spread of the virus. This research work was carried out inside a natural cave located in Viterbo (Terme dei Papi, Italy) where a waterfall of sulfur–sulfate–bicarbonate–alkaline earth mineral thermal water creates a warm-humid environment with 100% humidity and 48 °C temperature. Characterization of the aerosol and bioaerosol was carried out to estimate the personal exposure to aerosol concentrations, as well as particle size distributions, and to give an indication of the native microbial load. The data obtained showed a predominance of particles with a diameter greater than 8 µm, associated with low ability of penetration in the human respiratory system. A low microbial load was also observed, with a prevalence of noncultivable strains generated by the aerosolization of the thermal waters. Finally, the estimation of SARS-CoV-2 infection risk by means of mathematical modeling revealed a low risk of transmission, with a decisive effect given by the mechanical ventilation system, which together with the adoption of social distancing measures makes the risk of infection extremely low. Supplementary information The online version contains supplementary material available at (10.1007/s10653-021-00870-w)

After the WHO designated COVID‐19 a global pandemic, face masks have become a precious commodity worldwide. However, uncertainty remains around several details regarding face masks, including the potential for transmission of bioaerosols depending on the type of mask and secondary spread by face masks. Thus, understanding the interplay between face mask structure and harmful bioaerosols is essential for protecting public health. Here, we evaluated the microbial survival rate at each layer of commercial of filtering facepiece respirators (FFRs) and surgical masks (SMs) using bacterial bioaerosols. The penetration efficiency of bacterial particles for FFRs was lower than that for SMs; however, the microbial survival rate for all tested masks was >13%, regardless of filtration performance. Most bacterial particles survived in the filter layer (44%–77%) (e.g., the core filtering layer); the outer layer also exhibited significant survival rates (18%–29%). Most notably, survival rates were determined for the inner layers (

Ice-nucleating particles (INPs) influence the formation of ice crystals in clouds and many types of precipitation. This study reports unique properties of INPs collected from 42 precipitation samples in the Texas Panhandle region from June 2018 to July 2019. We used a cold stage instrument called the West Texas Cryogenic Refrigerator Applied to Freezing Test system to estimate INP concentrations per unit volume of air (nINP) through immersion freezing in our precipitation samples with our detection capability of > 0.006 INP L−1. A disdrometer was used for two purposes: (1) to characterize the ground-level precipitation type and (2) to measure the precipitation intensity as well as size of precipitating particles at the ground level during each precipitation event. While no clear seasonal variations of nINP values were apparent, the analysis of yearlong ground-level precipitation observation as well as INPs in the precipitation samples showed some INP variations, e.g., the highest and lowest nINP values at −25 ∘C both in the summer for hail-involved severe thunderstorm samples (3.0 to 1130 INP L−1), followed by the second lowest at the same temperature from one of our snow samples collected during the winter (3.2 INP L−1). Furthermore, we conducted bacteria community analyses using a subset of our precipitation samples to examine the presence of known biological INPs. In parallel, we also performed metagenomics characterization of the bacterial microbiome in suspended ambient dust samples collected at commercial open-lot livestock facilities (cattle feedyards hereafter) in the Texas Panhandle (i.e., the northernmost counties of Texas, also known as “West Texas”) to ascertain whether local cattle feedyards can act as a source of bioaerosol particles and/or INPs found in the precipitation samples. Some key bacterial phyla present in cattle feedyard samples appeared in precipitation samples. However, no known ice nucleation active species were detected in our samples. Overall, our results showed that cumulative nINP in our precipitation samples below −20 ∘C could be high in the samples collected while observing > 10 mm h−1 precipitation with notably large hydrometeor sizes and an implication of cattle feedyard bacteria inclusion.

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.

Aerosols are readily transported on airstreams through building sanitary plumbing and sewer systems and those containing microbial pathogens (known as bioaerosols) are recognised as contributors to infection spread within buildings. When a defect occurs in the sanitary plumbing system that affects the system integrity, a cross-transmission route is created that can enable the emission of bioaerosols from the system into the building. These emission occurrences are characterised as short-burst events (typically < 1 minute in duration) which makes them difficult to detect and predict. The characterisation of these emission events is the focus of this research.Two methods were used to characterise bioaerosol emission events in a full scale test rig: (i) an Aerodynamic Particle Sizer (APS) for particle size distribution and concentrations; and (ii) a slit-to-agar sampler to enumerate the ingress of a viable tracer microorganism (Pseudomonas putida). The APS data confirmed that most particles (> 99.5%) were 11μm anywhere in the system. Particle count was influenced by flush volume, but it was not possible to determine if there was any direct influence from airflow rate. Typical emissions resulting from a 6 litre flush were in the range of 280 – 400 particles per second at a concentration of typically 9 to 12 number per cm3 and a total particle count in the region of 3,000 to 4,000 particles, whereas the peak emissions from a 1.2 litre flush was 60 - 80 particles per second at a concentration of 2.4 to 3 number per cm3 and a total particle count in the region of 886 to 1045 particles. The reduction in particles is in direct proportion to the reduction in flush volume. The slit-to-agar sampler was able to provide viable time course CFU data and confirmed the origin of the particles to be the tracer microorganism flushed into the system. The time course data also has characteristics consistent with the unsteady nature of a toilet flush.

Landfilling is one of the indispensable parts of solid waste management in various countries. Solid waste disposed of in landfill sites provides nutrients for the proliferation of pathogenic microbes which are aerosolized into the atmosphere due to the local meteorology and various waste disposal activities. Bioaerosols released from landfill sites can create health issues for employees and adjoining public. The present study offers an overview of the microbial diversity reported in the air samples collected from various landfill sites worldwide. This paper also discusses other aspects, including effect of meteorological conditions on the bioaerosol concentrations, sampling techniques, bioaerosol exposure and potential health impacts. Analysis of literature concluded that landfill air is dominated by microbial dust or various pathogenic microbes like Enterobacteriaceae, Staphylococcus aureus, Clostridium perfringens, Acinetobacter calcoaceticus and Aspergillus fumigatus. The bioaerosols present in the landfill environment are of respirable sizes and can penetrate deep into lower respiratory systems and trigger respiratory symptoms and chronic pulmonary diseases. Most studies reported higher bioaerosol concentrations in spring and summer as higher temperature and relative humidity provide a favourable environment for survival and multiplication of microbes. Landfill workers involved in solid waste disposal activities are at the highest risk of exposure to these bioaerosols due to their proximity to solid waste and as they practise minimum personal safety and hygiene measures during working hours. Workers are recommended to use personal protective equipment and practise hygiene to reduce the impact of occupational exposure to bioaerosols.

A built environment is a human-made environment providing surroundings for human occupancy, activities, and settlement. It is supposed to safeguard humans from all undesirable and harmful pollutants; however, indoor concentrations of some pollutants are much greater than that of the outdoors. Bioaerosols infiltrate from the outdoors in addition to many indoor sources of bioaerosols including the use of various chemicals as well as activities like cooking, smoking, cleaning, or even normal movement. They are also associated with a number of serious health concerns. Various ecological factors associated with the generation, the persistence as well as the dispersal of these microbial components of indoor bioaerosols, are discussed in this review, that have not been considered all together till now. The factors like microbial taxa, environmental factors, and anthropogenic activities (human occupancy, activities, and impact of urbanization) are addressed in the review. Effects of both indoor environmental factors like architectural design, lighting, ventilation, temperature, humidity, indoor/outdoor ratio, particulate matter, indoor chemistry as well as outdoor environmental factors like geography, seasons, and meteorology on the microbial concentrations have been discussed. Efforts are underway to design selective pressures for microbes to create a healthy symbiotic built microbiome as the "right" indoor microbiome is a "healthy" indoor microbiome.

Exposure to bioaerosols can have adverse effects on human health and contribute to allergies, asthma, infectious diseases and pulmonary conditions. Bioaerosols are airborne particles of microbial, animal and plant origin. Animal- and plant-derived particles, which may disperse over long distances, are being increasingly addressed by environmental studies in addition to microorganisms. In this study, air samples were collected in various planned areas of three cities in China (Beijing, Hangzhou and Wuhan) using a new liquid-based sampler. Animal, plant and bacterial components were quantified according to the expression levels of housekeeping genes via real-time PCR and analysis of cycle threshold (Ct) values. The level of animal-derived particles in the air of Hangzhou was higher than those in the other two cities. More bacterial particles than animal or plant particles were detected in the air in Beijing compared with other cities. We also found a negative correlation between the bacterial content of bioaerosols and relative humidity and a positive correlation between bacterial content and temperature. By contrast, bioaerosol animal content was positively correlated with relative humidity and negatively correlated with temperature. In summary, high levels of bacterial particles were detected in atmospheric samples in China, although the lower concentrations of animal- and plant-derived particles should not be ignored. These data may provide important evidence for structural analyses of animal- and plant-derived bioaerosols as well as for risk assessment.

This comprehensive study aims to examine the relationships between ambient air quality (AAQ) and respiratory health of the participants residing in three different towns of Canakkale city, Turkey between August 2013 and 2014. AAQ measurements for bioaerosols, volatile organic compounds (VOCs), total particulate matter (PM) count, carbon dioxide (CO2), and carbon monoxide (CO) were performed and monthly pulmonary function test (PFT) was applied to volunteer participants residing in the study sites (n = 121) for one year. Additionally, concentrations of air pollutants for PM2.5/PM10, sulfur dioxide (SO2), nitrogen oxides, and ozone were gathered from AAQ monitoring stations. To estimate the contributions of the emission sources and their effects on human health in the region, an emission inventory was also prepared in the region and AERMOD modelling system was applied for the year of 2013. Accordingly, the industry was the most polluting sector for NOx and SO2, while road traffic and residential heating were the most polluting sectors for CO and PM10. Factor analysis revealed that organics, combustion, bioaerosol propagation, and ozone accumulation contributed to AAQ, in agreement with AQ modelling results. Can had the worst air quality (industrialized site), which affected the respiratory health indicators of the participants. Generalized linear model estimated that PF of the participants varied according to the residing district, gender, suffering from asthma, and lifelong smoking or environmental tobacco smoke exposure (p < 0.05). Also, PF of the participants were linked with VOCs levels in the Central town, total PM count in Lapseki, and ozone levels in Can (p < 0.05).

The aerosols harboring microorganisms and viruses released from the wastewater system into the air have greatly threatened the health and safety of human beings. The wastewater systems, including toilet and wastewater treatment plant (WWTP), are the major locations of epidemic infections due to the extensive sources of aerosols, as well as multifarious germs and microorganisms. Viruses and microorganisms may transport from both toilet and hospital into municipal pipes and subsequently into WWTP, which accounts for the main source of bioaerosols dispersed in the air of the wastewater system. This review aims to elaborate the generation, transmission, and diffusion processes of bioaerosols at toilet and WWTP. Moreover, the main factors affecting bioaerosol transmission and the corresponding prevention strategies for the airborne and inhaled bioaerosols are also discussed. Collectively, this review highlights the importance of managing bioaerosol occurrence in the wastewater system, which has aroused increasing concern from the public.

Purpose to perform comparative analyzes of the size distributions of bacteria and fungi in the air of overground therapy chambers in Szczawnica sanatorium and subterranean inhalation chambers in Bochnia Salt Mine health resort taking into account influence of the season and presence of pathogenic species. Methods bioaerosol samples were collected using 6-stage Andersen impactor. Bacterial and fungal aerosol concentrations and size distributions were calculated and isolated microorganisms were taxonomically identified based on their morphological, biochemical, and molecular features. Results: in both treatment rooms and atmospheric (outdoor) air, the acceptable microbial pollution levels were periodically exceeded. The size distribution analyzes revealed that in the case of bacteria – emission from the patients and in the case of fungi – transport with atmospheric (outdoor) air were the major processes responsible for microbiological contamination of indoor premises. The majority of microbial particulates were present in the air of studied premises as single bacterial vegetative cells, spores and fungal conidia or (most commonly) formed small microbial or microbial-dust aggregates. This phenomenon may have a significant effect on patients’ actual exposure (especially on those treated for respiratory diseases) in terms of the dose of inhaled particles. Conclusions the microbiological quality of the air in sanatoriums and health resorts is a key factor for their therapeutic and prophylactic functions. When microbial pollution crossed the acceptable level, the measures that enable reducing undesirable contamination should be introduced, especially if large groups of patients undergo such therapy.

Water-miscible metalworking fluids (MWFs) are used in metal removal and forming operations. For end use, formulation concentrates are diluted in water, providing conditions conducive to microbial g...

Nonnegligible emission of bioaerosols usually occurs during aeration of wastewater in aerator tanks in wastewater treatment plants (WWTPs). Literature had shown that the respiratory and intestinal diseases of workers at WWTPs are related to bioaerosols. Thus, quantitative microbial risk assessment (QMRA) based on Monte Carlo simulation was utilized in this research to assess the health risks of Gram-negative bacteria bioaerosol (GNBB) and Staphylococcus aureus bioaerosol (SAB) among academic visitors and staffs. Results showed that the concentrations of GNBB and SAB in the inverted umbrella aeration mode were consistently higher than those in the microporous aeration mode under all six size distribution ranges of the Anderson six-stage impactor. Thus, GNBB and SAB can be highly threatening to the weasand and first bronchus (or alveoli and third bronchus) for the exposure populations. The health risks (annual probability of infection (Py) and disease burden (DB)) of males were constantly higher than those of females for each certain exposure scenario. The health risks of staffs were higher than those of academic visitors when assessed by Monte Carlo simulation. The wearing of mask is an effective measure to minimize health risks through reducing the bioaerosol concentration intake. Especially, for the academic visitors and staffs exposed to GNBB, all their DB failed to meet the World Health Organization DB benchmark under various credible intervals when they were without a mask on. In a word, the results of health risk assessment in this research can be utilized as an educational tool and policy basis to facilitate the implementation of efficacious prevention measures to protect the public health from bioaerosol health threats in WWTPs.

Fitness centers are considered high risk for SARS-CoV-2 transmission due to their high human occupancy and the type of activity taking place in them, especially when individuals pre-symptomatic or asymptomatic for COVID-19 exercise in the facilities. In this study, air (N = 21) and surface (N = 8) samples were collected at a fitness center through five sampling events from August to November 2020 after the reopening restrictions were lifted in Florida. The total attendance was ~2500 patrons during our environmental sampling work. Air samples were collected using stationary and personal bioaerosol samplers. Moistened flocked nylon swabs were used to collect samples from high-touch surfaces. We did not detect SARS-CoV-2 by rRT-PCR analyses in any air or surface sample. A simplified infection risk model based on the Wells-Riley equation predicts that the probability of infection in this fitness center was 1.77% following its ventilation system upgrades based on CDC guidelines, and that risk was further reduced to 0.89% when patrons used face masks. Our model also predicts that a combination of high ventilation, minimal air recirculation, air filtration, and UV sterilization of recirculated air reduced the infection risk up to 94% compared to poorly ventilated facilities. Amongst these measures, high ventilation with outdoor air is most critical in reducing the airborne transmission of SARS-CoV-2. For buildings that cannot avoid air recirculation due to energy costs, the use of high filtration and/or air disinfection devices are alternatives to reducing the probability of acquiring SARS-CoV-2 through inhalation exposure. In contrast to the perceived ranking of high risk, the infection risk in fitness centers that follow CDC reopening guidance, including implementation of engineering and administrative controls, and use of personal protective equipment, can be low, and these facilities can offer a relatively safe venue for patrons to exercise.

Bioaerosol concentrations in residential buildings located in the Northeastern US have not been widely studied. Here, in 2011-2015, we studied the presence and seasonal variability of culturable fungi and bacteria in three multi-family apartment buildings and correlated the bioaerosol concentrations with building ventilation system types and environmental parameters. A total of 409 indoor and 86 outdoor samples were taken. Eighty-five percent of investigated apartments had indoor-outdoor (I/O) ratios of culturable fungi below 1, suggesting minimal indoor sources of fungi. In contrast, 56% of the apartments had I/O ratios for culturable bacteria above 1, indicating the prominence of indoor sources of bacteria. Culturable fungi I/O ratios in apartments serviced by central heating, ventilation, and air-conditioning (HVAC) system were lower than those in apartments with window AC. The type of ventilation system did not have a significant effect on the presence of indoor culturable bacteria. A significant positive association was determined between indoor dew point (DP) levels and indoor culturable fungi (P

An investigation on bioaerosol in a wastewater treatment plant (WWTP) located in Xi'an, China, was conducted to understand the characteristics of bioaerosol released from wastewater and sludge treatment facilities because the bioaerosols may pose a threat to human health. Using the Andersen impactor sampler collection and colony-counting method, bioaerosol concentrations and size distributions were detected. The risk quotient method was used to evaluate the health risks associated with inhalation of bioaerosol for WWTP staff, based on the average daily dose rates of exposure. The health risk in relation to Legionella pneumophila was quantitatively calculated using quantitative microbial risk assessment (QMRA), based on the assumption of the percentage. The maximum concentration of airborne bacteria (3,767 ± 280 colony forming units (CFU)/m3) and fungi (8,775 ± 406 CFU/m3) occurred from the aerated grit chamber and sludge thickening house, respectively, which all exceeded 500 CFU/m3 as the acceptable guideline proposed by the American Conference of Governmental Industrial Hygienists. The particle size of airborne bacteria was mainly distributed in the first three stages (>3.3 µm), while that of airborne fungi was from the second to the fourth stage (2.1–7.0 µm). The hazard index exposure to bioaerosol for adult males and females by inhalation were higher than 1. The proportion of L. pneumophila should be strictly controlled below 10−8, based on the QMRA approach.

Airborne biological aerosols are an integral part of the atmosphere–biosphere interface and significantly impact the environment and Earth’s climate. Primary biological particles such as fungal spo...

It has been proven that exposure to bioaerosols is associated with several health effects, such as pulmonary diseases and allergies. The present cross-sectional study was aimed to investigate fungal contamination in indoor air and on the surfaces of four traditional baths in Shiraz, Iran, one of the most historical cities in the world. Samples were taken from indoor air, using a microbial air sampler, as well as the surfaces of the shower, hallway, and dressing rooms of studied baths for 3 months. Totally 180 samples, including 45 air and 135 surfaces samples, were collected from studied baths. The concentrations of fungi collected from the air of studied baths were ranged from 22.6 to 34.6 CFU/m(3). Besides, the levels of fungi collected from the surface samples of studied baths were ranged from 21.2 to 60 CFU/m(2). The highest and lowest fungi species detected both in air and surfaces samples of the studied baths were Penicillium spp. and Mucor spp. respectively. Although the levels of fungi in the studied baths were lower than the levels recommended by the World Health Organization, some environmental health measures such as washing and disinfecting surfaces and tools after each working shift and periodic inspections are recommended ensuring the safety of costumers who are visiting such places.

The study of bioaerosol dispersion in wastewater treatment plants (WWTPs) has received considerable attention. This study aimed to investigate the seasonal changes and spatial distributions of airborne bacteria around different parts of Ahvaz WWTP, the capital city of Khuzestan Province, Iran, over 4 months in the cold and warm seasons. Samples were collected from 2 and 10-m intervals of grit chamber (GCh), primary sludge dewatering basin (PSDB), aeration tank (AT), as well as 60-m upstream (US) and downstream (DS) of the WWTP. Further, bacteria in the indoor air of administrative building (AB) of WWTP were investigated. Bioaerosols were collected by passive sampling method. The total bacteria count was 105.3 ± 98.5 CFU/plate/h. The dominant bacteria stood 2 m away from the AT with an average 244.2 ± 73.1 CFU/plate/h in the warm season while they were the lowest with an average 43 ± 11.4 CFU/plate/h in the 10-m distance of the GCh in the cold season. According to the sequencing results, the dominant bacterial species included Bacillus pumilus (26.7%), Staphylococcus arlettae (23.2%), Kocuria turfanensis (13.6%) and Alicycliphilus (9.2%), respectively. There was a positive relationship between the release of bacteria, temperature and wind speed. However, there was a significant negative correlation between total bacteria concentration and humidity. There are accumulative perils to WWTP workers and neighbors exposed by persistent exposure to airborne bacteria. Therefore, AT should be paid more attention as a dominant source of airborne bacteria emissions, especially in the warm season.

Bioaerosol pollution was estimated in Wastewater Treatment Plants "WWTPs" working by Active Sludge Process "ASP". It was estimated inside and around the WWTPs, the factors effecting on bioaerosol pollution were evaluated. This paper focuses on planting density, shads and solar radiation amount as major effecting factors which effects on bioaerosol pollution. Other secondary parameters such as boundary condition, wind direction, temperature and measurement times were taken in consideration. The bioaerosol pollution in free air has been measured by CFU/M3. A direct relationship was found between bioaerosol pollution in air and both of planting density as same as shading ratio. Conversely, there was an inversely relationship between solar radiation and bioaerosol pollution. Despite the air quality is improved by plants, plants increase microorganism account in air. Also, presence of shades in the WWTP and around it increases microorganisms account in air.

Significance We found that the summer airborne bacterial community in the marine boundary layer over the Southern Ocean directly south of Australia is dominated by marine bacteria emitted in sea spray, originating primarily from the west in a zonal band at the latitude of collection. We found that airborne communities were more diverse to the north, and much less so toward Antarctica. These results imply that sea spray sources largely control the number concentrations of nuclei for liquid cloud droplets and limit ice nucleating particle concentrations to the low values expected in nascent sea spray. In the sampled region, the sources of summer cloud-active particles therefore are unlikely to have changed in direct response to perturbations in continental anthropogenic emissions., Microorganisms are ubiquitous and highly diverse in the atmosphere. Despite the potential impacts of airborne bacteria found in the lower atmosphere over the Southern Ocean (SO) on the ecology of Antarctica and on marine cloud phase, no previous region-wide assessment of bioaerosols over the SO has been reported. We conducted bacterial profiling of boundary layer shipboard aerosol samples obtained during an Austral summer research voyage, spanning 42.8 to 66.5°S. Contrary to findings over global subtropical regions and the Northern Hemisphere, where transport of microorganisms from continents often controls airborne communities, the great majority of the bacteria detected in our samples were marine, based on taxonomy, back trajectories, and source tracking analysis. Further, the beta diversity of airborne bacterial communities varied with latitude and temperature, but not with other meteorological variables. Limited meridional airborne transport restricts southward community dispersal, isolating Antarctica and inhibiting microorganism and nutrient deposition from lower latitudes to these same regions. A consequence and implication for this region’s marine boundary layer and the clouds that overtop it is that it is truly pristine, free from continental and anthropogenic influences, with the ocean as the dominant source controlling low-level concentrations of cloud condensation nuclei and ice nucleating particles.

Frequent heavy air pollution occurred during the winter heating season of northern China. In this study, PM2.5 (particles with an aerodynamic diameter less than 2.5 μm) was collected from a coastal city of China during the winter heating season from January 1 to March 31, 2018, and the soluble ions, organic carbon (OC), elemental carbon (EC), bacterial, endotoxin, and fungal concentration in PM2.5 were analyzed. During the winter heating season, PM2.5 and bioaerosols increased on polluted days, and the secondary inorganic ions, including NO3-, NH4+, and SO42-, increased significantly. Meteorological factors, such as wind direction and wind speed, had major impacts on the distributions of PM2.5 and bioaerosols. Pollutant concentration was high when there was a westerly wind with the speed of 3-6 m/s from inland area. Using the air mass backward trajectories and principal component analysis, we elucidate the potential origins of bioaerosol in PM2.5. The backward trajectory suggested that air mass for polluted samples (PM2.5 > 75 μg/m3) commonly originated from continent (9.62%), whereas air masses for clean samples (PM2.5 < 35 μg/m3) were mainly from marine (56.73%). The interregional transport of pollutants from continental area contributed most to PM2.5. Principal component analysis of the water-soluble ions and bioaerosol indicated that air pollution of the coastal city was greatly affected by coal combustion, biomass burning, and regional transmission of high-intensity pollutants from continent. Among that, interregional transport, biomass burning, and dust from soil and plants were main sources of bioaerosol. Our findings provide important insights into the origins and characteristics of bioaerosol in PM2.5 during the winter heating season of the coastal city in northern China.

The indoor air quality (IAQ) of an ice rink, located in the Upper Silesia Region of Southern Poland, was assessed during the winter holidays. Ice rinks are characterized by unusual conditions and multiple sources of pollution. This study evaluated the relative importance of the ventilation system (VS) for maintaining the indoor microenvironment in the ice rink. A preliminary investigation of the concentration levels and characteristics of the indoor and outdoor bacterial aerosol was conducted. Bacterial concentration levels were obtained using a six-stage Andersen cascade impactor. Bioaerosol particles, captured on nutrient media on Petri dishes, were quantitatively evaluated and qualitatively identified using a GEN III Biolog system. Concentration levels of airborne bacteria were above 103 CFU/m³, both when the VS system was turned off (990 CFU/m3) and when it was operational (740 CFU/m3). Results show that the mean concentration of bacteria aerosol was lower when the VS was active. There was a dominance of Gram-positive cocci identified in the indoor environment, which indicates that most of the bacteria present in the studied building were relatively fresh and mostly of human-origin. These data were used to estimate the ice rink exposure dose (IRED) of bioaerosols for building personnel and for children. The highest value of IRED over the study period was obtained for children (220 CFU kg−1).

Introduction & Objective: Exposure to microorganisms suspended in the air of both occupational and residential indoor environments is associated with a wide range of adverse health effects with major public health impacts. The quality of indoor air is one of the most significant factors affecting the health and well being of people. So the present study was conducted to assess bacteriological and fungal concentration of the indoor air of a teaching tertiary care institute hospital. Materials and Methods: The present study was carried for a period of three months from June 2018 to August 2018. Air sampling was performed with passive air sampling (settle plate’s methods) according to the 1/1/1 scheme (a Petri dish with a diameter of 9 cm was placed for 1 hour, 1 meter above the floor, and about 1 meter away from the walls). Each ward Petri dishes was exposed for 60 min in the morning and afternoon. Bacteria and fungi was collected on nutrient Agar, Blood Agar and Sabouraud Dextrose Agar(SDA). To obtain the appropriate surface density for counting and to determine the load with respect to time of exposure, the sampling times were set at 60 min in the morning (at 10.00-11.00 AM) and afternoon (2:00-3.00 PM). Both quantitative and qualitative analyses was conducted. Observation: The results indicate that the bacterial CFU/m3 air has been recorded in the range of 65.52 CFU/ m3 to 1179 CFU/ m3 at 60 min exposure. The results indicate that the fungal CFU/m3 air has been recorded in the range no growth to 262 CFU/ m3 at 60 min exposure. Gram Positive Bacteria were isolated more than Gram Negative Bacteria with predominance of Staphylococcus auerus. Whereas, the fungal isolates includes dominance of Candida spp followed by Aspergillus spp. Conclusion: This study revealed that hospital buildings were being ventilated by the aid of natural ventilation system which may increase the possibility of entrance of pollutants from unhygienic external environment. Modern built environ

Microbial aerosols can be used as model particles for examining the dispersion and deposition of particles as well as assessing the reliability of the simulation methods. For example, the computational fluid dynamics model (CFD) can be used in the evaluation of indoor microbial contamination and the possible spread of harmful microbes in spaces with high densities of people or in special hermetic environments. The aim of this study was to compare the results of the CFD simulation, which predicts the deposition of biological particles on the surfaces of a spacecraft, and real particle deposition, usingBacillus licheniformis/aeriusbacterium particles as the model organism. The results showed that the particles were mainly deposited on floor surfaces, but also onto the supply air diffusers, where bacterial concentrations were higher than on the wall and ceiling surfaces. The CFD simulation showed similar trends with actual particle dispersal, conducted in this experiment withBacillusparticles.

The adverse impact of sewage treatment plants on the environment, resulting from the emission of harmful biological agents to the atmosphere, depends mainly on the size of the facility, the quantity and composition of treated sewage as well as the technologies and equipment used. The aim of the conducted research was to determine the microbiological quality of atmospheric air at Municipal-Industrial Sewage Treatment Plant in Oświęcim, which is one of the largest treatment plants in Lesser Poland. Bioaerosol measurements were made at four points (raw sewage inlet, aeration chamber, purified sewage outlet and 150 m from the treatment plant, at the background point) in the period from January to December 2018. Bioaerosol samples were collected using Microbiological Air Sampler MAS-100 by Merck. The tested atmospheric air was characterized by a qualitatively and quantitatively diverse microflora. The largest source of emission of microorganisms to the atmosphere was the mechanical part of the sewage treatment plant (raw sewage inlet) and the biological reactor. The highest number of mesophilic bacteria was observed near the biological reactor (in the summer), the least at the control point. During the research, the least β-hemolytic bacteria was isolated at the purified sewage outlet—on average 3 CFU m−3, the highest at the biological reactor 16 CFU m−3. Most of α-hemolytic bacteria was observed near the raw sewage inlet and was not found at the control point. Actinomycetes also occurred in a small amount (0–40 CFU m−3). A high concentration of mildew fungi occurred in summer when the air temperature was highest, the smallest quantities of these microorganisms were found in January and February.

The exposure to airborne dusts and microorganisms is associated with respiratory diseases and other health effects. Currently, research concerning fungal aerosol and particulate matter levels in animal enclosures of zoological gardens is very scarce. Such premises are characterized by numerous sources of air contamination, and they are both working environment and popular tourist attractions. This study aimed to assess the levels of fungal aerosol in animal premises (tapirs, giraffes, pygmy hippos, monkeys, meerkats, pheasants, ostriches, exotarium) of the Kraków Zoo. The bioaerosol samples were collected using a six-stage Andersen impactor to assess the concentrations and size distribution of airborne fungi. Particulate matter (PM10, PM4, PM2.5 and PM1) concentration was assessed using DustTrak Aerosol Monitor. PM concentrations were relatively low (0.048–0.204 mg/m3) and did not exceed the limit values for occupational exposure. Also, the levels of fungal aerosol in almost all cases did not exceed the limit values. The smallest concentration of the total fungal aerosol was observed in the rooms for hippos (approx. 970 CFU/m3) while the highest—in exotarium (16,800 CFU/m3). The share of respirable fraction of bioaerosol was quite high—from 62.6% in monkey houses to 89.2% in exotarium. Having in mind that bioaerosol-forming fungi may contain allergenic species, attention should be paid to thorough cleaning of animals and their premises, and maintaining appropriate levels of microclimatic parameters in the rooms.

Bioaerosols consisting of biologically originated airborne particles such as microbes, metabolites, toxins, and fragments of microorganisms are present ubiquitously in our living environment. The international interests in bioaerosols have rapidly increased because of their many potential health effects. Thus, accurate and fast detection of total bioaerosols in different environments has become an important task for safeguarding against biological threats and broadening the pool of bioaerosol knowledge. To quickly evaluate the total bioaerosol concentration, we developed a localized surface plasmon resonance biosensor based on succinimidyl-ester-functionalized gold nanoislands (SEF-AuNIs) for quantitative bioaerosol detection. The detection limit of our proposed SEF-AuNI sensors for model bacteria Escherichia coli and Bacillus subtilis can go to 0.5119 and 1.69 cells/mL, respectively. To demonstrate the capability of this bioaerosol sensing technique, we tested aerosol samples collected from Bern (urban station), Basel (suburban station), and Rigi mountain (rural and high altitude station) in Switzerland and further investigated the correlation with endotoxin and PM10. The results substantiated that our SEF-AuNI sensors could be a reliable candidate for total bioaerosol detection and air quality assessment.

Bioaerosol sampling is a critical step toward characterizing airborne pathogen exposure risks for many respiratory infectious diseases in human-to-human or human-to-animal outbreaks. The integrated performance-parameter design and sampling efficiency of aerosol-to-hydrosol samplers (cyclones) has been rarely published or studied. This review focuses on the determination of cyclone performance-parameter design and impact factors of the sampling efficiency, discusses their mechanisms of collection and describes their advantages and drawbacks. The crucial design parameters of cyclones in different applications are then discussed in detail. We also discuss how the aerosol-to-hydrosol sampling efficiency is intrinsically related to the performance parameters for bioaerosol cyclone design. In the final section of this review, scientific questions and challenges for future work are presented to encourage high collection efficiency design and high-quality cyclones.

Determining the hotspots and deposition efficiencies (DEs) for aerosols in human airways is important for both research and medical purposes. The complexity of the human airways and the breathing process limit the application of in vitro measurements to only two consecutive branches of the human airway. Herein, in-depth information on in vitro experiments and state-of-the-art review on various computational fluid dynamics (CFD) applications and finite element methods on airflow and aerosol motion in both healthy and obstructed human airways are provided. A brief introduction of the application of one-dimensional and two-dimensional mathematical models to investigate airflow and particle motion in the lungs are further discussed. As evident in this review, aerosol deposition in the upper and central human airway regions has been extensively studied under different inhalation statuses and conditions such as humidity as well as different aerosol sizes, shapes, and properties. However, there is little literature on the lower sections of the human airways. Herein, a detailed review of the fundamentals for both in vitro experiments and numerical simulation at different sections of human airways is done. Exceptional features and essential developments in numerical methods for aerosol motion in healthy and diseased human airways are also discussed. Challenges and limitations associated with the applications of in vitro experiments and CFD methods on both human-specific and idealized models are highlighted. The possibility of airborne transmission pathways for COVID-19 has been discussed. Overall, this review provides the most useful approach for carrying out two-phase flow investigations at different sections of the human lungs and under different inhalation statuses. Additionally, new research gaps that have developed recently on the role of bioaerosols motion in COVID-19 transmission, as well as the deposition of aerosols in impaired human airways due to coronavirus (COVID-19) are underlined.

Waste collection is associated with various health symptoms. The aims of this study were to obtain knowledge about exposure to bacteria, fungi, and endotoxin during waste collection, and to study whether it is possible to reduce the exposures and the total inflammatory potential (TIP) of those exposures through simple interventions. The study was performed with an initial baseline exposure assessment, a second assessment with intervention workers only, and a third with intervention and reference workers. The waste collection workers were exposed to 7.8 × 103 cfu bacteria/m3, 1.4 × 104 cfu fungi/m3, and 92 endotoxin units/m3 (geometric mean values). The potential exposures in the truck cabs were up to 23 times higher than outdoor reference concentrations. For the intervention trucks and workers, airborne fungi in the truck cab were reduced; fungi, bacteria, and yeasts on the steering wheels were reduced; and the concentration of fungi on the workers’ hands was reduced. Exposures were typically highest during collection of mixed household waste, in the summer, and for collection using trucks with low loading height. The TIP was highest for the reference group sampling mixed household waste, using trucks with low loading height, in the summer. Endotoxin, bacteria, and fungi contributed to the TIP of 42 personal exposure assessments. Conclusion Motivating workers to reduce exposure through simple interventions improved hand and truck cab hygiene, but only slightly reduced personal exposure to airborne bioaerosols. Exposure can be reduced by only using trucks with high loading height.

Open landfilling is a common practice of waste dumping in developing countries, generating a range of environmental and public health hazards. In this study, we determined the distribution, composition and exposure risk of the size-segregated fungal and bacterial bioaerosols in an open landfill site in Dehradun, India. Bioaerosol and particulate matter (PM) measurements were carried out using a six-stage viable Andersen Cascade Impactor and a Wide Range Aerosol Spectrometer, respectively. Pearson correlation analysis was used to determine the relation of bioaerosol concentration with meteorological parameters and PM. The mean concentration of fungal and bacterial aerosols was observed to be 4582.75 ± 1358.25 CFU/m3 and 3609.53 ± 1000.28 CFU/m3, respectively. The bioaerosol composition showed the predominance of potential pathogens including Aspergillus (25.42%), Penicillium (20.34%), Cladosporium (15.25%), Alternaria (13.56%); and gram-negative Bacillus (21.15%), Streptobacillus (17.31%), Coccus (13.46%). Also, an inhalation risk assessment was conducted for the age-specific predictions of bioaerosol and PM deposition in human airways using a multiple path particle dosimetry model. For bioaerosols, maximum submicron depositions in the pulmonary region were observed in adults, while for PM, in children and infants. Finally, to identify the bioaerosol exposure caused respiratory disorders, a questionnaire-based health survey was conducted among the exposed population around the landfill site. The chi-square test showed significantly higher respiratory complaints in females for cold, cough, chest pain and chest tightness than in males. This work highlights the role of bioaerosols and PM in human health disorders in occupational environments associated with waste management.