Concentrations and size distributions of fungal bioaerosols in a municipal landfill

The object of this research was to study the behavior of fungal bioaerosols during a sampling period of 12 months (April 2015–April 2016), in each treatment stages of a landfill located in Atlántico Department, Colombia. The fungi bioaerosol samples were collected using a Six-Stage Viable Andersen Cascade Impactor - Thermo Fisher Scientific, a vacuum pump with a flow rate of 28.3 L/min–1, and ammeter KESTREL 4500 for the weather conditions. With the large amount of data obtained, a database was made in excel and analyzed using Statgraphics Centurion XVI software. The processing of data mining was carried out applying to a generalized linear regression model and Multifactorial ANOVA. Golden Surfer 11 program was used to stablish the distribution of temporal and spational mold airborne. The Variables: sampling campaign, stage, taxa, temperature and relative humidity presented a statistically significant correlation with the concentration P-value = 0. The concentrations of fungal bioaerosols varied considerably over the whole sampling period with average concentrations from 73.02 ± 26, 75 CFUs/m3 to 1830.38 ± 971.28 CFUs/m3. The fungal bioaerosols presented in both the coarse and fine fraction; but the fraction of 2.1–3.3 μm (stage 4) was the fraction of the dominant size in terms of higher concentration. According to the taxa identification, there was a higher prevalence of Aspergillus: the highest concentration corresponds to A. fumigatus, associated to toxins that may be cytotoxic [1, 2]

Hospital admission and risk assessment associated to exposure of fungal bioaerosols at a municipal landfill using statistical models

The object of this research to determine the statistical relationship and degree of association between variables: hospital admission days and diagnostic (disease) potentially associated to fungal bioaerosols exposure. Admissions included acute respiratory infections, atopic dermatitis, pharyngitis and otitis. Statistical analysis was done using Statgraphics Centurion XVI software. In addition, was estimated the occupational exposure to fungal aerosols in stages of a landfill using BIOGAVAL method and represented by Golden Surfer XVI program. Biological risk assessment with sentinel microorganism A. fumigatus and Penicillium sp, indicated that occupational exposure to fungal aerosols is Biological action level. Preventive measures should be taken to reduce the risk of acquiring acute respiratory infections, dermatitis or other skin infections

Characteristics and Assessing Biological Risks of Airborne Bacteria in Waste Sorting Plant

Examining the concentration and types of airborne bacteria in waste paper and cardboard sorting plants (WPCSP) is an urgent matter to inform policy makers about the health impacts on exposed workers. Herein, we collected 20 samples at 9 points of a WPCSP every 6 winter days, and found that the most abundant airborne bacteria were positively and negatively correlated to relative humidity and temperature, respectively. The most abundant airborne bacteria (in units of CFU m−3) were: Staphylococcus sp. (72.4) \u3e Micrococcus sp. (52.2) \u3e Bacillus sp. (30.3) \u3e Enterococcus sp. (24.0) \u3e Serratia marcescens (20.1) \u3e E. coli (19.1) \u3e Pseudomonas sp. (16.0) \u3e Nocardia sp. (1.9). The lifetime average daily dose (LADD) for the inhalation and dermal routes for the intake of airborne bacteria ranged from 3.7 × 10−3 ≤ LADDInhalation ≤ 2.07 × 101 CFU (kg d)−1 and 4.75 × 10−6 ≤ LADDDermal ≤ 1.64 × 10−5 CFU (kg d)−1, respectively. Based on a sensitivity analysis (SA), the concentration of airborne bacteria (C) and the exposure duration (ED) had the most effect on the LADDInhalation and LADDDermal for all sampling locations. Although the Hazard Quotient of airborne bacteria was HQ \u3c 1, an acceptable level, the indoor/outdoor ratio (1.5 ≤ I/O ≤ 6.6) of airborne bacteria typically exceeded the threshold value (I/O \u3e 2), indicating worker’s exposure to an infected environment. Therefore, in the absence of sufficient natural ventilation the indoor ambient conditions of the WPCSP studied should be controlled by supplying mechanical ventilation

Exposure to bioaerosols at open dumpsites: A case study of bioaerosols exposure from activities at Olusosun open dumpsite, Lagos Nigeria

Activities associated with the open dumping of municipal solid waste has the potential for greater impact on the environment and public health compared to other forms of waste-to-land treatment of such wastes. However, there is a lack of quantitative data on the exposure to bioaerosols from open dumpsites, hence impeding the development of effective interventions that would reduce the risk of respiratory symptoms among scavengers and waste workers at such dumpsites. This study investigated exposure to bioaerosols at Olusosun open dumpsite, Lagos Nigeria using three methodologies; (1) Conducting a cross-sectional survey on the respiratory health of the population on the dumpsite, (2) Measuring bioaerosol concentrations in the ambient air by measuring four bioaerosols indicator groups (total bacteria, gram-negative bacteria, Aspergillus fumigatus and total fungi) using a Anderson six stage impactor sampler, (3) Measuring activity related exposures to bioaerosols using an SKC button personal sampler. After a cross sectional health survey of 149 participants (waste workers, scavengers, middlemen, food vendors and business owners), smokers reported higher symptoms of chronic cough (21%) and chronic phlegm (15%) compared to non-smokers (chronic cough 15%, chronic phlegm 13%). Years of work > 5 years showed no statistically significant association with chronic phlegm (OR 1.2, 95% CI 0.4–3.4; p > 0.05) or asthma (OR 1.8, 95% CI 0.6–5.2; p > 0.05). At the 95th percentile, the concentration of total bacteria was the highest (2189 CFU/m3), then gram negative bacteria (2188 CFU/m3), total fungi (843 CFU/m3) and Aspergillus fumigatus (441 CFU/m3) after ambient air sampling. A comparison of the data showed that the activity-based sampling (undertaken using body worn personal sampler) had higher bioaerosols concentrations (104 –106 CFU/m3), i.e. 2–3 logs higher than those recorded from static ambient air sampling. Bioaerosol exposure was highest during scavenging activities compared to waste sorting and site supervision. Particle size distributions showed that 41%, 46%, 76% and 63% of total bacteria, gram-negative bacteria, Aspergillus fumigatus and total fungi respectively were of respirable sizes and would therefore be capable of penetrating deep into the respiratory system, posing a greater human health risk. This study has shown that exposure to bioaerosols can be associated with activities undertaken at open dumpsites and may contribute to the high prevalence of the chronic respiratory symptoms among the workers in such environments

Monitoring bioaerosol and odour emissions from composting facilities - WR1121

Government policy requires that valuable resources should be recovered and recycled from biodegradable waste. A successful and growing organics recycling industry delivers this policy with composting being one of the principal technologies deployed to process suitable feedstock such as garden and food waste. Composting inevitably generates bioaerosols – particulate matter comprising cells or cellular components that are released into the air as a result of disturbance of composting feedstock or the processing of final product. Exposure to bioaerosols has the potential to be harmful to human and animal health. The Environment Agency adopts a precautionary and risk-based approach to the regulation of composting facilities which was developed on the basis of research by Wheeler et al. (2001) and which has been updated as new evidence has become available. The Environment Agency also requires site operators to monitor bioaerosols around their facilities using methods specified in a standard protocol which relies upon classical microbiology methods which are tried and tested but which are labour-intensive, slow and offer only a snapshot view of a highly dynamic system. A recent IOM review commissioned by Defra (Searl, 2009) on exposure-response relationships for bioaerosol emissions from waste treatment processes identified significant gaps in knowledge of exposure to bioaerosols and recommended that more research was needed into alternatives to viable microbial monitoring such as priority biomarkers (notably endotoxin) and potential surrogates such as particulate matter. The IOM review also concluded that there is a lack of information to support the development of appropriate stand-off distances. The overall aim of this project was to provide evidence on bioaerosol production, dispersion and potential exposures from composting facilities in support of future developments in policy and regulation of biowaste facilities. The objectives were: (i) to undertake a comprehensive set of standard and novel bioaerosol measurements at representative composting sites to assess comparability between different methods and also to measure spatial and temporal variations; and (ii) to determine the odour emissions and then compare these with bioaerosol emissions to see if odour is a marker of significant bioaerosol exposure. Standard (AfOR, 2009) and novel (CEN filter method, endotoxin, glucan, qPCR, real-time particulates) bioaerosols measurements were taken on a minimum of three to a maximum of six occasions over a twelve month period at four different composting facilities in England. The composting facilities were selected to represent sites of varying sizes (tonnages) and to allow a comparison of bioaerosol concentrations at standard open windrow sites versus a fully-contained site. Additional supporting information was collected including meteorological data at the time of sampling, observation of site operations and measurements of odour at one of the sites. Supporting bioaerosol and odour dispersion modelling was conducted at the site where the odour measurements were made. The spatial trend of bioaerosol concentrations described by Wheeler et al., (1991) and upon which EA regulatory policy is based was broadly corroborated by this dataset. Excursions above the EA acceptable levels at or beyond 250m from source were rare. Bioaerosol concentrations at the enclosed site were generally lower than at the open windrow sites. There was no evidence of a seasonal pattern in bioaerosol concentrations at any of the sites whereas between-sampling day variations were apparent. The cause(s) of these variations were not identified. No consistent relationship was observed between the concentration of bioaerosols measured by the two AfOR standard methods. The two methods displayed certain strengths and weakness in different situations. The IOM sampling device proved to be better suited to situations where high bioaerosol concentrations were encountered (close to source); the Andersen proving to be more effective in the lower concentration range typically found upwind of a site or at distance downwind from source. The higher volume filtration device tested in this project (referred to as the CEN method) produced data that did not consistently match either of the AfOR standard methods. This device demonstrated greater sensitivity than the IOM filter method but suffered drawbacks associated with its weight and a lack of ease of use in the field. Endotoxin concentrations were normally below the level recommended by the Dutch Expert Committee on Occupational Safety but occasional exceedances of this standard were detected at the larger open windrow sites. The majority of glucan measurements were below a widely referred to 10ng/m3 threshold. Significantly elevated concentrations were detected at one of the larger open windrow sites. The dynamic range of the qPCR method is wider (4-5-log) than either of the AfOR and the CEN methods. It is also quicker to carry out and has the potential for automation. The results from the qPCR method are mainly higher than standard AfOR methods, as the method does not distinguish viable and non-viable spores. The spatial distribution of Aspergillus fumigatus spores (by qPCR) along sampling transects, gives similar results compared to AfOR (and CEN) methods. Real time particle detection showed that both TSP and PM10 are correlated to Aspergillus fumigatus spore concentration. No consistent relationship was observed between odour and bioaerosol concentrations (although this was a limited dataset). The envelope of modelled (back-extrapolated) bioaerosol emission rates straddles several orders of magnitude. Distinguishing the influences of meteorological conditions on this variability was not possible. It was not possible to predict bioaerosol or odour emission rates with confidence. This continues to hamper confidence in modelling of odours and bioaerosols from open windrow facilities. The findings of this research have implications for the current standard monitoring protocol which should be reviewed accordingly. The findings of this multi-site survey accord with existing regulatory policy and are supportive of the general trend towards enclosed facilities. Notwithstanding this, continuing research is needed to enhance the database on emission from bioaerosol and odour abatement technologies (e.g. biofilters); to determine the cause(s) of occasional bioaerosol peaks from open facilities; to improve exposure assessments through better modelling protocols; and to link enhanced exposure information to future health impact studies

Improving performance of biofilters for bioaerosols and odour control in waste management facilities

This pilot-scale study aimed at improving the design and operation of biofilters to achieve simultaneous significant odour and bioaerosol reductions from waste air streams emitted from enclosed waste management facilities, using a materials recovery facility (MRF) as the source of contaminated air. The specific objectives included (i) to determine the key biofilter design and operating parameters required for a high level of odour and bioaerosol removal and to refine operational ranges and firmly define boundary conditions between normal and abnormal biofilter operations; (ii) to evaluate and characterise the concentrations of odour and bioaerosols that are being emitted as a result of waste management operations within the MRF; (iii) to evaluate the potential for biofilters to control bioaerosol emissions, and the potential for net emission of bioaerosols from biofilters both in terms of the overall concentration, and also the individual species; (iv) to determine the impact of gas residence time, media moisture content and media depth on simultaneous reduction of bioaerosols and odour in the process air; (v) to assess the impact of different biofilter media types (woodchips [old and new], peat and wheat straw) in terms of bioaerosol and odour emissions and removal; and (vi) to evaluate the possibility of improving a single biofilter for the removal of both bioaerosols and odour. A pilot-scale biofiltration system was constructed for this study and comprised of four vertical up-flow plastic reactors filled with wood chips as the initial biofilter media and connected to a common plenum. Each reactor had a media volume of 181.5 L located above an air-space (for air distribution) separated by a metal mesh which supported the media. A six-stage Andersen sampler was used to measure the concentrations of four groups of bioaerosols (Aspergillus fumigatus, total fungi, total mesophilic bacteria and Gram negative bacteria) in the airstream before and after passing through the biofilters and these were expressed as cfu m-3. Air for odour analysis was collected into air-tight Nalophan bags which were sent off to Concept Life Science odour testing laboratory for analysis within 30 hours of sampling. Olfactometry analysis was carried out on the odour samples in accordance with BS EN 13725 to determine the odour concentration of the samples in European odour units (OUE m-3). The performance of the pilot biofilters was evaluated on the basis of removal efficiency (%) for odour and bioaerosols. The data showed that the concentration of bioaerosols in the process air (as indicated by the inlet air samples) varied from visit to visit in the range of 103 – 105 cfu m-3. The concentration of odour in the process air also varied between visits typically ranging from 94 to 489 OUE m-3. This was thought to be due to the complex interactions between the specific process operating conditions, the types of waste being processed and the configuration of the air ventilation system installed on the site. Overall, this study shows that biofilters designed and operated for odour degradation can also achieve significant bioaerosol reductions in the process air of waste treatment facilities, provided that the inlet concentration is high - which is the case for most enclosed waste treatment facilities. The biofilters achieved average removal efficiencies of 70% (35 to 97%) for A. fumigatus, 71% (35 to 94%) for total fungi, 68% (47 to 86%) for total mesophilic bacteria and 50% (-4 to 85%) for Gram negative bacteria, while odour reduction efficiency was in the range of 34 – 76%. Thus, biofilters can be effective for the control of potentially pathogenic species in the emissions from such treatment facilities. The performance of the biofilters was highly variable at low inlet concentration with some cases showing an increase in outlet concentrations, suggesting that biofilters had the potential to be net emitters of bioaerosols. Bioaerosol particle size distribution varied between the inlet and outlet air, with the outlet having a predominantly greater proportion of smaller size particles (3.3 µm) that represent a greater human health risk as they can penetrate the respiratory system more deeply, and even to the lung alveoli where gaseous exchange occurs. However, the outlet concentrations were low, and further reduction would be achieved by the combined effect of wind dilution and dispersal as well as exposure to environmental stress from temperature, desiccation and oxygen in full scale biofilter applications. It appears that variations in gas residence time may not impact on bioaersosol removals; thus, gas residence time may not be critical for bioaerosol control. However, longer empty bed residence time (EBRT) delivered significant (p 0.05) in the bioaerosols reductions reported in this study. On the other hand, although not statistically significant (p > 0.05), differences did exist in odour performance between the two groups, with the higher moisture content (40 – 70%) consistently showing better removals (odour RE range of 44 – 63%) than media moisture content in the range of 10 – 40%. Furthermore, the two media depths (0.50 m and 0.25 m) investigated in this study showed potential capacity to control bioaerosols emissions from the process air of the MRF, and possibly other waste treatment facilities. Both depths achieved significant (p < 0.05) reductions of the inlet concentrations of bioaerosols as measured at the outlet. Although there were no statistically significant differences between the performances of both media depths, the 0.5 m media depth showed improved control of fungi than bacteria while the 0.25 m media depth had better removals of bacteria than fungi. This observation with the higher media depth has been thought to be a function of the large surface available for particles impaction; airflow rates and larger particles of fungi. From the data, there were variations in the performance of the different media types assessed. Peat consistently delivered the highest simultaneous reduction of odour and bioaerosols; however, this was a much more expensive option. The performance of the wheat straw was the poorest both in terms of bioaerosols and odour reductions. Woodchips appeared to be the preferred choice particularly because they are relatively cost effective and offered satisfactory odour and bioaerosol removals (though not as high as peat). Nonetheless, the data indicated that the performance of woodchips may improve over time especially as the one year old woodchips indicated better removals of odour than the new woodchips which were freshly acquired for this study. Overall, this study suggests that the ideal biofilter to simultaneously control bioaerosols and odour would be a woodchips-based reactor operated with a minimum media depth of 0.50 m and an EBRT of 16 s maintained at a moisture content level of between 40 and 70%, all of which lie within operational ranges reported in literature

Evaluation of the presence of bioaerosols in a neonatal intensive care unit

In this study, the emmission of the Bacterial bioaerosols in the different respiratory system in a neonatal intensive care unit (ICU). In this study, a six-stage Andersen impactor was used for the sampling of bioaerosols with a flow rate of 28.3 L / min. The concentrations obtained from bacterial bioaerosols ranged between 67 and 423 CFU / m3, with an average value of 110.13 CFU / m3, which can represent a possible threat to the health of the workers and neonates in the ICU. The results indicated than Staphylococcus saprophyticus and Staphylococcus epidermidis predominated, especially in the fifth and sixth stages, which means second bronchi and alveoli. While Staphylococcus was the most prevalent genus, Alloiococcus otitidis, Bacillus subtiles, Bacillus thuringiensis, Kocuria rosea and Pseudomonas pseudoalcaligene occurred in the alveoli

Antibiotic resistance of airborne viable bacteria and size distribution in neonatal intensive care units

Despite their significant impact on public health, antibiotic resistance and size distributions of airborne viable bacteria in indoor environments in neonatal intensive care units (NICU) remain understudied. Therefore, the objective of this study was to assess the antibiotic resistance of airborne viable bacteria for different sizes (0.65–7 µm) in private-style and public-style neonatal intensive care units (NICU). Airborne bacteria concentrations were assessed by a six-stage Andersen impactor, operating at 28.3 L/min. Public-style NICU revealed higher concentrations of airborne viable bacteria (53.00 to 214.37 CFU/m3) than private-style NICU (151.94–466.43), indicating a possible threat to health. In the public-style NICU, Staphylococcus was the highest bacterial genera identified in the present study, were Staphylococcus saprophyticus and Staphylococcus epidermidis predominated, especially in the second bronchi and alveoli size ranges. Alloiococcus otitidis, Bacillus subtiles, Bacillus thuringiensis, Kocuria rosea, and Pseudomonas pseudoalcaligene, were identified in the alveoli size range. In NICU#2, eight species were identified in the alveoli size range: Bacillus cereus, Bacillus subtilis, Bacillus thuringiensis, Eikenella corrodens, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus gordoni. Multi-drug-resistant organisms (MDROs) were found in both of the NICUs. Bacillus cereus strains were resistant to Ampicillin, Cefoxitin, Ceftaroline, and Penicillin G. Staphylococcus cohnii ssp. cohnii was resistant in parallel to ampicillin and G penicillin. Staphylococcus saprophyticus strains were resistant to Ampicillin, Penicillin G, Oxaxilin, and Erythromycin. Results may indicate a potential threat to human health due to the airborne bacteria concentration and their antibiotic resistance ability. The results may provide evidence for the need of interventions to reduce indoor airborne particle concentrations and their transfer to premature infants with underdeveloped immune systems, even though protocols for visitors and cleaning are well-established

Bioaerosol Emission From MSW Open Dumpsites And The Impact On Exposure And Associated Health Risks

The activities associated with the open dumping of municipal solid waste emit air pollutants, including bioaerosols that contaminates the air around dumpsites, rendering it unsafe for dumpsite workers and residents living near dumpsites. Quantitative data on the exposure to bioaerosols from open dumpsites are scarce, thus impeding the development of effective interventions that would reduce the risk of respiratory diseases among dumpsite workers and residents living near dumpsites. The specific objectives for this study included (i) to identify the key working areas and activities of the workers at open dumpsites; (ii) to identify the most important groups of local residents that may be affected by contaminated air due to the waste management activities carried out at open dumpsites; (iii) to obtain background information regarding the respiratory health condition of the workers and the local residents in order to determine the extent to which they suffer respiratory diseases that may be related to exposure to the contaminated air from dumpsite; (iv) to measure the concentrations of bioaerosols at key locations on the open dumpsite to determine the impact of different waste management activities and seasonal variations on bioaerosol concentrations; (v) to analyse the bioaerosol data and to compare the ambient concentrations to concentrations at the controls; (vi) to quantify the potential health risk associated with exposure to pathogenic bioaerosols from the open dumpsites using the Quantitative Microbial Risk Assessment (QMRA) tool. A cross sectional respiratory health survey was conducted in the study area between 12th -27th January 2017 with a total 414 respondents (workers = 149, resident = 145 and control = 120). A six-stage Anderson sampler and the SKC button sampler were used to measure ambient bioaerosol concentration and exposure concentration during key activities at the dumpsite respectively. The four bioaerosols indicator groups (total bacteria, gram-negative bacteria, Aspergillus fumigatus and total fungi) measured were expressed as cfu m-3. Using the Markov chain model, the deposition of inhaled bioaerosols in the workers lungs was computed. The infection risk estimates were computed using the beta-Poisson dose response model and the results reported within the QMRA framework. The result of the cross-sectional survey shows that cough was the most reported by the respondents. In all, up to 27% of respondents reported one or more symptoms of cough and phlegm and up to 8.7% reported three or more symptoms (cough, phlegm, asthma etc.). On the dumpsite, while chronic cough particularly affected smokers, it had a prevalence of 38%. Chronic phlegm and asthma was prevalent at 31% and 2% respectively. Only chronic cough and chronic phlegm showed prevalence that were significantly higher that the controls (p 5 years showed was not associated chronic cough, chronic phlegm asthma. Among residents, chronic cough particularly affected the non-smokers and had the prevalence of 31.7%. Chronic phlegm and asthma was prevalent at 28.9% and 8.2% respectively. Only chronic cough and chronic phlegm showed significantly higher prevalence compared to the control (p < 0.001). Daily exposure duration was also associated with chronic cough with odds ratio of 1.2 (95% CI 1.1–1.3, p < 0.001) but not with chronic phlegm and asthma. The frequent visit of a resident to the dumpsite had an associated odds ratio of 3.8 (95% CI 1.6–8.4, p < 0.001), 4 (95% CI 1.1-14.4, p < 0.05) and 6.8 (95% CI 1.3-33, p < 0.01) for chronic cough, chronic phlegm and asthma respectively, when compared to the controls. Only years of work <10 years showed associated with chronic cough with odds ratio 4.2 (95% CI 1.4–12.4, p < 0.01) when compared to the controls. At the 95th percentile, the ambient concentration of total bacteria was 2189 cfu m-3, gram-negative bacteria 2352 cfu m-3, total fungi 824 cfu m-3 and Aspergillus fumigatus 300 cfu m-3, and were significantly higher in magnitude than the control by 2-3 log (p< 0.05). The concentration of bioaerosols at the active operational area was the highest in comparison to the other three sampling locations. However, there were no significant differences in concentration across the four sampling points for total bacteria, gram-negative bacteria and the total fungi. Aspergillus fumigatus, on the other hand, recorded a drastic decrease in concentrations up to 80-81% between the active operational area and the boundary. The particle size distribution shows that the workers were at risk of inhaling air contacting 41%, 46%, 63%, 76% of total bacteria, gram-negative bacteria, total fungi and Aspergillus fumigatus respectively, that were of sizes capable of penetrating deep into the tracheobronchial and the pulmonary region of the lungs, posing a greater human health risk. This study has shown that exposure to bioaerosols were also associated with specific activities undertaken at the dumpsite. Workers were exposed to bioaerosol concentrations up to 106 cfu m-3 during scavenging, waste sorting and site monitoring. These concentrations were 3-log higher than the mean concentration measured in the ambient air. The result shows that on a daily basis, workers were likely inhaling bioaerosols at concentrations ranging from 8.9 × 105 -1.8 × 107 cfu m-3 of total bacteria, 4.0× 105-8.1× 106 cfu m-3 of gram-negative bacteria and 3.29× 105-1.5× 106 cfu m-3 of Aspergillus fumigatus that were of sizes capable of penetrating deep into the tracheobronchial and the pulmonary region of the lungs when undertaking scavenging, waste sorting and site monitoring. These concentrations were higher than expected limit by the UK Environment Agency. The result of the QMRA showed that that the activities at the dumpsite may contribute more to the likelihood of workers developing either respiratory infection or GI infection than anything else. The infection risk from inhaling contaminated air containing spores of Aspergillus fumigatus were in the magnitude of (10-1) all locations and activity types on the dumpsite. However, the risk of infection from ingesting E.coli O157:H7 from ambient exposures across all locations on the dumpsite ranged from 10-3-10-2 for the conservative and 10-4-10-3 for the least conservative of pathogen-indicator ratio. While the risk of infection due to undertaking scavenging, waste sorting and dumpsite monitoring were in the magnitude of 10-1. Overall, this study suggests that the high prevalence of respiratory disease among the workers and the residents are indications of exposure to contaminants in the air from the dumpsite, which includes bioaerosols, as the prevalence were similar among the workers and the residents. The risk estimates show that of infection from bioaerosols were high irrespective the activity the workers undertook at the dumpsite

Use of dispersion modelling for Environmental Impact Assessment of biological air pollution from composting: Progress, problems and prospects

© 2017 The Authors With the increase in composting as a sustainable waste management option, biological air pollution (bioaerosols) from composting facilities have become a cause of increasing concern due to their potential health impacts. Estimating community exposure to bioaerosols is problematic due to limitations in current monitoring methods. Atmospheric dispersion modelling can be used to estimate exposure concentrations, however several issues arise from the lack of appropriate bioaerosol data to use as inputs into models, and the complexity of the emission sources at composting facilities. This paper analyses current progress in using dispersion models for bioaerosols, examines the remaining problems and provides recommendations for future prospects in this area. A key finding is the urgent need for guidance for model users to ensure consistent bioaerosol modelling practices