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Exposure controls for nanomaterials at three manufacturing sites.

Authors
Heitbrink-WA; Lo-L-M; Dunn-KH
Source
J Occup Environ Hyg 2015 Jan; 12(1):16-28
NIOSHTIC No.
20044526
Abstract
Because nanomaterials are thought to be more biologically active than their larger parent compounds, careful control of exposures to nanomaterials is recommended. Field studies were conducted at three sites to develop information about the effectiveness of control measures including process changes, a downflow room, a ventilated enclosure, and an enclosed reactor. Aerosol mass and number concentrations were measured during specific operations with a photometer and an electrical mobility particle sizer to provide concentration measurements across a broad range of sizes (from 5.6 nm to 30 um). At site A, the dust exposure and during product harvesting was eliminated by implementing a wait time of 30 minutes following process completion. And, the dust exposure attributed to process tank cleaning was reduced from 0.7 to 0.2 mg/m3 by operating the available process ventilation during this task. At site B, a ventilated enclosure was used to control dust generated by the manual weigh-out and manipulation of powdered nanomaterials inside of a downflow room. Dust exposures were at room background (under 0.04 mg/m3 and 500 particles/cm3) during these tasks however, manipulations conducted outside of the enclosure were correlated with a transient increase in concentration measured at the source. At site C, a digitally controlled reactor was used to produce aligned carbon nanotubes. This reactor was a closed system and the ventilation functioned as a redundant control measure. Process emissions were well controlled by this system with the exception of increased concentrations measured during the unloading the product. However, this emission source could be easily controlled through increasing cabinet ventilation. The identification and adoption of effective control technologies is an important first step in reducing the risk associated with worker exposure to engineered nanoparticles. Properly designing and evaluating the effectiveness of these controls is a key component in a comprehensive health and safety program.
Keywords
Nanotechnology; Exposure-levels; Biological-effects; Biological-function; Particulates; Dusts; Dust-exposure; Ventilation; Aerosols; Air-contamination; Engineering-controls; Control-technology; Author Keywords: Engineered Nanomaterials; Engineering Controls; Hazard Prevention; Airborne Contaminants; Control Evaluation
CODEN
JOEHA2
Publication Date
20150101
Document Type
Journal Article
Fiscal Year
2015
NTIS Accession No.
NTIS Price
Identifying No.
M062014
Issue of Publication
1
ISSN
1545-9624
NIOSH Division
DART
Priority Area
Manufacturing
Source Name
Journal of Occupational and Environmental Hygiene
State
OH
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