Organic Dust Research Articles

Using a Standard Respiratory Air Filtering Device during Moderate Intensity Exercise does not Affect Post Exercise Pulmonary Function

Physical exercise requiring oxidative energy transfer increases pulmonary ventilation (VE). In an air polluted environment, the exercise-induced increase in VE increases the volume of toxic gases and number of toxic particles to which the pulmonary system is exposed. Using a respiratory air-filtering device (RAFD) during exercise decreases exposure to inhaled toxic gases and particles. However, a RAFD creates external resistance to inspiration and expiration which could decrease pulmonary muscle function and pulmonary volumes, and creates an external mechanical dead-space which produces fractional rebreathing which could increase pulmonary flowrates. This experiment tested the hypotheses that using a RAFD during exercise would; decrease post-exercise peak inspiratory pressure (PPI) and peak expiratory (PPE) pressure, FVC and FEV1, and increase post-exercise flowrates. Using a repeated-measures, counter-balanced design, six healthy moderately aerobically-trained, men (mean ± SD; age 24.7 ± 1.7 years; peak oxygen utilization [VO2peak] 42.8 ± 5.3 ml kg-1 min-1) completed two 30 min exercise test sessions at a power output equal to 75% VO2peak. One session was performed not using (NORAFD), and one using a RAFD (Moldex 8000) fitted with organic vapor cartridges and combined dust and mist pre-filters (inspiratory resistance = 0.216 kPa, expiratory resistance = 0.094 kPa at 85.0 l min-1). All pulmonary function tests were performed immediately pre-(Pre) and 0 (Post-0), 5 (Post-5), and 15 (Post-15) min post-exercise. There was a significant (p1, FEV1/FVC%, PEF, and FEF50% from Pre to Post-0. There were no other within or between condition differences in any of the pulmonary muscle pressures, volumes or flowrates. It was concluded that using a RAFD during moderate intensity medium duration exercise does not affect post exercise pulmonary function.

Using machine learning to derive cloud condensation nuclei number concentrations from commonly available measurements

Abstract. Cloud condensation nuclei (CCN) number concentrations are an important aspect of aerosol–cloud interactions and the subsequent climate effects; however, their measurements are very limited. We use a machine learning tool, random decision forests, to develop a random forest regression model (RFRM) to derive CCN at 0.4 % supersaturation ([CCN0.4]) from commonly available measurements. The RFRM is trained on the long-term simulations in a global size-resolved particle microphysics model. Using atmospheric state and composition variables as predictors, through associations of their variabilities, the RFRM is able to learn the underlying dependence of [CCN0.4] on these predictors, which are as follows: eight fractions of PM2.5 (NH4, SO4, NO3, secondary organic aerosol (SOA), black carbon (BC), primary organic carbon (POC), dust, and salt), seven gaseous species (NOx, NH3, O3, SO2, OH, isoprene, and monoterpene), and four meteorological variables (temperature (T), relative humidity (RH), precipitation, and solar radiation). The RFRM is highly robust: it has a median mean fractional bias (MFB) of 4.4 % with ≈96.33 % of the derived [CCN0.4] within a good agreement range of -60%<MFB<+60% and strong correlation of Kendall's τ coefficient ≈0.88. The RFRM demonstrates its robustness over 4 orders of magnitude of [CCN0.4] over varying spatial (such as continental to oceanic, clean to polluted, and near-surface to upper troposphere) and temporal (from the hourly to the decadal) scales. At the Atmospheric Radiation Measurement Southern Great Plains observatory (ARM SGP) in Lamont, Oklahoma, United States, long-term measurements for PM2.5 speciation (NH4, SO4, NO3, and organic carbon (OC)), NOx, O3, SO2, T, and RH, as well as [CCN0.4] are available. We modify, optimize, and retrain the developed RFRM to make predictions from 19 to 9 of these available predictors. This retrained RFRM (RFRM-ShortVars) shows a reduction in performance due to the unavailability and sparsity of measurements (predictors); it captures the [CCN0.4] variability and magnitude at SGP with ≈67.02 % of the derived values in the good agreement range. This work shows the potential of using the more commonly available measurements of PM2.5 speciation to alleviate the sparsity of CCN number concentrations' measurements.

Towards the identification of carriers of the unidentified infrared (UIR) bands in novae

AbstractThe unidentified infrared (UIR) bands, whose carriers are thought to be organics, have been widely observed in various astrophysical environments. However, our knowledge of the detailed chemical composition and formation process of the carriers is still limited. We have synthesized laboratory organics named Quenched Nitrogen-included Carbonaceous Composite (QNCC) by quenching plasma produced from nitrogen gas and hydrocarbon solids. Infrared and X-ray analyses of QNCC showed that infrared properties of QNCC well reproduce the UIR bands observed in novae and amine structures contained in QNCC play an important role in the origin of the broad 8 m feature, which characterizes the UIR bands in novae. QNCC is at present the best laboratory analog of organic dust formed around dusty classical novae, which carries the UIR bands in novae via thermal emission process [Endo et al.(2021)].

Determinant Factor of Pulmonary Function Impairment on Rice Mill Workers

Introduction: Exposure to organic dust in the agricultural industry can cause pulmonary function problems for workers. This study aims to know the determinant of pulmonary function impairment on rice mill workers in Ujung Pangkah, Gresik, East Java. Method: This study was an analytical observational study using a cross-sectional design. This study’s population were all rice mill workers in Ketapang and Glatik Villages, Ujung Pangkah, Gresik, East Java there were 25 people. The sample of this study was 16 people. The independent variable in this study was the sex, working period, smoking, and using a mask, while the dependent variable was the pulmonary function status of workers. The data respondent obtained a questionnaire, observations, and measurement of workers’ pulmonary function using a spirometer. Data analysis was performed in analytic descriptive with the Spearman correlation test. Result and Discussion: The Spearman test results are known that the working period (r = -0.022) and smoking (r = -0.160) were very weak and an inverse correlation with pulmonary function status. In comparison, the use of masks (r = 0.462) was adequate and directly correlated with pulmonary function status. Smoking and working period will describe the length of exposure to rice dust, affecting the pulmonary function status. The obedience of using masks to workers will reduce the risk of pulmonary function impairment. Conclusion: Working period, smoking, and using mask are determinants of pulmonary function impairment on rice mill workers in Ujung Pangkah, Gresik, East Java.

Fine particular matter and its constituents in air pollution and gestational diabetes mellitus: A nationwide survey in China

Background: Ambient air pollution has been linked to the development of gestational diabetes mellitus (GDM). However, previous studies provided inconsistent findings and no study has examined the effects of complex chemical constituents of the particular matter on GDM. Objectives: To investigate the associations of exposure to PM2.5 (particular matter ≤ 2.5μm) and its constituents with GDM. Methods: The China Labor and Delivery Survey was a cross-sectional investigation conducted in 24 provinces in China between 2015 and 2016. A random sample of all deliveries in each participating hospital was selected and detailed obstetric information was extracted from medical records. Average concentrations of PM2.5 and six constituents (organic matter, black carbon, sulfate, nitrate, ammonium and soil dust) were estimated (1km×1km) using a combined geoscience-statistical model. GDM was diagnosed based on an oral glucose tolerance test (OGTT) between 24th and 28th weeks of the pregnancy and according to IADPSG criteria. Generalized linear mixed models were used to adjust for potential confounders. Results: A total of 54,517 subjects from 55 hospitals were included. The incidence of GDM was 10.8%. An interquartile range (IQR) increase in PM2.5 exposure in the 2nd trimester of pregnancy was associated with an increased GDM risk in the single pollutant model, [adjusted odds ratio (aOR)=1.11 and 95% confidence interval (CI): 1.01-1.22]. Moderate to high degree of correlations were found among various PM2.5 constituents. Exposure to organic matter (aOR=1.14; 95%CI: 1.05-1.23), black carbon (aOR=1.15; 95%CI: 1.07-1.25) and nitrate (aOR=1.13; 95%CI: 1.02-1.24) during 2nd trimester were associated with increased risks of GDM. Associations between constituents and GDM were robust after controlling for total PM2.5 mass and accounting for multi-collinearity. Conclusions: Exposure to PM2.5 in 2nd trimester during pregnancy was associated with an increased risk of GDM. Organic matter, black carbon and nitrate may be the main culprits for the association.

IMPROVING THE DESIGN OF THE BRUSH MACHINE FOR GRAIN

The quality of the finished products of flour mills largely depends on the efficiency of grain cleaning equipment, in particular, on those intended for cleaning the grain surface from dense deposits of organic and mineral dust. In modern conditions of an acute shortage of household drinking water, when the use of washing and washer-hulling machines becomes impractical or completely impossible, the role of equipment for dry processing of grain surfaces - scouring and brushing machines - is significantly increasing. Scouring machines separate high-ash dust deposits from the surface of the grain, separate the embryo and bangs, destroy clods of earth commensurate with the grain, and also lead to partial peeling of fruit shells. But they cannot remove dust and microorganisms from the groove of the weevil. This task - in the absence of washing and washer-hulling machines - is solved exclusively by brushing machines. They remove dust and microorganisms from the groove, the remains of dust, embryos and bangs, fruit shells torn by the peeling machines, and reduce the ash content of the refined grain by 0.02 ... 0.03%. And although the efficiency of the brushing machines is less than the efficiency of the scourers, they are irreplaceable at the final stages of cleaning the grain surface. The decisive influence on the efficiency of the operation of brushing machines is created by the technical condition of the working bodies and the size of the working gap between the brush rotor and the brush deck, which should be 4 ... 8 mm. However, over time, the brush surfaces of the rotor and deck will wear out, become dirty, clogged with dust and deform - the bristles get a slope and the working gap increases. In many respects, this is corrected by regulation with a special adjusting mechanism. But its capabilities are limited, and the longer the brush is used, the more often the regulation is required and the less effective it becomes. Specialists from many countries are engaged in the improvement of brush machines: Russia, Switzerland, Poland, etc. An overview of the designs and functional diagrams of machines of various companies, as well as inventions and patents in this area, can contribute to the improvement of the А1-БЩМ-12 brush machine, which is most often used in production lines of domestic enterprises. Invention "Brush machine for cleaning grain surface" for copyright certificate No. 459248 is just about the equipment for cleaning wheat and rye. The aim of the invention is to improve the efficiency of processing the surface ofthe grain by lengthening the path of its friction along the working surfaces of the rotor and the deck and continuous extraction of particles separated from the grain over the entire surface of the deck. For this, the proposed machine has a deck, which consists of a set of cylindrical brush rollers that rotate in mutually opposite directions. Externally, the deck is covered by a sieve shell, which can be made corrugated to increase the grain cleaning effect. The working area is formed by a rotary brush rotor and a brush-roller deck. Rollers of odd numbers rotate in the direction opposite to the direction of rotation of the rotor at half the speed, and rollers of paired numbers rotate at the same speed as odd numbers, but in the same direction as the rotor. Grain in the working area goes through a complex zigzag path, after which it is blown with air and goes outside. To compensate for the wear of the brushes and regulate the size of the working gap, the axes of the rollers on both sides are installed in the radial grooves of the two fixed sidewalls and simultaneously in the inclined grooves of the rotary plates mounted on the cylindrical protrusions of these sidewalls. Since the total surface area of the brush rollers is almost 4 times larger than the deck area of the А1-БЩМ-12 machine, the specific load on the surface of the rollers is significantly reduced, which guarantees a longer and more efficient operation of the brush machine.

Bacterial extracellular vesicles isolated from organic dust induce neutrophilic inflammation in the lung.

Inhalation of organic dust is an occupational hazard leading to the development of respiratory symptoms and respiratory diseases. Bioaerosols from concentrated animal feeding operations are rich in bacteria and could carry bacterial extracellular vesicles (EVs) that could induce lung inflammation. It is not known if organic dust contains bacterial EVs and whether they modulate lung inflammation. Herein, we show that poultry organic dust contains bacterial EVs (dust EVs) that induce lung inflammation. Treatment of airway epithelial cells, THP-1-monocytes and -macrophages with dust EVs rapidly induced IL-8, IL-6, ICAM-1, proIL-1β, and TNF-α levels. In airway epithelial cells, induction of inflammatory mediators was due to increased mRNA levels and NF-κB activation. Induction of inflammatory mediators by dust EVs was not inhibited by polymyxin B. Single and repeated treatments of mice with dust EVs increased lung KC, IL-6, and TNF-α levels without significantly altering IL-17A levels. Increases in cytokines were associated with enhanced neutrophil infiltration into the lung. Repeated treatments of mice with dust EVs increased lung mean linear intercept and increased collagen deposition around airways indicating lung remodeling. Peribronchial cell infiltrates and airway epithelial thickening were also observed in treated mice. Because bacterial EVs are nanometer-sized particles, they can reach and accumulate in the bronchiolar and alveolar regions causing lung injury leading to the development of respiratory diseases. Our studies have provided new evidence for the presence of bacterial EVs in organic dust and for their role as one of the causative agents of organic dust-induced lung inflammation and lung injury.

Work Lung Disease Due to Rice Dust

Indonesia is one of the third largest rice producers globally; therefore, rice dust-related lung diseases will be more significant. Rice dust is easily exposed to humans, triggers lung damage, and decline the lung function. Rice dust exposure is associated with occupational lung diseases, for instance, acute reversible airflow obstruction, chronic obstructive pulmonary disease, grain fever, organic dust syndrome, and hypersensitivity pneumonitis. Smoking and the environment might aggravate rice dust-related respiratory problems. The average tolerated dose of rice dust is about less than 3 mg/m3. Avoiding exposure to rice dust is primer prevention.

Occupational exposure to organic dust and risk of lymphoma subtypes in the EPILYMPH case-control study.

Objectives:This study aimed to estimate the risk of lymphoma and its major subtypes in relation to occupational exposure to specific organic dusts.Methods:We explored the association in 1853 cases and 1997 controls who participated in the EpiLymph case–control study, conducted in six European countries in 1998–2004. Based on expert assessment of lifetime occupational exposures, we calculated the risk of the major lymphoma subtypes associated with exposure to six specific organic dusts, namely, flour, hardwood, softwood, natural textile, synthetic textile, and leather, and two generic (any types) groups: wood and textile dusts. Risk was predicted with unconditional regression modeling, adjusted by age, gender, study center, and education.Results:We observed a 2.1-fold increase in risk of follicular lymphoma associated with ever exposure to leather dust [95% confidence interval (CI) 1.01–4.20]. After excluding subjects who ever worked in a farm or had ever been exposed to solvents, risk of B-cell lymphoma was elevated in relation to ever exposure to leather dust [odd ratio (OR) 2.2, 95% CI 1.00–4.78], but it was not supported by increasing trends with the exposure metrics. Risk of Hodgkin lymphoma was elevated (OR 2.0, 95% CI 0.95–4.30) for exposure to textile dust, with consistent upward trends by cumulative exposure and three independent exposure metrics combined (P=0.023, and P=0.0068, respectively).Conclusions:Future, larger studies might provide further insights into the nature of the association we observed between exposure to textile dust and risk of Hodgkin lymphoma.

Chemical Characterization and Seasonality of Ambient Particles (PM2.5) in the City Centre of Addis Ababa.

Ambient air pollution is a growing public health concern in major African cities, including Addis Ababa (Ethiopia), where little information is available on fine particulate matter (PM2.5, with aerodynamic diameter <2.5 µm) pollution. This paper aims to characterize annual PM2.5, including bulk composition and seasonal patterns, in Addis Ababa. We collected 24-h PM2.5 samples in the central city every 6 days from November 2015 to November 2016. The mean (±SD) daily PM2.5 concentration was 53.8 (±25.0) µg/m3, with 90% of sampled days exceeding the World Health Organization’s guidelines. Principal components were organic matter (OM, 44.5%), elemental carbon (EC, 25.4%), soil dust (13.5%), and SNA (sulfate, nitrate, and ammonium ions, 8.2%). Higher PM2.5 concentrations were observed during the heavy rain season, while crustal dust concentrations ranged from 2.9 to 37.6%, with higher levels during dry months. Meteorological variables, vehicle emissions, biomass fuels, unpaved roads, and construction activity contribute to poor air quality. Compared to the Air Quality Index (AQI), 31% and 36% of observed days were unhealthy for everyone and unhealthy for sensitive groups, respectively. We recommend adopting effective prevention strategies and pursuing research on vehicle emissions, biomass burning, and dust control to curb air pollution in the city.

Assessment of Children’s Potential Exposure to Bioburden in Indoor Environments

The exposure to particles and bioaerosols has been associated with the increase in health effects in children. The objective of this study was to assess the indoor exposure to bioburden in the indoor microenvironments more frequented by children. Air particulate matter (PM) and settled dust were sampled in 33 dwellings and four schools with a medium volume sampler and with a passive method using electrostatic dust collectors (EDC), respectively. Settled dust collected by EDC was analyzed by culture-based methods (including azole resistance profile) and using qPCR. Results showed that the PM2.5 and PM10 concentrations in classrooms (31.15 μg/m3 and 57.83 μg/m3, respectively) were higher than in homes (15.26 μg/m3 and 18.95 μg/m3, respectively) and highly exceeded the limit values established by the Portuguese legislation for indoor air quality. The fungal species most commonly found in bedrooms was Penicillium sp. (91.79%), whereas, in living rooms, it was Rhizopus sp. (37.95%). Aspergillus sections with toxigenic potential were found in bedrooms and living rooms and were able to grow on VOR. Although not correlated with PM, EDC provided information regarding the bioburden. Future studies, applying EDC coupled with PM assessment, should be implemented to allow for a long-term integrated sample of organic dust.

Occupational and environmental risk factors for idiopathic pulmonary fibrosis in Australia: case–control study

IntroductionIdiopathic pulmonary fibrosis (IPF) is a lung disease of unknown cause characterised by progressive scarring, with limited effective treatment and a median survival of only 2–3 years. Our aim was...

Occupational Exposure to Mycotoxins-Different Sampling Strategies Telling a Common Story Regarding Occupational Studies Performed in Portugal (2012-2020).

In occupational settings where exposure to organic dust occurs (e.g., intensive animal production, waste management, farming and many others) workers can also be exposed to mycotoxins. However, recognizing exposure to mycotoxins in workplace environments does not happen commonly and, consequently, remains as a not identified occupational risk factor. In the last decade, work developed in different occupational settings, using different sampling approaches reported that occupational exposure to mycotoxins occurs and it’s of upmost importance to be seen as an occupational concern that needs to be tackled. This paper intends to discuss the several possibilities available for assessing and characterizing the occupational exposure to mycotoxins through the description of the advantages and limitations of the different sampling strategies. Overviewing the approaches and the main achievements used in several field campaigns developed in Portugal, the knowledge obtained will be used to support the identification of the main aspects to consider when designing new occupational studies. The need for additional research work will also be discussed where new directions to follow will be debated.

A High Docosahexaenoic Acid Diet Alters the Lung Inflammatory Response to Acute Dust Exposure.

Agricultural workers are at risk for the development of acute and chronic lung diseases due to their exposure to organic agricultural dusts. A diet intervention using the omega-3 fatty acid docosahexaenoic acid (DHA) has been shown to be an effective therapeutic approach for alleviating a dust-induced inflammatory response. We thus hypothesized a high-DHA diet would alter the dust-induced inflammatory response through the increased production of specialized pro-resolving mediators (SPMs). Mice were pre-treated with a DHA-rich diet 4 weeks before being intranasally challenged with a single dose of an extract made from dust collected from a concentrated swine feeding operation (HDE). This omega-3-fatty-acid-rich diet led to reduced arachidonic acid levels in the blood, enhanced macrophage recruitment, and increased the production of the DHA-derived SPM Resolvin D1 (RvD1) in the lung following HDE exposure. An assessment of transcript-level changes in the immune response demonstrated significant differences in immune pathway activation and alterations of numerous macrophage-associated genes among HDE-challenged mice fed a high DHA diet. Our data indicate that consuming a DHA-rich diet leads to the enhanced production of SPMs during an acute inflammatory challenge to dust, supporting a role for dietary DHA supplementation as a potential therapeutic strategy for reducing dust-induced lung inflammation.

Literature Review : Risk Factors Wood Dust Exposure on Workers Lung Status

Introduction: Health problems caused by environmental factors are still one of the main things to note. One of the dangers in the work environment is the presence of organic dust including wood dust. Organic dust flying in the air is able to interfere with the health of the workers through the respiratory tract. The resulting wood dust is at risk causing lung faal status disorders in workers. This article aims to explore risks factors for wood dust exposure to the status of lung faal in wood industry workers based on the previously performed research from published journals. Discussion: This research used a method of literature study with a comparative study approach. The selected research should be in appropriated with the topic and through the protocols that have been set to become secondary data. The results of data analysis indicated that almost all research use observational analytic types with cross sectional approaches. Wood dust that has entered through the respiratory tract worker is influenced by several variables. The most often used risk factors as a research variable are dust levels, age, use of PPE, and smoking habit. Conclusion: The research can be concluded that independent variables of selected research are less varied. The selected research variables already existed in previous research. Upcoming researchers are expected to be able display new variables that are suspected to affect the status of the lung Faal on wood industry workers.

Maternal occupational exposure and congenital heart defects in offspring.

Objectives:Congenital heart defects (CHD) are the most prevalent congenital anomalies. This study aims to examine the association between maternal occupational exposures to organic and mineral dust, solvents, pesticides, and metal dust and fumes and CHD in the offspring, assessing several subgroups of CHD.Methods:For this case–control study, we examined 1174 cases with CHD from EUROCAT Northern Netherlands and 5602 controls without congenital anomalies from the Lifelines cohort study. Information on maternal jobs held early in pregnancy was collected via self-administered questionnaires, and job titles were linked to occupational exposures using a job exposure matrix.Results:An association was found between organic dust exposure and coarctation of aorta [adjusted odds ratio (ORadj) 1.90, 95% confidence interval (CI) 1.01–3.59] and pulmonary (valve) stenosis in combination with ventricular septal defect (ORadj 2.68, 95% CI 1.07–6.73). Mineral dust exposure was associated with increased risk of coarctation of aorta (ORadj 2.94, 95% CI 1.21–7.13) and pulmonary valve stenosis (ORadj 1.99, 95% CI 1.10–3.62). Exposure to metal dust and fumes was infrequent but was associated with CHD in general (ORadj 2.40, 95% CI 1.09–5.30). Exposure to both mineral dust and metal dust and fumes was associated with septal defects (ORadj 3.23, 95% CI 1.14–9.11). Any maternal occupational exposure was associated with a lower risk of aortic stenosis (ORadj 0.32, 95% CI 0.11–0.94).Conclusions:Women should take preventive measures or avoid exposure to mineral and organic dust as well as metal dust and fumes early in pregnancy as this could possibly affect foetal heart development.

Evaluation of the Reduction in PM2.5 Concentration During the National Traditional Games of Ethnic Minorities in Zhengzhou

To evaluate the effect of the implementation of emission reduction measures and the improvement in air quality during the National Traditional Games of Ethnic Minorities in Zhengzhou, a series of online instruments were used to continuously observe air pollutants and components of PM2.5 from August 5 to September 30, 2019. Three cases, including before emission reduction (August 5-24), during emission reduction (August 25 to September 18), and after emission reduction (September 19-30), were classified by the implementation of control measures. The results show that the growing concentration of PM2.5 after the cancellation of emission abatement measures (11.7 μg·m-3) was greater than that during the emission reduction (2.3 μg·m-3) compared to the PM2.5 concentration before emission reduction. This thus indicates that the control measures have a significant effect on reducing particulate matter. The main components of PM2.5 were organic matter, nitrate, ammonium, sulfate, and crustal elements. Compared to the proportion of components in PM2.5 before and during the control periods, organic matter and nitrate increased by 3.9% and 0.9%, respectively, while sulfate, ammonium, and crustal elements decreased by 1.1%, 1.9%, and 2.2%, respectively. The results of source appointment by positive matrix factorization show that secondary sulfate, secondary nitrate, secondary organic aerosols, vehicular emissions, industrial emissions, dust, and coal combustion are the main sources of PM2.5. Emission abatement measures reduced the contributions of primary sources such as dust, coal combustion, and industry by 8.3%, 8.2%, and 8.1%, respectively. In contrast, the contributions of secondary organic and nitrate aerosols increased during the control periods, which suggested that the control measures implemented in Zhengzhou had a weaker emission reduction effect on nitrogen oxide and volatile organic compounds than on primary sources of PM2.5.

Kinetic free mathematical model for the prediction of Kst values for organic dusts with arbitrary particle size distribution

Risk mitigation in production facilities has been an issue of great interest for decades, especially in activities which represent a serious hazard to human health, environment and industrial plants. Dust explosions are a major hazard in many industrial processes: only in the first part of 2019 (January–June) 34 dust explosions, mainly due to organic powders, occurred worldwide. An explosion may take place whenever there is the presence of combustible dusts, which are frequently generated by activities such as grinding, crushing, conveying and storage. Currently, a relatively expensive experimental test, carried out into a 20-L Siwek apparatus, is used to address the order of magnitude (class) of explosive dust: this piece of information is referred to as the deflagration index, Kst. At the current state, only a few pioneering models have been developed in order to predict the value of the Kst as a function of some relevant properties of the dust: e.g. particle size distribution (PSD), humidity, thermal conductivity, etc‥ Most of these models condense the information about the PSD of a given dust into an average value, referred to as D50. In this work, a kinetic free mathematical model aimed at predicting the deflagration index for organic dusts is presented. This model, unlike the older ones, considers the whole particle size distribution for the computation of the deflagration index. In order to be implemented, only a single experimental Kst value (which works as a reference) and a particle size analysis on the dust are required. The model was validated using the whole granulometric distribution of three different organic powders (fosfomycin, sugar and niacin). In addition, the same estimations were done by considering only the D50 data. It was noticed that, for highly polydispersed dusts, results were less accurate with respect to those obtained using the complete PSD, highlighting the importance of considering a complete granulometric distribution for process safety purposes.

Assessment of Worker Exposure to Occupational Organic Dust in a Hemp Processing Facility.

The cultivation and processing of industrial hemp, Cannabis sativa L., is a developing industry in Australia. Exposure to hemp dust is demonstrated as producing reactive and respiratory health effects, potentially causing permanent lung disease or damage. The aim of this study was to assess the airborne organic dust concentrations generated in an Australian hemp processing facility. Personal sampling, in the breathing zone of exposed workers was undertaken for exposure to respirable dust, along with parallel static sampling for airborne concentrations of inhalable and respirable dust fractions. Both static and personal sampling showed that respirable dust concentrations (mg m-3) exceeded the Australian Institute of Occupational Hygienists (AIOH) recommended maximum exposure limit of 1 mg m-3 (respirable fraction) for dusts not otherwise specified, with mean exposures (mg m-3) of M = 1.33, standard deviation (SD) = 1.09 (range 0.07-3.67 mg m-3) and M = 4.49, SD = 4.49 (range 0.77-11.08 mg m-3). The results of the investigation indicate that workers in the hemp processing industry are at risk of developing permanent and disabling respiratory disease due to high dust exposure. There is no Australian occupational exposure limit specifically for hemp dust. It is recommended further research is needed and industry-specific guidance material or model code of practice developed to effectively control exposures.

In Patients with Mild-to-Moderate COPD, Tobacco Smoking, and Not COPD, Is Associated with a Higher Risk of Cardiovascular Comorbidity.

BackgroundComorbidities including cardiovascular diseases are very common in chronic obstructive pulmonary disease (COPD) secondary to tobacco smoking and contribute to the overall severity of the disease. In non-smoking COPD, which accounts for about 25% of COPD cases worldwide, current knowledge on the frequency and determinants of comorbidities remains scarce. The aims of the current study were to assess the frequency of major comorbidities and to evaluate their determinants in a group of non-selected patients with mild-to-moderate COPD who were exposed to organic dust (dairy farmers), to tobacco smoking, or to both, and in controls without COPD who were exposed to organic dust (dairy farmers), or to tobacco smoking, or to both, or who were without exposure.Patients and MethodsA total of 4665 subjects (2323 dairy farmers and 2342 non-farmers) including 355 patients with COPD and 4310 controls with normal spirometry were recruited through a large COPD screening program. Self-reported physician-diagnosed diseases with plausible links to COPD were recorded in this cross-sectional study.ResultsWhatever the exposure, cardiovascular comorbidities were not more frequent in patients with COPD than their counterparts without airflow limitation. A higher risk of major cardiovascular comorbidities was associated with tobacco smoking and a lower risk was associated with exposure to organic dusts.ConclusionTobacco smoking (but not COPD) is associated with higher frequency of cardiovascular comorbidities. By contrast, being a dairy farmer exposed to organic dusts is associated with a lower frequency of the same comorbidities. This reinforces the crucial need for controlling established cardiovascular risk factors even in patients with mild-to-moderate COPD.