Showing papers on "Bioaerosol published in 2003"

Single-Particle Fluorescence Spectrometer for Ambient Aerosols

Abstract: A fluorescence particle spectrometer (FPS) for real-time measurement of the fluorescence spectra of aerosol particles in the size range 1-10 w m diameter is reported The prototype FPS has a sufficiently high sample rate (from 5 to 28 l/min for 35 w m to 11 w m diameter particles) to measure aerosol within buildings at practical rates (from 1 up to 600 particle fluorescence spectra per minute) Previously reported bioaerosol prototype detectors for measurement of single particle spectra (Pan et al, Opt Lett , 24, 116-118 (1999); Hill et al, Field Anal Chem Tech , 3, 221-239 (1999)) were unable to sample the ambient environment; air containing particles had to be forced under pressure into a sample cell In addition, sample rates were so small (less than 001 l/min) as to be impractical for most applications The present design overcomes these deficiencies by the use of an airtight cell that highly concentrates micrometer-sized particles A virtual impactor first concentrates aerosol particles, whi

Airway inflammation in waste handlers exposed to bioaerosols assessed by induced sputum

Abstract: Work-associated lower airway inflammation in waste collectors was examined by induced sputum and correlated with the bioaerosol exposure. Organic waste collectors (n=25) underwent induced sputum collection and spirometry before work on Monday and the following Thursday. Total cells, cell differentials, interleukin (IL)-8 and eosinophilic cationic protein were determined. Personal full-shift exposure measurements were performed Monday, Tuesday and Wednesday and analysed for total bacteria, fungal spores, endotoxins and beta(1-3)-glucans. The percentage of neutrophils (46-58%) and the IL-8 concentration (1.1-1.4 ng x mL(-1)) increased from Monday to Thursday. Forced expiratory volume in one second (FEV1) was significantly reduced on Thursday, and the decrease in FEV1/forced vital capacity correlated with the increase in the percentage of neutrophils. The median exposure to endotoxin (range 7-180 EU x m(-3)) and beta(1-3)-glucan (range 5-220 ng x m(-3)) was correlated with the increase in IL-8. Bioaerosol exposure during waste collection induced an inflammatory response in the lower airways, characterised by neutrophils and interleukin-8 secretion, that influenced the lung function. The inflammatory response was related to microbial components in the bioaerosol and was more pronounced for endotoxin than beta(1-3)-glucan exposure. No associations were found for mould spores or bacteria.

Exposure to bioaerosols in a municipal sewage treatment plant.

Abstract: Microbiological air sampling was performed in a medium-size sewage treatment plant processing municipal wastewater from a city located in eastern Poland. Air samples for determination of the concentrations of viable mesophilic bacteria, Gram-negative bacteria, thermophilic actinomycetes, fungi and endotoxin were collected at 12 sites associated with various phases of sewage treatment process. The concentrations of total mesophilic bacteria (both Gram-positive and Gram-negative) were within a range of 2.4-70.7 x 10(2) cfu/m(3). Gram-positive coryneform bacteria and cocci were dominant, forming respectively 56.6 % and 24.0 % of the total count. The concentrations of Gram-negative bacteria, thermophilic actinomycetes, and fungi were respectively within ranges of 0.2-5.7 x 10(2) cfu/m(3), 0-0.5 x 10(2) cfu/m(3), and 0.24-1.4 x 10(2) cfu/m(3). Among Gram-negative bacteria, commonly occurred Enterobacter cloacae (17.3 % of the total count), followed by Acinetobacter calcoaceticus (16.2 %), Pseudomonas spp. (14.0 %) and Stenotrophomonas maltophilia (11.1 %). Among thermophilic actinomycetes prevailed Thermoactinomyces thalpophilus (47.2 %) and Thermoactinomyces vulgaris (22.2 %), while among fungi, Geotrichum candidum (32.2 %), Penicillium spp. (20 %), Cladosporium lignicola (12.2 %), and Alternaria alternata (10.4 %). Altogether, 20 potentially pathogenic species or genera of bacteria and fungi were identified in the air samples taken in the examined plant. The values of the respirable fraction of airborne microflora varied within a fairly wide range and were between 24.1-100 %. The concentrations of airborne endotoxin were in the range of 0.104-5.2 ng/m(3). In conclusion, the concentrations of microorganisms and endotoxin in the examined municipal sewage treatment plant were low and did not exceed proposed occupational exposure limit values. A moderate risk for the workers may be associated with the presence of potentially pathogenic microbial species having allergenic and/or immunotoxic properties.

Bioaerosol emission from wastewater treatment plants

Abstract: In this report we describe the results of astudy conducted to better estimate airbornemicroorganisms present in wastewater treatmentplants (WWTP) environments. Air samples weretaken with the Air Sampler MAS 100 impactor(Merck) at each stage of an activated-sludgeWWTP (pre-treatment, primary clarifiers,aeration basins and sludge processors), inorder to determine levels of contaminationaccording to work stations. Culture methodswere used to investigate heterotrophic platecount, moulds and yeasts, total and fecalcoliforms, Pseudomonas aeruginosa andspecies belonging to Mycobacteriumtuberculosis complex, whereas these lastmicroorganisms were also analysed by PolymeraseChain Reaction (PCR) methods. Statisticalanalysis showed that pretreatment and primaryclarifiers were the stages with the highestemission of bioaerosols, and that bioaerosolconcentration at each stage depended on windspeed and daily inflow at the WWTP. Lowconcentrations of P. aeruginosa werefound isolated at pretreatment and primaryclarifiers; however, species of M.tuberculosis complex were not detected at anystage of the treatment plant.

Laser power dependence of mass spectral signatures from individual bacterial spores in bioaerosol mass spectrometry.

Abstract: Bioaerosol mass spectrometry is being developed to analyze and identify biological aerosols in real time. Characteristic mass spectra from individual bacterial endospores of Bacillus subtilis var. niger were obtained in a bipolar aerosol time-of-flight mass spectrometer using a pulsed 266-nm laser for molecular desorption and ionization. Spectra from single spores collected at an average fluence of ∼0.1 J/cm2 frequently contain prominent peaks attributed to arginine, dipicolinic acid, and glutamic acid, but the shot-to-shot (spore-to-spore) variability in the data may make it difficult to consistently distinguish closely related Bacillus species with an automated routine. Fortunately, a study of the laser power dependence of the mass spectra reveals clear trends and a finite number of “spectral types” that span most of the variability. This, we will show, indicates that a significant fraction of the variability must be attributed to fluence variations in the profile of the laser beam.

Biofiltration at Composting Facilities: Effectiveness for Bioaerosol Control

Abstract: Biofiltration was evaluated as a method to control the airborne microorganisms released at composting facilities. Seven commercial composting plants were selected for this study because of their different operating conditions and biofilter designs. In all plants, the biofilters were originally designed for odor control. The concentrations of both Aspergillus fumigatus and mesophilic bacteria were measured in the air stream before and after passing through the biofilters and compared with the background concentrations in the surrounding area. Results showed that biofiltration achieved an average reduction greater than 90% and 39% in the concentrations of A. fumigatus and mesophilic bacteria, respectively. In all the plants, the airborne A. fumigatus concentration after the biofilter was lower than 1.2 x 10(3) cfu m(-3), independent of the inlet concentration, whereas the mesophilic bacteria concentration was dependent on the inlet concentration. The different behaviors of the two microorganism groups were thought to be due to the different aerodynamic characteristics of the particles that affected the capture by impact in the biofilter bed. The fungus, whose spores had a maximum of diameter size distribution between 2.1 and 3.3 microm, were more effectively captured in the biofilter than the bacteria, which had diameters mainly between 1.1 and 2.1 microm.

Assessment and modeling of indoor fungal and bacterial bioaerosol concentrations

Abstract: In recent years, potentially harmfulmicroorganisms such as Stachybotryschartarum have garnered national attentionwhen implicated with indoor air problems. However, accurate assessment of biologicallycontaminated indoor air has proven to beprohibitively labor, time, cost, and trainingintensive. The model developed in this studyaccurately predicts the levels of biologicalindoor air contaminants for the GreaterCincinnati area using a number of independentvariables that can be quickly calculatedwithout expensive, time-consuming methods. Thirty-nine single-family residences in theGreater Cincinnati area were sampled usingAndersen two-stage viable microbial particlesizing sampler instruments loaded with MaltExtract Agar, Trypicase Soy Agar, Czapek'sCellulose Agar, and Corn Meal Agar. After airsampling, the Petri dishes were incubated, thenumber of colonies from each plate wereenumerated, and the total number of viablecolony forming units per cubic meter of airwere calculated. Independent variables (indoorrelative humidity, indoor temperature, outdoormold, season, water damage, visible mold,damaged materials, home age, remediationfactors, health questionnaire, number ofoccupants, and indoor pets) were then compared tothe dependent variable (fungal and bacterialbioaerosol counts) by multiple linearregression using Analyze-it® for Microsoft Excel®. The final air model predicted thetotal number of viable colony forming units percubic meter with 97% accuracy; the goal forthis model was 90% accuracy.

Effectiveness of Titanium Dioxide Photocatalyst Filters for Controlling Bioaerosols

Abstract: Currently, photocatalytic oxidation (PCO) is considered to be an effective process for removing and destroying low-level pollutants, which makes it a strong candidate for indoor air quality applications. Our study evaluated the titanium dioxide (TiO 2 ) filter media in controlling bioaerosols in a laboratory test chamber. The influences of microorganism species, relative humidity, and face velocity on the germicidal effectiveness of a TiO 2 -coated filter with 365 nm 8 W and 36 W blacklight irradiation were investigated. A Collison nebulizer generated Escherichia coli ( E. coli ), Bacillus subtilis ( B. subtilis ) endospores, yeast cells of Candida famata ( C . famata ) var. flareri , and spores of Penicillium citrinum ( P. citrinum ). The PCO control effectiveness was determined as the ratio, N S / N 0 , where N S and N 0 were the culturable concentrations collected by an Andersen one-stage sampler downstream of TiO 2 -coated filters with and without blacklight irradiation, respectively. Our results demo...

Method and apparatus for detection of bioaerosols

Abstract: A method and apparatus for evaluating a bioaerosol sample is provided which includes detecting frequency and/or time resolution factors that allow discriminate between a plurality of signals emitted by the bioaerosol to selectively detect biological materials contained in the bioaerosol sample from materials of non-biological origin and potentially associated with a pathogenic bioaerosol.

Bioaerosol data distribution: probability and implications for sampling in evaluating problematic buildings.

Abstract: Airborne fungal contamination in the indoor environment is a substantial contributor to indoor air quality (IAQ) problems, yet there are no set numerical standards by which to evaluate air sampling data. Intuitively appealing is the operational model that the indoor air should not be significantly different from the outdoor air, but determining what is "significant" as well as where to sample and how many samples to collect to determine significance have not been firmly established. The purpose of this study was to determine the number of samples and their locations necessary to determine significant differences in airborne fungi between the ambient and indoor environments. Sampling results from several hundred air samples for culturable fungi from various sites were used to derive a probability of detection in the outdoor air for problematic or "marker" fungal species. Under the assumption that indoor fungal growth results in an increase in the probability of detection for a given fungal species, mathema...

Application of a fluorometric method for the detection of mold in indoor environments.

Abstract: Mold growth on building materials poses a risk to the health of building occupants. Available guidance from public health and occupational health agencies recognize the need for immediate remediation of mold-affected building materials when the potential for occupant exposure exists, regardless of the species present.(1−3) However, specific guidance on appropriate methods to detect sources of fungal growth have not been provided. Ordinarily, deference has been made to experienced consultants using professional judgment.(2,3) With the absence of validated bioaerosol sampling methods capable of consistently detecting fungal growth in buildings, and the recognition that most methods underestimate actual concentrations in the room air as well as the occupant exposures, investigators often find interpretation of bioaerosol sampling results difficult.(1,4) An air sample may be collected to detect and estimate bioaerosol concentrations or to estimate bioaerosol exposures associated with disturbance of a suspected source, but is not very useful in detecting the presence or absence of fungal growth in a building.(1) Due to the multiple factors involved in bioaerosol release, transport, sample collection, and analysis, the ability to detect sources of fungal growth indoors is often questionable. Nevertheless, many consultants continue to rely primarily on air samples for diagnosis of building environments and clearance of post-remediation sites. A glaring problem with the use of air samples for post-remediation clearance testing is that low bioaerosol concentrations cannot be used to demonstrate the absence of fungal growth sources on building surfaces. Moreover, a positive sample (i.e., one with a high spore count and/or predominance of one mold species) might indicate a mold problem. However, if mold damage is present, it still must be located by visual inspection and surface sampling.(1) Many investigators and researchers have found that, even with massive amounts (>100 square meters) of visible mold growth in buildings or heating, ventilation, and airconditioning (HVAC) systems, air sampling of fungal spores may not reveal the presence of the source.(5) The great variability in fungal spore air concentrations combined with the episodic nature of spore release makes air sampling for fungal spores susceptible to false negative results.(1,4) To test the efficacy of mold remediation (i.e., removal of mold from building surfaces), the best, most reliable, and most highly predictive sample may be a surface sample.

Monitoring of Bioaerosol Emission from a Sludge Composting Facility

Abstract: This paper presents results of one-year monitoring of bioaerosol dispersion from a full-scale sludge composting facility in the east coast of the USA. By using two-stage Andersen air samplers with a sequential sampling procedure developed in this study, a total of 24 sets of bioaerosol samples were collected on petri dishes for plate counting. The sampling program utilized a computer air dispersion model (ISCST) to predict the downwind distance at the maximum concentration. Field samplings were performed at upwind, onsite, and predicted downwind locations. The results of this study conclude that the 95% confidence intervals esti- mated for the background concentrations were: 75-173 cfu/m

Airborne bacteria control under chamber and test-home conditions

Abstract: The research reported in this paper investigates the ability of a portable UV-based control device (size=21in.×12in.×12in.) to reduce airborne indoor bacteria levels to at or below outdoor ambient levels. Under controlled conditions, laboratory scale chamber (size=48in.×36in.×48in.) experiments and field scale residence experiments were conducted using the UV control device. Pure cultures of Staphylococcus aureus were grown in culture media and atomized into bioaerosols in the laboratory chamber. The airborne levels of the bacteria were sampled using a six-stage Andersen sampler containing selective culture media plates, and the levels were counted as number of colony forming units per cubic meter of air. The UV control device reduced the atomizer-generated laboratory chamber Staphylococcus aureus levels from a range of 5,000–15,000 cfu/m3 to below 120 cfu/m3 within a 2 h period. Continuous operation of the UV control device in the bedroom and bathroom of a single-resident apartment reduced the Staphyloco...

Continuous bioaerosol monitoring using UV excitation fluorescence

Abstract: We describe an instrument developed to monitor the biological fraction of ambient aerosol. This device simultaneously sizes individual particles in an air stream, and measures their total fluorescence following excitation at 266 nm. Recent results of single blind outdoor tests carried out in Alberta, Canada are described. In these, aerosols were generated containing four different types of biological material: ova albumin, MS-2 phage, Erwinia herbicola vegetative cells and Bacillus subtilis spores. Results indicate a probability of detection of 87% was achieved for target aerosol concentrations as low as a few (1-5) P particles/liter. Absolute quantitative detection efficiencies for individual bioaerosols were at least 70%. During the tests, nonbiological aerosols were also released and found not to generate any significant fluorescent signals.

Enclosure of Composting Operations to Minimize Bioaerosol Emissions into Ambient Air—Part 2

Abstract: A fungal (spore trap) air sampling evaluation was performed under springtime conditions at a composting facility where all mechanical agitation of composting materials occurred in an enclosed, negatively pressurized structure in which air was filtered before being discharged into the atmosphere. During a previous evaluation under wintertime conditions when snow and ice covered outdoor soil and botanical materials, it was determined that the enclosed facility did not add to the bioaerosol burden in nearby ambient air. In the springtime evaluation, Penicillium—Aspergillus and Chaetomium were the dominant kinds of identified fungal spores found in the air within the processing areas of the facility. Cladosporium dominated the spores found in the ambient air around the facility. The concentration of Penicillium—Aspergillus spores in ambient air was 1! order of magnitude less than that in air within compost processing areas and Chaetomium was not detected outdoors. The results suggested that composting within the enclosed facility during springtime conditions does not add fungal spore burden into nearby ambient air.

Bioaerosol Sampling and Analysis

Abstract: Bioaerosol Sampling Sample Analysis Keywords: airborne microorganisms, methodology; bioaerosols, sampling of; detection of airborne microorganisms; methodology

Relationship of Ambient Atmosphere and Biological Aerosol Responses from a Fielded Pyrolysis-Gas Chromatography-Ion Mobility Spectrometry Bioanalytical Detector

Abstract: : Interrogation of the ambient atmosphere for identification of bioaerosol material has predominately been accomplished by aerosol particulate collection, concentration, and growth on agar plates coupled with biochemical tests. A challenge facing the aerobiological community is characterizing the ambient atmospheric aerosol burden with respect to a relatively rapid monitoring for distinct biological species. A pyrolysis-gas chromatography-ion mobility spectrometry stand-alone bioaerosol system was interfaced to an aerosol concentrator to collect ambient background aerosols and produce bioanalytical baseline/background signal levels over 28-hr. Random, discrete, deliberate bursts of biological aerosol near the aerosol concentrator inlet were performed during the continuous bioanalytical interrogation of an outdoor urban atmospheric environment. In the presence of outdoor aerosol background, detection, classification, and characterization of the bioaerosol were accomplished from relatively low to high concentration aerosol bursts of Bacillus subtilis spores and ovalbumin protein. This work provides initial attempts to shepherd continuous bioanalytical instrumentation monitoring of the ambient atmospheric aerosol for detection and classification of specific bioaerosols.

Modeling the Transport of Bioaerosols

Abstract: Bioaerosol Survival Models Dispersion Models Keywords: bioaerosols, modeling; modeling bioaerosol transport