Journal of occupational and environmental hygiene
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J Occup Environ Hyg · Oct 2006
Comparative StudyUV air cleaners and upper-room air ultraviolet germicidal irradiation for controlling airborne bacteria and fungal spores.
In-room air cleaners (ACs) and upper-room air ultraviolet germicidal irradiation (UVGI) are engineering control technologies that can help reduce the concentrations of airborne bacteria and fungal spores in the indoor environment. This study investigated six different types of ACs and quantified their ability to remove and/or inactivate airborne bacteria and fungal spores. Four of the air cleaners incorporated UV lamp(s) into their flow path. ⋯ Culturing, direct microscopy, and optical particle counting revealed similar CADRm. The ACs performed similarly when challenged with three different microorganisms. Testing two of the ACs showed that no additional air cleaning was provided with the operation of an internal UV-C lamp; the internal UV-C lamps, however, inactivated 75% of fungal spores and 97% of bacteria cells captured in the air filter medium within 60 min.
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J Occup Environ Hyg · Sep 2006
Comparative StudyComparison of performance of three different types of respiratory protection devices.
Respiratory protection is offered to American workers in a variety of ways to guard against potential inhalation hazards. Two of the most common ways are elastomeric N95 respirators and N95 filtering-facepiece respirators. Some in the health care industry feel that surgical masks provide an acceptable level of protection in certain situations against particular hazards. ⋯ After passing the saccharin tests, the elastomeric respirators provided a 5th percentile of 11.7, and the filtering-facepiece respirators provided a 5th percentile of 11.0. The 5th percentiles after passing the N95-Companion were 13.0 for the elastomeric respirators and 20.5 for the filtering-facepiece respirators. The data supports fit testing as an essential element of a complete respiratory protection program.
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J Occup Environ Hyg · Jun 2006
House dust collection efficiency of the high volume small surface sampler on worn carpets.
The High Volume Small Surface Sampler (HVS3) is a dust-sampling vacuum that allows for set airflow and back pressure during sampling, increasing precision. Total dust collection efficiency of the HVS3 has been evaluated only on new carpets-not worn carpets. We performed a factorial study to assess the impact of carpet wear, dust deposition level, carpet type, and relative humidity during sampling on HVS3 collection efficiency. ⋯ Collection efficiency of carpets with high wear was significantly lower than those with midlevel wear (p = 0.01). These results demonstrate that the design of the HVS3 partially corrects for differences in dust load and carpet type. However, collection efficiency of the HVS3 is affected by high levels of carpet wear and ambient humidity during sampling.
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J Occup Environ Hyg · Oct 2005
Test for the integrity of environmental tractor cab filtration systems.
Cab filtration systems can be used to protect vehicle operators from hazardous air contaminants. In a cab filtration system, a fan draws air through filters and pressurizes the cab with this filtered air. This article describes the application of a low-cost, optical particle counter to evaluate the performance of tractor cab filtration systems. ⋯ All 13 tractors were tested for leak sites. Leak sites were identified and sealed. This process was repeated until each cab showed an exposure reduction ratio Co/Ci of at least 50 (aerosol penetration into the cab Ci/Co x 100 was less than 2%) at the 0.3-0.5 microm particle size interval.
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J Occup Environ Hyg · Jun 2005
Comparative StudyEvaluation of a modified scavenging system to reduce occupational exposure to nitrous oxide in labor and delivery rooms.
We developed a new scavenging mask for the administration of nitrous oxide to mothers-to-be during labor in order to minimize leakage of the patient's exhaled breath into the room and, therefore, decreasing staff exposure to nitrous oxide. The scavenging system was designed with an inner mask for gas delivery, an outer mask to capture exhaled breath, and a continuous exhaust airflow based on breathing flow rates. In this study we field tested the scavenging system by measuring personal exposures of nurses (N = 30) and room air concentrations (N = 33), while patients self-administered nitrous oxide either through the conventional or modified scavenging system. ⋯ Other factors associated with lower concentrations included larger distances between the nurse and the patient, and greater times since nitrous oxide was used. Observations during the field trial indicated that subjects did not hold the scavenging mask close enough to the face to capture exhaled breath during much of the time when the breath was highly contaminated. Additional modifications to the scavenging system are required to further reduce nitrous oxide concentrations and to improve comfort and usability.