Continuous air purification by aqueous interface filtration and absorption.

The adverse impact of particulate air pollution on human health1,2 has prompted the development of purification systems that filter particulates out of air3-5. To maintain performance, the filter units must inevitably be replaced at some point, which requires maintenance, involves costs and generates solid waste6,7. Here we show that an ion-doped conjugated polymer-coated matrix infiltrated with a selected functional liquid enables efficient, continuous and maintenance-free air purification. As the air to be purified moves through the system in the form of bubbles, the functional fluid provides interfaces for filtration and for removal of particulate matter and pollutant molecules from air. Theoretical modelling and experimental results demonstrate that the system exhibits high efficiency and robustness: its one-time air purification efficiency can reach 99.6%, and its dust-holding capacity can reach 950 g m-2. The system is durable and resistant to fouling and corrosion, and the liquid acting as filter can be reused and adjusted to also enable removal of bacteria or odours. We anticipate that our purification approach will be useful for the development of specialist air purifiers that might prove useful in a settings such as hospitals, factories and mines.

Preliminary investigation of a hypertonic saline nasal rinse as a hygienic intervention in dairy workers.

Livestock workers experience an increased burden of bioaerosol-induced respiratory disease including a high prevalence of rhinosinusitis. Dairy operations generate bioaerosols spanning the inhalable size fraction (0-100 µm) containing bacterial constituents such as endotoxin. Particles with an aerodynamic diameter between 10 and 100 µm are known to deposit in the nasopharyngeal region and likely affect the upper respiratory tract. We evaluated the effectiveness of a hypertonic saline nasal lavage in reducing inflammatory responses in dairy workers from a high-volume dairy operation. Inhalable personal breathing zone samples and pre-/post-shift nasal lavage samples from each participant over five consecutive days were collected. The treatment group (n = 5) received hypertonic saline while the control group (n = 5) received normotonic saline. Personal breathing zone samples were analyzed for particulate concentrations and endotoxin using gravimetric and enzymatic methods, respectively. Pro- and anti-inflammatory cytokines (i.e., IL-8, IL-10, and TNF-α) were measured from nasal lavage samples using a multiplex assay. Inhalable dust concentrations ranged from 0.15 to 1.9 mg/m3. Concentrations of both pro- and anti-inflammatory cytokines, specifically IL-6, IL-8, and IL-10, were significantly higher in the treatment group compared to the control group (p < 0.02, p < 0.04, and p < 0.01, respectively). Further analysis of IL-10 anti-inflammatory indicates a positive association between hypertonic saline administration and IL-10 production. This pilot study demonstrates that hypertonic saline nasal lavages were successful in upregulating anti-inflammatory cytokines to support larger interventional studies.

Use of prototype side stream filtration system to control dust levels in a commercial swine farrowing building.

Swine meat provides an essential global food source. Due to economies of scale, modern U.S. swine production primarily occurs indoors to maintain an optimal environment across the stages of swine production. Indoor concentrations of dust and contaminant gases in swine production buildings increase in the winter months due to reduced ventilation to optimal building temperature. In this study, an engineering control technology designed to recirculate the air in a swine farrowing room through a mobile air handling unit containing high-efficiency particulate filters was presented. A mobile solution could be easily deployed as an intervention method if an infectious disease outbreak occurs at a swine operation. The performance of this control technology was evaluated following deployment in a production farrowing barn for a period of 6 weeks during the winter in the Midwestern United States. Contaminant concentrations of inhalable dust, respirable dust, and carbon dioxide were measured in the room treated by the prototype system and compared to contaminant concentrations measured in an untreated "control" room. Over 6 weeks, the mean inhalable and respirable dust concentrations observed during the study period for the "treatment" room were 2.61 and 0.14 mg/m3, respectively, compared to 3.51 and 0.25 mg/m3, respectively, for the control room. The mobile recirculating ventilation system, operating at a flow rate of 45 m3/min (5 room air exchanges per hour), reduced the inhalable dust by 25% and respirable dust by 48% as measured with a real-time aerosol monitor, when compared to the control room. In addition, no concentration differences in carbon dioxide and relative humidity between the treatment and the control rooms were observed. Inhalable and respirable concentrations of dust were significantly reduced (p = 0.001), which demonstrates an essential improvement of the air quality that may prove beneficial to reduce the burden of disease among both workers and animals.

A study protocol to evaluate the impact of a personal and domestic hygiene intervention on lead exposure in a community next to a mine dump.

BACKGROUND: Lead has been associated with adverse health effects, especially neurocognitive and behavioural effects, in children. Communities living close to mining land are at risk of elevated exposure to lead. METHODS: This paper outlines a before and after intervention study protocol to evaluate the impact of a personal and domestic hygiene intervention on lead exposure in a community located adjacent to a mine dump. In each participating household, parents or guardians will be interviewed using a structured questionnaire to obtain information on socio-demographic characteristics, living conditions, domestic hygiene practices and potential alternative sources of exposure to lead. A registered nurse will collect hand wipe samples from children aged one to five years, for whom parental consent and where possible child assent has been obtained. Environmental dust samples will be collected from the floors and/or windowsills of children's dwellings for lead content analysis. Soil samples will be collected from yards to determine lead content. An educational intervention will then be applied to the intervention group, including the engagement of households or guardians in an educational discussion on the sources, pathways of exposure, health effects of lead exposure and protective measures, with the aid of a specially designed educational brochure. Data will be analysed for descriptive and inferential statistics using Stata version 16. DISCUSSION: The study will determine whether the intervention led to a reduction in indoor dust lead levels, and if shown to be effective, will inform the development of an awareness campaign to reduce lead exposure in communities located in close proximity to mine dumps. TRIAL REGISTRATION: The study is retrospectively registered on ClinicalTrials.gov Protocol Registration and Results System with registration number NCT05265572 and first release date of 18th February 2022.

Influence of face shields on exposures to respirable aerosol.

The objective of this study was to determine the influence of face shields on the concentration of respirable aerosols in the breathing zone of the wearer. The experimental approach involved the generation of poly-dispersed respirable test dust aerosol in a low-speed wind tunnel over 15 min, with a downstream breathing mannequin. Aerosol concentrations were measured in the breathing zone of the mannequin and at an upstream location using two laser spectrophotometers that measured particle number concentration over the range 0.25-31 µm. Three face shield designs were tested (A, B, and C) and were positioned on the mannequin operated at a high and low breathing rate. Efficiency-the reduction in aerosol concentration in the breathing zone-was calculated as a function of particle size and overall, for each face shield. Face shield A, a bucket hat with flexible shield, had the highest efficiency, approximately 95%, while more traditional face shield designs had efficiency 53-78%, depending on face shield and breathing rate. Efficiency varied by particle size, but the pattern differed among face shield designs. Face shields decreased the concentration of respirable aerosols in the breathing zone when aerosols were carried perpendicular to the face. Additional research is needed to understand the impact of face shield position relative to the source.

Measurement of the Workplace Protection Factor of Replaceable Particulate and Powered Air-purifying Respirators in Japanese Dust-generating Occupations.

Although measuring the workplace protection factor (WPF) is important to verify the performance of particulate respirators in a real work environment, there are no reports of such measurements in Japan. The aim of this study was to measure the WPF of a replaceable particulate respirator (RPR) and a powered air-purifying respirator (PAPR). Eight participants were subjected to three conditions: wearing a RPR correctly (C-RPR), wearing a RPR as usual (but incorrectly) (U-RPR), and wearing a PAPR in the same way as U-RPR (PAPR). Subjects performed dust-generating tasks for 15 min, during which the WPF was measured. The WPF was calculated by dividing the concentration of particles outside the particulate respirator (Co) by that inside the particulate respirator (Ci). A fit testing instrument was used to measure the number of particles. Ci was measured by inserting the test guide into the face piece, and Co was measured by fixing the test guide near the breathing area of the subjects. The WPF geometric mean values (standard deviations) for C-RPR, U-RPR, and PAPR were 17.7 (2.59), 27.0 (3.86), and 117.3 (5.25), respectively. It is important to generate knowledge about the performance of particulate respirators to prevent occupational respiratory diseases.

Experimental study on dust removal optimization of shearer external spray in air velocity.

In order to clarify the influence of air velocity on the atomization effect of shearer external spray and optimize dust suppression performance, the dust removal experiment was carried out by utilizing the self-designed external spray experiment platform. The effect of three kinds of air velocity on the atomization effect of main spray parameters was investigated to clarify the influence of air velocity on the atomization effect of shearer external spray and optimize dust suppression performance. The results showed that the influence of air velocity on droplet size and distribution width of the droplet size was slightly less than the spray pressure. The average diameter of the droplet was 54.211 µm, and the particle size distribution of the droplet was more uniform and concentrated when air velocity was 2 m/s, the pressure was 5 MPa and nozzle diameter was 1.0 mm. When the air velocity was less than 2 m/s and the spray pressure was 3-5 MPa, the atomization effect was better by using 1.0 or 1.2 mm diameter nozzle. Through on-site applications and optimization, the leeward total dust removal efficiency of the shearer can reach 79.43%, and the maximum increase range can reach 18.51 percentage points. The respiratory dust removal efficiency of the shearer can reach 87.45%, and the maximum increase range can reach 11.87 percentage points.

Amphiregulin modulates murine lung recovery and fibroblast function following exposure to agriculture organic dust.

Exposure to agricultural bioaerosols can lead to chronic inflammatory lung diseases. Amphiregulin (AREG) can promote the lung repair process but can also lead to fibrotic remodeling. The objective of this study was to determine the role of AREG in altering recovery from environmental dust exposure in a murine in vivo model and in vitro using cultured human and murine lung fibroblasts. C57BL/6 mice were intranasally exposed to swine confinement facility dust extract (DE) or saline daily for 1 wk or allowed to recover for 3-7 days while being treated with an AREG-neutralizing antibody or recombinant AREG. Treatment with the anti-AREG antibody prevented resolution of DE exposure-induced airway influx of total cells, neutrophils, and macrophages and increased levels of TNF-α, IL-6, and CXCL1. Neutrophils and activated macrophages (CD11c+CD11bhi) persisted after recovery in lung tissues of anti-AREG-treated mice. In murine and human lung fibroblasts, DE induced the release of AREG and inflammatory cytokines. Fibroblast recellularization of primary human lung mesenchymal matrix scaffolds and wound closure was inhibited by DE and enhanced with recombinant AREG alone. AREG treatment rescued the DE-induced inhibitory fibroblast effects. AREG intranasal treatment for 3 days during recovery phase reduced repetitive DE-induced airway inflammatory cell influx and cytokine release. Collectively, these studies demonstrate that inhibition of AREG reduced, whereas AREG supplementation promoted, the airway inflammatory recovery response following environmental bioaerosol exposure, and AREG enhanced fibroblast function, suggesting that AREG could be targeted in agricultural workers repetitively exposed to organic dust environments to potentially prevent and/or reduce disease.

Respiratory surveillance for coal mine dust and artificial stone exposed workers in Australia and New Zealand: A position statement from the Thoracic Society of Australia and New Zealand.

Coal mine lung dust disease (CMDLD) and artificial stone (AS) silicosis are preventable diseases which have occurred in serious outbreaks in Australia recently. This has prompted a TSANZ review of Australia's approach to respiratory periodic health surveillance. While regulating respirable dust exposure remains the foundation of primary and secondary prevention, identification of workers with early disease assists with control of further exposure, and with the aims of preserving lung function and decreasing respiratory morbidity in those affected. Prompt detection of an abnormality also allows for ongoing respiratory specialist clinical management. This review outlines a medical framework for improvements in respiratory surveillance to detect CMDLD and AS silicosis in Australia. This includes appropriate referral, improved data collection and interpretation, enhanced surveillance, the establishment of a nationwide Occupational Lung Disease Registry and an independent advisory group. These measures are designed to improve health outcomes for workers in the coal mining, AS and other dust-exposed and mining industries.

Household interventions for secondary prevention of domestic lead exposure in children.

BACKGROUND: Lead exposure is a serious health hazard, especially for children. It is associated with physical, cognitive and neurobehavioural impairment in children. There are many potential sources of lead in the environment, therefore trials have tested many household interventions to prevent or reduce lead exposure. This is an update of a previously published review. OBJECTIVES: To assess the effects of household interventions intended to prevent or reduce further lead exposure in children on improvements in cognitive and neurobehavioural development, reductions in blood lead levels and reductions in household dust lead levels. SEARCH METHODS: In March 2020, we updated our searches of CENTRAL, MEDLINE, Embase, 10 other databases and ClinicalTrials.gov. We also searched Google Scholar, checked the reference lists of relevant studies and contacted experts to identify unpublished studies. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs of household educational or environmental interventions, or combinations of interventions to prevent lead exposure in children (from birth to 18 years of age), where investigators reported at least one standardised outcome measure. DATA COLLECTION AND ANALYSIS: Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS: We included 17 studies (three new to this update), involving 3282 children: 16 RCTs (involving 3204 children) and one quasi-RCT (involving 78 children). Children in all studies were under six years of age. Fifteen studies took place in urban areas of North America, one in Australia and one in China. Most studies were in areas with low socioeconomic status. Girls and boys were equally represented in those studies reporting this information. The duration of the intervention ranged from three months to 24 months in 15 studies, while two studies performed interventions on a single occasion. Follow-up periods ranged from three months to eight years. Three RCTs were at low risk of bias in all assessed domains. The other 14 studies were at unclear or high risk of bias; for example, we considered two RCTs and one quasi-RCT at high risk of selection bias and six RCTs at high risk of attrition bias. National or international research grants or governments funded 15 studies, while the other two did not report their funding sources. Education interventions versus no intervention None of the included studies in this comparison assessed effects on cognitive or neurobehavioural outcomes, or adverse events. All studies reported data on blood lead level outcomes. Educational interventions showed there was probably no evidence of a difference in reducing blood lead levels (continuous: mean difference (MD) -0.03, 95% confidence interval (CI) -0.13 to 0.07; I² = 0%; 5 studies, 815 participants; moderate-certainty evidence; log-transformed data), or in reducing floor dust levels (MD -0.07, 95% CI -0.37 to 0.24; I² = 0%; 2 studies, 318 participants; moderate-certainty evidence). Environmental interventions versus no intervention Dust control: one study in this comparison reported data on cognitive and neurobehavioural outcomes, and on adverse events in children. The study showed numerically there may be better neurobehavioural outcomes in children of the intervention group. However, differences were small and the CI included both a beneficial and non-beneficial effect of the environmental intervention (e.g. mental development (Bayley Scales of Infant Development-II): MD 0.1, 95% CI -2.1 to 2.4; 1 study, 302 participants; low-certainty evidence). The same study did not observe any adverse events related to the intervention during the eight-year follow-up, but observed two children with adverse events in the control group (1 study, 355 participants; very low-certainty evidence). Meta-analysis also found no evidence of effectiveness on blood lead levels (continuous: MD -0.02, 95% CI -0.09 to 0.06; I² = 0%; 4 studies, 565 participants; moderate-certainty evidence; log-transformed data). We could not pool the data regarding floor dust levels, but studies reported that there may be no evidence of a difference between the groups (very low-certainty evidence). Soil abatement: the two studies assessing this environmental intervention only reported on the outcome of 'blood lead level'. One study showed a small effect on blood lead level reduction, while the other study showed no effect. Therefore, we deem the current evidence insufficient to draw conclusions about the effectiveness of soil abatement (very low-certainty evidence). Combination of educational and environmental interventions versus standard education Studies in this comparison only reported on blood lead levels and dust lead levels. We could not pool the studies in a meta-analysis due to substantial differences between the studies. Since the studies reported inconsistent results, the evidence is currently insufficient to clarify whether a combination of interventions reduces blood lead levels and floor dust levels (very low-certainty evidence). AUTHORS' CONCLUSIONS: Based on available evidence, household educational interventions and environmental interventions (namely dust control measures) show no evidence of a difference in reducing blood lead levels in children as a population health measure. The evidence of the effects of environmental interventions on cognitive and neurobehavioural outcomes and adverse events is uncertain too. Further trials are required to establish the most effective intervention for reducing or even preventing further lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in low- and middle-income countries and in differing socioeconomic groups in high-income countries.

Development and validation of dust exposure prevention questionnaire for cardiovascular patients based on the health belief model.

BACKGROUND: Many cardiovascular patients suffer from respiratory failure. Environmental conditions can exacerbate symptomatology. It is necessary to prevent exposure to dust by taking educational steps to identify and modify patient behavior. This study aimed to develop and validate a dust exposure behavior questionnaire based on the Health Belief Model. METHODS: A mixture of qualitative and quantitative methods was employed to design and develop the desired tool. Qualitative methods were used to identify the preventive behaviors needed by cardiovascular patients at risk of dust exposure using the opinions of two expert panels and a literature review. The quantitative phase of the research was performed to evaluate the psychometric properties of the research tool. The research population comprised 417 people with cardiovascular disease referred to a heart hospital in Bushehr, Iran in 2018. Consenting participants entered the study through consecutive sampling. RESULTS: The final version of the questionnaire included 27 items across six domains, namely perceived susceptibility, perceived barriers, perceived severity, perceived benefits, cues to action, and self-efficacy. The mean values of the content validity ratio and content validity index were 0.93 and 0.9, respectively. In addition, all items had a good correlation with the total score of their parent domain (P < 0.01). The model fit was initially unsuitable, according to the related indices. Hence, to achieve a better model fit, the model was improved by releasing some parameters based on the modifications suggested by the AMOS software. The modified model featured an acceptable fit (χ2/df = 2.2, P < 0.001). Cronbach's alpha coefficients also confirmed appropriate reliability for all six domains. CONCLUSION: The Dust Exposure Prevention questionnaire has desirable psychometric properties and appropriate validity to determine the behavioral factors involved in harm from dust exposure among cardiovascular disease patients. This marks an effective step toward evaluating the factors effective in preventing complications related to dust exposure among such patients.

Quantitative analysis of eco-economic benefits of reclaimed water for controlling urban dust.

With the acceleration of urbanization and industrialization, urban air pollution, especially dust pollution, has become a global problem. The traditional method to control dust problem is to spray roads with tap water. However, this method will inevitably lead to a huge waste of water resources. Using reclaimed water instead of tap water for dust control can not only achieve the same effect of reducing dust and haze, but also save water resources. In addition, the saved tap water can be used for production and life, thereby obtaining additional benefits. In order to quantify the eco-economic benefits of sprinkling water for dust control, a quantitative method was proposed based on the emergy theory of ecological economics. It was used to calculate the cost of different water resources, the cooling and humidifying benefit, the dust control and haze reduction benefit, and the other use benefit. Taking the 2017 data of Zhengzhou as an example, the results indicated that the cost of using reclaimed water to control dust was reduced by 54%. The total benefit of using reclaimed water was about 1.30-1.80 times that of using tap water, and the net benefit was 4.65-7.17 times. Therefore, the use of reclaimed water instead of tap water for road dust control has advantages of low cost and high eco-economic benefits. The method proposed in this paper can provide quantitative basis for the popularization of using reclaimed water to dust control in cities with serious air pollution and water resource shortage.

New technology and practice of dust pollution control with foam jet in underground mines.

Foam is used as an efficient means of dust suppression in underground coal mines. The poor performance of conventional adding device of foaming agent restricts its wide application. The objective of this study is to propose and investigate a new parallel jet adding device (PJAD). Experimental results show that PJAD requires a greater water flow to produce negative pressure than the single stage jet adding device (SJAD) and is harder to generate cavitation. PJAD consumes a less pressure loss than SJAD and realizes any adding proportion below 1%, which is especially suitable for precision addition of foaming agent. A foaming system used for dust suppression is put forward with PJAD adding foaming agent. Field application indicates that foam achieves a far better dust suppression effect than the roadheader water spraying, and the foam cost is significantly reduced due to the low adding proportion of foaming agent. The marked dust suppression effect makes us believe that the proposed PJAD will greatly promote the large-scale application of foam technology used for dust suppression in underground coal mines.

Occupational risk factors for idiopathic pulmonary fibrosis in Southern Europe: a case-control study.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia of unknown cause associated with the histopathologic and/or radiologic pattern of usual interstitial pneumonia (UIP). Occupational risk factors have been proposed to be associated with UIP. The aim of this case-control study is to evaluate the relationship between UIP pattern and occupational exposure in Southern Europe. METHODS: Sixty nine cases with a UIP radiological pattern at CT-scan were selected from a clinical database of the University Hospital of Perugia, Umbria, between January 2010 and December 2013. Controls (n = 277) not reporting doctor diagnosed pulmonary fibrosis, were ascertained casually among general population from the same catching area of cases. Data were collected by a questionnaire used previously in a similar study. Logistic regression models, adjusted for gender, age and smoking, were performed to evaluate the association between UIP and occupational exposure. RESULTS: Farmers, veterinarians and gardeners (OR = 2.73, 95%CI = 1.47-5.10), metallurgical and steel industry workers (OR = 4.80, 95%CI = 1.50-15.33) were occupations associated with UIP. Metal dust and fumes and organic dust were risk factors for UIP. Increasing the length of occupational exposure in jobs at risk of pulmonary fibrosis, increased the risk of having UIP. CONCLUSIONS: This case control study confirm partially the results from previous similar studies. Some discrepancies could be explained by the different geographical origins of the population under study, reflecting also different occupational exposures.

Simulations of dust dynamics around a cone hood in updraft conditions.

A cone hood is an efficient device for capturing dust releases generated by a variety of process equipment. For stationary airflow conditions, a circular cone hood with a round flange is the most efficient design. The goal of this article is to determine the effect that inflow velocity, suction velocity, and terminal settling velocity of dust particles have on the aspiration coefficient in combination with hood length and inclination angle. No studies have yet addressed the efficiency of an exhaust hood facing an updraft flow of air with suspended dust particles. To simulate the moving fluid, we used the discrete vortices method accounting for flow separation at sharp edges of the cone hood. A custom test bench was built to validate the velocity field distribution around the exhaust hood. To evaluate capture efficiency, we determined the aspiration coefficient using plotted limiting trajectories of dust particles by solving equations of particle dynamics numerically in view of gravity and streamlining airflow patterns. In order to validate our estimate of the aspiration coefficient, we compared our findings with regularities identified by earlier researchers for a simpler problem of dust-air mixture approaching a circular exhaust opening. The following conditions were considered: the ratio of updraft velocity to the exhaust hood suction velocity varying between 0.01 and 0.5; the ratio of dust particle terminal velocity to the suction velocity varying between 0.000625 and 0.2; flange angle varying between 0° and 90°; and the ratio of flange length to the exhaust opening radius varying between 1 and 4. Using regularities discovered by us, exhaust hood designs can be tailored to a variety of application conditions in terms of dust release capture efficiency.

Characterization of wood dust emission from hand-held woodworking machines.

This article focuses on the prevention of exposure to wood dust when operating electrical hand-held sawing and sanding machines. A laboratory methodology was developed to measure the dust concentration around machines during operating processes. The main objective was to characterize circular saws and sanders, with the aim of classifying the different power tools tested in terms of dust emission (high dust emitter vs. low dust emitter). A test set-up was developed and is described and a measurement methodology was determined for each of the two operations studied. The robustness of the experimental results is discussed and shows good tendencies. The impact of air-flow extraction rate was assessed and the pressure loss of the system for each machine established. For the circular saws, three machines over the nine tested could be classified in the low dust emitter group. Their mean concentration values measured are between 0.64 and 0.98 mg/m3 for the low dust emitter group and from 2.55 and 4.37 mg/m3 for the high dust emitter group. From concentration measurements, a machine classification is possible-one for sanding machines and one for sawing machines-and a ratio from 1-7 is obtained when comparing the results. This classification will be helpful when a choice of high performance power tools, in terms of dust emission, must be made by professionals.

The mechanics of bolt drilling and theoretical analysis of drilling parameter effects on respirable dust generation.

The respirable dust generated during bolt-hole drilling can present serious health problems to the miners involved in roof drilling operations. A proactive dust control approach, different from the conventional passive approaches, is proposed. Laboratory experiments have been conducted to validate the dust reduction effects of the approach. A mechanical model has been developed to simulate the rotary drag bits drilling process under different cutter conditions. The functions of the area of the total friction, drilling power, and specific energy are all presented in the model. According to this model, drilling bite depth and bit wear condition were identified as key factors influencing the respirable dust generation and energy consumption. The relationships among drilling specific energy, airborne dust concentrations of respirable and larger (1-100 µm) particles, and drilling bite depth were established. It was found that by achieving a low specific energy with a proper drilling bite depth and by avoiding worn bit use, a significant reduction of quartz-rich respirable dust from its generation source could be achieved. Once validated, the mechanical model can be used for roof bolter drilling optimization and automation control.

Comparison of the CAS-POL and IOM samplers for determining the knockdown efficiencies of water sprays on float coal dust.

Float coal dust, generated by mining operations, is distributed throughout mine airways by ventilating air designed to purge gases and respirable dust. Float coal dust poses an explosion hazard in the event of a methane ignition. Current regulation requires the application of inert rock dust in areas subjected to float coal dust in order to mitigate the hazard. An alternate method using water sprays, which have been effective in controlling respirable dust hazards, has been proposed as a way to control float coal dust generated on longwall faces. However, the knockdown efficiency of the proposed water sprays on float coal dust needs to be verified. This study used gravimetric isokinetic Institute of Occupational Medicine (IOM) samplers alongside a real-time aerosol monitor (Cloud Aerosol Spectrometer with polarization; CAS-POL) to study the effects of spray type, operating pressure, and spray orientation on knockdown efficiencies for seven different water sprays. Because the CAS-POL has not been used to study mining dust, the CAS-POL measurements were validated with respect to the IOM samplers. This study found that the CAS-POL was able to resolve the same trends measured by the IOM samplers, while providing additional knockdown information for specific particle size ranges and locations in the test area. In addition, the CAS-POL data was not prone to the same process errors, which may occur due to the handling of the IOM filter media, and was able to provide a faster analysis of the data after testing. This study also determined that pressure was the leading design criteria influencing spray knockdown efficiency, with spray type also having some effect and orientation having little to no effect. The results of this study will be used to design future full-scale float coal dust capture tests involving multiple sprays, which will be evaluated using the CAS-POL.

Experimental study on effects of drilling parameters on respirable dust production during roof bolting operations.

Underground coalmine roof bolting operators exhibit a continued risk for overexposure to airborne levels of respirable coal and crystalline silica dust from the roof drilling operation. Inhaling these dusts can cause coal worker's pneumoconiosis and silicosis. This research explores the effect of drilling control parameters, specifically drilling bite depth, on the reduction of respirable dust generated during the drilling process. Laboratory drilling experiments were conducted and results demonstrated the feasibility of this dust control approach. Both the weight and size distribution of the dust particles collected from drilling tests with different bite depths were analyzed. The results showed that the amount of total inhalable and respirable dust was inversely proportional to the drilling bite depth. Therefore, control of the drilling process to achieve proper high-bite depth for the rock can be an important approach to reducing the generation of harmful dust. Different from conventional passive engineering controls, such as mist drilling and ventilation approaches, this approach is proactive and can cut down the generation of respirable dust from the source. These findings can be used to develop an integrated drilling control algorithm to achieve the best drilling efficiency as well as reducing respirable dust and noise.

Adherence to treatment recommendations and short-term outcome of pleasure and sport horses with equine asthma.

Treatments for mild forms of equine asthma are extrapolated from those recommended for severe equine asthma (heaves), but little is known about owner's adherence to recommendations and treatment efficacy. The objective was to determine which recommendations are implemented by owners and their perception of the clinical response to treatment. Medical records of 43 horses diagnosed with moderate asthma between 2010 and 2012 were retrieved from the Université de Montréal database. Treatments and perceived responses were recorded by telephone survey, 2 to 35 months after diagnosis. All 33 owners who completed the survey attempted to decrease exposure to dust and half had also administered medication. Twenty-four owners (73%) described a > 50% improvement in the clinical signs. There was no association between a specific treatment and outcome. A majority of owners of pleasure and sport horses with equine asthma perceived improvement when limiting exposure to hay and barn dust (alone or with medications).

Respect des recommandations de traitement et résultats à court terme pour les chevaux d'agrément et de sport atteints d'asthme des équidés. Les traitements pour des formes bénignes d'asthme des équidés sont extrapolés de ceux recommandés pour le traitement de l'asthme des équidés grave (emphysème chronique), mais on en sait encore peu à propos de l'observance des recommandations par les propriétaires et de l'efficacité du traitement. L'objectif consistait à déterminer quelles recommandations sont mises en oeuvre par les propriétaires et leur perception de la réponse clinique au traitement. Les dossiers médicaux de 43 chevaux diagnostiqués avec un asthme modéré entre 2010 et 2012 ont été récupérés de la base de données de l'Université de Montréal. Les traitements et les réactions perçues ont été consignés lors d'un sondage par téléphone, de 2 à 35 mois après le diagnostic. Les 33 propriétaires qui ont répondu au sondage avaient tenté de réduire l'exposition à la poussière et la moitié avaient aussi administré des médicaments. Vingt-quatre propriétaires (73 %) ont décrit une amélioration de > 50 % des signes cliniques. Il n'y avait aucune association entre un traitement spécifique et un résultat. La plupart des propriétaires possédant des chevaux d'agrément et de sport atteints d'asthme modéré ont perçu une amélioration lorsqu'ils limitaient l'exposition à la poussière de foin et de grange (comme seule mesure ou avec des médicaments). lorsqu'ils limitaient l'exposition à la poussière de foin et de grange (comme seule mesure ou avec des médicaments).(Traduit par Isabelle Vallières).