Concentrations Of Respirable Particles Research Articles

Respiratory Effects and Pulmonary Functions Related to Wood Dust Exposure among Workers in a Rubber Wood Factory

This study aimed to determine the effects of wood dust exposure on respiratory symptoms and pulmonary functions in wood dust factory workers and the association between wood dust exposure and pulmonary functions. This cross-sectional study comprised of one hundred workers who answered a self-reported questionnaire. Two factory areas, the production department and the back office, were explored using stationary air sampling. The wood dust concentration was collected using NIOSH Method 0600. Pulmonary function parameters were evaluated through spirometry. A descriptive statistics analysis was done for personal information. Binary logistic regression determined the association between wood dust exposure and respiratory symptoms. The prevalence of respiratory symptoms related to wood dust exposure at work was 49.00 percent. Three major symptoms in the exposed group includes chest pain, shortness of breath, and asthma. The average amount of PM10 in the saw mill area was significantly higher than in the back office (7.23 vs. 1.60 mg/m3). There was a significant difference in forced expiratory capacity between the reference and exposure groups (mean difference = -4.03, p-value = 0.011). The adjusted odd ratio showed that the high wood dust-exposed group had a lower runny nose and dry cough than the reference group. All workers need to consider using personal protective equipment with appropriate specifications in the sawmill area and also the other areas where wood dust levels are high. To control the concentration of respirable particles, resource and pathway control must be applied to reduce the concentration of respirable particles in the workplace.

Evaluating silicosis risk: Assessing dust constitution and influence of water as a primary prevention measure in cutting and polishing of silica agglomerates, granite and marble

An increasing number of silicosis cases have been reported related to the use of silica agglomerates. Many studies agree on the severity of this disease, which often presents with severe clinical forms in young workers and after a short latency period.Are there differences in the composition of dust generated by cutting and polishing with silica agglomerates versus granite and marble? Does the use of water injection reduce the risk associated with the use of these materials?We carried out a comparative observational-analytical study, measuring the concentration of dust generated during different machining operations on three different materials: granite, marble, and silica agglomerates. The effect of water injection on dust generation was evaluated.Personal sampling pumps were used, connected to a cyclone with polyvinyl chloride filters. The flow rate of the pumps was adjusted using a piston flowmeter. Measurements with a cascade impactor were made to assess the size distribution of respirable crystalline silica particles within the respirable fraction. In addition, environmental measurements with a spectrometer were made.10 tests were carried out on granite and silica agglomerates for each procedure. In the case of marble, with very low silica content, only 2 tests of each type were carried out. Duration of each measurement was between 6 and 25 min. Cleaning times were set for each of the operations.The amount of dust collected in the respirable fraction was 70.85, 32.50 and 35.78 mg/m3 for dry cutting; 6.50, 3.75 and 3.95 mg/m3 for wet cutting; and 21.35, 13.68 and 17.50 mg/m3 for dry polishing, for granite, marble, and silica agglomerates respectively.Dry procedures in marble, silica agglomerates and granite showed higher dust concentration of particles smaller than 0.5 μm. Silica agglomerates showed higher concentrations of respirable crystalline silica particles than granite and marble, mainly with dry procedures. The greater production of small particles in dry and wet procedures with silica agglomerates shows that water injection is an insufficient preventive measure.

Estimation of Particle Emission Rates and Calculation of Human Dose from Arc Welding and Cutting of Stainless Steel in a Simulated Confined Workspace

The objective of this study was to estimate the particle emission rates, human dose and retention from two arc welding processes and cutting of stainless steel. The two arc welding processes were Shielded Metal Arc Welding (SMAW) and Tungsten Inert Gas (TIG). In a simulated confined workspace of experimental chamber under controlled conditions, four different scenarios were considered, including the use of filtering face piece respirator (FFR), leaving or staying in the workspace after the emission. Deposited and retained dose in the respiratory tract was assessed for the different regions of the human respiratory tract using a dosimetry model (ExDoM2). The three investigated processes generated high particle number concentrations ranging from 2.4 to 3.6 × 106 particles/cm3 and were the highest during TIG. Among all three processes, PM10 concentrations from cutting reached the highest levels [11 and 22 (× 103) μg/m3], while SMAW had the highest contribution of fine particles [~ 4.1 (× 103) μg/m3], consisting mostly of PM1–2.5. The examination of different scenarios revealed that there is only a slight difference in respect to deposited dose while staying in the workspace for the entire investigated time period (4 h) with or without use of Filtering Facepiece Respirator (FFR). It would be more beneficial in respect to deposited dose if the exposed subject was not wearing a FFR during the emission process and would leave the polluted workspace immediately after the emission period. In the first two scenarios (staying 4 h in the polluted workspace with and without FFR), both welding processes had higher cumulative deposited (~ 23%) and retained dose (~ 20%) in thoracic region compared to cutting (~ 9% and ~ 7%). These results demonstrate that even a short emission period can cause a considerable increase in concentrations of harmful respirable particles, thus increasing the human dose. The approach applied in this study could be used for the determination of personal exposure and dose to particles of known composition particularly in confined workspaces.

Mitigation of Respirable Aerosol Particles from Speech and Language Therapy Exercises

Phonation and speech are known sources of respirable aerosol in humans. Voice assessment and treatment manipulate all the subsystems of voice production, and previous work (Saccente-Kennedy et al., 2022) has demonstrated such activities can generate >10 times more aerosol than conversational speech and 30 times more aerosol than breathing. Aspects of voice therapy may therefore be considered aerosol generating procedures and pose a greater risk of potential airborne pathogen (eg, SARS-CoV-2) transmission than typical speech. Effective mitigation measures may be required to ensure safe service delivery for therapist and patient. To assess the effectiveness of mitigation measures in reducing detectable respirable aerosol produced by voice assessment/therapy. We recruited 15 healthy participants (8 cis-males, 7 cis-females), 9 of whom were voice-specialist speech-language pathologists. Optical Particle Sizers (OPS) (Model 3330, TSI) were used to measure the number concentration of respirable aerosol particles (0.3 µm-10 µm) generated during a selection of voice assessment/therapy tasks, both with and without mitigation measures in place. Measurements were performed in a laminar flow operating theatre, with near-zero background aerosol concentration, allowing us to quantify the number concentration of respiratory aerosol particles produced. Mitigation measures included the wearing of Type IIR fluid resistant surgical masks, wrapping the same masks around the end of straws, and the use of heat and moisture exchange microbiological filters (HMEFs) for a water resistance therapy (WRT) task. All unmitigated therapy tasks produced more aerosol than unmasked breathing or speaking. Mitigation strategies reduced detectable aerosol from all tasks to a level significantly below, or no different to, that of unmasked breathing. Pooled filtration efficiencies determined that Type IIR surgical masks reduced detectable aerosol by 90%. Surgical masks wrapped around straws reduced detectable aerosol by 96%. HMEF filters were 100% effective in mitigating the aerosol from WRT, the exercise that generated more aerosol than any other task in the unmitigated condition. Voice therapy and assessment causes the release of significant quantities of respirable aerosol. However, simple mitigation strategies can reduce emitted aerosol concentrations to levels comparable to unmasked breathing.

Quantification of Respirable Aerosol Particles from Speech and Language Therapy Exercises

Voice assessment and treatment involve the manipulation of all the subsystems of voice production, and may lead to production of respirable aerosol particles that pose a greater risk of potential viral transmission via inhalation of respirable pathogens (eg, SARS-CoV-2) than quiet breathing or conversational speech. To characterise the production of respirable aerosol particles during a selection of voice assessment therapy tasks. We recruited 23 healthy adult participants (12 males, 11 females), 11 of whom were speech-language pathologists specialising in voice disorders. We used an aerodynamic and an optical particle sizer to measure the number concentration and particle size distributions of respirable aerosols generated during a variety of voice assessment and therapy tasks. The measurements were carried out in a laminar flow operating theatre, with a near-zero background aerosol concentration, allowing us to quantify the number concentration and size distributions of respirable aerosol particles produced from assessment/therapy tasks studied. Aerosol number concentrations generated while performing assessment/therapy tasks were log-normally distributed among individuals with no significant differences between professionals (speech-language pathologists) and non-professionals or between males and females. Activities produced up to 32 times the aerosol number concentration of breathing and 24 times that of speech at 70-80 dBA. In terms of aerosol mass, activities produced up to 163 times the mass concentration of breathing and up to 36 times the mass concentration of speech. Voicing was a significant factor in aerosol production; aerosol number/mass concentrations generated during the voiced activities were 1.1-5 times higher than their unvoiced counterpart activities. Additionally, voiced activities produced bigger respirable aerosol particles than their unvoiced variants except the trills. Humming generated higher aerosol concentrations than sustained /a/, fricatives, speaking (70-80 dBA), and breathing. Oscillatory semi-occluded vocal tract exercises (SOVTEs) generated higher aerosol number/mass concentrations than the activities without oscillation. Water resistance therapy (WRT) generated the most aerosol of all activities, ∼10 times higher than speaking at 70-80 dBA and >30 times higher than breathing. All activities generated more aerosol than breathing, although a sizeable minority were no different to speaking. Larger number concentrations and larger particle sizes appear to be generated by activities with higher suspected airflows, with the greatest involving intraoral pressure oscillation and/or an oscillating oral articulation (WRT or trilling).

Equine asthma syndrome: managing the environment

Equine asthma syndrome is arguably the most common non-septic lower respiratory condition diagnosed in horses. In a hospital environment, it is important to be aware of its clinical signs, especially as many horses with the condition will go unnoticed by their owners. Prompt identification can help reduce morbidity within the hospital. Focus on environmental management practices, including feed, bedding and ventilation are well known to reduce the prevalence of the disease within the equine population. This review provides practical advice to equine professionals operating within a hospital environment to minimise respirable particle concentration and the incidence of equine asthma syndrome. A checklist is provided to allow interactive discussion with owners at discharge into how best to reduce the clinical signs of equine asthma syndrome at home.

Particulate matter pollution in Hookah lounges in Palestine

Hookahs, or water pipes, are ornate glass bowl structures used to smoke tobacco products, often in private or public social settings. Hookah smoking is believed to have originated in ancient India in the 16th century; however, it has seen rapid global expansion over the last two decades. A number of studies using high-cost, regulatory or research grade instruments have found respirable particulate concentrations in hookah lounges up to several hundred micrograms per cubic meter. In the summer of 2018, a study was initiated examining the PM2.5 concentrations in several hookah lounges in Nablus and Tulkarm, Palestine (West Bank). However, rather than using the typical high-cost system, low-cost laser light scattering and detection systems were used. Observed PM2.5 concentrations ranged from 84 to 371 μg/m3, concentrations considered to be of notable health concerns in the indoor environment and well within the range of hookah-related particulate matter reported in the literature. Further, examination of the 10-min average temporal PM2.5 concentrations showed variable correlation with the number of active smokers and a seeming dependency on the type of building ventilation. The employed low-cost particulate systems proved capable of reliably quantifying PM2.5 levels in a variety of hookah lounges, as well as being able to characterize the temporal nature of the PM2.5 concentration changes. The results of this study suggest that these systems may be an economic and reliable alternative for particulate studies.

Particulate matter exposure of combine harvester operator during wheat harvesting in northern India

A study was carried out to assess the quantum of particulate matter in the breathing zone and workspace of combine harvester operator during 2018-19 in wheat fields of ICAR-Indian Agricultural Research Institute, New Delhi. Mass concentration and particle size distribution of dust were assessed in the breathing zone for different size fractions related to health during wheat harvesting using a personal dust monitor. Sticky papers were used to determine the characteristics of particulate matter and wheat straw (>100 μm) in the workspace of the combine harvester. The average mass concentration of inhalable, thoracic and respirable particles were 9500, 4150 and 940 μg/m3 and PM10, PM2.5 and PM1 particles were 3722, 453 and 120 μg/m3 in the breathing zone. Particulate matter concentrations were 37 and 8 times (daily basis) and 62 and 11 times (annual basis) higher than the permissible value of PM10 and PM2.5. The equivalent diameter of wheat straw ranged up to 1400 μm with a density of 9-12 particles per mm2 surface area. It amounts to 1.2 million particles in the workspace with the potential of sticking on exposed body of the operator considering a 10% body surface area.

The Effects of Virgin and Recycled PA12 Powders in SLS Processes on Occupational Exposures

Particulate matter and ultrafine particles are emitted during the pre-processing and post-processing activities of selective laser sintering (SLS) processes, which is major concern to operators exposed to the powders. This study aims to determine the occupational exposure (in terms of the total particle concentration and respirable particulate concentration) during the pre-processing and post-processing activities of SLS processes using virgin and recycled polyamide 12 (PA12) powders. Personal air sampling was performed for each activity according to the NIOSH 0500 and NIOSH 0600 methods. Based on the results, both powders were uniform spheres with a particle size of 40–60 μm. The total particulate concentration was most significant during the following pre-processing activities: 1) pouring powder into the mixing machine and 2) transferring the powder to the SLS AM machine. The total particulate concentration and respirable particulate concentration were slightly higher for the virgin powder for these activities. In conclusion, the virgin and recycled PA12 powders were both inhalable and respirable, which poses serious health hazards to the SLS AM operators. Hence, it is essential for operators to use suitable personal protective equipment (including respirators) and the working practices need to be improved by automating

Occupational Exposure and Environmental Release: The Case Study of Pouring TiO2 and Filler Materials for Paint Production.

Pulmonary exposure to micro- and nanoscaled particles has been widely linked to adverse health effects and high concentrations of respirable particles are expected to occur within and around many industrial settings. In this study, a field-measurement campaign was performed at an industrial manufacturer, during the production of paints. Spatial and personal measurements were conducted and results were used to estimate the mass flows in the facility and the airborne particle release to the outdoor environment. Airborne particle number concentration (1 × 103–1.0 × 104 cm−3), respirable mass (0.06–0.6 mg m−3), and PM10 (0.3–6.5 mg m−3) were measured during pouring activities. In overall; emissions from pouring activities were found to be dominated by coarser particles >300 nm. Even though the raw materials were not identified as nanomaterials by the manufacturers, handling of TiO2 and clays resulted in release of nanometric particles to both workplace air and outdoor environment, which was confirmed by TEM analysis of indoor and stack emission samples. During the measurement period, none of the existing exposure limits in force were exceeded. Particle release to the outdoor environment varied from 6 to 20 g ton−1 at concentrations between 0.6 and 9.7 mg m−3 of total suspended dust depending on the powder. The estimated release of TiO2 to outdoors was 0.9 kg per year. Particle release to the environment is not expected to cause any major impact due to atmospheric dilution

Exposure to Ultrafine Particles in the Ferroalloy Industry Using a Logbook Method.

Background: It is difficult to assess workers’ exposure to ultrafine particles (UFP) due to the lack of personal sampling equipment available for this particle fraction. The logbook method has been proposed as a general method for exposure assessment. This method measures the time and concentration components of the time-weighted average concentration separately and could be suitable for investigation of UFP exposure. Objectives: In this study, we have assessed workers’ exposure to UFP in a ferrosilicon plant. The main tasks of the furnace workers were identified, and the logbook method was used in combination with stationary measurements of UFP taken as close to the identified task areas as possible. In order to verify the results, respirable particles were collected using stationary sampling in close proximity to the UFP measuring instrument, and personal full-shift sampling of respirable particles was performed simultaneously. Thus, exposure to respirable particles determined using the logbook method could be compared to the results of standard measurement. Methods: The particle number concentration of ultrafine particles was determined using a NanoScan SMPS. Respirable particle concentration and exposure were determined using a sampling train consisting of a pump, filter, filter cassettes, and SKC Cyclone for the respirable fraction. Attendance times for workers at each work location were registered via thorough observations made by the research team. Results: The logbook method for exposure estimation based on stationary sampling equipment made it possible to calculate UFP exposure for workers operating the furnaces at a ferrosilicon plant. The mid-size furnace and the large furnace were evaluated separately. The workers operating the largest furnace were exposed to 1.47 × 104 particles/cm3, while workers operating the mid-size furnace were exposed to 2.06 × 104 particles/cm3, with a mean of 1.74 × 104 particles/cm3. Substantial contributions from the casting area, ladle transport corridor, and both tapping areas were made. Exposure to respirable particles was 2.04 mg/m3 (logbook); 2.26 mg/m3 (personal sampling) for workers operating the large-sized furnace, 3.24 mg/m3 (logbook); 2.44 mg/m3 (personal sampling) for workers operating the medium-sized furnace, and 2.57 mg/m3 (logbook); 2.53 mg/m3(personal sampling) on average of all tappers. The average ratio of these two methods’ results was 1.02, which indicates that the logbook method could be used as a substitute for personal sampling when it is not possible to perform personal sampling, at least within this industry. Conclusions: The logbook method is a useful supplement for exposure assessment of UFP, able to identify the most polluted areas of the workplace and the contribution of different work tasks to the total exposure of workers, enabling companies to take action to reduce exposure.

Comparative Analysis of Indoor and Outdoor Particulate Matter Concentrations and Air Quality in Ogbomoso, Nigeria

Background.Airborne particulates are an issue in many urban regions around the world and their detrimental impact on human health has increasingly become a public health concern.Objectives.The aim of the present study was to examine particle pollution in an urban settlement in Nigeria. This study examines the extent, spatial variation, and sources of indoor and outdoor particulate matter (PM) concentrations in Ogbomoso, Nigeria.Methods.The survey research method was adopted. Sampling included 385 buildings across selected precincts and different residential zones in the town of Ogbomoso. Particulate matter analytes (PM1, PM2.5 and PM10) within/around each building were measured with a particle counter and details on domestic utilities/practices were obtained with a questionnaire. Analysis of variance was used to determine inter-zonal variations in PM levels and simple linear regression was used to analyze the relationship between indoor and outdoor air quality.Results.Indoor and outdoor respirable particle (PM2.5) concentrations were lower than the World Health Organization (WHO) Interim Target limit of 75 μg/m3, while concentrations of inhalable particles (PM10) were higher than the set limit of 150 μg/m3 for daily averages. Coarse particles dominated, with an accumulative PM2.5/PM10 ratio of 0.24. The inter-zonal analysis of PM concentrations revealed that indoor and outdoor PM levels varied significantly by residential zone (p = 0.0005; p = 0.01, respectively). Regression analysis showed a significant but weak relationship between indoor and outdoor PM levels (r = +0.221), while the coefficient of determination (R2 = 0.049) showed that only about 5% of the variation in indoor air quality was associated with outdoor air quality. Particle pollution inducers were identified in the residents' waste disposal methods and adopted fuels/energy sources, with firewood and charcoal linked with increased concentrations of particulate matter.Conclusions.Air quality was relatively poor in the study area given observed particulate matter concentrations. Cleaner fuels, effective waste management systems and improved roads are needed to foster better air quality in the study area.Competing Interests.The authors declare no competing financial interests

Exposure to welding fumes suppresses the activity of T-helper cells

Welders have an increased susceptibility to airway infections with non-typeable Haemophilus influenzae (NTHi), which implicates immune defects and might promote pneumonia and chronic obstructive pulmonary disease (COPD). We hypothesized that welding-fume exposure suppresses Th1-lymphocyte activity. Non-effector CD4+ T-cells from blood of 45 welders (n = 23 gas metal arc welders, GMAW; n = 16 tungsten inert gas welders, TIG; n = 6 others) and 25 non-welders were ex vivo activated towards Th1 via polyclonal T-cell receptor stimulation and IL-12 (first activation step) and then stimulated with NTHi extract or lipopolysaccharide (LPS) (second activation step). IFNγ and IL-2 were measured by ELISA. In the first activation step, IFNγ was reduced in welders compared to non-welders and in the GMAW welders with higher concentrations of respirable particles compared to the lower exposed TIG welders. IFNγ was not influenced by tobacco smoking and correlated negatively with welding-fume exposure, respirable manganese, and iron. In the second activation step, NTHi and LPS induced additional IFNγ, which was reduced in current smokers compared to never smokers in welders as well as in non-welders. Analyzing both activation steps together, IFNγ production was lowest in smoking welders and highest in never smoking non-welders. IL-2 was not associated with any of these parameters. Welding-fume exposure might suppress Th1-based immune responses due to effects of particulate matter, which mainly consists of iron and manganese. For responses to NTHi this is strongest in smoking welders because welding fume suppresses T-cell activation towards Th1 and cigarette smoke suppresses the subsequent Th1-response to NTHi via LPS. Both effects are independent from IL-2-regulated T-cell proliferation. This might explain the increased susceptibility to infections and might promote COPD development.

Efficacy of dexamethasone, salbutamol, and reduced respirable particulate concentration on aerobic capacity in horses with smoke-induced mild asthma.

BackgroundMild asthma in horses decreases racing performance and impairs gas exchange. The efficacy of treatment on performance is unknown.HypothesisTreatment targeting lung inflammation improves V˙O2peak in horses with mild asthma.AnimalsThoroughbred polo horses (n = 12) with smoke‐induced mild asthma. Horses were exposed to increased ambient particulate matter (35.51 μg/m3 [PM2.5]; day mean, centrally measured) from day −33 to 0, from bushfire smoke (natural model).MethodsProspective, randomized, placebo‐controlled, double‐blinded clinical trial. All horses completed 3 V˙O2peak tests, measuring aerobic and anaerobic variables: day 0 ‐baseline; day 16 ‐after dexamethasone (20 mg IM q24h; DEX, n = 6) or saline treatment (SALINE, n = 6), under improved ambient PM2.5 concentrations (7.04 μg/m3); day 17‐15‐30mins after inhaled salbutamol (1500 μg). Bronchoalveolar lavage and mucus scoring were performed on day −8 and day 20. Linear mixed effects models were used to examine the effects of timepoint and treatment group on BAL differential cell counts, mucus scores, aerobic and anaerobic variables.ResultsHorses’ mucus scores improved significantly from day −8 to 20 by 1.27 ± .38 (P = .01). There was a significant increase in V˙O2peak of 15.5 ± 4.0 mL(min.kg)−1 from day 0 to 17 (P = .002), representing an average (mean) increase in V˙O2peak of 13.2%. There was no difference in V˙O2peak between treatment groups (SALINE versus DEX) at any timepoint.Conclusions and Clinical ImportanceThis study highlighted the key role of improved air quality on functionally important airway inflammation. Evidence provided is central to increasing owner compliance regarding improved air quality for the treatment and prevention of mild asthma.

Variability of aerosol mass and number concentrations during taconite mining operations

This study characterized concentration metrics of airborne nanoparticles and their time series across major operations of a taconite mine through monitoring respirable and ultrafine particle concentrations at four major processing departments of the mine: crushing, dry milling, wet milling, and pelletizing (United Taconite Mine, Iron Junction, MN, USA). We used three area stations of direct-reading instruments to estimate concentration metrics including PM1 (particles with an aerodynamic diameter <1 µm), respirable dust (particles sampled according to the respirable convention with a 50% sampling efficiency at an aerodynamic diameter of 4 µm), PN (total number concentration of particles), and lung-deposited surface area concentrations (LDSA) of particles smaller than 300 nm, on two different days. Results for each station were compared using bivariate correlation analysis to obtain insight into the spatial distribution, and intra-class correlation coefficients (ICCs) to evaluate the between-day repeatability between the measurements. Comparability of the LDSA concentrations measured by two different devices was also investigated using linear regression. Results revealed that the pelletizing operation produced the highest average LDSA concentration on both days (with a maximum concentration of 199 ± 48 µm2/cm3 in pelletizing, 141 ± 52 µm2/cm3 in crushing, 91 ± 9 µm2/cm3 in dry milling, and 85 ± 7 µm2/cm3 in wet milling). Concentrations in all operations showed a fair to excellent between-day repeatability but they were significantly different within stations of each operation. Measured LDSA concentrations did not show a linear correlation between different instruments, except for crushing.

A comparison of the abrasive sanding dust emission characteristics of oil palm wood and rubberwood

With the increasing interest in using oil palm wood (OPW) in the manufacture of value-added wood products in the South East Asian region, the subject of dust emission in relation to the variable density of OPW is a matter of concern. Therefore, this study evaluated the dust emission characteristics of untreated and phenol-formaldehyde-treated OPW during the abrasive sanding process. Rubberwood was the solid wood material used in this study for comparison purposes. The abrasive sanding process was carried out using an orbital sander with aluminium oxide abrasive paper with a grit size of 150. The sample boards were weighed before and after sanding to determine the amount of stock removed. The dust concentration and dust particles diameter was influenced by the material type, material density variation, and material hardness. The study revealed that both untreated and treated OPW produced higher dust concentration and higher proportions of fine respirable dust particles compared with rubberwood during the abrasive sanding processes, and therefore, it is important for a more stringent permissible exposure level (PEL) standard for dust emission to be established for OPW processing. In this context, the existing PEL of 5 mg/m3 of dust is inappropriate and needs a revision if OPW is to be successfully used in the value-added wood products industry.

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.

Functional disorders of the lung and symptoms of respiratory disease associated with occupational inhalation exposure to wood dust in Iran.

OBJECTIVESThe possible adverse respiratory effects of airborne pollutants in sawmills have not been thoroughly investigated in Iran. Additionally, the extent to which workers are exposed to this organic dust and its associated bioaerosols has not been extensively quantified. Likewise, the predominant bacterial and fungal species associated with wood dust have not been characterized. The present study was undertaken to address these issues.METHODSOne hundred male individuals exposed to wood dust and 100 unexposed male subjects were investigated. They completed a standardized respiratory symptom questionnaire and underwent spirometry testing. Additionally, airborne concentrations of respirable and inhalable dust particles, bacteria, and fungi were measured.RESULTSThe mean concentrations of inhalable and respirable dust particles, bacteria, and fungi were found to be 2.44, 6.76 mg/m3 , 756.38, and 299.15 colony-forming units/m3 , respectively. The predominant Gram-negative bacteria in the sawmills included the Pseudomonadaceae, Klebsiella pneumoniae, and Rhinoscleromatis spp., and the predominant fungi consisted of the zygomycetes and Aspergillus spp. Respiratory symptoms were significantly more prevalent among exposed workers. Significant cross-shift decrements were noted in some pulmonary function parameters. Similarly, pre-shift spirometry results indicated that some pulmonary function parameters were significantly lower in the exposed group.CONCLUSIONSExposure to wood dust and its bioaerosols was associated with significantly higher prevalence of respiratory symptoms and both acute (i.e., partially reversible) and chronic (i.e., irreversible) decrements in the functional capacity of the lung. Additionally, the characterized bioaerosols did not differ significantly from those isolated in other parts of the world.

Spatial and temporal variation of respirable particles around a surface coal mine in India

People living around surface mines are exposed to enhanced respirable particle level. Not many studies are available that evaluated the contribution of mining to it. The paper presented the result of study that investigated spatio-temporal variability of particle concentrations around a surface coal mine in eastern part of India. Particle concentration and concurrent meteorological parameters at 24 locations were measured along four sections from the mine boundary up to 500 m using an aerosol spectrometer and portable weather station. SPSS 20.0 was used for statistical analysis. Average PM10, PM2.5 and PM1 concentration varied in the range 212.67 ± 168.76–524.46 ± 137.57 μg m−3, and 89.53 ± 77.62–297.41 ± 107.10 μg m−3 and 66.22 ± 58.05–246.66 ± 84.26 μg m−3 respectively. This is equivalent to 2.74, 1.34 and 2.77 times the background concentration of PM2.5-10, PM1-2.5 and PM1 respectively. Respirable particles up to 500 m from the mine comprised of 27–73%, 8–12% and 18–61% of PM2.5-10, PM1-2.5 and PM1. During peak production period, the concentration of respirable particles around the mine increased by a factor 5–15 of the average concentrations. Distance and meteorological parameters explained up to 55% of the variability of particle concentration. Present Indian norm to allow an ambient PM10 concentration of 250 μg m−3 at a distance of 500 m is not met, in spite of the study mine is only 10 years old. Extremely limited literature suggests that more studies are required for better understanding and evaluation of mining contribution to the local PM level.

Qualitative and Quantitative Evaluation of Airborne Microorganisms and the Concentrations of Particulate and Respirable Matter Causing from Dust Storm in the Air of Ilam City: Six-month Cross Sectional Study

Introduction: In recent years, dust storms frequently have occurred in large areas of the western half of Iran. Dust particles have negative effects on the environment and living animals, especially men's lives; hence, the current study was conducted with the aim of evaluation of airborne microorganisms and the concentrations of particulate and respirable matter causing from dust storm. Materials & methods: This cross - sectional study was done in Ilam city (2012). For sampling and reading of TSP amounts used from direct reading devices in concentration range of 1µg/m3-2500 mg/m3. Cyclone was used for determination of respirable dusts with diameter less than ten microns. Also to determine microbial state of dusts used from the cellulose membrane filters (37 mm diameter). Finally, data were analyzed with spss software. Findings: Results showed that the highest concentration of total suspended particles (TSP) and respirable particles (PM10) have been recorded in June with the amount of 22.5 and 1.3 mg per cubic meter. Comparison of Ilam air quality with standard values ​​( less-than 150 μ g/m3) for respirable particles and total suspended particles showed that except in August that TSP concentration was below the standard value. In other months, the concentration of PM10 and total suspended particles were above the standard amount. Discussion & conclusions: The results of this study showed that particulate concentration levels were higher than those of standard values and also contained microorganisms which can threaten human health; therefore, it seems necessary to control them.