Showing papers on "Bioaerosol published in 1998"

Organic Dust Exposures from Work in Dairy Barns

Abstract: Environmental surveys were conducted in 85 barns, predominantly dairy, in central Wisconsin to characterize exposures to organic dusts and dust constituents from routine barn work. Environmental analytes included airborne dusts (total, inhalable inlet, and respirable), particle size distributions, endotoxins, total spore and bacteria counts, viable bacteria and fungi, histamine, cow urine antigen, mite antigen, ammonia, carbon dioxide, and hydrogen sulfide. The geometric mean (GM) concentration of airborne dusts include area total, 0.74 mg/m3; personal inhalable inlet, 1.78 mg/m3; and area respirable, 0.07 mg/m3. Viable bacteria and fungi, spores, endotoxins, histamine, cow urine antigen, and mite antigen were quantifiable constituents of these organic dusts and potential respiratory exposure hazards from routine dairy barn work. Endotoxin concentrations from the inhalable inlet samples ranged from 25.4 endotoxin units per cubic meter of air (EU/m3) to 34,800 EU/m3. The GM endotoxin concentration from the...

The adaptation of existing personal inhalable aerosol samplers for bioaerosol sampling.

Abstract: Health-related monitoring of bioaerosol exposures in the workplace should ideally be carried out using size-selective personal samplers that separate the aerosol into biologically relevant size fractions and allow both quantification and identification of the microorganisms present in each fraction. As a first stage in the development of personal bioaerosol samplers a number of collection substrates were assessed for their ability to maintain the viability of the collected microorganisms, so that subsequent culturing and species identification may be carried out. The substrates were tested with bioaerosols of varying robustness, consisting of Saccharomyces cerevisiae cells, Escherichia coli cells, and Penicillium expansum spores, aerosolized under controlled environmental conditions. The survival of microorganisms on each test substrate, assessed on the basis of the culturable fractions of cells recovered, was compared with that of microorganisms collected in a reference glass cyclone sampler. These bioef...

Measurements of total and culturable bacteria in the alfresco atmosphere using a wet-cyclone sampler

Abstract: Alfresco (def. clean, outdoor) airborne bacteria were collected with a commercially available wet-cyclone bioaerosol sampler to demonstrate its use, sample processing and resultant observations of total and culturable bacteria in mid-summer in the mid-Willamette River Valley, OR. Some critiques of the system are given. The maximum and minimum total and culturable airborne bacterial concentrations in the samples were 5.9 × 105 and 8.8 × 102 cells m−3, and 1.3 × 104 and 3.1 CFU m−3, respectively. What is thought to be a diurnal cycle was also observed for both fractions with highest concentrations during the day and lowest at dawn and dusk. The culturable bacteria as a percentage of the total, was maximal at mid-day (≈ 3%) and minimal at early morning and late evening (≈ 0.5–2%). Contrarily, the total bacteria in the downwind dust plume of a grass seed combine was 2.9 × 106 cells m−3 and of these approximately 73% were culturable, a much greater culturable percentage than found in the alfresco outdoor atmosphere.

in living rooms occupied by cigarette smokers and non-smokers in Sosnowiec, Upper Silesia, Poland

Abstract: 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 101–102 μg/m3, 101–103 cfu/m3, 100–102 cfu/m3 and 10−2–10−1 ng/m3, 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 5μm.

Improved methods for generation, sampling, and recovery of biological aerosols in filter challenge tests

Abstract: In preparation for filter efficiency tests and sampler comparison studies, methods of biological aerosol generation, sampling, and filter recovery were modified from previous studies. Methods described include (1) techniques for generating aerosols that reduced nuisance particles to negligible levels and increased the cell culturability of Mycobacterium abscessus by 30%, (2) sampling techniques that lowered the detectable range of biological particle size from 0.65 to 0.45 µm and reduced the sampling flow from the chamber from 28.3 to 1.5 L/min, and (3) development of methods to remove culturable organisms from respirator filter media. These methods were developed for filter challenge tests with M. abscessus and were applied to two other bacteria. They may also have application to a wider variety of organisms and bioaerosol assessments.

Effect of a Diffused Essential Oil Blend on Bacterial Bioaerosols

Abstract: Thieves, a commercial blend of five essential oils, was tested for its antibacterial activity against Micrococcus lutens, Pseudomonas aeruginosa and Staphylococcus aureus bioaerosols. An aerosol suspension of each bacterial culture was sprayed into a 0.4 m(3) enclosed fume hood previously sterilized by ultraviolet light. Thieves essential oil blend was then diffused into the hood for a given time. Depositional sampling results showed a significant reduction (P < 0.0001) in the aerosol-borne bacterial load after diffusion of the oil blend. Controls showed no inhibitory effect of oil that may have settled on the exposed plate surfaces during bacterial depositional sampling. Inhibition levels appear to be organism specific. There was an 82% reduction in M. luteus bioaerosol, a 96% reduction in the P. aeruginosa bioaerosol, and a 44% reduction in the S. aureus bioaerosol following 10 min of exposure. Results for the time exposure threshold of diffused oil showed that after only six min a 90% reduction in M. luteus viability occurred. Diffusion of the oil blend, Thieves, can significantly reduce the number of aerosol-borne bacteria and may have application in treating air for enclosed environments and preventing transmission of aerosol-borne bacterial pathogens.

Basic aerobiology

Abstract: The study of the presence of the various types of bioaerosol in the atmosphere should be backed up by a deep knowledge of the features of the sources from which they are generated: terrestial and aquatic, natural and anthropogenic. The first step needed to work out aerobiological models is the precise description of the location, seasonality, timing and release flow of the particles produced. One of the greatest problems encountered in aerobiology lies in the precise assessment of the airborne particle concentration. The difficulty varies with the kind of particle to be recorded and strongly depends on the method and system utilised. Many aspects in the monitoring of indoor and outdoor bioaerosol have still to be thoroughly investigated. More functional and accurate methods, morphological, chemical, microbiological and inmunological analyses are actual requirements in the fields of atmosphere microbiology, allergenic aerosol and phytopathology. Bioaerosol monitoring is carried out for three principal reasons. Firstly, for general scientific interest and research. Secondly, to meet legal requirements or to comply with guidelines which often state that air quality may have to be monitored but do not specify methodology and thirdly to collect epidemiological data. Physicists expert at aerosol sampling are frequently involved in the research and investigation of proper sampling systems for non viable particles, whereas physicists and biologists should be necessarily involved together in the monitoring of viable bioaerosol. The stress undergone by viable particles during sampling procedures causes steadily an increased death rate of the sampled organisms due to thermal, mechanical chock or dehydratation of the particles. The need for further information on biological aerosol or bioaerosol, is brought about by the availability of approximate data only or worse, by the total lack of the data in papers dealing overall with atmospheric particles. Even keeping into account the difficulty to be overcome when carrying out this kind of measurements, researchers should follow this path further.

Semiquantitative and qualitative analysis of pre‐seasonal airborne birch pollen allergens in different particle sizes

Abstract: Bet v 1, the major allergen of birch pollen, has been reported to be synthetized in pollen grains shortly before anthesis. In order to obtain a better understanding of the causative agents of allergic symptoms which appear before the actual pollen season, the activity birch pollen antigen in outdoor air have been studied, using polyclonal antibodies against birch pollen, and monoclonal antibodies against Bet v 1. Using a size‐selective bioaerosol sampler (SSBAS), birch pollen antigen concentrations were analysed separately in different particle size classes, down to the molecular size range. About a week before the anthesis of alder, antigens were already detected in outdoor air samples. They were found mainly in the smallest particle size classes and might have had their origin in the developing leaves and flower structures of Betulaceae trees. At the beginning of birch anthesis Bet v 1 activity in the air increased markedly. The smallest particles may have been orbicules (2–4 μm) and starch granules (0....

Efficiency of a Low-Energy Wetted-Surface Multi-Annulus Denuder Sampler for Viable and Nonviable Aerosol Collection

Abstract: Capture efficiency of a wetted-surface low-energy sampler (LES) was evaluated for polystyrene latex (PSL) microsphere aerosol and a Bacillus subtilis aerosol. The observed absolute capture efficiency for PSL microspheres was higher than predicted by theory for the particle sizes used (0.7, 1.6, and 3.0 μm), suggesting hygroscopic particle growth via water uptake by residual detergent coatings. Bio-aerosol capture efficiency was evaluated relative to the AGI-30 impinger using mature B. subtilis. The bioaerosol was quasi-monodisperse with MMAD approximately 1 μm and GSD 1.2–1.3. Observed efficiencies for B. subtilis were substantially better for the LES than the AGI-30 at the lowest sampling flow rate used (5 L/min), but relatively poor at higher flow rates. Factors potentially influencing sampling efficiency were improved viability maintenance and adequate hygroscopic bioorganism growth in the LES. These results demonstrate that low-energy bioaerosol sampling using a wetted-surface multi-annulus d...

Characterisation of Background Biological Aerosol.

Abstract: : Sampling of ambient air using a glass cyclone system for fluorescence background determination is described. Twice weekly samples were taken at the University College Galway's atmospheric research field station at Mace Head on the west coast of Ireland. The work is undertaken in collaboration with the Aerobiological Laboratory at ERDEC, MD. The bioaerosol sampling system and procedures are described in this first Interim Report. Use is made of a fluorescence protocol developed in the ERDEC Laboratories. Preliminary analyses have also been carried out of the natural background aerosol particle size distribution, measures using a TSI aerodynamic particle sizer at the same time as the bioaerosol sampling. Representative measurements of background aerosol size, surface and volume distributions for clean marine air and for polluted air at the Mace Head site are also presented.

Background Bioaerosol Characterization.

Abstract: : Total aerosol and biological size distributions have been determined for both background (marine) and continental air masses at the Mace Head atmospheric research station on the west coast of Ireland. A combination of meteorological and condensation nuclei number concentration data were used to characterise the air masses. The aerosol size distribution, ranging in diameter from 0.5 microns up to about 50 microns, was obtained from stained samples, using both conventional microscopy and a digital imaging system. In general, lower biological aerosol number concentration levels, by factors from about 2-3 were found for marine background air in comparison with the more polluted continental air. Fluorescence emission spectra were also obtained for both background and polluted conditions.