Opportunistic fungi in soils and surface air of a megalopolis (for the Tushino Region,Moscow)

The number and composition of opportunistic microscopic fungi was studied in soils and surface air (0.2 and 1.5 m above the surface) in the megalopolis districts (Tushino, Moscow) of different age of construction (6 and 40 years) and in urban recreational forests. The highest number (up to 1500 CFU/m³) determined by plating from air was found in the summer in new-built quarters. Direct count of fungal diaspores in airborne dust yielded significantly higher values (up to 4 × 10⁵/m³). The composition of the soil fungal population differed significantly from that of the air. In soil, the diversity of potentially pathogenic fungi was higher, while in air, their abundance was greater. The highest content of opportunistic fungi in soil and air was observed in spring and late summer-autumn, respectively. The fungi known as allergenic (mostly Cladosporium spp.) predominate in the air in autumn, especially in the new-built quarters.     

Exposure to airborne microorganisms,hyphal fragments,and pollen in a field of organically grown strawberries

Many working environments are predisposed for larger than average amounts of fungi and other microorganisms often due to organic material being handled. From 2003 to 2007, the area used for strawberry production in Denmark increased by 62%. The purpose of this study was to determine the levels of exposure to microorganisms, endotoxin, (1→3)-β-d-glucan (β-glucan), and pollen in a field of strawberries. The study was carried out in eastern Denmark from the middle of June to the beginning of August 2008. The strawberries were grown organically, and microbiological pest control agents (MPCAs) were applied during this and former growth seasons. In order to measure exposure to inhalable bioaerosol components, we used stationary filter samplers. Bioaerosol sampling was performed during 4 working days, and a total of 57 samplings were performed. The filters were analysed for contents of fungi, MPCAs, endotoxin, β-glucan, and pollen. The mean exposure was 6,154 CFU Cladosporium sp. m⁻³, 1.0 × 10⁵ fungal spores m⁻³, 4.1 × 10⁴ hyphal fragments m⁻³, 5.8 × 10³ pollen m⁻³, 57.3 ng β-glucan m⁻³, and 8.9 endotoxin units (EU) m⁻³. A significant and positive correlation was found between β-glucan and fungal spores and between CFU of Cladosporium sp. and CFU of fungi. We selected specifically for Metarhizium anisopliae, Beauveria bassiana, and the applied MPCAs Trichoderma harzianum, T. polysporum, and Bacillus thuringiensis but found none of these species. In conclusion, our study shows that berry pickers in this organic strawberry field were potentially subjected to higher levels of fungal spores, Cladosporium sp., hyphal fragments, pollen, and thus also β-glucan than is usually seen in outdoor air. Exposure to MPCAs was not seen. The exposure to endotoxin was only slightly higher than e.g. in a town.     

Contribution of leaf surface fungi to the air spora

High concentrations of airborne fungal spores frequently occur from spring through fall in temperate areas of the world. Although it is generally assumed that fungi on leaf surfaces are contributors to the air spora, little data are available comparing the types of fungi found on leaf surfaces with those in the atmosphere. Air sampling was carried out with a Burkard Spore Trap located on the roof of a building on the University of Tulsa campus using standard methods. Leaf samples were aseptically collected from Ulmus americana and Quercus palustris trees on campus, placed in sterile plastic bags, and brought to the lab. For each leaf, 4 cm² areas of both upper and lower leaf surfaces were swabbed and plated on malt extract agar with streptomycin. Cultures were incubated at room temperature for 5–7 days and then examined microscopically. Results were expressed as colony forming units (CFU)/cm². Twenty-one fungal taxa were identified from the air samples. The most abundant taxa were Cladosporium, ascospores, basidiospores, and Alternaria; together these four spore types comprised over 90% of the yearly total. Yeasts were the most abundant fungi isolated from both leaf types. Among the mycelial fungi were Phoma species, followed by Cladosporium and Alternaria. Overall twenty genera of filamentous fungi were identified. Yeasts and Phoma are normally splash dispersed and were not identified in the Burkard air samples. However, 10 taxa isolated from leaf surfaces were registered in air samples. Crude estimates of the leaf surface area of each tree suggest that the total fungal load was approximately 5.04×10⁸ CFU for Ulmus and 2.71×10⁸ CFU for Quercus. Of these levels, 19% were from fungi also detected in air samples. The data suggest that some leaf-surface fungi are major contributors to the air spora.     

A comparative study on the airborne fungi in Athens,Greece, by viable and non-viable sampling methods

Airborne fungi were studied in the city of Athens using two complementary methods in which 136 concurrent samplings were carried out during the 12-month period from January until December 1998. A portable Burkard air sampler for agar plates was used for trapping the culturable portion of the mycobiota. Nineteen genera of fungi were identified and assessed in terms of total numbers and fluctuations in concentration (Alternaria, Arthrinium, Aspergillus, Aureobasidium, Botrytis, Chrysonilia, Cladosporium, Drechslera, Epicoccum, Fusarium, Mucor, Nigrospora, Paecilomyces, Penicillium, Rhizopus, Sclerotinia, Scopulariopsis, Trichoderma and Ulocladium), with the exception of those included in the Sphaeropsidales, the yeasts, and the non-sporulating fungi, which were counted as groups. A volumetric Burkard air sampler for glass slides was operating simultaneously for detecting the total mycobiota, including the non-culturable and the non-viable portion. Ascospores, basidiospores, spores of Myxomycetes, Ustilaginales, Uredinales and Erysiphales, teliospores of Puccinia, as well as conidia of the genera Curvularia, Helminthosporium, Periconia, Pestalotiopsis, Pithomyces, Polythrincium, Stachybotrys, Stemphylium and Torula were also recorded. Only seven of the genera were recovered by both samplers. The total numbers of fungal spores, which had a maximum concentration of 3,175 spores/m³, as well as the spore concentrations of the genera Cladosporium (2,565 spores/m³) and Alternaria (280 spores/m³) were underestimated by the viable method (2,435 CFU/m³ for the total, 2,169 CFU/m³ for Cladosporium and 180 CFU/m³ for Alternaria). The non-viable method fails to resolve the identification of the genera Penicillium and Aspergillus, which are major components of the airborne mycobiota (1,068 CFU/m³ and 204 CFU/m³, respectively) based on recovery by the viable method.     

Exposure of Workers to Airborne Microorganisms in Open-Air Swine Houses

This study quantified the levels of airborne microorganisms in six swine farms with more than 10,000 pigs in subtropical Taiwan. We evaluated breeding, growing, and finishing stalls, which were primarily open-air buildings, as well as partially enclosed farrowing and nursery piggeries. Airborne culturable bacteria, gram-negative bacteria, and fungi were placed on appropriate media by using an all-glass impinger or single-stage Andersen microbial sampler. Results showed that mean concentrations of culturable bacteria and gram-negative bacteria were 3.3 × 10⁵ and 143.7 CFU/m³, respectively. The concentration of airborne culturable fungi was about 10³ CFU/m³, with Cladosporium the predominant genus. The highest airborne levels of culturable bacteria and gram-negative bacteria were identified in the finishing units. The air of the nursery stalls was the least contaminated with culturable and gram-negative bacteria. Irregular and infrequent cleaning, high pig density, no separation of wastes from pen floors, and accumulation of water as a result of the processes for cleaning and reducing pig temperature possibly compromise the benefits of the open characteristic of the finishing units with respect to airborne bacterial concentration.     

Incidence of allergenically significant fungal aerosol in a rural bakery of West Bengal,India

The frequency of fungal spores in the air of three different sections of a rural bakery was analyzed using a Burkard personal slide sampler and Andersen two stage viable sampler. In average concentration of spores (No./m³) was 228–26770/m³ and concentration of viable colony forming units (CFU/m³) was 65-2061 CFU/m³. Dominant fungus species both culturable and nonculturable, were species of Aspergillus and Penicillium, Cladosporiumsp., Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Cladosporium cladosporioides, Penicillium citrinum and Alternaria alternata. Seasonal variations in the spore concentrations were clearly observed in case of some fungi. Total culturable mould concentration of different bakery sections sometimes exceeded the acceptable limit for a healthy indoor environment. Antigenic extracts prepared from some dominant culturable fungi showed high level of allergenicity in skin prick tests indicating that they could be responsible for allergic respiratory dysfunction of bakery workers.This revised version was published online in October 2005 with corrections to the Cover Date.     

Indoor and outdoor atmospheric fungal spores in the São Paulo metropolitan area (Brazil): species and numeric concentrations

The aim of this study was to estimate the indoor and outdoor concentrations of fungal spores in the Metropolitan Area of Sao Paulo (MASP), collected at different sites in winter/spring and summer seasons. The techniques adopted included cultivation (samples collected with impactors) and microscopic enumeration (samples collected with impingers). The overall results showed total concentrations of fungal spores as high as 36,000 per cubic meter, with a large proportion of non culturable spores (around 91% of the total). Penicillium sp. and Aspergillus sp. were the dominant species both indoors and outdoors, in all seasons tested, occurring in more than 30% of homes at very high concentrations of culturable airborne fungi [colony forming units(CFU) m⁻³]. There was no significant difference between indoor and outdoor concentrations. The total fungal spore concentration found in winter was 19% higher than that in summer. Heat and humidity were the main factors affecting fungal growth; however, a non-linear response to these factors was found. Thus, temperatures below 16°C and above 25°C caused a reduction in the concentration (CFU m⁻³) of airborne fungi, which fits with MASP climatalogy. The same pattern was observed for humidity, although not as clearly as with temperature given the usual high relative humidity (above 70%) in the study area. These results are relevant for public health interventions that aim to reduce respiratory morbidity among susceptible populations.     

Preliminary survey of indoor and outdoor airborne microfungi at coastal buildings in Egypt

Forty six species and two sterile fungi and yeast species were isolated from samples collected both indoors and outdoors of coastal buildings located in an Egyptian coastal city. Twenty flats from ten buildings were investigated; children living in these buildings have been reported to suffer from respiratory illnesses. Samples were taken using a New Brunswick sampler (model STA-101) operating for 3.0 min at a flow rate of 6.0 l/min. Most of the species isolated have been associated with symptoms of respiratory allergies. Indoors the total culturable fungal count was 1548 CFU/m³; outdoors, it was 1452 CFU/m³. Indoor values of culturable fungal count, total spores count and ergosterol content ranged from 52 to 124 CFU/m³, 100 to 400 spore/m³ and 5 to 27.7 mg/m³, respectively, whereas outdoor levels typically varied between 25 and 222 CFU/m³, 110 and 900 spore/m³ and 3.3 and 67.2 mg/m³, respectively. The maxima for these parameters were detected indoors in house no. 6 and outdoors, outside of house no. 7. The most abundant species were primarily mitosporic (2832 CFU/m³). The most frequent species in both the indoor and outdoor samples were Cladosporium cladosporioides followed by Alternaria alternata and Penicillium chrysogenum,with inside:outside ratios of 1.4, 1.8 and 1.9, respectively. The patterns of fungal abundance were influenced to some extent by changes in the relative humidity and temperature. Other factors, such as type of culture media, rate of sedimentation, size, survival rates of spore and species competition,also affected fungal counts and should be taken into consideration during any analysis of bioaerosol data.     

Abundance and Diversity of Psychrotolerant Cultivable Mycobiota in Winter of a Former Aluminous Shale Mine

This paper is a speleomycological report from a former aluminous shale mine in Janowiec, Poland. Fungi were identified morphologically and molecularly. Microclimatic conditions differed significantly between locations of the study. However, the external environment around the mine did not directly increase the community composition and concentration of fungi in the mine. The density of fungi isolated from the air outside the mine was 63.1 colony forming units (CFU) per 1 cm³ of air. Inside the mine, fungal density ranged from 287.5 to 655 CFU per 1 m³ from the air, 28.4 to 131.1 CFU per 1 cm² from the rock surfaces and 288.1 to 335.1 CFU per 1 cm³ from the water. Pearson correlation analysis showed that the levels of fungi isolated from the air were correlated positively with temperature, relative humidity and CO₂ concentration. The concentration of fungi isolated from the rock surfaces showed a positive correlation with air flow. Five species of filamentous fungi were isolated from the sampled external air, 10 species from the internal air, six species from the rock surface and 11 species from the water. The fungi most frequently isolated from the air and water of the mine belonged to Penicillium spp., whereas from the rock surface, Geomyces pannorum was most frequently isolated. Some of the fungi present in the mine can be psychrotolerant and pathogenic for humans and animals, and they can also cause degradation of rocks.     

Indoor and outdoor airborne fungal propagule concentrations in Mexico City

Thirty homes of asthmatic adults located in Mexico City were examined to determine the predominant culturable fungi and the changes in their airborne concentrations. Fungi were cultured and identified microscopically from air samples collected in naturally ventilated homes, during both wet (July–August) and cool dry (November–December) seasons, and from settled dust from the same homes. Airborne dust from indoor yielded 99–4950 cfu m⁻³, and settled dust 10²–10⁶ cfu g⁻¹ on DG18 agar. The indoor geometric mean concentration of airborne fungi during the cool dry season was 460 cfu m⁻³ while in the wet season it was 141 cfu m⁻³. Similarly, numbers of airborne fungal propagules out of doors decreased 60% between the dry and wet season. In general, the total fungal concentrations in indoor air were less than 10³ cfu m⁻³ and a large proportion of them was collected in Stage-2 of the Andersen sampler. Moreover, the ratio between indoor and outdoor concentrations was <3:1. Five of the 30 sampled homes yielded >500 cfu m⁻³ of one genus, with up to 1493Cladosporium cfu m⁻³ or 2549Penicillium cfu m⁻³. Also, these two genera were predominant in both airborne and settled dust, and their concentrations were greater indoors than out, indicating a possible indoor source of fungal propagules. The predominant species wereCladosporium herbarum, Penicillium aurantiogriseum andP. chrysogenum. These results suggest that exposure to large concentrations of fungi occurs indoors and is associated with both seasons of the year and with particular home characteristics.     

Seasonal Variations of Indoor Microbial Exposures and Their Relation to Temperature,Relative Humidity,and Air Exchange Rate

Indoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m³) and were lowest in winter (median, 26 CFU/m³). Indoor bacteria peaked in spring (median, 2,165 CFU/m³) and were lowest in summer (median, 240 CFU/m³). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi and N-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates.     

Diversity and spatial–temporal distribution of airborne fungi at the world culture heritage site Maijishan Grottoes in China

The deposition of the airborne microorganisms onto cultural heritage is associated closely with the subsequent biodeterioration. In this study, a systematic investigation was carried out to detect the seasonal variation and diversity of airborne fungal concentration at the World Cultural Heritage Site Maijishan Grottoes in western China. A bio-aerosol sampler was deployed to collect samples over four seasons in 2016. The culturable airborne fungi were isolated, purified and then identified with the extraction of genomic DNA, PCR amplification of ITS rRNA region, sequencing, and phylogenetic analysis. The concentrations of culturable fungi ranged from 216 to 1389 CFU/m³, which varied seasonally with significant differences among the sampling sites. Fifteen different fungal genera were confirmed, among them, Cladosporium was the most predominant fungal genus, followed by Penicillium. The fungal community structure and their relationship with environmental factors were also delineated. The spatial–temporal differences of airborne fungi at Maijishan Grottoes were mainly due to height, rainfall, relative humidity, and temperature. The dominant genera Cladosporium and Penicillium may pose potential threats to the ancient painted sculptures and murals, and monitoring of the airborne fungi at such a heritage site could provide supporting data for the pre-warning and control of fungal outbreaks inside the caves for better management.

     

Profiles of Airborne Fungi in Buildings and Outdoor Environments in the United States

We examined 12,026 fungal air samples (9,619 indoor samples and 2,407 outdoor samples) from 1,717 buildings located across the United States; these samples were collected during indoor air quality investigations performed from 1996 to 1998. For all buildings, both indoor and outdoor air samples were collected with an Andersen N6 sampler. The culturable airborne fungal concentrations in indoor air were lower than those in outdoor air. The fungal levels were highest in the fall and summer and lowest in the winter and spring. Geographically, the highest fungal levels were found in the Southwest, Far West, and Southeast. The most common culturable airborne fungi, both indoors and outdoors and in all seasons and regions, were Cladosporium, Penicillium, nonsporulating fungi, and Aspergillus. Stachybotrys chartarum was identified in the indoor air in 6% of the buildings studied and in the outdoor air of 1% of the buildings studied. This study provides industrial hygienists, allergists, and other public health practitioners with comparative information on common culturable airborne fungi in the United States. This is the largest study of airborne indoor and outdoor fungal species and concentrations conducted with a standardized protocol to date.     

Air biocontamination in a variety of agricultural industry environments in Egypt: a pilot study

Inhalation of airborne microorganisms and organic dust is an occupational concern among workers in agricultural industries. Airborne microorganisms and particulate matter samples were collected from poultry house, flourmill, textile, and food industry sites by use of liquid impinger and gravimetric samplers. Particulate matter concentrations were recorded at median concentrations of 1.56, 1.92, 4.39, and 0.7 mg/m³ in the occupied poultry house, textile, flourmill, and food indoor working environments, respectively. The highest median particulate matter concentration (27.9 mg/m³) was detected at the flourmill’s stack site. The highest median indoor concentration of culturable airborne bacteria (6.23 × 10⁵ CFU/m³) was found at the occupied poultry-house site and the lowest concentration (4.6 × 10³ CFU/m³) was found at the food industry site. The highest median indoor concentration of culturable airborne fungi (3.15 × 10⁴ CFU/m³) was found at the flourmill site whereas the lowest (1.24 × 10³ CFU/m³) was found at the textile industry site. Bacillus and Staphylococcus were the predominant Gram-positive bacteria whereas Acinetobacter and Klebsiella were the predominant Gram-negative bacteria. Escherichia coli and Salmonella were only detected in the indoor air at the poultry house site. Aspergillus flavus, Aspergillus niger, Penicillium, and yeast were the predominant fungal types at flourmill, textile, food industry, and poultry house, respectively. Workers were continuously exposed to airborne microorganisms at a median value of 10⁴ CFU/m³ in all the industries studied.     

Composition and variability of airborne fungi in an enclosed rabbit house in China

Sampling was conducted from June 2007 to May 2008 in an enclosed rabbit house to investigate composition and variability of airborne fungi. Samples were collected using an Andersen-6 sampler, with Sabouraud culture medium as sampling medium. The results showed that monthly mean concentration was 2.79–5.46 × 10³ colony forming unit/m³ air (CFU/m³ air), with the maximum level in October, and the minimum level in January. Within a day, the maximum level occurred at 09:00, followed by 17:00 and then 13:00. A total of 6,523 fungal colonies, belonging to 17 genera and 36 species, were obtained. The predominant genera included Cladosporium, Penicillium, Aspergillus and Altemaria, comprising 71.45% of the colony count. The obtained fungi of the year were mainly centralized in the stage D of the sampler (2.0–3.0 μm), accounting for 37.8% of the colonies. The minimum value occurred at stage F (<0.65 μm), accounting for 1.10% of the colonies.     

Exposure to indoor fungi in different working environments: A comparative study

In this study an attempt was made to evaluate the qualitative and quantitative fungal burden (load) in five different working environments of South Assam (India) and the possible risks of indoor fungi to employees and stored products. Fungal concentrations in different working environments were studied using a Burkard personal petriplate sampler. The survey was done in five different working environments for one year. A total of 76 fungal types were recorded in the indoor air of South Assam during the survey period. The maximum fungal concentration (5,437.6 ± 145.3 CFU m⁻³ air) was recorded in the indoor air of medical wards, followed by the paper-processing industry (3,871.7 ± 93.4 CFU m⁻³ air). However the lowest concentration was observed in the indoor air of a bakery (1,796.8 ± 54.4 CFU m⁻³ air). The most dominant fungal genera were Aspergillus (34.2%) followed by Penicillium (17.8%), Geotrichum (7.0%) and the most dominant fungal species were Aspergillus fumigatus (2,650.4 CFU m⁻³ air) followed by Aspergillus flavus (1,388.2 CFU m⁻³ air), Geotrichum candidum (1,280.3 CFU m⁻³ air), Aspergillus niger (783.3 CFU m⁻³ air), and Penicillium aurantiovirens (774.0 CFU m⁻³ air). The fungal species viz., Aspergillus fumigatus, Penicillium aurantiovirens, Aspergillus flavus, Aspergillus niger, Geotrichum candidum, and Penicillium thomii, which were recorded well above threshold levels, may lead to adverse health hazards to indoor workers. Setting occupational exposure limits for indoor fungal spores as reference values is obligatory for prevention and control of adverse effects of indoor fungal exposure.     

Airborne concentrations of bacteria and fungi in Thailand border market

Thailand border market is where the local Thais, Cambodians, Laotians, and Burmeses exchange their goods and culture at the border checkpoints. It is considered to be the source of aerial disease transmission especially for foreigners because it is always very crowded with people from all walks of life. Unhealthy air quality makes this area high risk of spread of airborne diseases. This study assessed airborne concentrations of bacteria and fungi in a border market to improve exposure estimates and develop efficient control strategies to reduce health risk. The density and distribution of airborne bacteria and fungi were investigated in the Chong Chom border market in Surin Province, Thailand. Eighteen air sampling sites were taken from outdoors and various work environments including indoor footpaths, wooden handicraft shops, electronic shops, the secondhand clothing shops, and fruit market areas. Exposed Petri plate method and liquid impinger sampler were used for sampling at the breathing zone, 1.5 m above the floor level, during weekend and holiday. Meteorological factors such as relative humidity, temperature, and light intensity were collected by portable data logger. The relative humidity was 67–73%, and temperature 29–33°C, and light varied between 18 and 270 Lux m⁻². Gram-positive and Gram-negative bacteria were found at a mean value of 10⁴ CFU m⁻³, and airborne fungi of 10³ CFU m⁻³ were recorded. The highest concentration of culturable airborne microorganisms was found along the indoor footpath (9.62 × 10⁴ CFU m⁻³ and 750.00 CFU/plate/h for impingement and sedimentation methods, respectively), the fruit market area (7.86 × 10⁴ CFU m⁻³ and 592.42 CFU/plate/h for impingement and sedimentation methods, respectively), and the secondhand clothing shop (4.59 × 10³ CFU m⁻³ and 335.42 CFU/plate/h for impingement and sedimentation methods, respectively) for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The lowest concentration of Gram-positive bacteria, Gram-negative bacteria, and fungi was found only at the outdoor area at 1.53 × 10⁴ CFU m⁻³, 0.93 × 10⁴ CFU m⁻³ and 0.80 × 10³ CFU m⁻³ by means of impingement method and 136.67 CFU/plate/h, 69.25 CFU/plate/h, and 62.00 CFU/plate/h by means of sedimentation methods for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The most frequently present airborne bacteria were identified as Bacillus, Corynebacteria, Diplococcus, Micrococcus, Acinetobacter, Alcaligenes, Enterobacter, and spore former rods. Acremonium, Aspergillus, Cladosporium, Penicillium, and Sporotrichum were the most frequently found aerosol fungi genera. The distribution of airborne microorganisms correlated with relative humidity and light factors based on principal component analysis. In conclusion, the border market is a potential source of aerial disease transmission and a various hazards of bioaerosols for workers, consumers, sellers, and tourists. The bioaerosol concentration exceeded the standard of occupational exposure limit. Many major indicators of allergenic and toxigenic airborne bacteria and fungi, Acinetobacter, Enterobacter, Pseudomonas, Cladosporium, Alternaria, Aspergillus, and Penicillium, were found in the various market environments.     

Assessment of microbial aerosol emissions in an urban wastewater treatment plant operated with activated sludge process

Wastewater that enters wastewater treatment plants contains lots of pathogenic and nonpathogenic microorganisms which can become bioaerosols during treatment processes and pose health hazard to workers and nearby residents. The emission of the bioaerosols from an urban wastewater treatment plant in spring and summer in different locations and downwind of the plant adopting an extended mechanical aeration system was investigated. Samples of bacteria and fungi were collected within 6 months at 10 selected points by an Anderson one-stage impactor. The highest concentration of bacteria (mean 1373 CFU/m³, 741–2817 CFU/m³) and fungi (mean 1384 CFU/m³, 212–1610 CFU/m³) was found in downwind of the aeration basins. Statistical analysis showed a significant relationship between concentration of bacterial bioaerosols at downwind side of the aeration basins and wind speed (p value <0.05) and temperature (p value <0.05). Also, in the spring and summer, between the number of bacteria and fungi inside the plant and outside the plant (downwind) a significant correlation was observed (p value ≤0.05). The concentrations of bacteria at a distance of 500 m downwind were much higher than those at the background (upwind) point in spring and summer. The processes of wastewater treatment especially using mechanical equipment to create turbulence can be considered as a major source of spreading airborne microorganisms to ambient air of wastewater treatment plants, and the bioaerosols can be dispersed to downwind distances affecting the nearby neighboring. Therefore, in order to decrease the bioaerosols emission, doing some course of actions such as covering the surface of aeration basins, changing the aeration methods and aeration equipment (e. g using diffuser aerator) may be effective.     

Airborne Fungal Colony-Forming Units in Outdoor and Indoor Environments in Yokohama,Japan

The fungal concentration and flora in indoor and outdoor air in Yokohama, Japan were analyzed with a Reuter centrifugal air sampler and dichloran 18% glycerol agar (DG18), and compared with the levels assessed with potato dextrose agar (PDA). The number of fungal colony-forming units (CFU) in outdoor air was < 13–2750/m³; Cladosporium spp. predominated, followed by Alternaria spp. and Penicillium spp. The fungal concentration in outdoor air peaked in September. The concentrations of fungi in outdoor air (n = 288) were significantly correlated with the maximum temperature of the day, minimum temperature of the day, average temperature of the day, average velocity of wind of the day, average temperature of the month, average relative humidity of the month and precipitation of the month. In indoor air, the fungal CFU was < 13–3750/m³. Cladosporium spp. predominated, followed by the xerophilic fungi such as the Aspergillus restrictus group, Wallemia sebi, the A. glaucus group, and Penicillium spp. The fungal concentration in indoor air peaked in October. The concentrations of fungi in indoor air (n = 288) were significantly correlated with the indoor temperature, indoor relative humidity and the outdoor climatic factors mentioned above, except for the average velocity of wind of the day. This revised version was published online in June 2006 with corrections to the Cover Date.     

Bioaerosol emissions in a poultry litter burning plant

This study investigates the exposure of workers to biological particles in a poultry litter burning plant in operation. The microorganism concentrations were examined at different workplaces during procedures leading to increased emissions. The concentrations of culturable airborne mesophilic, xerophilic and thermophilic microorganisms in the ambient air were tested inside and outside of the burning plant using two different methods of measuring. The focus of this study was on the quantitative evaluation of culturable bacteria as well as the quantitative and qualitative evaluation of gram-negative bacteria, fungi and thermophilic actinomycetes. The maximum airborne concentrations were found in the delivery hall. Mesophilic bacteria concentrations reached up to 1.7 × 10⁶ CFU/m³; gram-negative bacteria up to 9.1 × 10² CFU/m³. Fungal propagule concentrations for xerophilic fungi were between 1.2 × 10³ and 2.9 × 10⁴ CFU/m³ and for mesophilic fungi between 4.4 × 10² and 2.9 × 10⁴ CFU/m³. Among fungi, Aspergillus niger, Eurotium herbariorum and Scopulariopsis brevicaulis species were dominant. Thermophilic actinomycetes reached airborne concentrations of 8.7 × 10⁴ CFU/m³, with increased concentrations of the pathogens causing extrinsic allergic alveolitis. The high concentrations of airborne microorganisms in poultry litter burning plants and the potential hazard of the intake of microorganisms including potential pathogens require the introduction of consistent measures in both technical areas and personnel management.