Bioaerosol

About: Bioaerosol is a research topic. Over the lifetime, 1347 publications have been published within this topic receiving 34791 citations.

The potential for community exposures to pathogens from an urban dairy.

Abstract: The objectives of the study described in this article were to evaluate the variation and transport of fungal and bacterial concentrations in the air of a northern Mexico dairy cattle confined animal feeding operation (CAFO) and to determine the concentration and incidence of antibiotic-resistant Staphylococcus aureus isolates. Two-stage viable cascade impactors were used to measure the culturable airborne fungal organisms and bacteria. S. aureus resistant to penicillin, ampicillin, or cefaclor was identified. Samples were collected at three locations that were designated as on site, upwind of the cattle, and downwind of the cattle. The highest concentrations of culturable bacterial bioaerosols were consistently recovered from the on-site location. More than half of the organisms were antibiotic resistant at the on-site location. Elevated levels of culturable bacterial bioaerosols were recovered from the upwind site that may have been associated with the surrounding community. Bioaerosol concentrations were found in higher amounts than in a facility in the southwestern U.S. examined in the authors' previous study. The urban setting of the CAFO resulted in a higher potential for immediate community exposures.

The Effect of Green Waste Composting on the Concentration and Composition of Ambient Bioaerosols

Abstract: The emission and dispersal of bioaerosols from commercial composting facilities has become an issue of increasing concern over the past decade, as historical evidence links bioaerosol exposure to negative human health impacts. As a result, recommended concentrations and risk assessment limits were imposed in 2001. However, more recent research has suggested that these limits may be exceeded under certain circumstances. For example, underestimation of bioaerosol concentrations may occur through „snapshot‟ sampling, and the use of methods that may reduce culturability of bioaerosols. This study aimed to address several gaps in knowledge, including quantification of bioaerosol concentrations downwind from sites, analysis of the effect that operational and environmental influences have on emission and downwind concentrations, and investigation of methods for the enumeration of non-culturable bioaerosols. The concentrations of bioaerosols upwind, on-site and downwind from two open-air green waste windrow composting facilities were enumerated in extensive detail, producing the first detailed and validated database of bioaerosol concentrations at green-waste composting facilities. The effects of composting processing activities, season, and meteorological conditions on concentrations were also investigated utilising this dataset. Results from these studies suggested that bioaerosols are able to disperse in elevated concentrations to distances beyond the 250 m risk assessment limit. Downwind peaks in concentration were directly linked to compost processing activities on-site, with the risk of sensitive receptor exposure to bioaerosols during non-operational hours minimal. Further, it was found that patterns in downwind concentrations of bioaerosols are likely to be governed by buoyancy effects, as a second peak in concentrations was found at 100-150m downwind. This finding was further supported through the use of a novel direct counting method. Finally, molecular methods allowed the composition of bioaerosols emitted from composting to be determined and showed that composting significantly alters the aerobiotic community at distances downwind. The methods investigated provide the potential for detailed, continuous measurements of bioaerosols, alongside identification of potentially pathogenic microorganisms, and could ultimately lead to source apportionment of bioaerosols.

An overview about varieties and detection methods of pathogenic microorganisms in indoor air

Abstract: Various microorganisms of different size ranges present in air are called bioaerosol which mainly includes fungi and bacteria, their metabolites, virus, pollens, etc. Bioaerosols can travel hundreds of meters or even kilometers through air, so that bioaerosols can be transmitted to all corners of public places, greatly increasing the scope of their hazards. Tiny biological particles can directly reach to human lungs through human respiration, resulting in lung diseases and increasing the risk of suffering from lung related disease. Diseases caused by pathogenic species are classified as bacterial diseases, fungal diseases, viral diseases and diseases caused by other pathogenic microorganisms. Everyone spends about 90% of their time indoors. Indoor environments with poor air quality are more likely to cause harm to vulnerable groups such as children, adolescents, the elderly, patients with chronic respiratory diseases and patients with cardiovascular diseases than outdoor pollutions. Bioaerosols may cause human health problems, severely resulting in death. In addition, Candida , Aspergillus fumigatus , Staphylococcus aureus and some other pathogenic microorganisms may cause nosocomial infections. The medical equipment and hospital environment are the main sources of these microorganisms. There are many studies on the types of microorganisms in different indoor environments. However, there are few studies on the sources of microorganisms, especially pathogenic microorganisms, in indoor air. Source-sink analysis shows that the outdoor air is the main source of most indoor microorganisms. In addition, indoor factors (such as occupants, pets, moldy substances, ventilation, etc.) also affect the distribution of indoor microorganisms. Bioaerosol sampling methods are diverse and many methods are still in development. So far, neither a sampling method nor a sampling standard is suitable for collecting various types of airborne microorganisms. Impaction, impingement and filtration are the most common methods for collecting bioaerosols. In addition, the natural sedimentation method, electrostatic precipitation and cyclone are also used to collect bioaerosols. The detection of microorganisms is the second step in bioaerosol monitoring process. Detection methods of microorganisms can be divided into two major categories called culturable approach and nonculturable approach. Culturable approach is a traditional microbiological detection method, which is simple and low cost. The main drawback of the culturable approach is that the proportion of microorganisms that can be cultured and identified in the environment is small (about 10%), so the culturable approach cannot provide information on the total number of microorganisms in the air. With the development of fluorescent dyes, it is possible to quantitate all the microorganisms (including culturable and nonculturable microorganisms) collected in the liquid medium. Advances in genomics and sequencing technologies, as well as advances in nonculturable molecular technologies (such as Genetic Fingerprinting, Metagenomics and Next Generation Sequencing) not only help identify and quantify microbial loads, but also help understand the possible microbial populations changes. In addition, advances in methods such as Chromatography, Immunoassay and PCR are also useful for microorganism identification. Bioaerosol sampling techniques and detection techniques are crucial for assessing bioaerosol levels. Different sampling and detection methods have different advantages and disadvantages, so multiple technologies can be combined to overcome the limitations of each technology. Through comprehensive and systematic understanding of the types and sources of these pathogenic microorganisms, as well as sampling and detection methods, it will help people to understand the influencing factors of indoor microbial communities, reduce the risk of indoor biological aerosols.

A job exposure matrix related to bioaerosol exposure during collection of household waste

Abstract: Personal bioaerosol exposure in collecting household waste is correlated to governing parameters including type of the waste, collection unit at the houses, type of collection vehicle, and the waste collector's job description. It is difficult to generalize from exposure data on an individual waste collector to a large group of collectors. To solve this problem a job-exposure matrix (JEM) was constructed using matrix elements characterized in terms of governing parameters. Exposure data for a matrix element were obtained by personal sampling in the field. For elements with no measured data the exposure was extrapolated from elements with measured data using exposure modifiers and a multiplicative model. It is concluded that the matrix allows exposure of subgroups of waste collectors to be estimated on the basis of easily obtained data on governing parameters. Address for correspondence: Niels O. Breum, National Institute of Occupational Health, Lersø Parkallè 105, DK-2100 Copenhagen Ø, Denmark.

Investigation of coastal sea-fog formation using the WIBS (wideband integrated bioaerosol sensor) technique

Abstract: . A wideband integrated bioaerosol sensor (WIBS-4) was deployed in Haulbowline Island, Cork Harbour, to detect fluorescence particles in real time during July and September 2011. A scanning mobility particle sizer (SMPS) was also installed providing sizing analysis of the particles over the 10–450 nm range. During the campaign, multiple fog formation events occurred; they coincided with dramatic increases in the recorded fluorescent particle counts. The WIBS sizing and fluorescence intensity profiles indicated that the origin of the signals was potentially non-biological in nature (i.e. PBAPs, primary biological aerosol particles). Furthermore, the data did not support the presence of known fluorescing chemical particles like SOA (secondary organic aerosol). Complementary laboratory studies showed that the field results could potentially be explained by the adsorption of molecular iodine onto water droplets to form I2 ⋅ (H2O)x complexes. The release of iodine into the coastal atmosphere from exposed kelp at low tides has been known for many years. This process leads to the production of small IxOy particles, which can act as cloud condensation nuclei (CCN). While the process of molecular iodine release from coastal kelp sources, subsequent particle formation, and the observations of sea mists and fogs have been studied in detail, this study provides a potential link between the three phenomena. Of mechanistic interest is the fact that molecular iodine included into (rather than on) water droplets does not appear to fluoresce as measured using WIBS instrumentation. The study indicates a previously unsuspected stabilizing transport mechanism for iodine in the marine environment. Hence the stabilization of the molecular form would allow its more extensive distribution throughout the troposphere before eventual photolysis.