Fungal Aerosol Concentrations Research Articles

Microbial pollution assessment in semi-exposed relics: A case study of the K9901 pit of the mausoleum of emperor Qin Shihuang

Summer and autumn are peak tourist seasons, during which tourists congregate in semi-exposed site museums, heightening the possibility of damage both to the tourists and the exposed relics by airborne microorganisms. This study investigated the spatiotemporal distribution of microbial aerosols and the diversity of the microbial genera inside and outside the Emperor Qin Shihuang Mausoleum K9901 Pit. Furthermore, the risk of museum personnel exposure to microbial aerosols was also quantitatively assessed. The results showed that the bacterial aerosol concentrations were 3.5 and 2.5 times the WHO limits (500 CFU/m3) in summer and autumn, respectively. Similarly, the fungal aerosol concentrations in summer and autumn were, respectively, 0.9 and 4.3 times the ACGIH limits (500 CFU/m3). The percentages of bacterial and fungal aerosols in the museum with particle sizes smaller than 4.7 μm were as high as 80.2–89.5 % and 83.2 %–93.2 %, respectively. The count median diameter was at level V of the Anderson sampler (1.1–2.1 μm). The risk of these aerosols being inhaled by personnel and entering the lower respiratory tract was significant. The dominant microbial genera detected had conditional pathogenicity (e.g., Acinetobacter and Pseudomonas) and allergenicity (e.g., Aspergillus and Talaromyces). Regarding tourists, the potential exposure dose (PED) was higher for children than for adults and the elderly. Staff were exposed for longer periods and had 18 times the PED of tourists of the same age, which put them at greater risk. This study offers valuable insights for developing effective environmental optimization measures to protect site museums and public health.

Comparison of bioaerosol release characteristics between windrow and trough sludge composting plants: Concentration distribution, community evolution, bioaerosolization behaviour, and exposure risk

Windrow and trough composting are two mainstream composting methods, but the effect of composting methods on bioaerosol release from sludge composting plants is unclear. The study compared the bioaerosol release characteristics and exposure risks between the two composting methods. The results showed that the bacterial aerosol concentrations in the windrow composting plant ranged from 14,196 to 24,549 CFU/m3, while the fungal aerosol concentrations in the trough composting plant reached 5874 to 9284 CFU/m3; there were differences in the microbial community structures between the two sludge composting plants, and the composting method had a greater effect on bacterial community evolution than on fungal community evolution. The biochemical phase was the primary source of the bioaerosolization behaviour of the microbial bioaerosols. In the windrow and trough composting plants, the bacterial bioaerosolization index ranged from 1.00 to 999.28 and from 1.44 to 24.57, and the fungal bioaerosolization index ranged from 1.38 to 1.59 and from 0.34 to 7.72, respectively. Bacteria preferentially aerosolized mainly in the mesophilic stage, while the peak of the fungal bioaerosolization index appeared in the thermophilic stage. The total non-carcinogenic risks for bacterial aerosols were 3.4 and 2.4, while those for fungi were 1.0 and 3.2 in the trough and windrow sludge composting plants, respectively. Respiration is the main exposure pathway for bioaerosols. It is necessary to develop different bioaerosol protection measures for different sludge composting methods. The results of this study provided basic data and theoretical guidance for reducing the potential risk of bioaerosols in sludge composting plants.

Particulate Matter Concentrations and Fungal Aerosol in Horse Stables as Potential Causal Agents in Recurrent Airway Disease in Horses and Human Asthma and Allergies

Exposure to bioaerosols associated with horse stable indoor environment and their health effects on people and horses has recently become of particular interest. Moreover, increasing frequency of recurrent airway disease (RAO) among horses made it necessary to search for the most probable causal agents of this disease and methods of their eradication. The study was conducted in two horse stables in southern Poland (Kraków and Tarnów). Particulate matter (PM2.5, PM4, and PM10) concentrations were determined photometrically, the concentration of fungal aerosol was determined by a six-stage impactor, and next generation sequencing (NGS) was used to determine fungal community composition in one of these stables. The highest PM concentrations were observed in Tarnów, but fungal aerosol levels were higher in the Kraków stable. Based on the NGS results, the three most prevalent fungal species were Wallemia sebi, Aspergillus penicillioides, and Epicoccum nigrum, all highly allergenic and potentially involved in the occurrence of RAO in horses. Spores of the detected fungi can penetrate deeply into the respiratory system. Therefore, this study suggests that examinations of particulate matter and fungal aerosol concentrations, along with species composition assessment, should be regularly conducted in horse stables.

Comprehensive health risk assessment of microbial indoor air quality in microenvironments.

The higher airborne microbial concentration in indoor areas might be responsible for the adverse indoor air quality, which relates well with poor respiratory and general health effects in the form of Sick building syndromes. The current study aimed to isolate and characterize the seasonal (winter and spring) levels of culturable bio-aerosols from indoor air, implicating human health by using an epidemiological health survey. Microorganisms were identified by standard macro and microbiological methods, followed by biochemical testing and molecular techniques. Sampling results revealed the bacterial and fungal aerosol concentrations ranging between (300-3650 CFU/m3) and (300-4150 CFU/m3) respectively, in different microenvironments during the winter season (December-February). However, in spring (March-May), bacterial and fungal aerosol concentrations were monitored, ranging between (450-5150 CFU/m3) and (350-5070 CFU/m3) respectively. Interestingly, Aspergillus and Cladosporium were the majorly recorded fungi whereas, Staphylococcus, Streptobacillus, and Micrococcus found predominant bacterial genera among all the sites. Taken together, the elevated levels of bioaerosols are the foremost risk factor that can lead to various respiratory and general health issues in additional analysis, the questionnaire survey indicated the headache (28%) and allergy (20%) were significant indoor health concerns. This type of approach will serve as a foundation for assisting residents in taking preventative measures to avoid exposure to dangerous bioaerosols.

Morning–evening variation and determinants of bacterial and fungal aerosol concentration in historical objects in Kraków

Cultural heritage objects are very frequently visited by tourists, the presence of which is considered to affect the bacterial and fungal aerosol levels in these facilities. Therefore, this study had two main aims with the first to determine the morning/evening changes in the concentration of bacterial and fungal aerosol as well as particulate matter in the selected historical objects of Krakow: churches, crypts, libraries, and museums. The second aim was to establish the most possible factors affecting the quality of air in the examined sites using data mining techniques: principal component analysis (PCA) and cluster analysis (CA). Bacterial and fungal aerosol levels were measured in ten historical objects by six-stage Andersen impactor. Particulate matter (PM10, PM4, PM2.5 and PM1), temperature, and relative humidity (RH) were also assessed. Unlike dusts, the microbial aerosol concentrations were not always significantly lower in the morning than in the evening. For bacteria, these relationships varied depending on the site, while for fungi, the morning concentrations were mostly higher than the evening ones. Both PCA and CA indicated that the bacterial and fungal aerosol concentrations were not associated with the particulate matter levels, which might suggest different sources of those two air pollution components. Temperature and RH appear to be more important in shaping the microbial aerosol levels and fungi are more dependent on RH than bacteria.

Mycological Air Quality at Animal Veterinary Practice

The objective of the study was to characterize the mycological quality of air at animal veterinary practice in Krakow. Bioaerosol measurements were performed during the summer season of 2017. The samples of outdoor and indoor air at animal veterinary practice were collected using a 6-stage Andersen`s air sampler. The highest concentration of fungal aerosol was observed in the treatment room. The analysis showed various fungal contamination in different measuring points at different measuring times of the day. Based on the analysis of bioaerosol particle size distribution it was found that the largest "load" of fungi, isolated form the air, can reach (in the human respiratory tract) to the region of the throat, trachei and primary bronchi. The predominant fungi in indoor air was Penicillium spp. and Cladosporium cladosporoides. Fungi that can cause dermatophytoses have also been isolated from indoor air: Microsporum canis and Trichophyton verrucosum. The study confirmed that the animal veterinary practice can be a workplace related to exposure to microbial agents.

Effectiveness and Eco-Costs of Air Cleaners in Terms of Improving Fungal Air Pollution in Dwellings Located in Southern Poland—A Preliminary Study

Epidemiological evidence shows that air pollution is responsible for several million premature deaths per year. By virtue of being responsible for these deaths, economic evidence shows that air pollution also imposes a so-called economic cost to society of several trillion dollars per year. The diseases caused by biological air pollutants are of primary global concern for both social and economic reasons, and given that people may spend more than 90% of their time in enclosed spaces, the investigation into methods to remove indoor air pollutants is of paramount importance. One of the methods to improve indoor air quality (IAQ) is to use air cleaners (ACLs) with high-efficiency particulate air filters (HEPA) that remove biological indoor air pollutants from indoor environments. This work presents the results of a study of fungal aerosol samples collected during the summer season from inside two dwellings (DG1 and DG2) before and after starting the use of ACLs. The fungal aerosol samples collected from each of the six stages of the sampler were incubated on agar plates at 26 °C, and the colony forming units (CFU) were manually counted and statistically corrected. The concentration of living airborne fungi was expressed as the CFU in the volume of air (CFU·m−3). The average concentration of fungal aerosol decreased the most when the ACLs were active for 24 min. The reduction was from 474 CFU·m−3 to 306 CFU·m−3, and from 582 CFU·m−3 to 338 CFU·m−3 in DG1 and DG2, respectively. The use of ACLs was assessed by the life cycle assessment (LCA) methodology. This study highlights the benefits of controlling biological air pollutants in order to keep occupants of buildings happy and healthy.

Size distribution of microbial aerosols in overground and subterranean treatment chambers at health resorts

Purposeto 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.Methodsbioaerosol 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.Conclusionsthe 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.

Size distribution and concentration of fungal aerosol in animal premises of a zoological garden

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.

Exposure to Bacterial and Fungal Aerosols: Microorganism Indices in A Waste-Sorting Plant in Poland.

An increased understanding of airborne microorganism populations should enable a better interpretation of bioaerosol exposure found in a working environment. An assessment of the contamination levels of mesophilic bacterial aerosol (MBA) and fungal aerosol (FA) was carried out using two evaluation indices for microbiological pollution—the total index of microbiological contamination per cubic meter (TIMC/m3) and the indoor–outdoor index (IOI). An advantage of selected indices is the inclusion of several co-existing factors that have an impact on the formation of bioaerosol. When properly used, they also highlight the low efficiency of the ventilation system caused by an insufficient air exchange. In this study, the microbial air quality (MAQ) of the working environment was assessed during the spring season at a sorting plant located in Southern Poland. Sampling was undertaken in the plant using an Andersen six-stage impactor which allows the obtainment of information about the size distribution of the air microflora. The value of average concentrations of MBA and the average concentration of FA collected in the preliminary cabin of the sorting plant (PCSP) and the cleaning cabin of the sorting plant (CCSP) were analyzed. The obtained values of MBA were 1.6 times higher indoors, compared to outdoors, while FA was 1.7 times higher outdoors than indoors. The maximum TIMC/m3 value was obtained in PCSP (2626). The calculated IOI in this study suggests that MBA concentrations are influenced by internal sources, as opposed to FA. The purpose of this work was to present the usefulness of using indices in assessing air quality.

Nasal lavage as analytical tool in assessment of exposure to particulate and microbial aerosols in wood pellet production facilities

Occupational exposure to wood dust and bioaerosols may lead to numerous respiratory tract diseases. We aimed to assess a degree of workplace contamination with dust, bacteria, fungi, endotoxins, and (1 → 3)-β-D-glucans released into the air during wood processing in pellet production facilities and to check against this background the usefulness of nasal lavage (NAL) as analytical tool for assessment of combined workers' exposure to airborne dust and microbiological contaminants. In 10 pellet plants, the particulate (wood dust) aerosol concentrations were determined by using Grimm aerosol spectrometer and CIS filter sampler. The collected CIS samples were subsequently used to evaluate endotoxin and (1 → 3)-β-D-glucan concentrations. Simultaneously with particulate aerosol, bioaerosol samples were collected by using 6-stage Andersen and single-stage MAS impactors. Bacterial and fungal aerosol concentrations were calculated and all isolated microorganisms were taxonomically identified. NAL fluid samples were collected from workers exposed to studied aerosols and the concentrations of proinflammatory mediators (IL-1β, IL-6, IL-8, and TNFα) and cytological image of nasal mucosa (expressed as cell counts) were established. The dynamics of production activities resulted in wide range of observed wood dust, microorganism, endotoxin and (1 → 3)-β-D-glucan concentrations reaching periodically extremely high values up to 65 mg m−3, 19,320 CFU m−3, 215 ng m−3 and 1525 ng m−3, respectively. Environmental stress caused by exposure to particulate and microbial aerosols stimulated immune response among workers of pellet production facilities. Correlation analysis revealed that interleukin levels and the number of cells in NAL were significantly affected by both wood dust and bioaerosol concentrations. As nasal mucosa serves as the primary barrier against inhaled pollutants, NAL seems a reliable analytical material to assess work-related adverse respiratory health outcomes derived from such exposure.

Fungal Fragments and Fungal Aerosol Composition in Sawmills.

Assessment of exposure to fungi has commonly been limited to fungal spore measurements that have shown associations between fungi and development or exacerbation of different airway diseases. Because large numbers of submicronic fragments can be aerosolized from fungal cultures under laboratory conditions, it has been suggested that fungal exposure is more complex and higher than that commonly revealed by spore measurements. However, the assessment of fungal fragments in complex environmental matrix remain limited due to methodological challenges. With a recently developed immunolabeling method for field emission scanning electron microscope (FESEM), we could assess the complex composition of fungal aerosols present in personal thoracic samples collected from two Norwegian sawmills. We found that large fungal fragments (length >1 µm) dominated the fungal aerosols indicating that the traditional monitoring approach of spores severely underestimate fungal exposure. The composition of fungal aerosols comprised in average 9% submicronic fragments, 62% large fragments, and 29% spores. The average concentrations of large and submicronic fragments (0.2–1 µm) were 3 × 105 and 0.6 × 105 particles m−3, respectively, and correlated weakly with spores (1.4 × 105 particles m−3). The levels of fragments were 2.6 times higher than the average spore concentration that was close to the proposed hazardous level of 105 spores per m3. The season influenced significantly the fungal aerosol concentrations but not the composition. Furthermore, the ratio of spores in the heterogeneous fungal aerosol composition was significantly higher in saw departments as compared to sorting of green timber departments where the fungal fragments were most prevalent. Being the dominating particles of fungal aerosols in sawmills, fungal fragments should be included in exposure-response studies to elucidate their importance for health impairments. Likewise, the use of fungal aerosol composition in such studies should be considered.

Concentration and Size Distribution Characteristics of Culturable Bioaerosols at Various Air Quality Levels During Fall and Winter in Xi'an, China

The concentration and size distribution of culturable bacteria and fungi were studied in Xi'an city at various air quality levels. The culturable bioaerosols were collected by an Andersen bioaerosol aerosol sampler between Sept. 2014 and Jan. 2015. Principal component analysis and multiple linear regressions were applied to link the concentrations with meteorological conditions including ambient temperature and relative humidity, as well as the levels of air pollutants such as PM2.5, PM10, NO2, SO2, and O3. These measured results showed that the concentration of culturable bacteria and fungi were in the ranges of 97-1909 CFU·m-3 and 92-1737 CFU·m-3, respectively. The concentrations of culturable bioaerosols increased along with a deterioration in air quality. The size distribution of the bacteria migrated to coarse particles. Fungal aerosols showed a normal distribution at low pollution levels, while for a high levels, they preferenced fine particles. Results from the principal component analysis (PCA) indicate that the concentration of culturable bioaerosols is mainly influenced by haze, solar radiation, and relative humidity. Multiple linear regression analysis showed that bacterial aerosol concentrations are positively correlated with haze (P<0.05) and relative humidity, while no significant negative correlations with solar radiation exists. Fungal aerosol concentrations did not have significant positive correlations with haze, solar radiation, or relative humidity. The results of this study will provide basic data for evaluating the effects of bioaerosols on human health and the environment.

Indoor and outdoor microbial aerosols at the holy mosque: A case study

The aim of this study was to evaluate bacterial and fungal aerosol concentrations at the holy mosque (Al-Masjid Al-Haram). Air samples were collected from different locations inside and outside the holy mosque, during the month of Ramadan-2011 (the fasting month), using a portable Air-port MD8 gelatin filter sampler. Trypticase soya agar and Capek's dox agar media were used to count bacteria and fungi, respectively. The mean concentrations of airborne bacteria and fungi ranged between 105–106 colony forming unit per cubic meter of air (CFU/m3) outside, and ∼102–105 CFU/m3 inside locations. The highest outside bacterial concentrations 106 CFU/m3 were found at the Al Umra, Al Fatah and eastern plazas, and the highest inside fungal concentrations ∼105 CFU/m3 were found at the courtyard, expansion of 1st floor, and roof. Significant differences (P < 0.05) were found between bacterial and fungal concentrations inside and outside sampling locations, higher concentrations shifted towards to outside locations. Significant differences were also found between the bacterial and fungal concentrations inside–unclosed and semi-closed (P < 0.05) with inside-closed locations. Gram-positive bacteria, Bacillus and Micrococcus, and fungi, Aspergillus niger were the dominant microbial aerosol genera. The obtained data is considered a step to make up the gap about airborne microbial contamination inside the holy mosque, and microbial air quality should be studied along over the year at the holy mosque in the future.

Seasonal variation of airborne fungal propagules indoor and outdoor of domestic environments in Mérida, Mexico

The aim of this study was to establish the seasonal variation of fungal propagules in homes of Mérida, Mexico, and to examine the relation between their concentrations in enclosed and open locations taking into account environmental parameters such as temperature, humidity and wind speed. Samples were taken inside and outside domestic environments during the most characteristic weather seasons in the region: dry season (sampled in May), rainy season (sampled in October), and cold fronts season (sampled in February). The geometric mean of the indoors and outdoors concentration of airborne fungal propagules was 1653 and 1432 CFU/m3 during the cold fronts period, 125 and 92 CFU/m3 during the dry period, and 1326 and 1145 CFU/m3 during the rainy period. The respirable fraction during the three periods sampled was always within a range of 50 to 100%. The composition of fungal genera exhibited a seasonal change, and 19 of these were identified. The main genera found during the three periods were Cladosporium spp., Penicillium spp., Aspergillus spp., Fusarium spp., andAcremonium spp. The fungal aerosol concentrations and diversity found in Mérida, Mexico, were similar to those from other reports of cities with comparable tropical humid climate. This study concludes that the concentration of airborne fungal propagules and its respirable fraction can be related to several meteorological factors, mainly to relative humidity.

Assessment of relationship between fungal aerosol within a municipal dump and epiphytic mycoflora of crop plants

A field study was performed to assess whether fungal aerosol of a municipal dump may impact on quantitative and qualitative characteristics of epiphytic mycoflora of crop plants cultivated in vicinity of the dump. Sampling sites were located at every side of the dump. Plant samples were collected from field bean, spring wheat and potato. The highest concentration of fungal aerosol was found at the field located south of the dump within the zone of 250 m next to its borders. For this zone, the most numerous and diverse mycoflora was ascertained, and the plants cultivated were the most damaged. The results suggest that the municipal dump was not the source of phytopathogenic fungi; however, different emissions of contaminants from the dump might cause a decline in the intrinsic plant resistance against the pathogens.

Airborne and dust borne microorganisms in selected Polish libraries and archives

The aims of this work were to quantitatively and qualitatively study culturable fungi and bacteria in the air and settled dust in the storerooms of five Polish libraries and archives as well as to estimate the effect of water intrusion on the microbial air quality indoors. In all studied storerooms, the total bioaerosol concentrations at the workplaces ranged from 100 to 1000 cfu/m 3. The most prevalent part of the storerooms’ bioaerosol consisted of bacteria, mainly Staphylococcus spp. and Micrococcus spp., followed by filamentous fungi. In four of the studied premises, fungal aerosol concentrations were below 100 cfu/m 3. The only exception was observed in the fifth storeroom, which has been periodically flooded with rainwater and where significantly higher concentrations of fungal aerosol were measured. Among the identified fungal species, those of the genus Penicillium were the most numerous. Moreover, Trichothecium laxicephalum and Alternaria tenuis were present in all of the examined storerooms. The other objective of this study was to evaluate the effect of renovation and mechanical cleaning of the flooded storeroom collection on the level of microbial contamination. The obtained results show that both of the applied procedures reduced the concentration of fungal and bacterial aerosols by almost 80% and 50%, respectively. A significant reduction in the number of airborne microbial species was also noted. Hence, if the source of moisture is removed and mechanical cleaning is subsequently applied, the hygienic quality of a storeroom collection can be significantly improved.

Exposure to airborne fungi and bacteria while commuting in passenger cars and public buses

The present study examined airborne microbe levels inside and outside passenger cars and public buses during two seasons (winter and summer). The prevalence level of individual fungal genera depended on the fungi and agar type, whereas a constant higher prevalence (>90%) was found for the total bacteria and total fungi. The four most prevalent fungal genera were Cladosporium, Penicillium, Aspergillus, and Alternaria in a descending order. The major parameters associated with the airborne microbe measurements included agar type, vehicle type, and seasonal variation. When compared to the malt extract agar (MEA), the dichloran glycerol 18 agar (DG-18) was found to produce better counts for the target fungi. The summer in-vehicle bacterial concentrations were significantly higher for public buses than for the passenger cars, whereas the reverse was true for summer in-vehicle total fungal concentrations. This pattern was also consistent with summer outdoor results. In contrast, the winter in-vehicle and outdoor airborne microbe levels were similar for cars and buses. Meanwhile, summer was generally found to have higher in-vehicle fungal concentrations than winter. The current in-vehicle airborne microbe concentrations were found to be similar to residential indoor values from other reports, such as bacterial values between 10 and 10 3 CFU m −3 and total fungal aerosol concentrations ranging from 10 to 10 3 CFU m −3. It was suggested that motor vehicles in which many individuals spend a certain percentage of their day or week for travel are also a potential microenvironment for individual exposure to airborne microbes.

Characteristics of indoor and outdoor bioaerosols at Korean high-rise apartment buildings

This study attempted to evaluate the bioaerosol exposure of apartment residents at high-rise apartment buildings in a Korean city. The characteristics associated with the bioaerosol exposure included the apartment floor, seasonal variation, summer survey period (seasonal rain-front period (SRFP) or no rain-front period (NRFP)), and room location inside an apartment. Four most prevalent fungal genera detected in both the indoor and the outdoor air were Cladosporium, Penicillium, Aspergillus, and Alternaria. The outdoor bacterial concentrations were significantly higher in the low-floor apartments than in the high-floor apartments. However, the bacterial and fungal concentrations in the interior air of the apartments were not significantly different between the low- and the high-floor apartments. The current bioaerosol concentrations were comparable to those in other reports, with geometric mean (GM) bacterial values between 10 and 10 3 CFU m −3 and fungal aerosol concentrations in homes ranging also from 10 to 10 3 CFU m −3. The indoor and outdoor fungal concentrations and the outdoor bacterial concentrations were usually higher in the summer than in the winter. The indoor and outdoor bioaerosol concentrations were both higher for the SRFP than for the NRFP. The difference in the total bacterial concentrations was not significant among the surveyed five rooms. The GM total fungal and Cladosporium concentrations, however, were significantly higher for the kitchen than for the other rooms.

Microbial Air Quality in Offices at Municipal Landfills

The purpose of this study was to evaluate the influence of two municipal landfills on the microbiological air quality in offices on landfill sites. The evaluation was based on the concentration levels of airborne bacteria and fungi and the identification of isolated strains. Air samples were collected with a six-stage Andersen impactor. The concentrations of bacterial aerosol ranged from 1.0 × 103 to 7.2 × 104 colony forming units (CFU)/m3 indoors, and from 7.0 × 10 to 4.0 × 104 CFU/m3 outdoors. The corresponding fungal aerosol ranges were from 2.3 × 102 to 7.3 × 103 CFU/m3 indoors and from 2.0 × 102 to 1.2 × 104 CFU/m3 outdoors. The concentration levels were affected by the season of the year. The study showed that both indoor and outdoor air were heavily contaminated with bacteria and fungi. The proximity of the unpaved transport route and the weighing of refuse loads contributed to the increase of bacterial and fungal aerosol concentrations significantly. The air in the offices was characterized not only by elevated concentrations of bacteria and fungi but also by high frequencies of gram-negative bacteria, along with fungal species characteristic of landfills. The quantitative and qualitative changes in the composition of the bacterial and fungal aerosol posed a possible health risk to office workers at municipal waste landfill sites.