Comparison of two Condensation Particle Counters (CPCs) below and above their dynamic upper limits (100,000 #/cc).

<p>The solid lines indicate mean percent difference; the dot-dashed lines indicate ±1.96 standardized deviations (SD) around the mean percent difference; the vertical dashed line represents the CPC's dynamic upper limit; the horizontal dashed line in A represents the CPC's dynamic upper limit; the horizontal dashed line in B represents a percent difference of 0.</p

Result of comparing CPC with SMPS.

<p>The solid lines indicate the mean percent difference; the dashed lines indicate ±1.96 standardized deviations (SD) around the mean percent difference; the vertical dashed line represents the CPC's dynamic upper limit; the horizontal dashed line represents a percent difference of 0.</p

Particle number size distributions of the NaCl aerosol particles measured by SMPS.

<p>The vertical solid line indicate a particle diameter of 100 nm.</p

Mean count and proportion of particle size ranges of 300 to 500 nm and 500 to 1000 nm according to OPC measurements.

<p>Mean count and proportion of particle size ranges of 300 to 500 nm and 500 to 1000 nm according to OPC measurements.</p

Comparison of 500 to 1000 nm particle measurements by two Optical Particle Counters (OPCs).

<p>The solid lines indicate mean percent difference; the dot-dashed lines indicate ±1.96 standardized deviations (SD) around the mean percent difference.</p

Comparison of 300 to 500 nm particle measurements by two Optical Particle Counters (OPCs).

<p>The solid lines indicate mean percent difference; the dot-dashed lines indicate ±1.96 standardized deviations (SD) around the mean percent difference.</p

NIOSH field studies team assessment: Worker exposure to aerosolized metal oxide nanoparticles in a semiconductor fabrication facility

<p>The ubiquitous use of engineered nanomaterials—particulate materials measuring approximately 1–100 nanometers (nm) on their smallest axis, intentionally engineered to express novel properties—in semiconductor fabrication poses unique issues for protecting worker health and safety. Use of new substances or substances in a new form may present hazards that have yet to be characterized for their acute or chronic health effects. Uncharacterized or emerging occupational health hazards may exist when there is insufficient validated hazard data available to make a decision on potential hazard and risk to exposed workers under condition of use. To advance the knowledge of potential worker exposure to engineered nanomaterials, the National Institute for Occupational Safety and Health Nanotechnology Field Studies Team conducted an on-site field evaluation in collaboration with on-site researchers at a semiconductor research and development facility on April 18–21, 2011. The Nanomaterial Exposure Assessment Technique (2.0) was used to perform a complete exposure assessment. A combination of filter-based sampling and direct-reading instruments was used to identify, characterize, and quantify the potential for worker inhalation exposure to airborne alumina and amorphous silica nanoparticles associated with the chemical mechanical planarization wafer polishing process. Engineering controls and work practices were evaluated to characterize tasks that might contribute to potential exposures and to assess existing engineering controls. Metal oxide structures were identified in all sampling areas, as individual nanoparticles and agglomerates ranging in size from 60 nm to >1,000 nm, with varying structure morphology, from long and narrow to compact. Filter-based samples indicated very little aerosolized material in task areas or worker breathing zone. Direct-reading instrument data indicated increased particle counts relative to background in the wastewater treatment area; however, particle counts were very low overall, indicating a well-controlled working environment. Recommendations for employees handling or potentially exposed to engineered nanomaterials include hazard communication, standard operating procedures, conservative ventilation systems, and prevention through design in locations where engineered nanomaterials are used or stored, and routine air sampling for occupational exposure assessment and analysis.</p