Health and safety in welding and allied processes. Sampling of airborne particles and gases in the operator's breathing zone

2000 ◽  
Keyword(s):  
Health And Safety ◽  
Airborne Particles ◽  
Breathing Zone

scholarly journals Characterization of Airborne Particles Emitted During Application of Cosmetic Talc Products

2019 ◽  
Vol 16 (20) ◽  
pp. 3830 ◽  
Author(s):  
Pat Rasmussen ◽  
Christine Levesque ◽  
Jianjun Niu ◽  
Howard Gardner ◽  
Gregory Nilsson ◽  
...  
Keyword(s):  
Particle Size ◽  
Consumer Products ◽  
Airborne Particles ◽  
Aerodynamic Diameter ◽  
Breathing Zone ◽  
Direct Reading ◽  
Detailed Characterization ◽  
Adult Body ◽  
Reading Instruments

A pilot study was undertaken to characterize the concentration, duration and particle size distribution of the talc cloud that forms in the personal breathing zone (PBZ) during application of certain talc-containing cosmetics. Multiple direct-reading instruments were employed to simultaneously monitor PM4 concentrations (particulate matter with aerodynamic diameter < 4 µm; mg/m3) at different distances from each of three subjects while they applied talc products. Results indicated that the purpose and method of applying the talc product, combined with behavioral and physical differences amongst subjects, all strongly influenced airborne talc concentrations and the duration of the cloud. Air concentrations of talc in the PBZ averaged around 1.0 mg/m3, and the duration of exposure varied from less than one minute to more than ten minutes. The real-time monitors captured the occasional formation of secondary clouds, likely caused by resuspension of talc particles from skin or other surfaces. Measurements of aerosolized baby powder, face powder, and two adult body powders indicated that the median aerodynamic diameter of the talc cloud ranged from 1.7 to 2.0 µm. These direct-reading approaches were valuable for providing detailed characterization of short duration exposures to airborne talc particles, and will be useful to support future exposure assessments of talc and other powders in consumer products.

scholarly journals Assessment of Fabric Masks as Alternatives to Standard Surgical Masks in Terms of Particle Filtration Efficiency

2020 ◽  
Author(s):  
Amy Mueller ◽  
Loretta Fernandez
Keyword(s):  
Health Care Providers ◽  
Ambient Air ◽  
Filtration Efficiency ◽  
Airborne Particles ◽  
Particle Removal ◽  
Breathing Zone ◽  
Care Providers ◽  
Particle Filtration ◽  
Surgical Masks ◽  
Mask Design

AbstractIn response to the critical shortage of medical masks resulting from the COVID-19 pandemic, large portions of the population are mobilizing to produce cloth masks using locally-sourced fabrics, however the efficacy of these masks as a means of protecting the wearer from airborne particles carrying virus is not well known. Further, existing protocols are designed for testing the fit and performance N95 respirators and tight-fitting facemasks rather than the relatively more loose-fitting surgical mask style most cloth masks follow. In this study tools and methods typically used to assess tight-fitting facemasks were modified to assess the efficacy of community-produced fabric and commercially-produced surgical masks in terms of protecting the wearer from airborne particles that may be carrying virus. Two TSI PortaCount (model 8028) instruments were operated concurrently to collect particle counts (particles/cm3) in size range 0.02 to >1 µm from ambient air and air just inside the breathing zone of the mask (1 measurement per second, evaluation period of 1 minute per test). Percent particle removal was determined for ten home-made, fabric masks of different designs, with and without filter layers, as well as three commercially-produced surgical-type masks. N95 masks were used to validate the method, and a 3M model 1826 surgical mask was used as a baseline for comparison of other masks of this style. Home-made masks worn as designed always had lower particle removal rates than the 3M masks, achieving between 38% and 96% of this baseline. As has been previously observed by Cooper et al. (1983), adding a layer of nylon stocking over the masks minimized the flow of air around the edges of the masks and improved particle filtration efficiency for all masks, including all commercial products tested. Use of a nylon stocking overlayer brought the particle filtration efficiency for five of the ten fabric masks above the 3M surgical mask baseline. This rapid testing method (<2 hours per mask design) provides a holistic evaluation of mask particle removal efficacy (material, design, and fit), and use of this method for testing a wider range of mask materials and designs will provide the public and health care providers with information needed to optimize health protection given resources at hand.

Identifying groups of airborne particles by ordination

1994 ◽  
Vol 52 ◽  
pp. 856-857
Author(s):  
M. Shlepr ◽  
C. M. Vicroy
Keyword(s):  
Elemental Analysis ◽  
Energy Dispersive Spectroscopy ◽  
Manufacturing Process ◽  
Spatial Representation ◽  
Airborne Particles ◽  
Common Source ◽  
Data Set ◽  
Microelectronics Industry ◽  
Induced Changes ◽  
Source Materials

The microelectronics industry is heavily tasked with minimizing contaminates at all steps of the manufacturing process. Particles are generated by physical and/or chemical fragmentation from a mothersource. The tools and macrovolumes of chemicals used for processing, the environment surrounding the process, and the circuits themselves are all potential particle sources. A first step in eliminating these contaminants is to identify their source. Elemental analysis of the particles often proves useful toward this goal, and energy dispersive spectroscopy (EDS) is a commonly used technique. However, the large variety of source materials and process induced changes in the particles often make it difficult to discern if the particles are from a common source.Ordination is commonly used in ecology to understand community relationships. This technique usespair-wise measures of similarity. Separation of the data set is based on discrimination functions. Theend product is a spatial representation of the data with the distance between points equaling the degree of dissimilarity.

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