Nanoparticle aerosol generation methods from bulk powders for inhalation exposure studies

Assessing the human health risks associated with engineered nanomaterials is challenging because of the wide range of plausible exposure scenarios. While exposure to nanomaterials may occur through a number of pathways, inhalation is likely one of the most significant potential routes of exposure in industrial settings. An aerosolization system was developed to administer carbon nanomaterials from a dry bulk medium into airborne particles for delivery into a nose-only inhalation system. Utilization of a cannula-based feed system, diamond-coated wheel, aerosolization chamber, and krypton-85 source allows for delivery of otherwise difficult to produce respirable-sized particles. The particle size distribution (aerodynamic and actual) and morphology were characterized for different aerosolized carbon-based nanomaterials (e.g., single-walled carbon nanotubes and ultrafine carbon black). Airborne particles represented a range of size and morphological characteristics, all of which were agglomerated particles spanning in actual size from the nanosize range (<0.1 µm) to sizes greater than 5 and 10 µm for the particle's largest dimension. At a mass concentration of 1000 µg/m 3 , the size distribution as measured by the inertial impactor ranged from 1.3 to 1.7 µm with a σ g between 1.2 and 1.4 for all nanomaterial types. Because the aerodynamic size distribution is similar across different particle types, this system offers an opportunity to explore mechanisms by which different nanomaterial physicochemical characteristics impart different health effects while theoretically maintaining comparable deposition patterns in the lungs. This sys-

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Aerosolization System for Experimental Inhalation Studies of Carbon-Based Nanomaterials

Madl

Teague²,

et al. 2012

“…Similarly, inhalation of engineered nanoparticles and nanomaterials is considered to be potentially toxic for humans (Savolainen et al 2010;Yokel and MacPhail 2011). The inhalation pathway is considered as the predominant route of workplace exposure and uptake (Schmoll et al 2009), however the health effects of inhaled particles are not completely understood.…”

Section: Introductionmentioning

confidence: 99%

First measurements of the number size distribution of 1–2 nm aerosol particles released from manufacturing processes in a cleanroom environment

Ahonen

Kangasluoma

Lammi

et al. 2017

This study was conducted to observe a potential formation and/or release of aerosol particles related to manufacturing processes inside a cleanroom. We introduce a novel technique to monitor airborne sub 2 nm particles in the cleanroom and present results from a measurement campaign during which the total particle number concentration (>1 nm and >7 nm) and the size resolved concentration in the 1 to 2 nm size range were measured. Measurements were carried out in locations where atomic layer deposition (ALD), sputtering, and lithography processes were conducted, with a wide variety of starting materials. During our campaign in the clean room, we observed several time periods when the particle number concentration was 10 5 cm ¡3 in the sub 2 nm size range and 10 4 cm ¡3 in the size class larger than 7 nm in one of the sampling locations. The highest concentrations were related to the maintenance processes of the manufacturing machines, which were conducted regularly in that specific location. Our measurements show that around 500 cm ¡3 sub 2 nm particles or clusters were in practice always present in this specific cleanroom, while the concentration of particles larger than 2 nm was less than 2 cm ¡3 . During active processes, the concentrations of sub 2 nm particles could rise to over 10 5 cm ¡3 due to an active new particle formation. The new particle formation was most likely induced by a combination of the supersaturated vapors, released from the machines, and the very low existing condensation sink, leading to pretty high formation rates J 1.4 nm D (9 § 4) cm ¡3 s ¡1 and growth rates of particles (GR 1.1-1.3 nm D (6 § 3) nm/h and GR 1.3-1.8 nm D (14 § 3) nm/h).

“…Schmoll et al (2009) used a speaker and a function generator to produce sub-100 nm aerosol from SiO 2 and SWCNT. Size distributions for both particle types were bimodal, however, and the larger peak exceeded 100 nm.…”

Section: Introductionmentioning

confidence: 99%

A Cost-Effective Method of Aerosolizing Dry Powdered Nanoparticles

Tiwari

Fields

Marr

2013

The ability to produce nanoscale aerosols from dry powdered material is needed for studies of the toxicity and environmental transformation and fate of manufactured nanoparticles. Wet aerosol generation methods can alter particle chemistry, while dry methods often cannot produce truly nanoscale aerosols. We have developed a cost-effective dry dispersion technique for manufactured nanoparticles and have demonstrated its use with C 60 fullerene, TiO 2 , and CeO 2 . The system disperses dry powders to create aerosols with mode diameters below 100 nm. Average mode and median diameters for each of the tested manufactured nanoparticles are 91 and 107 nm for C 60 , 65 and 77 nm for TiO 2 , and 40 and 43 nm for CeO 2 . All aerosols exhibit right-skewed unimodal distributions and irregular morphology. Aerosol mass concentrations produced by the dispersion system vary linearly with the mass of nanomaterial loaded into it and are of a magnitude appropriate for inhalation nanotoxicology studies. This work demonstrates the ability of a simple device to produce nanoscale aerosols from powdered engineered nanoparticles.