29. The Workplace Performance of an N95 Respirator in a Concrete Block Manufacturing Plant

Bidwell, J.; Janssen, Larry

doi:10.3320/1.2758227

Cited by 11 publications

(23 citation statements)

References 14 publications

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“…Mask efficiencies to various airborne inert particles have been investigated in laboratories as well as under workplace conditions (Nelson et al, 2000;Bidwell and Janssen, 2004;Lee et al, 2005;Kim et al, 2007;Eninger et al, 2008). However, the number of studies regarding natural and engineered nanoparticles is limited.…”

Section: Introductionmentioning

confidence: 99%

Exposure to Manufactured Nanostructured Particles in an Industrial Pilot Plant

Demou

Peter

Hellweg

2008

The Annals of Occupational Hygiene

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Objectives: Nanomaterial production and the number of people directly in contact with these materials are increasing. Yet, little is known on the association between exposure and corresponding risks, such as pulmonary inflammation and oxidative stress.Methods: Condensation Particle Counters, a DustTrakä and Scanning Mobility Particle Sizerä quantified real-time size, mass and number concentrations in a nanostructure particle pilot-scale production facility, using a high-temperature gas-phase process, over a 25-day period. Temporal and spatial analysis of particle concentrations and sizes was performed during production, maintenance and handling. Number-based particle retention of breathing mask filters used under real-time production and exposure conditions in the workplace was quantified.Results: The results demonstrate elevated number concentrations during production, which can be an order of magnitude higher than background levels. Average concentrations during production were 59 100 cm 23 and 0.188 mg m 23 for submicron particles. Mask filters decreased particle number concentrations by >96%.Conclusions: This study demonstrates real-time worker exposure during gas-phase nanoparticle manufacturing. Qualitative and quantitative analysis of emission sources and concentration levels in a production plant is accomplished. These results are important for workers, employers and regulators in the nanotechnology field as they provide information on encountered exposures and possibilities for mitigation measures.

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Section: Introductionmentioning

confidence: 99%

Exposure to Manufactured Nanostructured Particles in an Industrial Pilot Plant

Demou

Peter

Hellweg

2008

The Annals of Occupational Hygiene

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“…In accord with earlier studies, (7) the same sampling probe used for C i sampling was attached to the C o cassette inlet. The C i and C o samples were collected simultaneously with Escort Elf personal sampling pumps (MSA, Pittsburgh, Pa.) at a flow rate of 2 L/min.…”

Section: Sample Collectionmentioning

confidence: 79%

“…(1) All the estimated WPFs in this study were well above the APF of 50 typically assigned to this class of respirator. Previous authors have analyzed WPF values as a function of C o (7,(9)(10)(11) or sought correlation between WPFs and quantitative fit factors (QNFFs). (12)(13)(14)(15) Because all but one of the C i measurements in this study were below the detection limit for lead, it is not meaningful to attempt these analyses.…”

Section: Wpf Resultsmentioning

confidence: 99%

“…was attached directly to the probe outside the facepiece for collection of the C i sample. A cassette heater used in previous studies (6,7) was used to prevent condensation of water vapor from exhaled breath inside the C i sample cassette. The heater bonnet fit snugly over the cassette and contained a coiled heating element powered by a rechargeable Ni-Cd battery.…”

Section: Sample Collectionmentioning

confidence: 99%

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Performance of a Full Facepiece, Air-Purifying Respirator Against Lead Aerosols in a Workplace Environment

Janssen¹,

Bidwell²

2007

Journal of Occupational and Environmental Hygiene

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This study evaluated workplace performance of a full facepiece, negative pressure, air-purifying respirator with P100 filters in a lead refining plant. Air samples for lead were collected inside and outside the respirators worn by workers who were properly trained and quantitatively fit tested. Trained observers assisted in the study to ensure sample validity. Three to four pairs of air samples per day were collected from each worker for a total of 52 valid sample sets. Lead was found on all the outside samples, and concentrations were below the detection limit for all but one of the inside samples. The single measurable inside sample yielded a workplace protection factor (WPF) of 297. WPFs for the rest of the samples were estimated using the assumption that lead was present at the detection limit for the in-facepiece samples. Calculated WPFs were rounded down to the nearest 100 then subjected to a rank and percentile function. The 5th percentile WPF was approximately 900 using this approach. These WPFs exceed the assigned protection factor (APF) of 50 for this respirator class recommended by the National Institute for Occupational Safety and Health and listed by the Occupational Safety and Health Administration. These results support the APF of 50 for this respirator and indicate the respirator provided adequate protection as used in this study.

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“…Several WPF studies (15,29,30) have replaced concentrations less than the detection limit by 50 or 70% of the detection limit. However, this replacement method is known to lead to inaccurate statistics and poor and misleading regression models.…”

Section: Discussionmentioning

confidence: 99%