title: Evaluation of leakage from fume hoods using tracer gas, tracer nanoparticles and nanopowder handling test methodologies.
abstract: The most commonly reported control used to minimize workplace exposures to nanomaterials is the chemical fume hood. Studies have shown, however, that significant releases of nanoparticles can occur when materials are handled inside fume hoods. This study evaluated the performance of a new commercially available nano fume hood using three different test protocols. Tracer gas, tracer nanoparticle, and nanopowder handling protocols were used to evaluate the hood. A static test procedure using tracer gas (sulfur hexafluoride) and nanoparticles as well as an active test using an operator handling nanoalumina were conducted. A commercially available particle generator was used to produce sodium chloride tracer nanoparticles. Containment effectiveness was evaluated by sampling both in the breathing zone (BZ) of a mannequin and operator as well as across the hood opening. These containment tests were conducted across a range of hood face velocities (60, 80, and 100 ft/min) and with the room ventilation system turned off and on. For the tracer gas and tracer nanoparticle tests, leakage was much more prominent on the left side of the hood (closest to the room supply air diffuser) although some leakage was noted on the right side and in the BZ sample locations. During the tracer gas and tracer nanoparticle tests, leakage was primarily noted when the room air conditioner was on for both the low and medium hood exhaust airflows. When the room air conditioner was turned off, the static tracer gas tests showed good containment across most test conditions. The tracer gas and nanoparticle test results were well correlated showing hood leakage under the same conditions and at the same sample locations. The impact of a room air conditioner was demonstrated with containment being adversely impacted during the use of room air ventilation. The tracer nanoparticle approach is a simple method requiring minimal setup and instrumentation. However, the method requires the reduction in background concentrations to allow for increased sensitivity.
authors.affiliation: a Division of Applied Research and Technology, Engineering and Physical Hazards Branch , National Institute for Occupational Safety and Health , Cincinnati , Ohio.
authors.forename: Kevin H
authors.initials: KH
authors.lastname: Dunn
authors.forename: Candace Su-Jung
authors.initials: CS
authors.lastname: Tsai
authors.forename: Susan R
authors.initials: SR
authors.lastname: Woskie
authors.forename: James S
authors.initials: JS
authors.lastname: Bennett
authors.forename: Alberto
authors.initials: A
authors.lastname: Garcia
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Ellenbecker
mesh_terms: D000392:Air Movements; D000395:Air Pollutants, Occupational / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000517:prevention & control; D004867:Equipment Design; D005740:Gases / Q000032:analysis; D006801:Humans; D019570:Inhalation Exposure / Q000517:prevention & control*; D007753:Laboratories; D008348:Manikins; D053768:Metal Nanoparticles / Q000032:analysis*; D053758:Nanoparticles; D016273:Occupational Exposure / Q000517:prevention & control*; D013459:Sulfur Hexafluoride; D014691:Ventilation / Q000592:standards
chemical_list: D000395:Air Pollutants, Occupational; D005740:Gases; D013459:Sulfur Hexafluoride