Mean Particle Concentration Research Articles

Air Cleaners and Respiratory Infections in Schools: A Modeling Study Based on Epidemiologic, Environmental, and Molecular Data.

Using a multiple-measurement approach, we examined the real-world effectiveness of portable HEPA air filtration devices (air cleaners) in a school setting. We collected data over 7 weeks during winter 2022/2023 in 2 Swiss secondary school classes: environmental (CO2, particle concentrations), epidemiologic (absences related to respiratory infections), audio (coughing), and molecular (bioaerosol and saliva samples). Using a crossover design, we compared particle concentrations, coughing, and risk of infection with and without air cleaners. All 38 students participated (age, 13-15 years). With air cleaners, mean particle concentration decreased by 77% (95% credible interval, 63%-86%). There were no differences in CO2 levels. Absences related to respiratory infections were 22 without air cleaners vs 13 with them. Bayesian modeling suggested a reduced risk of infection, with a posterior probability of 91% and a relative risk of 0.73 (95% credible interval, 0.44-1.18). Coughing also tended to be less frequent (posterior probability, 93%), indicating that fewer symptomatic students were in class. Molecular analysis detected mainly non-SARS-CoV-2 viruses in saliva (50/448 positive) but not in bioaerosols (2/105) or on the HEPA filters of the air cleaners (4/160). The molecular detection rate in saliva was similar with and without air cleaners. Spatiotemporal analysis of positive saliva samples identified several likely transmissions. Air cleaners improved air quality and showed potential benefits in reducing respiratory infections. Airborne detection of non-SARS-CoV-2 viruses was rare, suggesting that these viruses may be more difficult to detect in the air. Future studies should examine the importance of close contact and long-range transmission and the cost-effectiveness of using air cleaners.

Indoor Particulate Matter Transfer in CNC Machining Workshop and The Influence of Ventilation Strategies—A Case Study

Particulate matter in Computer Numerical Control (CNC) machining workshop is harmful to workers’ health. This paper studies particulate matter transfer and the performance of various ventilation strategies in a CNC machining workshop. To obtain the boundary condition of the particle field, instruments were installed to obtain the particle size attenuation characteristics and source strength, respectively. The results show that the 99% cumulative mass concentration of particles is distributed within 1.5 μm, and the release rate of particles from the full enclosure. Next, the indoor flow field and particle field were simulated by numerical simulation with the measured boundary conditions. The working area’s age of air, particle concentration, and ventilation efficiency were compared between four displacement ventilation methods and one mixed ventilation method. The results show that the working area’s mean particle concentration and ventilation efficiency under longitudinal displacement ventilation is better than other methods. At the same time, the mean age of air is slightly worse. In addition, mixed ventilation can obtain lower mean age of air, but the particle concentration is higher in the working area. The bilateral longitudinal ventilation can be improved by placing axial circulation fans with vertical upward outlets in the center of the workshop.

Aerosol Concentrations During Otolaryngology Procedures in a Negative Pressure Isolation Room

To evaluate the role of a negative pressure room with a high-efficiency particulate air (HEPA) filtration system on reducing aerosol exposure in common otolaryngology procedures. Prospective quantification of aerosol generation. Tertiary care. The particle concentrations were measured at various times during tracheostomy tube changes with tracheostomy suctioning, nasal endoscopy with suctioning, and fiberoptic laryngoscopy (FOL), which included 5 times per procedurein a negative pressure isolation room with a HEPA filter and additional 5 times in a nonpressure-controlled room without a HEPA filter. The particle concentrations were measured from the baseline, during the procedure, and continued until 30 minutes after the procedure ended. The particle concentrations were compared to the baseline concentrations. The particle concentration significantly increased from the baseline during tracheostomy tube changes (mean difference [MD] 0.80 × 106 p/m3 , p = .01), tracheostomy suctioning (MD 0.78 × 106 p/m3 , p = .004), at 2 minutes (MD 1.29 × 106 p/m3 , p = .01), and 3 minutes (MD 1.3 × 106 p/m3 , p = .004) after suctioning. There were no significant differences in the mean particle concentrations among various time points during nasal endoscopy with suctioning and FOL neither in isolation nor nonpressure-controlled rooms. A negative pressure isolation room with a HEPA filter was revealed to be safe for medical personnel inside and outside the room. Tracheostomy tube change with tracheostomy suctioning required an isolation room because this procedure generated aerosol, while nasal endoscopy with suctioning and FOL did not. Aerosol generated in an isolation room was diminished to the baseline after 4 minutes.

Limited Health Risks in Performing Drug Reconstitution and Handling Tasks in Pharmacies-Results of an Occupational Risk Assessment Study.

Some drugs need processing before they can be administered or dispensed. We measured airborne exposure of pharmacy staff to small particles when performing these tasks. Reconstitution of powdered drugs in vials; crushing, splitting, and counting of tablets; and opening of capsules, using different ventilation strategies, were investigated in five pharmacies after in a worst-case approach. Airborne particulate matter was determined for a range of particles sizes. Mean particle concentrations ranged from not detectable to 1.03 μg/m 3 (<1 μm) and 589.7 μg/m 3 (<10 μm). Dust exhaust made tasks safer. Most hazardous was pouring out tablets from a bulk supply, and least hazardous was reconstitution of a powder for injection. Occupational exposure during routine handling of drugs can occur, but the risks vary greatly with the nature and duration of the tasks.

A precise nanoparticle quantification approach using microfluidics and single-particle tracking

Due to the limited available amounts of components, especially of low water-soluble drugs, formulation development is often impeded by a careful characterization. The use of small batch sizes might solve this problem but requires also adequate analytics. Concentration of nanoparticulate formulations lack straightforward evaluation techniques. In this work, a precise and straight-forward method is established to individually count nanoparticles. A microfluidic chip with known dimensions was used to visualize single particles flowing through the channel (single-particle tracking (SPT)). A sequence of 10,000 images was analyzed to determine the mean particle concentration. The proposed method is independent of the particular flow rate through the microfluidic chip as long as there is no particle overlap and a continuous exchange of particles. Monodisperse Rhodamine B labeled poly (methyl methacrylate) (PMMA) nanoparticles (267.03 ± 9.79 nm) were used as a model and reference particle system for the evaluation process of SPT allowing for a gravimetric determination based on density analysis using analytical ultracentrifugation (AUC) and gas pycnometry. The SPT method was evaluated and compared to other techniques used for concentration measurement. Both approaches (SPT and gravimetry) provide very similar and comparable results indicating the applicability of this novel quantification approach. In contrast, multi angle dynamic light scattering (MADLS) could not yield a precision as good as SPT (number density rel. standard deviation SD nSPT = 11.67%; SD nMADLS = 49.45%). Finally, the measured particle number concentrations can be realized in low concentration ranges (0.8249 μg mL−1 – 0.08249 μg mL−1) not accessible for MADLS (0.08249 mg mL−1 – 0.008249 mg mL−1) and gravimetric analysis.

Exosome miR-3184-5p inhibits gastric cancer growth by targeting XBP1 to regulate the AKT, STAT3, and IRE1 signalling pathways.

MicroRNAs can regulate the transcription of protein-coding genes associated with the development and progression of cancer. In this study, we explored the potential diagnostic function of exosome miR-3184-5p in gastric cancer. This exosome was isolated from the blood samples of 150 patients with gastric cancer and 60 healthy participants. The mean particle size and concentration of serum exosome in the patients with gastric cancer were 104.6 nm (93.97-115.84) and 6.21e+009 particles/ml (5.15e+009-7.12e+009), respectively. miR-3184-5p expression was substantially downregulated in the patients with gastric cancer compared with that in the healthy participants. The gastric cancer cell line HGC-27 was cultured and transfected with the mimic and an inhibitor to overexpress and inhibit miR-3184-5p expression. miR-3184-5p strongly suppressed cell proliferation, migration, and invasion but induced cell apoptosis. Luciferase reporter assay revealed that XBP1 was the target of miR-3184-5p. miR-3184-5p substantially downregulated the expression of CD44, cyclin D1, MMP2, p65, p-AKT, and p-STAT3 but upregulated that of GRP78, IRE1, p-JNK, and CHOP. Moreover, miR-3184-5p cleaved caspase-12 and inhibited BCL-2 expression. These results suggested that the downregulation of miR-3184-5p in patients with gastric cancer might regulate the AKT, STAT3, and IRE1 pathways to promote the vitality of gastric cancer cells.

Aerosol generation during general anesthesia is comparable to coughing: An observational clinical study.

ABSTRACTBackgroundIntubation, laryngoscopy, and extubation are considered highly aerosol‐generating procedures, and additional safety protocols are used during COVID‐19 pandemic in these procedures. However, previous studies are mainly experimental and have neither analyzed staff exposure to aerosol generation in the real‐life operating room environment nor compared the exposure to aerosol concentrations generated during normal patient care. To assess operational staff exposure to potentially infectious particle generation during general anesthesia, we measured particle concentration and size distribution with patients undergoing surgery with Optical Particle Sizer.MethodsA single‐center observative multidisciplinary clinical study in Helsinki University Hospital with 39 adult patients who underwent general anesthesia with tracheal intubation. Mean particle concentrations during different anesthesia procedures were statistically compared with cough control data collected from 37 volunteers to assess the differences in particle generation.ResultsThis study measured 25 preoxygenations, 30 mask ventilations, 28 intubations, and 24 extubations. The highest total aerosol concentration of 1153 particles (p)/cm³ was observed during mask ventilation. Preoxygenations, mask ventilations, and extubations as well as uncomplicated intubations generated mean aerosol concentrations statistically comparable to coughing. It is noteworthy that difficult intubation generated significantly fewer aerosols than either uncomplicated intubation (p = .007) or coughing (p = 0.006).ConclusionsAnesthesia induction generates mainly small (<1 µm) aerosol particles. Based on our results, general anesthesia procedures are not highly aerosol‐generating compared with coughing. Thus, their definition as high‐risk aerosol‐generating procedures should be re‐evaluated due to comparable exposures during normal patient care.Implication StatementThe list of aerosol‐generating procedures guides the use of protective equipments in hospitals. Intubation is listed as a high‐risk aerosol‐generating procedure, however, aerosol generation has not been measured thoroughly. We measured aerosol generation during general anesthesia. None of the general anesthesia procedures generated statistically more aerosols than coughing and thus should not be considered as higher risk compared to normal respiratory activities.

Simulation on air temperature and particle distribution under natural make-up air in indoor environment with a Chinese-style residential kitchen

Kitchen is an important place in Chinese residential building. However, unfavourable thermal environment and unsatisfied air quality occur during cooking. Studies on kitchen environment are experimentally investigated with enough make-up airflow. But mostly normal kitchens are merely installed with a exhaust hood and have not installed air supply system. This work carried out numerical simulation to investigate kitchen indoor environment under natural air make-ups. Air inflow under window fully open, insufficient air inflow from window crack and well-controlled constant inflow volume from window opening are included. Results show that there was a uniform temperature distribution in occupant’s working zone under window open condition. Vertical temperature differences were 4.0 °C under insufficient air make-up. In breathing zone, temperature difference was 6.0 °C and 4.7 °C under uncontrolled and well-controlled airflow, respectively. Mean particle concentration could be largely reduced under controlled and well-organized enough make-up air in kitchen.

Determination of murine norovirus aerosol concentration during toilet flushing

Murine norovirus (MNV) was used as a surrogate for human viral pathogens (e.g., norovirus) to determine if toilet flushing resulted in the aerosolization of virus. A flushometer type toilet was seeded with a viral solution of 105 and 106 PFU mL-1 of MNV and then flushed. Upon flushing, two bioaerosol samplers were activated to collect aerosolized MNV. Prior to the experiment, two optical particle counters monitored particle size and number distribution of aerosol produced from flushing a toilet across height, position, and side. The location with the highest mean particle concentration, was behind the toilet and 0.15 m above the toilet bowl rim, which is where bioaerosol sampling occurred. Bioaerosol and toilet water samples were collected, extracted and then quantified using RT-ddPCR. The concentration of MNV collected after seeding the toilet water ranged from 2.18 × 105 to 9.65 × 106 total copies of MNV. Positive samples of airborne MNV were detected with collected concentrations ranging from 383 to 684 RNA copies/m3 of air. This study provides evidence that viral pathogens may be aerosolized when a toilet is flushed. Furthermore, the MNV used in this study is a model organism for human norovirus and may be generalizable to other viral pathogens (e.g., coronavirus). This study suggests that virus is aerosolized from toilet flushing and may contribute to human exposure to viral pathogens.

High particulate matter burden by cigarillos: A laser spectrometric analysis of second-hand smoke of common brands with and without filter.

Although the global tobacco market of cigarillos is substantial, little is known about their particulate matter (PM) emissions. For exposure risk assessment of cigarillos, the PM fractions PM10, PM2.5, and PM1 of eight cigarillo brands (four with filters) and a reference cigarette were measured. For this purpose, second-hand smoke was generated by an automatic smoke pump in a measuring chamber with a volume of 2.88 m³. The mean particle concentrations of the cigarillos ranged from 2783 μg/m³ to 6686 μg/m³ for PM10, from 2767 μg/m³ to 6585 μg/m³ for PM2.5, and from 2441 to 4680 μg/m³ for PM1. Mean concentrations of the reference cigarette for PM10, PM2.5, and PM1 were 4400 μg/m³, 4335 μg/m³, and 3289 μg/m³, respectively. Filter-tipped cigarillos showed between 5% and 38% lower PM10 and PM2.5 levels, respectively, and between 4% and 30% lower PM1 levels. Our findings show generally high PM emissions for all investigated tobacco products. Therefore, the declaration of PM amounts to government authorities should be mandatory for all tobacco products. Policymakers should ensure that corresponding information will be provided in the future.

Identification of the source events for aerosol generation during oesophago-gastro-duodenoscopy

ObjectiveTo determine if oesophago-gastro-duodenoscopy (OGD) generates increased levels of aerosol in conscious patients and identify the source events.DesignA prospective, environmental aerosol monitoring study, undertaken in an ultraclean environment, on patients...

Quantitative Determination of Local Density of Iron Oxide Nanoparticles Used for Drug Targeting Employing Inverse Magnetomotive Ultrasound.

Numerous medical applications make use of magnetic nanoparticles, which increase the demand for imaging procedures that are capable of visualizing this kind of particle. Magnetomotive ultrasound (MMUS) is an ultrasound-based imaging modality that can detect tissue, which is permeated by magnetic nanoparticles. However, currently, MMUS can only provide a qualitative mapping of the particle density in the particle-loaded tissue. In this contribution, we present an enhanced MMUS procedure, which enables an estimation of the quantitative level of the local nanoparticle concentration in tissue. The introduced modality involves an adjustment of simulated data to measurement data. To generate these simulated data, the physical processes that arise during the MMUS imaging procedure have to be emulated which can be a computing-intensive proceeding. Since this considerable calculation effort may handicap clinical applications, we further present an efficient approach to calculate the decisive physical quantities and a suitable way to adjust these simulated quantities to the measurement data with only moderate computational effort. For this purpose, we use the result data of a conventional MMUS measurement and the knowledge on the magnetic field quantities and on the mechanical parameters describing the biological tissue, namely, the density, the longitudinal wave velocity, and the shear wave velocity. Experiments on tissue-mimicking phantoms demonstrate that the presented technique can indeed be utilized to determine the local nanoparticle concentration in tissue quantitatively in the correct order of magnitude. By investigating test phantoms of simple geometry, the mean particle concentration of the particle-laden area could be determined with less than 22% deviation to the nominal value.

Granular mixture deflation and generation of pore fluid pressure at the impact zone of a pyroclastic fountain: Experimental insights

We present the results of analogue laboratory experiments on pyroclastic fountain collapse. Mixtures of air and glass beads ranging in size around 75 ± 15 μm, with Stokes number of ~10−3−101 and representative of 0.1–1 mm sized particles in nature, were released from a hopper at heights of 0.45–2.95 m above the base of a horizontal channel. Free fall caused continuous dilation of the granular material and led to mean particle concentrations of ~9–36 vol%, with concentration inversely proportional to drop height, before the particles impacted the channel base. Decoupling between the particles and the ambient air upon impact caused deflation of the mixture, which then propagated laterally as a dense granular flow overridden by a dilute suspension. Measurements at the impingement surface revealed that pore fluid pressure, generated through high air-particle relative velocity during deflation, counterbalanced up to ~50% of the weight of the emerging granular flow. The runout distance of the dense flow increased linearly with the fall height, similar to published results on unidirectional flows generated from collapse of packed granular columns. This suggests that the runout of flows resulting from release of granular material is controlled essentially by conversion of potential to kinetic energy and that the initial particle concentration is a second order parameter. We conclude that fountaining of pyroclastic material containing large amounts of particles with Stokes numbers of the order 10−3−101 can generate dense pyroclastic flows with some degree of pore fluid pressure.

Aerosolisation in endonasal endoscopic pituitary surgery.

PurposeTo determine the particle size, concentration, airborne duration and spread during endoscopic endonasal pituitary surgery in actual patients in a theatre setting.MethodsThis observational study recruited a convenience sample of three patients. Procedures were performed in a positive pressure operating room. Particle image velocimetry and spectrometry with air sampling were used for aerosol detection.ResultsIntubation and extubation generated small particles (< 5 µm) in mean concentrations 12 times greater than background noise (p < 0.001). The mean particle concentrations during endonasal access were 4.5 times greater than background (p = 0.01). Particles were typically large (> 75 µm), remained airborne for up to 10 s and travelled up to 1.1 m. Use of a microdebrider generated mean aerosol concentrations 18 times above baseline (p = 0.005). High-speed drilling did not produce aerosols greater than baseline. Pituitary tumour resection generated mean aerosol concentrations less than background (p = 0.18). Surgical drape removal generated small and large particles in mean concentrations 6.4 times greater than background (p < 0.001).ConclusionIntubation and extubation generate large amounts of small particles that remain suspended in air for long durations and disperse through theatre. Endonasal access and pituitary tumour resection generate smaller concentrations of larger particles which are airborne for shorter periods and travel shorter distances.

Determination of the mean velocity of mudflows (debris flows) taking into account their life cycle

The paper is about calculation of the mean velocity of the mudflows. A mudflow is unsteady, non-uniform two-phase flows with high concentration of solid particles. Basic characteristics (depth, width, particle mean concentration and diameter) of a mudflow change in wide range (in time and in space), thus should be considered as a dynamic system. Existing empirical formulas for the mean velocity not for its. However, the principle of calculating the mean velocity must change for each phase of the lifecycle. Comparison of the calculated formulas and search for the closest ones to the measured also discussed. We give recommendations for calculating mean velocity of mudflows at any time during its moving.

Quantification of Aerosol Concentrations During Endonasal Instrumentation in the Clinic Setting.

ObjectiveRecent anecdotal reports and cadaveric simulations have described aerosol generation during endonasal instrumentation, highlighting a possible risk for transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) during endoscopic endonasal instrumentation. This study aims to provide a greater understanding of particle generation and exposure risk during endoscopic endonasal instrumentation.Study DesignProspective quantification of aerosol generation during office‐based nasal endoscopy procedures.MethodsUsing an optical particle sizer, airborne particles concentrations 0.3 to 10 microns in diameter, were measured during 30 nasal endoscopies in the clinic setting. Measurements were taken at time points throughout diagnostic and debridement endoscopies and compared to preprocedure and empty room particle concentrations.ResultsNo significant change in airborne particle concentrations was measured during diagnostic nasal endoscopies in patients without the need for debridement. However, significant increases in mean particle concentration compared to preprocedure levels were measured during cold instrumentation at 2,462 particles/foot3 (95% CI 837 to 4,088; P = .005) and during suction use at 2,973 particle/foot3 (95% CI 1,419 to 4,529; P = .001). In total, 99.2% of all measured particles were ≤1 μm in diameter.ConclusionWhen measured with an optical particle sizer, diagnostic nasal endoscopy with a rigid endoscope is not associated with increased particle aerosolization in patient for whom sinonasal debridement is not needed. In patients needing sinonasal debridement, endonasal cold and suction instrumentation were associated with increased particle aerosolization, with a trend observed during endoscope use prior to tissue manipulation. Endonasal debridement may potentially pose a higher risk for aerosolization and SARS‐CoV‐2 transmission. Appropriate personal protective equipment use and patient screening are recommended for all office‐based endonasal procedures.Level of Evidence3 Laryngoscope, 131:E1415–E1421, 2021

Measurement of velocity and concentration profiles of pneumatically conveyed particles in a square-shaped pipe using electrostatic sensor arrays

Cross-sectional measurement of particle velocity and concentration in a pneumatic conveying pipe is desirable for the characterisation of particle flow dynamics and determination of particle mass flow rate. In this study, an inner-inserted electrostatic sensor array consisting of nine pairs of electrodes is implemented to measure the cross-sectional velocity and concentration profiling of particles over the whole cross section in a square-shaped pipe. Experimental tests were conducted on both vertical and horizontal pipe sections on a test rig under dilute conditions with different air velocities and particle mass flow rates. Test results show that the slope-shaped particle concentration profile changes to an arch-shaped one when the particles flow from a horizontal pipe to a vertical one. The particle velocity profile is arch-shaped in both vertical and horizontal pipes. A comparative study of cross-sectional mean particle velocity and concentration measured by the developed electrostatic sensor arrays is conducted.

Experimental Analysis of a Particle Separator Design With Full-Field Three-Dimensional Measurements

Abstract Particle ingestion into turbine engines can cause significant damage through deposition in internal cooling passages. Musgrove et al. proposed a compact particle separator installed between the combustor bypass exit and turbine vane cooling passage inlet. The design had small pressure losses but provided limited particle separation. Its performance has proved difficult to replicate. Borup et al. recently developed a magnetic resonance imaging (MRI)-based technique for full-field, 3D measurements of the mean particle concentration distribution in complex flows. A particle separator based on the Musgrove et al. design was fabricated out of plastic using 3D printing, with the addition of a drain from the collector through which 3% of the total flow was extracted. The separator efficiency was measured at two Reynolds numbers, using water as the working fluid and 33-μm titanium microspheres to represent dust particles. Stokes number was shown to play the dominant role in determining efficiency across studies. MRI was used to obtain the 3D particle volume fraction and three-component velocity fields. The velocity data showed that flow was poorly distributed between the separator louvers, while the collector flow followed the optimal pattern for particle retention. The MRI data revealed that strong swirling flow in the collector centrifuged particles toward the outer wall of the collector and into a partitioned region of quiescent flow, where they proceeded to exit the collector. Future designs could be improved by re-arranging the louvers to produce a more uniform flow distribution, while maintaining the effective collector design.

Cyclists' exposure to air pollution: in situ evaluation with a cargo bike platform.

Cyclists' exposure to air pollutants near roadways has been associated with numerous health effects. While the adverse health effects concerning aerosols have traditionally been assessed with data of particle mass concentrations, it appears that the number concentration is also another important indicator of toxicity. Thus, to holistically evaluate one's exposure to aerosol particles, assessments should be based on mass concentrations and number concentrations. In order to assess individual cyclists' exposure as they move through space and time, spatiotemporal high-resolution approaches are needed. Therefore, a mobile, fast-response monitoring platform was developed that uses a cargo bicycle as a base. Data of particle mass concentrations (PM1, PM2.5, PM10) and particle number concentrations (PN10) were collected along two different routes, one characterized by high-intensity vehicle traffic and one by low-intensity vehicle traffic. While high spatiotemporal heterogeneity was observed for all measured quantities, the PN10 concentrations fluctuated the most. High concentrations of PN10 could be clearly associated with vehicle traffic. For PM2.5, this relation was less pronounced. Mean particle concentrations of all measures were significantly higher along the high-traffic route. Comparing route exposures, the inhalation of PM2.5 was similar between both routes, whereas along the high-traffic route, cyclists were exposed to twice the particle number. We conclude that the cargo bike, featuring high-frequency mobile measurements, was useful to characterize the spatial distribution of mass concentrations and number concentrations across an urban environment. Overall, our results suggest that the choice of route is a key factor in reducing cyclists' exposure to air pollution.

Occupational monitoring and health risks assessment of respiratory exposure to dust in an industrial unit of producing China Clay

Introduction: The respiratory system, as one of the most important organs of the human body is affected by adverse health effects and consequences of particulate matter. The main purpose of recent study was to determine the occupational exposure to workers to crystalline silica and inhalable dust and determine its health risks. Methods: In this analytical cross-sectional study, sampling was performed in an industrial unit producing China Clay based on standard methods and individual and environmental sampling methods. Then the obtained data analyzed by SPSS software version 22 .The risk assessment of occupational exposure of workers to crystalline silica was carried out based on the proposed EPA procedure. Results: The average exposure of workers to inhalable dust and crystalline silica was measured 4.46±1.34 mg/m3 and 0.57±0.10 mg/m3, respectively. The mean environmental concentration of the inhalable particles was 6177.71 µg/m3 (range: 4088.30- 8289.70 µg/m3). In all occupational groups the risk of cancer was obtained less than 10-6. Hazard quotient (HQ) values ​​for operator one (5.34) and two (4.79) crusher machine, crusher machine loading operator (8.49), dryer operator (1.91), slurry operator (3.01) and filter press operator (1.78) was more than permissible limit. Conclusion: The average concentration of inhalable dust and crystalline silica was more than permissible limit in this industry. According to the results of the risk assessment, the priority of serious control actions is necessary to reduce the risk of non-cancerous complications in the crushing, drilling, slurry and filter press occupational groups.