The radiation properties of burning clouds of metal dust. 3. Modification of the emission spectrum

In this work we studied the emission spectra of the combustion products of low-volume dust clouds (V = 5 L) from aluminum (ASD-4), as well as clouds from mixed compositions of aluminum with inorganic powdery oxidizing agents (NaNO3, NaCl, Na2CO3·10H2O, Sr(NO3)2, Ba(NO3)2, KNO3, CuSO4, CuSO4·10H2O) and combustible (B, AlB2, Cu). This article discusses the possibilities of purposeful modification of the emission spectrum of the base composition using various inert and optically active dispersed additives that shift the maximum of the emission spectrum of the fuel composition to the region of longer waves or cause a local change in the emission spectrum in the corresponding spectral regions. In the course of the experiments, it was revealed that the introduction of additives into the basic composition of dispersed fuel does not significantly change the dynamic characteristics of the suspension. However, the additives lead to a decrease in temperature (by about 100–200°K in the presence of an additive up to 25% by weight) and to a corresponding shift in the maximum of the radiation spectrum. The possibility of a significant local modification of the spectrum in the yellow region with the help of inorganic additives to the fuel of sodium salts with a low decomposition temperature (additives Na2CO3·10H2O) was shown experimentally. Boron additives and boron compounds (B, AlB2) leads to a significant increase in the luminosity of the flame in the green region of the spectrum with a maximum radiation in the range Δλ = 530 ÷ 580 nm. The article presents the lighting characteristics (luminous intensity, light sum) of large clouds (V ≥ 10 m3) of mixed compositions based on PAP-2 aluminum powder. It was found that the introduction of inorganic additives to the base fuel does not lead to a noticeable change in the lighting characteristics, but somewhat increases the time of the cloud glow both in the visible and infrared parts of the spectrum.

Effects of Occupational Hazards on Pulmonary Health among Lathe Machine Workers: A Cross-Sectional Study in Tangail, Bangladesh

Background: Occupational exposure to metal dust particles leads to irritation and initiation of inflammatory responses in the respiratory system that subsequently onsets lung diseases. Lathe machine workers have a greater risk of having lung diseases due to continuously conducting metal dust particles. This study aimed to explore the pulmonary health status of lathe machine workers. Methods: In this cross-sectional study, 80 individuals (lathe workers) were adopted from a different area of the Tangail district in Bangladesh. A questionnaire’s survey was accomplished along with oximetry and spirometry. After that, blood was drawn for measuring Erythrocyte Sedimentation Rate (ESR), C-reactive protein (CRP), and Immunoglobulin E (IgE) test to the lung function abnormalities. Results: Among 80 lathe machine workers, 12% had breathing problems, 13.8% had coughing, 16.2% had to sneeze and 8.7% had a chest. In addition, spirometry results including, FVC, FEV1, FEV1%, PEF, PEF%, FEF25, FEF75, and FEF2575 were significantly lower in lathe workers compared to control. Moreover, higher levels of IgE (264.93±141) and ESR (11.5±4.77) were reported in lathe machine workers than in the control group. Not using protective masks and smoking were considered as risk factors for having respiratory diseases in lathe machine workers. Conclusion: This study concludes that exposure to metal dust particles can cause respiratory disease symptoms and lower pulmonary function in lathe machine workers. Furthermore, metal dust might also augment the blood IgE and ESR level.

Exposure to inorganic particles in paediatric sarcoidosis: the PEDIASARC study

Inorganic antigens may contribute to paediatric sarcoidosis. Thirty-six patients matched with 36 healthy controls as well as a group of 21 sickle-cell disease (SCD) controls answered an environmental questionnaire. Patients’ indirect exposure to inorganic particles, through coresidents’ occupations, was higher than in healthy and SCD controls (median score: 2.5 (0.5–7) vs 0.5 (0–2), p=0.003 and 1 (0–2), p=0.012, respectively), especially for construction, exposures to metal dust, talc, abrasive reagents and scouring products. Wood or fossil energies heating were also linked to paediatric sarcoidosis. This study supports a link between mineral environmental exposure due to adult coresident occupations and paediatric sarcoidosis.

Analysis of deposition of heavy metal dust on the leaves of few selected tree species in Kanchipuram town, Tamil Nadu, India

Biomonitoring of heavy metals is one of the economic methods to identify and improve the quality of air. The aim of this work was to identify the concentration of nine heavy metals viz. Fe, Pb, Cu, Zn, Al, Cd, As, Cr and Mn in the ambient air deposited on the leaves of five tree species such as Saraca asoca, Terminalia catappa, Syzygium cumini, Ficus religiosa and Pongamia glabra collected from six sites such as Pallavarmedu (Site I), CSI hospital (Site II), Moongilmandapam (Site III), Collectrate (Site IV), Near Cancer Institute (Site V) and VellaGate (Site VI) of the Kanchipuram town of TamilNadu State, in the months of February - March 2019. Even with some differences in the concentration of nine heavy metals on the species, few were identified with significant correlation, suggesting that these pollutants were emitted from similar sources. The deposition of iron (235.53mg/kg) and aluminium (157.91mg/kg) were higher on the leaves of S.asoca compared with other species. The metals such as Cu, Cd, As, Pb and Cr were nil and not detected on the leaves, but Pb concentration was high (185.79 mg/kg) only on P. glabra at Site 2 and Cr (2.37 mg/kg) was found on the leaves of S. asoca at Site 1. The heavy metal dust deposited on the leaf surface was probably due to vehicular emission and other anthropogenic activities. The analysis showed that all the selected tree species acted as a biomonitor and should be grown that may help to improve the air quality of the area.

Experimental studies of the properties of metal dust

Introduction. The issues of ensuring the environmental safety of metalworking industries are still very relevant. Moreover, the primary role in these issues is played by the protection of atmospheric air from the emissions of industrial enterprises in this industry. For the successful implementation of measures aimed at ensuring the environmental safety of atmospheric air, it is important to study in detail the composition and properties of the emission components. Problem Statement. The aim of the study is to analyze the entire range of modern methods for measuring the parameters of the properties of metal dust, as the main component of emissions from metalworking industries; to select the method of experimental research; to conduct a dispersion analysis of metal dust particles. Theoretical Part. As a rule, the productivity of experimental studies of the parameters of the properties of pollutants largely depends on the methods that were used in the performance of the work. To solve these problems, the authors have analyzed modern methods for measuring the parameters of the properties of metal dust. The choice is made according to the basic principles: relativity, relevance, completeness, labor intensity. The conditions for the final results of the research, their accuracy and reliability, the conditions for the terms, resources, technical means of research used, and the positive and negative aspects of each of the methods under consideration are also taken into account. Conclusion. The article presents the result of the choice of the research method and the results of experimental studies of the properties of metal dust.

Occupational and environmental risk factors of idiopathic pulmonary fibrosis: a systematic review and meta-analyses

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung disease of unknown cause. It has a high risk of rapid progression and mortality. We conducted a systematic review and meta-analysis to evaluate the risk factor of IPF. We searched Medline, Embase, and the Cochrane library from the earliest record to March, 2020. Case–control studies on occupational and environmental risk factors or on jobs with a risk of IPF were searched for. From 2490 relevant records, 12 studies were included. Any occupational or environmental exposure to metal dust (OR 1.83, 95% CI 1.15–2.91, I2 = 54%), wood dust (OR 1.62 5% CI 1.04–2.53, I2 = 5%) and pesticide (OR 2.07, 95% CI 1.24–3.45, I2 = 0%) were associated with an increased risk of IPF. Farming or agricultural work (OR 1.88, 95% CI 1.17–3.04, I2 = 67%) was also associated with an increased risk of IPF. Moreover, smoking increased IPF risk with an odds ratio of 1.39 (95% CI 1.01–1.91, I2 = 29%). In conclusion, metal dust, wood dust, pesticide, occupational history of farming or agriculture and ever smoking increased the risk of IPF.