Size specific indoor aerosol deposition measurements and derived I/O concentrations ratios

Fogh, C.L.; Byrne, Mary; Roed, Jørn; Goddard, A.J.H.

doi:10.1016/s1352-2310(97)00037-x

Cited by 97 publications

(74 citation statements)

References 16 publications

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“…Also this study was excluded as it most probably overestimates the deposition velocity in laboratory conditions. Fogh et al 1997 5 Thatcher et al 2002 The air flow to chamber 2 (CH2) and from chamber 1 (CH1) were defined by measuring air flow velocities. The penetration factor for inert particles was calculated from the values when both chambers had reached steady state.…”

Section: E-06mentioning

confidence: 99%

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: E-06mentioning

confidence: 99%

Fungal spore transport through a building structure

Airaksinen¹,

Kurnitski²,

Pasanen

et al. 2004

Indoor Air

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“…Several authors have arrived at the conclusion that the filtration coefficient for reactive compounds (ozone) and particles < 10 µm is also very low-approaching that of a non-reactive gas. 15,18,19 The value of the exchange rate depends on the activities of the people using the indoor environment. Measurements have indicated that profound differences in the air exchange rate exist between households.…”

Section: Model Parametersmentioning

confidence: 99%

“…The transient IO ratio of two simultaneous observations at time t is given as (6) Because measurements generally refer to an averaging period, T, we can also define a time-integrated IO ratio. This can be accomplished by evaluating the following ratio of integrals: 19 (7…”

Section: Indoor-outdoor Ratiosmentioning

confidence: 99%

“…19,23 However, the validity of the assumptions going from eq 9 to eq 10 should always be checked before employing eq 11.…”

Section: Indoor-outdoor Ratiosmentioning

confidence: 99%

“…Table 4 presents the parameters related to the indoor environment (volume, internal area) and the interaction of ozone and benzene with reactive surfaces (deposition velocity and filtration coefficient). Although the parameters reflect realistic values, 15,19 in our modeling exercises they should be considered as case-specific examples.…”

Section: Modeling Exercisesmentioning

confidence: 99%

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Modeling Relationships between Indoor and Outdoor Air Quality

Freijer

Bloemen

2000

Journal of the Air & Waste Management Association

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Information about the ratio between indoor and outdoor concentrations (IO ratios) of air pollutants is a crucial component in human exposure assessment. The present study examines the relationship between indoor and outdoor concentrations as influenced by the combined effect of time patterns in outdoor concentrations, ventilation rate, and indoor emissions. Two different mathematical approaches are used to evaluate IO ratios. The first approach involves a dynamic mass balance model that calculates distributions of transient IO ratios. The second approach assumes a linear relationship between indoor and outdoor concentrations. We use ozone and benzene as examples in various modeling exercises. The modeled IO ratio distributions are compared with the results obtained from linear fits through plots of indoor versus outdoor concentrations.

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References

2012

Personal Protective Equipment for Chemical, Biological, and Radiological Hazards

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Size specific indoor aerosol deposition measurements and derived I/O concentrations ratios

Cited by 97 publications

References 16 publications

Fungal spore transport through a building structure

Fungal spore transport through a building structure

Modeling Relationships between Indoor and Outdoor Air Quality

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