Solid particle penetration into enclosures

Lewis, Steven R.

doi:10.1016/0304-3894(95)00037-u

Cited by 28 publications

(18 citation statements)

References 7 publications

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“…The estimated penetration factors are similar to the observed penetration factors for particle sizes <0.4 ¹m, but decrease with particle size thereafter. The penetration factor is expected to decrease with particle size above about 0.5 ¹m (Lewis 1995), however, the penetration factors observed in the current study for particles >0.4 ¹m are considerably larger than ex- Figure 8. Comparison of experimentally determined penetration factors using particle deposition rates from Figure 7 (Observed) and estimated penetration factors using particle deposition rates computed using the model of Crump and Seinfeld (1981).…”

Section: Indoor Particle Deposition Rates and Penetration Factorscontrasting

confidence: 42%

Characterization of Indoor-Outdoor Aerosol Concentration Relationships during the Fresno PM Exposure Studies

Vette

Rea

Lawless

et al. 2001

Aerosol Science and Technology

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Particle size distributions were measured indoors and outdoors of a single, detached residence during the Fresno particulate matter exposure studies in winter (February 1 -28, 1999) and spring (April 18 -May 16, 1999). Data was collected for particle sizes ranging from about 0.01 to 2.5 ¹m. These data were used to investigate the temporal relationships between indoor and outdoor aerosol concentrations and to determine particle deposition rates and penetration factors for discrete particle sizes. Indoor/outdoor aerosol concentration ratios for particle sizes >1 ¹m were diurnally variable with highest ratios occurring during daytime (6:00-18:00) due to resuspension from indoor activities. Daytime and nighttime (19:00-7:00) aerosol concentration ratios were very similar for particle sizes <1 ¹m. Particle deposition rates were determined by measuring the decay in indoor aerosol concentrations after indoor levels were elevated by in ltration of native ambient aerosols. Deposition rates varied depending on particle size and were consistent with model results up to about 0.4 ¹m. The experimentally determined deposition rates were considerably higher than model results at larger particle sizes, suggesting the possibility of an additional indoor loss mechanism. Penetration factors were determined to be less than unity for all particle sizes and ranged from 0.5 to 0.9.

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Section: Indoor Particle Deposition Rates and Penetration Factorscontrasting

confidence: 42%

Characterization of Indoor-Outdoor Aerosol Concentration Relationships during the Fresno PM Exposure Studies

Vette

Rea

Lawless

et al. 2001

Aerosol Science and Technology

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show abstract

“…Lewis (1995) reported penetration factors between 0.97 and 0.29 for particles between 1 and 6 µm passing through a Perspex (plastic) slit 0.1 mm high and 40 mm wide with a pressure differential of 10 Pa across the slit. Mosely, et al (2001) passed monodispersed particles through manufactured aluminum slits 0.508 mm high and 10 cm wide.…”

Section: Particle Penetration Efficienciesmentioning

confidence: 99%

Factors affecting the concentration of outdoor particles indoors (COPI): Identification of data needs and existing data

Thatcher¹,

McKone²,

Fisk³

et al. 2001

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The process of characterizing human exposure to particulate matter requires information on both particle concentrations in microenvironments and the timespecific activity budgets of individuals among these microenvironments. Because the average amount of time spent indoors by individuals in the US is estimated to be greater than 75%, accurate characterization of particle concentrations indoors is critical to exposure assessments for the US population. In addition, it is estimated that indoor particle concentrations depend strongly on outdoor concentrations. The spatial and temporal variations of indoor particle concentrations as well as the factors that affect these variations are important to health scientists. For them, knowledge of the factors that control the relationship of indoor particle concentrations to outdoor levels is particularly important. In this report, we identify and evaluate sources of data for those factors that affect the transport to and concentration of outdoor particles in the indoor environment. Concentrations of particles indoors depend upon the fraction of outdoor particles that penetrate through the building shell or are transported via the air handling (HVAC) system, the generation of particles by indoor sources, and the loss mechanisms that occur indoors, such as deposition. To address these issues, we (i) identify and assemble relevant information including the behavior of particles during air leakage, HVAC operations, and particle filtration; (ii) review and evaluate the assembled information to distinguish data that are directly relevant to specific estimates of particle transport from those that are only indirectly useful and (iii) provide a synthesis of the currently available information on building air-leakage parameters and their effect on indoor particle matter concentrations.

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“…Therefore, it is not surprising to nd that Thatcher and Layton (1995) calculated average penetration factors of one considering their deposition rates were the highest, while Koutrakis et al (1992) and Tung et al (1999) used lower deposition rates to calculate penetration factors less than unity. Interestingly, Lewis (1995) measured deposition velocities 4 to 8 times lower than Thatcher and Layton over the same particle size range, and calculated penetration factors less than unity. Wallace (1996) did not present de nite penetration factor values for PM 2.5 and PM 10 , so his work cannot be compared appropriately to the other results.…”

Section: Previous Physical Factor Researchmentioning

confidence: 99%

“…Tung et al reported an extremely low average deposition velocity of 0.037 m/h and an average penetration factor of 0.78 for PM 10 in an enclosed of ce. In an enclosed chamber, Lewis (1995) experimentally measured penetration factors between 0 and 0.8 for 1 to 7 l m aerodynamic diameter particles with particle deposition rates between 0.25 and 1.1 h ¡ 1 . The equivalent deposition velocities are 0.15 m/h and 0.65 m/h, assuming a surface-area-to-volume ratio of 1.7 m ¡ 1 .…”

Section: Previous Physical Factor Researchmentioning

confidence: 99%

Penetration of Particles into Buildings and Associated Physical Factors. Part I: Model Development and Computer Simulations

Thornburg

Ensor

Rodes

et al. 2001

Aerosol Science and Technology

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Solid particle penetration into enclosures

Cited by 28 publications

References 7 publications

Characterization of Indoor-Outdoor Aerosol Concentration Relationships during the Fresno PM Exposure Studies

Characterization of Indoor-Outdoor Aerosol Concentration Relationships during the Fresno PM Exposure Studies

Factors affecting the concentration of outdoor particles indoors (COPI): Identification of data needs and existing data

Penetration of Particles into Buildings and Associated Physical Factors. Part I: Model Development and Computer Simulations

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