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1.
The project was aimed at evaluating the potential occupational exposure of swine farm workers to dust and microorganisms present
in piggery bioaerosols (especially in its respirable fraction) under various breeding conditions. Sampling was carried out
in 14 buildings located at 13 pig breeding and production farms in Poland. Concentrations of inhalable and respirable dusts
in the air of the piggeries were low (means, respectively, 1.76 and 0.23 mg/m 3). The concentration of microorganisms was generally high (mean = 3.53 × 10 5 cfu/m 3). More than 96% of determined microorganisms were bacteria (mean = 3.42 × 10 5 cfu/m 3). The fungal concentration was distinctly lower (mean = 2.71 × 10 3 cfu/m 3). The concentration of bacteria in the respirable fraction of bioaerosol (mean = 1.51 × 10 5 cfu/m 3) made up for 48.2% of their total concentration, while the level of fungi in that fraction (mean = 1.50 × 10 3 cfu/m 3) formed 68.8% of the total fungal concentration. The concentration of inhalable dust was significantly modified by the type
of breeding system. The factors that significantly affected the total concentrations of microbes and bacteria, as well as
their levels in the bioaerosols’ respirable fraction were as follows: herd size, breeding system, feeding method and the type
of ventilation system. In the case of fungi, these were the livestock breeding system and the feeding method. Moreover, there
was a high positive correlation of inhalable dust concentrations with the fungal concentration, CO 2 and relative humidity. A negative correlation was found between concentrations of each microbe group and the airflow velocity.
Swine farm workers are exposed to relatively low dust concentrations and high concentrations of microorganisms, bacteria in
particular. Fungi, to a much larger extent than bacteria, are correlated with the respirable particles of a piggery bioaerosol,
which may harm the respiratory system of exposed workers. 相似文献
2.
In recent years, monitoring of airborne bacteria and fungi concentrations has obtained increasing universal attraction not only for influences on ecological balance but also for evaluating their public health consequences. In this study, we aimed to investigate culturable airborne bacteria and fungi levels in different sites of Abadan, and their association with meteorological parameters and PM2.5 levels. Abadan is one of the most industrialized cities in the southwest of Iran where over the current decade has experienced lots of dust storm episodes. In total, 400 air samples were collected in 6 months (autumn and winter) using a single-stage viable Andersen cascade impactor for sampling airborne bacteria and fungi and portable DustTrak Aerosol Monitor 8520 for measuring PM2.5 concentrations and meteorological parameters. Microbial concentrations showed a significant difference between various sites over the study period with averages of 569.57?±?312.64 and 482.73?±?242.86 CFU/M3 for bacteria and fungi, respectively. The air temperature had a significant effect on the concentration of both airborne bacteria and fungi. A significant positive correlation between relative humidity and fungi but no correlation between relative humidity and bacteria concentrations were observed. The average airborne PM2.5 concentrations of all sites among the study period was 93.24?±?116.72 μg/m3. The atmospheric bacterial and fungal communities were strongly positively correlated with the ambient PM2.5 level. The levels of airborne bacteria and fungi along with PM2.5 in the air of the city were relatively higher than the recommended levels. Therefore, the best course of action is needed to control emission sources. Further studies are also needed to evaluate the clinical analysis of the health effects of exposure to these pollutants. 相似文献
3.
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 10 4 CFU m −3, and airborne fungi of 10 3 CFU m −3 were recorded. The highest concentration of culturable airborne microorganisms was found along the indoor footpath (9.62 × 10 4 CFU m −3 and 750.00 CFU/plate/h for impingement and sedimentation methods, respectively), the fruit market area (7.86 × 10 4 CFU m −3 and 592.42 CFU/plate/h for impingement and sedimentation methods, respectively), and the secondhand clothing shop (4.59 × 10 3 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 × 10 4 CFU m −3, 0.93 × 10 4 CFU m −3 and 0.80 × 10 3 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. 相似文献
4.
Compost windrows for bioremediation of soil were built at a wood-preserving site contaminated with chlorophenols, polychlorinated dibenzo- p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). Sampling of airborne particles during the mixing of the compost windrows found concentrations of PCDDs and PCDFs in different particle sizes. The congener distribution of PCDDs and PCDFs in the collected air particle fractions was similar to that in the compost windrows, and the level of PCDDs and PCDFs was 1000-fold higher than the atmospheric background values reported previously. Viable particle-sizing samplers and several selective growth media were used to enumerate bacteria and fungi in the airborne particles. From the collected air samples, 40 bacteria were isolated and identified. Among the isolated bacteria, 80% were Gram-positive and spore-forming. Two of the identified airborne bacteria, Pseudomonas aeruginosa and Bacillus cereus, may cause human disease and are classified in biological agent hazard group 2. The amounts of airborne fungi, molds, and yeasts were 1000 to 2000 colony-forming units (CFUs) per m 3. The number of actinomycetes was up to 6-fold, and the number of bacteria was 2- to 20-fold compared to background values. The overall level of airborne bacteria (200 to 3500 CFUs per m 3) was low compared to the level of bacteria (10 5 to 10 8 CFUs per m 3) found when composting municipal waste. 相似文献
5.
Airborne transmission is an important route for many microbial pathogens in outdoor and indoor environments, including hospitals.
A 2-year-long survey of bioaerosol quality in operating theatres (OT), hospital rooms (HR) and maternity wards (MW) at a hospital
in Murcia, Spain, was performed. Total aerobic counts (TAC) and fungal load (FL) were assessed using a microbiological air
sampler (MAS-100 single-stage impactor). While fungal levels were below 1 cfu/m 3 (0–7.33 cfu/m 3) in OT, they were higher in MW (mean, 6.9 cfu/m 3; range 0.44–44.67 cfu/m 3) and in HR (mean, 10.6 cfu/m 3; range, 0–266 cfu/m 3). In OT the aerobic counts were considerably higher, with a mean of 25.6 cfu/m 3 (range, 1.67–157 cfu/m 3). MW and HR also showed higher means for total aerobic counts compared to OT. Seasonal changes were not detected in mould
and bacteria levels in OT. Hospital renovation occurred during this study and OT adjacent to renovated areas were closed.
A survey of TAC and FL in OT resumed when renovation was completed. We observed an outstanding increase in FL (more than 100 cfu/m 3), particularly Aspergillus spp., during this period, but no significant changes in TAC were observed after renovation. 相似文献
6.
Fertilization of nutrient-depleted and degraded forest soils may be required to sustain utilization of forests. In some European countries, the application of composts may now be an alternative to the application of inorganic fertilizers because commercial compost production has increased and compost quality has been improved. There is, however, concern that compost amendments may cause increased leaching of nitrogen, trace metals and toxic organic compounds to groundwater. The objective of this study was to assess the risk of ammonium (NH 4
+), nitrate (NO 3
–) and dissolved organic nitrogen (DON) leaching following a single compost application to silty and sandy soils in mature beech ( Fagus sylvatica L.), pine ( Pinus silvestris L.) and spruce ( Picea abies Karst.) forests at Solling and Unterlüß in Lower Saxony, Germany. Mature compost from separately collected organic household waste was applied to the soil surface at a rate of 6.3 kg m –2 in the summer of 1997 and changes in NH 4
+, NO 3
– and DON concentrations in throughfall and soil water at 10 and 100 cm soil depths were determined for 32 months. The spruce forests had the highest N inputs by throughfall water and the highest N outputs in both the control and compost plots compared with the pine and beech forests. Overall, the differences in total N outputs at 100 cm soil depth between the control and compost plots ranged between 0.3 and 11.2 g N m –2 for the entire 32-month period. The major leaching of these amounts occurred during the first 17 months after compost amendments, but there was no significant difference in total N outputs (–0.2 to 1.8 g N m –2) between the control and compost plots during the remaining 15 months. Most of the mineral soils acted as a significant sink for NO 3
– and DON as shown by a reduction of their outputs from 10 to 100 cm depth. Based on these results, we conclude that application of mature compost with high inorganic N contents could diminish the groundwater quality in the first months after the amendments. A partial, moderate application of mature compost with low inorganic N content to nutrient depleted forest soils can minimize the risk of NO 3
– leaching. 相似文献
7.
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 10 2–10 6 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 10 3 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 1493 Cladosporium cfu m −3 or 2549 Penicillium 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 were Cladosporium herbarum, Penicillium aurantiogriseum and P. 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. 相似文献
8.
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 × 10 6 CFU/m 3; gram-negative bacteria up to 9.1 × 10 2 CFU/m 3. Fungal propagule concentrations for xerophilic fungi were between 1.2 × 10 3 and 2.9 × 10 4 CFU/m 3 and for mesophilic fungi between 4.4 × 10 2 and 2.9 × 10 4 CFU/m 3. Among fungi, Aspergillus niger, Eurotium herbariorum and Scopulariopsis brevicaulis species were dominant. Thermophilic actinomycetes reached airborne concentrations of 8.7 × 10 4 CFU/m 3, 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. 相似文献
9.
When microorganisms are used for pest control in vegetable production, the active organisms become part of the microbiota growers are exposed to. The aim of this study was to quantify vegetable growers' exposure to the bacterial strain Bacillus thuringiensis kurstaki strain HD1 (termed HD1) from the biocontrol agent Dipel®, and other airborne mesophilic bacteria. Personal ( n=102) and stationary ( n=43) measurements of exposure were performed in greenhouses and open fields. Air samples were analysed by plate counts, and total counts with a microscope. Isolates resembling HD1 were identified by PCR analysis. HD1-like bacteria were only detected in environments where Dipel® was used. In a greenhouse with Dipel® treated tomato plants, the growers' exposure to airborne HD1-like bacteria reached 5300 cfu/m 3 and 1400 cfu/m 3 during harvest and clearing of old plants, respectively. In untreated greenhouses, the highest concentration of total mesophilic bacteria, 1,100,000 cfu/m 3, was detected in a cucumber greenhouse. The median concentrations of mesophilic bacteria in tomato greenhouses were significantly lower than the median concentrations in cucumber greenhouses. There was no significant difference in exposure to mesophilic bacteria in tomato greenhouses and in vegetable fields. We found that greenhouse workers, especially in cucumber production, were exposed to high concentrations of total bacteria. Thus, the already present airborne bacteria in greenhouses might have a greater influence on growers' health than applied biocontrol strains. However, further studies are needed to establish an occupational threshold limit for airborne bacteria and to secure a healthy working environment for vegetable growers. 相似文献
10.
Ex-Situ Bioremediation has been increasingly viewed as an appropriate remediation technology for hydrocarbon contaminated soils under cold climates conditions in countries like Canada. A response surface methodology (RSM) based on a factorial design was performed to investigate and optimize the effects of the microbial consortia application rate and amount of mature compost amendment on the TPH removal (964 μg g −1 initial concentration). 18 field-scale biopiles (16 m 3 each) were constructed, maintained and subjected to different microbial consortium and mature compost application rates under cold climate conditions over a period of 94 days. TPHs removal rates in the range of 74–82% was observed in the treatments setups where mature compost and microbial consortia were used simultaneously, compared to an average 48% of TPHs removal in control setup.The interaction between these two factors were studied and modelled using a statistical regression model, which showed that the microbial consortia application rate, the mature compost amendment and their interactions had a significant effect on TPHs degradation with a coefficient of determination ( R2) of 0.88. Furthermore, using a numerical optimization approach, the optimum rates predicted via RSM were estimated at 4.1 ml m −3 and 7% for microbial consortia and compost application rates to obtain a maximum TPH removal of 90.7%. 相似文献
11.
Monitoring campaigns in two different seasons were carried out at two underground stations (Tacubaya and Azcapotzalco) of the subway of Mexico City, in order to assess airborne bacterial and fungi concentrations, as well as their relationship with several factors, such as depth of the station, sampling site, temperature, and relative humidity. Sixteen sampling sites were selected according to the depth of the lines and the transit of passengers in the corridors, concourses, and platforms. In addition, samples were also collected in the carriages when they were in movement. Outdoor samples were taken at the two stations for comparison. Two-stage multi-orifice cascade impactors were used to collect aerobiological particles, and with the aid of macroscopic and microscopic characterization were found 57 fungi and 61 bacteria colonies. Outdoor bacteria concentrations ranged from 1 to 68 CFU m ?3, while fungi concentrations varied from 6 to 80 CFU m ?3. The indoor concentration levels of bacteria and fungi ranged from 1 to 484 CFU m ?3 and from 51 to 715 CFU m ?3, respectively. Fungi and bacteria indoor concentrations in the subway were higher than outdoor, up to 8 times. Most of bacteria were identified as Gram-positive nonsporulating short bacillus, while the most abundant fungi genera identified were Aspergillus, Penicillium, and Alternaria in that order of frequency. Statistical analysis showed significant differences between the stations and the lines of different depths, showing a greater microorganisms’ concentration with a greater depth. Although bacteria and fungi concentrations were higher in the spring than in winter, this difference was not significant. Even if indoor microbiological pollution in underground stations was higher than outdoor, the concentrations found in this study were lower than indoor air international standards. 相似文献
12.
The microbial biodiversity of bioaerosols in recently occupied hospital rooms was assessed in a pulmonology unit. Environmental
samples and isolates were also screened for antibiotics resistance genes. Biofilms from sink drains were also studied to evaluate
whether sink drains constitute a potential source of bioaerosols in this environment and a reservoir for opportunistic bacteria
and antibiotic resistance genes. Stenotrophomonas maltophilia was by far the most frequently isolated microorganisms from the biofilm, followed by Enterobacter cloacae. Airborne bacterial concentration ranged from 14 to 74 CFU m −3 and fungi ranged from 50 to 600 CFU m −3. Biofilm bacteria were outnumbered in aerosols by microorganisms affiliated with human skin flora. Nonetheless, they were
recovered from air samples in low concentrations. Erythromycin resistance genes were detected in all air samples collected
from hospital rooms, and tetracycline resistance genes were detected sporadically. Antibiotic resistance genes were found
in a single drain suggesting that genes present in DNA extracts from air samples were not aerosolized from sink drains, but
rather from an unknown source. Results obtained in this study suggest that bacteria from sink drains were not aerosolized
in significant concentration. They still remain a concern because of the risk of aerial transmission associated with their
presence. 相似文献
13.
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. 相似文献
14.
The aerobiology can play a key role in protecting the rice crop since many fungi can cause serious damage to agricultural
areas. In this way, the ideal time to implement different security measures can be identified. To determine the presence of
potentially pathogenic fungi in the air of the rice agroecosystem, a weekly monitoring of viable fungi was carried out using
a volumetric sampler. Collected fungi were quantified, isolated, and identified based on their morphological characteristics.
The results obtained demonstrated that the annual average concentration of filamentous fungi in the atmosphere of rice agroecosystem
studied was 1,225 cfu m −3 levels ranging between 115 cfu m −3 (April) and 2,865 cfu m −3 (August). Pyricularia grisea was detected in the air for 5 months, since the second week of June until the first week of October, and highest average
concentration (25 cfu m −3) was observed in August. Of the meteorological factors evaluated, temperature and relative air humidity influence the concentration
of propagules of P. grisea in the air. Besides, other fungi were detected such as Curvularia, Bipolaris, Alternaria, and Cercospora, all with relevance to rice cultivation. This is the first characterization of aeromycological biodiversity in the studied
region. 相似文献
15.
This is the first study to quantify the dependence on wind velocity of airborne bacterial emission fluxes from soil. It demonstrates that manure bacteria get aerosolized from fertilized soil more easily than soil bacteria, and it applies bacterial genomic sequencing for the first time to trace environmental faecal contamination back to its source in the chicken barn. We report quantitative, airborne emission fluxes of bacteria during and following the fertilization of agricultural soil with manure from broiler chickens. During the fertilization process, the concentration of airborne bacteria culturable on blood agar medium increased more than 600 000-fold, and 1 m 3 of air carried 2.9 × 10 5 viable enterococci, i.e. indicators of faecal contamination which had been undetectable in background air samples. Trajectory modelling suggested that atmospheric residence times and dispersion pathways were dependent on the time of day at which fertilization was performed. Measurements in a wind tunnel indicated that airborne bacterial emission fluxes from freshly fertilized soil under local climatic conditions on average were 100-fold higher than a previous estimate of average emissions from land. Faecal bacteria collected from soil and dust up to seven weeks after fertilization could be traced to their origins in the poultry barn by genomic sequencing. Comparative analyses of 16S rRNA gene sequences from manure, soil and dust showed that manure bacteria got aerosolized preferably, likely due to their attachment to low-density manure particles. Our data show that fertilization with manure may cause substantial increases of bacterial emissions from agricultural land. After mechanical incorporation of manure into soil, however, the associated risk of airborne infection is low. 相似文献
16.
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/m 3, 741–2817 CFU/m 3) and fungi (mean 1384 CFU/m 3, 212–1610 CFU/m 3) 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. 相似文献
17.
Thermophilic ammonium-tolerant bacterium Bacillus sp. TAT105 grows and reduces ammonia (NH 3) emissions by assimilating ammonium nitrogen during composting of swine feces. To evaluate the efficacy of a biological additive containing TAT105 at reducing NH 3 emissions, composting tests of swine manure on a pilot scale (1.8 m 3) were conducted. In the TAT105-added treatment, NH 3 emissions and nitrogen loss were lower than those in the control treatment without TAT105. No significant difference was detected in losses in the weight and volatile solids between the treatments. Concentration of thermophilic ammonium-tolerant bacteria in the compost increased in both treatments at the initial stage of composting. In the TAT105-added treatment, bacterial concentration reached ~10 9 colony-forming units per gram of dry matter, several-fold higher than that in the control and stayed at the same level until the end. These results suggest that TAT105 grows during composting and reduces NH 3 emissions in TAT105-added treatment. 相似文献
18.
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/m 3) and were lowest in winter (median, 26 CFU/m 3). Indoor bacteria peaked in spring (median, 2,165 CFU/m 3) and were lowest in summer (median, 240 CFU/m 3). 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. 相似文献
19.
The objective of this study was to estimate the possible travel distance of airborne bacteria emitted from a naturally ventilated
broiler house by using staphylococci as indicator organisms. Air samples were taken during the second half of three fattening
periods with Impinger (AGI-30) in the barn and simultaneously upwind and downwind from the building. Staphylococci concentrations
varied between 1 × 10 6 and 1 × 10 7 cfu m −3 in the barn. No Staphylococci were detected in air samples at the upwind side. A strong exponential decrease of these bacteria
was observed at three sampling heights (1.5, 4.0 and 9.5 m) in the main wind direction downwind of the barn. Staphylococci
concentrations up to 5.9 × 10 3 cfu m −3 were detected at the farthest sampling point (333 m) downwind. Identification to the species level by means of a 16S–23S
ITS PCR confirmed that Staphylococcus spp. from downwind samples originated from the barn. Staphylococci served as an useful indicator to demonstrate the travel
distance of bacterial emissions originating from a naturally ventilated broiler house. These findings indicate that airborne
transmission of viable bacteria from this type of housing system to adjacent residential dwellings or animal houses several
hundred metres away is possible. 相似文献
20.
In 12 selected flats in Sosnowiec, Upper Silesia, the concentrations of particulate aerosol, bioaerosol and bacterial endotoxin
were examined. Concentrations of particulate aerosol, bacteria, fungi and endotoxin were in the order of 10 1–10 2
μg/m 3, 10 1–10 3 cfu/m 3, 10 0–10 2 cfu/m 3 and 10 −2–10 −1 ng/m 3, respectively. The most numerous group of microorganisms in indoor air during the winter season were Gram positive mesophilic
bacteria. They were more common in flats polluted with tobacco smoke. The concentrations of airborne endotoxins were higher
in flats polluted with tobacco smoke in all size ranges. The highest level of endotoxins was found in the fraction of fine
particles below 5 μm. 相似文献
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