Workplace Evaluation of a Disposable Respirator in a Dusty Environment

Reed, Laurence D.; Lenhart, Steven W.; Stephenson, R.L.; Allender, Joan

doi:10.1080/08828032.1987.10389249

Cited by 10 publications

(7 citation statements)

References 5 publications

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“…( 27 ) The average penetration factor from a 1987 workplace study involving fit‐tested respirators is ≈0.1. ( 28 ) However, it may not be practical to fit‐test everyone in the event of an influenza pandemic. Two more recent studies that test a variety of respirators find large variations across respirator models in their face‐seal leakage in the absence of fit‐testing.…”

Section: Resultsmentioning

confidence: 99%

Assessing Infection Control Measures for Pandemic Influenza

Wein

Atkinson

2009

Risk Analysis

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We construct a mathematical model of aerosol (i.e., droplet-nuclei) transmission of influenza within a household containing one infected and embed it into an epidemic households model in which infecteds occasionally infect someone from another household; in a companion paper, we argue that the contribution from contact transmission is trivial for influenza and the contribution from droplet transmission is likely to be small. Our model predicts that the key infection control measure is the use of N95 respirators, and that the combination of respirators, humidifiers, and ventilation reduces the threshold parameter (which dictates whether or not an epidemic breaks out) by approximately 20% if 70% of households comply, and by approximately 40% if 70% of households and workplaces comply (approximately 28% reduction would have been required to control the 1918 pandemic). However, only approximately 30% of the benefits in the household are achieved if these interventions are used only after the infected develops symptoms. It is also important for people to sleep in separate bedrooms throughout the pandemic, space permitting. Surgical masks with a device (e.g., nylon hosiery) to reduce face-seal leakage are a reasonable alternative to N95 respirators if the latter are in short supply.

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Section: Resultsmentioning

confidence: 99%

Assessing Infection Control Measures for Pandemic Influenza

Wein

Atkinson

2009

Risk Analysis

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“…(24) Twenty-two sample pairs of approximately four-hour durations were collected inside and outside of respirators during this study, and a 5th percentile protection factor of 3 was calculated.…”

Section: Discussionmentioning

confidence: 99%

Manganese Dioxide Exposures and Respirator Performance at an Alkaline Battery Plant

Hanley

Lenhart²

2000

Applied Occupational and Environmental Hygiene

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Two industrial hygiene studies were conducted at an alkaline battery plant to evaluate worker exposures to manganese dioxide particulate and the effectiveness of filtering facepiece respirators. The work areas studied included the plant's powder-processing tower and press rooms where manganese was blended, compacted with graphite, and inserted into battery cans. Full-shift personal breathing zone monitoring was conducted to estimate manganese dust exposures of press operators, mechanics, and material handlers. In-facepiece and personal breathing zone air sampling pairs were also collected using a program protection factor protocol to estimate the protection provided by the respirators. Particle size evaluations were made using nylon cyclones and Marple personal multi-stage impactors. All samples were analyzed for manganese by inductively coupled argon plasma, atomic emission spectroscopy via NIOSH analytical method 7300 utilizing a modified acid digestion procedure. Fifty-four, full-shift, time-weighted average (TWA) exposures to total manganese ranged from 0.1 to 5.4 milligrams per cubic meter (mg/m3); worker exposures were substantially lower during a follow-up study due to engineering control improvements. Concurrent area sample comparisons of total and respirable manganese revealed that the respirable particulate mass fractions ranged from 6 to 32 percent, and mass median aerodynamic diameters determined from personal breathing zone air samples were mostly greater than 10 micrometers. Fifteen respirator performance evaluations were conducted using Moldex 2200 respirators fitted with 25 millimeter cassettes and light weight sampling probes. Protection factors ranged from 5 to 220, with a geometric mean and standard deviation of 31 and 2.97, respectively. The 5th percentile protection factor estimate was 5, as calculated from the protection factor distribution for this sample set. In 1995, the American Conference of Governmental Industrial Hygienists (ACGIH) lowered the elemental and inorganic manganese dust Threshold Limit Value (TLV) from 5 mg/m3 to 0.2 mg/m3 to address adverse pulmonary and central nervous system effects and male infertility. Although most personal breathing zone concentrations were above 0.2 mg/m3, none of the in-facepiece concentrations exceeded this concentration. Parkinson's-like symptoms have been reported in the literature for high manganese dust and fume exposures, but the importance of low dust exposures for producing neurological effects is uncertain.

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“…7 We have noted this fact as a particular weakness of the "differential prevalence" methodology in malingering research. At the same time it must be made clear that we did not in our original article nor have we ever contended that all patients filing a workers compensation claim are malingering.…”

Section: Replymentioning

confidence: 99%