Background and Objective: Inhalation of crystalline silica particles in the workplace can lead to occupational diseases, such as silicosis. This study aims to evaluate and compare airborne concentrations of crystalline silica and respirable dust in the refractory brick industries in Isfahan province. Materials and Methods: In this cross-sectional study, the airborne concentrations of crystalline silica and respirable dust were measured among 79 workers from large industries and 30 workers from small refractory brick industries over a three-year period. Personal sampling was conducted using individual sampling pumps and cyclones. Data analysis was performed in SPSS 24 software using the Mann-Whitney U and Kruskal-Wallis tests. Results: The results indicated that 65.1% of the samples exceeded the occupational exposure limits, while 34.9% were below the limits. There was no significant difference in the mean three-year airborne crystalline silica concentration between the two occupational groups (P=0.791). However, a significant difference was observed in the mean airborne respirable dust concentrations between the groups (P=0.002). Conclusion: The findings of this study suggest that the implementation of safety, health, and environmental management systems has effectively reduced airborne crystalline silica and respirable dust concentrations, creating a safer work environment for employees.

Background and Objective: Due to the presence of many workshops related to the production of industrial silica in Hamadan province, the workers in these units are constantly exposed to the risks of inhaling crystalline silica dust. Therefore, the present study aimed to investigate the epidemiological characteristics of patients with silicosis in Hamadan province in Iran. Materials and Methods: An observational cross-sectional study was conducted on 25 patients with silicosis between 2011 and 2021. The study examined the files of all silicosis patients hospitalized in Hamadan hospitals. In this work, the data collection tool included a researcher-made checklist containing eight question sections. Results: According to the results obtained, among 25 patients examined, 4, 4, 5, 6, and 2 were mine workers, stone cutters, stone crushers, glass and silica factory workers, and well diggers, respectively. In addition, 52% of silicosis patients were suffering from cardiovascular diseases, and 20% of the silicosis patients had kidney failure. Conclusion: The results of the present study indicated that people working in silica mines and workhouses are at a higher risk of contracting irreversible silica disease, which highlights the importance of annual and periodic monitoring of exposure to free crystalline silica in their occupations, as well as to control and reduce exposure through the installation of dust control devices. Moreover, in some cases, simple humidification methods and the careful use of personal protective equipment are recommended.

Introduction: Occupational exposure to crystalline silica increases the risk of lung cancer and restrictive lung disease with extensive fibrosis. Silica dust is a major health hazard in foundry factories. The aim of this study was to determine core making workers’ exposure to respirable crystalline silica dust in a foundry factory.Material and Method: This cross-sectional study was conducted in core-making unit of a foundry factory in 2015. Occupational exposure of 55 workers to respirable crystalline silica aerosols was evaluated by using the improved NIOSH7602 method in core-making unit. Risk assessments for silicosis and excess lifetime risk of mortality from lung cancer were done according to Manettej and Rice models, respectively. Data was analyzed with Spss19 software.Result: The mean of respirable crystalline silica dust was 0.246±0.351 (mg/m3). All workers’ exposure to respirable crystalline silica was higher than recommended occupational exposure limits. Silicosis mortality risk and excess lifetime risk of mortality from lung cancer were estimated in the range of 6-63 and 65 per thousand people, respectively.Conclusion: The mean of workers’ exposure to respirable crystalline silica was higher than recommended occupational exposure standards in core making unit. The risk assessment of silicosis mortality and excess lifetime risk of mortality from lung cancer were higher than acceptable levels of risk.

Background: The term "crystalline silica" refers to crystallized form of SiO2 and quartz, as the most abundant compound on the earth’ s crust; it is capable of causing silicosis and lung cancer upon inhaling large doses in the course of occupational exposure. The aim of this study was to assess occupational exposure to dust and crystalline silica in foundries in Pakdasht, Iran. Materials and Methods: In this study, airborne dust samples were collected on PVC filters (37 mm diameter, 0. 8 mm pore size), by using a sampling pump and open face cyclone at a flow rate of 2. 2 l/min for a maximum volume of 800 liters. For determining crystalline silica spectrometry was used according to the National Institute of Occupational Safety and Health (NIOSH) method No. 7601 for analysis of samples. Results: Results showed that crystalline silica concentration was higher than NIOSH and the American Conference of Government Industrial Hygienist (ACGIH) allowed extent (0. 025 mg/m3). Concentration of crystalline silica was 0. 02-0. 1 mg/m3. Total dust concentration average was higher than the allowed extent by Permissible Exposure Limit (PEL) of the Occupational Safety and Health Administration (OSHA). Conclusion: It is essential to take necessary measures to control crystalline silica dust regarding the fact that 50% of workers are exposed to higher than the allowed extent.

Introduction: Silicosis is an occupational lung condition that can lead to permanent physical disability, primarily due to inflammation, scarring of lung tissue, and breathing difficulties. In regions with high rates of tuberculosis (TB), such as South Asia, the presence of TB accelerates the development of pulmonary fibrosis. Additionally, smoking significantly increases the likelihood of further lung damage. Case Presentation: This case report presents a 65-year-old gentleman who presented to the Department of Pulmonology, Bahawal Victoria Hospital, Bahawalpur, with exertional shortness of breath for 6 months, which worsened in the last month to the extent that he experienced dyspnea at rest. This was associated with a productive cough and yellowish sputum for 3 weeks. He had a past history of pulmonary TB 4 years ago and was an active smoker with a 30-pack-year history. He had worked in a stone-crushing factory for the last 35 years but was unable to work in the last few months due to his illness. His chest X-ray and high-resolution computed tomography (HRCT) demonstrated loss of lung volume bilaterally, diffuse nodularity with ground-glass opacifications, bulky hilum, and a left upper lobe fibro-cavitary lesion. Sputum examination was positive for acid-fast bacilli (AFB) stain, and GeneXpert MTB/RIF PCR confirmed the presence of Mycobacterium TB but showed no drug resistance. Based on clinical and radiographic findings, he was diagnosed with active pulmonary TB (relapse) with underlying chronic silicosis by the pulmonology team and managed with supportive oxygen inhalation therapy, category II anti-TB therapy, smoking cessation counseling, and occupational rehabilitation. Conclusions: This case underscores the significance of coexisting silicosis and TB, especially in individuals with a significant smoking history and occupational exposure to silica. This report emphasizes the importance of early detection, multidisciplinary management, and comprehensive treatment strategies, including anti-TB therapy, smoking cessation counseling, and occupational rehabilitation, to improve patient outcomes in complex cases with overlapping lung diseases.

Background and Objectives: The dust raised in construction activities is one of the most important occupational hazard for health of construction workers. Due to the nature of the raw materials used, dust contains crystalline silica, which is classified as a confirmed human carcinogen. Due to the lack of personal monitoring of construction workers in Iran, this study was designed to evaluate occupational exposure to the general dust and its component crystalline silica.Materials and Methods: In this cross-sectional study, occupational exposure of 85 construction workers was evaluated. Workers were monitored for respirable general dust and crystalline silica using methods issued by the National Institute of Occupational Safety and Health (No.0600 and No.7602). Risk assessments in the form of excess mortality rate due to silicosis and lung cancer based on the models presented by Rice and Manettej were calculated.Results: The mean exposure of workers to general respirable dust and respirable crystalline silica dust were 9.8±0.35 and 0.13±0.019 as mg/m3 respectively. Workers’ exposure in various task groups had statically significant differences in exposures to respirable dust (P<0.001) and respirable crystalline silica (P=0.007). Task groups batching and concrete workers had the highest average exposure to general respirable dust (11.38±0.77 mg/m3). Cement workers had highest mean exposure to respirable crystalline silica dust (0.184±0.07 mg/m3). Construction workers’ risk for Mortality rate of silicosis and lung cancer were predicted to be in range of 1-40 and 49-21 per thousand respectively.Conclusion: Due to the high exposure and unacceptable risk assessment of Iranian construction workers to respirable crystalline silica and respirable general dusts, administrative and technical control measures are justified.

Introduction: Azandarian industrial zone with about 40 active silica crushing units is one of the largest industrial area in Hamadan province, Iran. Materials and methods: In this study, the personal exposure of workers in the activated silica crushing units was measured. Assessing the risk of mortality due to exposure to Respirable Crystalline Silica (RCS) in the workplace was then estimated through measuring the personnel exposure in accordance with the National Institute for Occupational Safety and Health (NIOSH) 7601 method. Moreover, the mortality rate of lung cancer and risk of mortality due to exposure to RCS were estimated. Results: Based on the results, the average exposure of employees to RCS in the crushing units was in the range of 1. 70-0. 14 mg/m 3. As observed, the lowest and highest exposure was obtained for the admission unit and sandstone, respectively. In general, it can be inferred that in all studied occupation positions, the exposure level was higher than the recommended standard (0. 25 mg/m 3 ). As can be seen, the carcinogenic risk level for the exposed workers was in the range 2-26/1000. The results of risk assessment showed that the highest risk level was related to the stamping machine operator unit and the lowest was related to the administrative unit. Conclusion: Therefore, the workers working in high-risk units such as stamping machine operator and stone separation operator are more likely to suffer from adverse health complications such as silicosis, lung cancer and other respiratory complications.

Background and Objectives: Cyclone is one of the most utilized dust collectors for airborne particles control. It separates particles from airflow by centrifugal force. However, it is not effective in collecting very fine particles smaller than 10mm in diameter. The aim of this study was to assess the performance of charging particles on cyclone efficiency in collecting particles smaller than 1mm.Materials and Methods: To achieve the above aim, a pilot air conditioning system equipped with conventional cyclone of Lapple model was designed and installed. A high voltage (18 KV) DC power supply was used for charging silica particle in corona charger. Isokinetic probe was used for particles sampling at upstream and downstream of cyclone under different study conditions and measurement was carried out using Grimm 1.08 dust counter.Results: Charging fine airborne silica particles caused a significant increase in collection efficiency. There is a direct relationship between collection efficiency and charging voltage, so that the total particles collection efficiency was increased from 2.7 to about 72% with respect of increasing charging voltage from zero to 18 Kv. However, inlet air velocity has a negative effect on the collection efficiency of particles charged.Conclusion: Applying electrocyclone in collecting fine particles smaller than 1 μm is more efficient compared with that of conventional cyclones.