Penetration of Ultrafine Particles and Ion Clusters Through Wire Screens

Ichitsubo, Hirokazu; Hashimoto, Tatsuya; Alonso, M.; Kousaka, Yasuo

doi:10.1080/02786829608965357

Cited by 49 publications

(37 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Performance evaluation of filters and respirators using nanoparticles showed diffusion and interception are the dominant deposition mechanisms for ultrafine particles (Cheng and Yeh 1980;Ichitsubo et al 1996;Kim et al 2007;Rengasamy et al 2009;Chen et al 2014Chen et al , 2015Zhou and Cheng 2016). Experimental data agreed with the filtration theory for spherical particles in fan model filters such as screen filters Kirsch and Chechuev 1985;Ichitsubo et al 1996) and in Nuclepore filters (Chen et al 2015).…”

Section: Introductionsupporting

confidence: 67%

See 1 more Smart Citation

Effects of size and shape on filtration of TiO₂ nanoparticles

Cheng

Zhou

2017

Aerosol Science and Technology

View full text Add to dashboard Cite

Titanium dioxide (TiO 2 ) is one of the most widely used nanoscale materials to date and could result in human exposures. The main objective of this study was to perform detailed characterization of TiO 2 agglomerate particles and how these properties influence particle penetration in a screen filter. Transmission electron microscope (TEM) photos showed compact agglomerates of nanoscale primary particles. The projected area diameter was close to the mobility diameter, where the length was about 25% larger than the mobility diameter. The mean aspect ratio of TiO 2 agglomerate was constant between 1.39 and 1.55. Using the tandem differential mobility analyzer-aerosol particles mass analyzer (DMA-APM) technique, we were able to measure aerodynamic diameter, mass, and fractal dimension. The value of fractal dimension based on mass and mobility diameter was 2.8. Penetration of classified TiO 2 particles through a screen filter was measured. Penetration increased with increasing mobility diameter and flow rate indicating that diffusion and interception were the main filtration mechanism. The measured physical dimensions, mobility diameter, and aerodynamic diameter were used in a single-fiber filtration theory for the fan model filter to predict the penetration of TiO 2 particles. The interception parameter was the key to estimate the penetration. Experimental penetration data were in best agreement with the model in which the maximum length was used to calculate the interception model. This result was consistent with the assumption that the rotation time of a non-spherical particle of small aspect ratio was much less than the transport time for the particle to pass through the filter fiber.

show abstract

Section: Introductionsupporting

confidence: 67%

“…Experimental filtration efficiencies in several screen filters showed that the FMF single-fiber filtration equation is valid for spherical particles in the size range of 2 to 900 nm (Cheng et al , 1985Kirsch and Chechuev 1985;Ichitsubo et al 1996). Figure 2 shows examples of mobility-classified TiO 2 particles collected on TEM grids.…”

Section: ½5mentioning

confidence: 99%

Effects of size and shape on filtration of TiO₂ nanoparticles

Cheng

Zhou

2017

Aerosol Science and Technology

View full text Add to dashboard Cite

show abstract

“…However, Alonso et al detected no particle rebound phenomenon in the same size range as that studied by Ichitsubo et al 42,45) . They reported that the disagreement between the theoretical and experimental studies could be attributed to an unreliable sizing of the particles below 3 nm by the current available techniques.…”

Section: Filtration Efficiency Affecting Factorsmentioning

confidence: 85%

“…The results showed a higher particle penetration through the tube for particles below 2 nm 41) . Ichitsubo et al found that the collection efficiency of the particles was lower than that predicted by the theoretical model for particles below 2 nm: this could likewise be due to thermal rebound effect 42) . Similarly, Balazy et al suggested that this phenomenon occurred for liquid diethyl-hexyl-sebacate (DEHS) aerosol particles by showing that the efficiency of fibrous filters increased with decreasing particle diameter down to 20 nm and then decreased for particles smaller than that size 43) .…”

Section: Filtration Efficiency Affecting Factorsmentioning

confidence: 99%

“…They reported that the disagreement between the theoretical and experimental studies could be attributed to an unreliable sizing of the particles below 3 nm by the current available techniques. In addition, Heim et al challenged Ichitsubo et al, attributing their findings to inaccurate particle size measurement of particles below 2-3 nm caused by an artefact of differential mobility analyzer (DMA) diffusional broadening 42,46). Kim et al investigated nanoparticle filtration characteristics of several commercial filter media including four fiberglass filter media, four electret filter media and one nano-fiber filter media by using silver nanoparticles from 3 nm to 20 nm 47) .…”

Section: Filtration Efficiency Affecting Factorsmentioning

confidence: 99%

See 1 more Smart Citation

Performance of Mechanical Filters and Respirators for Capturing Nanoparticles ―Limitations and Future Direction

et al. 2010

View full text Add to dashboard Cite

There is an increasing concern about the health hazard posed to workers exposed to inhalation of nanoparticles. Inhaling nanoparticles posses an occupational hazard due to elevated amount emitted to the atmosphere and working environment. Nanoparticles have potential toxic properties: the high particle surface area, number concentration, and surface reactivity. Inhalation, the most common route of nanoparticle exposure, has been shown to cause adverse effects on pulmonary functions and the deposited particles in the lung can be translocated to the blood system by passing through the pulmonary protection barriers. Filtration is the simplest and most common method of aerosol control. It is widely used in mechanical ventilation and respiratory protection. However, concerns have been raised regarding the effectiveness of the filters for capturing nanoparticles. This paper reviews the literature on the filtration performance of mechanical filters and respirators against nanoparticles. It includes the discussion about filtration mechanisms, theoretical models, affecting factors of the filtration efficiency, and testing protocols for respirator and filter certification.

show abstract