Particle Penetration Through Building Cracks

Liu, De-Ling; Nazaroff, William W.

doi:10.1080/02786820300927

Cited by 177 publications

(123 citation statements)

References 14 publications

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“…These results cover the size distribution of fungal spores; and the peak of spores of 1-2 µm seems to be very capable for penetration if the crack height is higher than 0.1 mm (Liu and Nazaroff 2003). Liu and Nazaroff (2001) have estimated that the penetration through mineral wool insulation is negligible.…”

Section: Discussionmentioning

confidence: 58%

Fungal spore transport through a building structure

Airaksinen¹,

Kurnitski²,

Pasanen

et al. 2004

Indoor Air

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The study carried out laboratory measurements with a full-scale timber frame structure to determine penetration of inert particles with size distribution from 0.6 to 4 µm and spores of Penicillium and Cladosporium through the structure. Pressure difference over and air leakage through the structure were varied. Measurements at moderate pressure differences resulted in the penetration factors within the range of 0.05 to 0.2 for inert particles, and indicated also the penetration of fungal spores through the structure. The measurements showed that the penetration was highly dependent on pressure difference over the structure but not on holes in surface boards of the structure. The results show that surface contacts between the frames and mineral wool may have a significant effect on penetration. The penetration was approximately constant within particle size rage of 0.6-2.5 µm, but particles with diameter of 4.0 µm did not penetrate through the structure at all even at a higher-pressure difference of 20 Pa, except in the case of direct flow-path through the structure. Results have important consequences for practical design showing that penetration of fungal spores through the building envelope is difficult to prevent by sealing. The only effective way to prevent penetration seems to be balancing or pressurizing the building. In cold climates, moisture condensation risk should be taken into account if pressure is higher indoors than outdoors. Determined penetration factors were highly dependent on the pressure difference. Mechanical exhaust ventilation needs a special consideration as de-pressurizing the building may cause health risk if there is hazardous contamination in the building envelope exists. PRACTICAL IMPLICATIONSMeasurements at moderate pressure differences allowed determining penetration factors within the range of 0.05 to 0.2 for inert particles in a size range of 0.6-2.5 µm and indicative results with fungal spores confirmed the penetration through the wooden floor structure. Both measurements showed that the penetration was highly dependent on pressure difference and not dependent on holes in surface boards of the structure. The results are likely to show that surface contacts of mineral wool with other building elements may have an important role on the penetration.

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Section: Discussionmentioning

confidence: 58%

Fungal spore transport through a building structure

Airaksinen¹,

Kurnitski²,

Pasanen

et al. 2004

Indoor Air

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“…Deposition rates, k, were determined by Ozkaynak et al (1996) from co-temporal measurements indoors and nearby outdoors, assuming P equals unity. Note that empirical (Liu and Nazaroff, 2003;Long et al, 2001) and modeling (Liu and Nazaroff, 2001) studies of PM 2.5 suggest P values less than unity, typically between 0.6 and 1.0. However, to the extent that P is less than unity, this fact is accounted for in the experimentally determined k values (Kopperud et al, 2004).…”

Section: Inhalation Intake Ratesmentioning

confidence: 99%

Inhalation intake of ambient air pollution in California's South Coast Air Basin

Marshall

Granvold

Hoats

et al. 2006

Atmospheric Environment

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Reliable estimates of inhalation intake of air pollution and its distribution among a specified population are important for environmental epidemiology, health risk assessment, urban planning, and environmental policy. We computed distributional characteristics of the inhalation intake of five pollutants for a group of $25,000 people ($29,000 persondays) living in California's South Coast Air Basin. Our approach incorporates four main inputs: temporally resolved information about people's location (latitude and longitude), microenvironment, and activity level; temporally and spatially explicit model determinations of ambient concentrations; stochastically determined microenvironmental adjustment factors relating the exposure concentration to the ambient concentration; and, age-, gender-, and activityspecific breathing rates. Our study is restricted to pollutants of outdoor origin, i.e. it does not incorporate intake in a microenvironment from direct emissions into that microenvironment. Median estimated inhalation intake rates (mg d À1 ) are 53 for benzene, 5.1 for 1,3-butadiene, 8.7 Â 10 À4 for hexavalent chromium in fine particulate matter (Cr-PM 2.5 ), 30 for diesel fine particulate matter (DPM 2.5 ), and 68 for ozone. For the four primary pollutants studied, estimated median intake rates are higher for non-whites and for individuals in low-income households than for the population as a whole. For ozone, a secondary pollutant, the reverse is true. Accounting for microenvironmental adjustment factors, population mobility and temporal correlations between pollutant concentrations and breathing rates affects the estimated inhalation intake by 40% on average. The approach presented here could be extended to quantify the impact on intakes and intake distributions of proposed changes in emissions, air quality, and urban infrastructure. r

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“…3. Size-segregated ranges of important input parameters for the in-cabin model (a) penetration factor (Liu and Nazaroff 2003), (b) filtration efficiency (Qi et al 2008), (c) deposition coefficient (Gong et al 2009), and (d) respiratory deposition fraction (Hinds 1999). Figure 3a illustrates penetration factors over studied UFP size ranges.…”

Section: Penetration Factor (P)mentioning

confidence: 99%

Quantitative Analysis of the Parameters Affecting In-Cabin to On-Roadway (I/O) Ultrafine Particle Concentration Ratios

Zhu

2009

Aerosol Science and Technology

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A mass-balance indoor particle dynamic model was adopted and modified to investigate how on-roadway ultrafine particle (UFP, diameter < 100 nm) concentrations and vehicle ventilation settings affect UFP levels inside vehicles. The model was first parameterized focusing on a mechanistic, simulation-based interpretation of in-cabin data reported in Zhu et al. Under condition (3), the effects of penetration factor, deposition coefficient, and vehicle speed were comparable. The modeled I/O ratio was inversely proportional to the airflow rate from mechanical ventilation in the whole range (0-360 m 3 h −1 ) with 10-20% influence depending on the particle size.

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Particle Penetration Through Building Cracks

Cited by 177 publications

References 14 publications

Fungal spore transport through a building structure

Fungal spore transport through a building structure

Inhalation intake of ambient air pollution in California's South Coast Air Basin

Quantitative Analysis of the Parameters Affecting In-Cabin to On-Roadway (I/O) Ultrafine Particle Concentration Ratios

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