Modeling Relationships between Indoor and Outdoor Air Quality

Abstract

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.

Estimating Separately Personal Exposure to Ambient and Nonambient Particulate Matter for Epidemiology and Risk Assessment: Why and How

“…The equations probably will not be valid, for example, for air-conditioned homes, for homes with HVAC or air cleaners that cycle on and off, or for ambient pollutants with rapidly varying concentrations. For these conditions, non-equilibrium versions of the mass balance model 26,29,47 should be used. However, the equilibrium model provides a useful, if simplified, example of the basic relationships.…”

Investigation of A Potted Plant (Hedera helix) with Photo-Regulation to Remove Volatile Formaldehyde for Improving Indoor Air Quality

“…However, specific pathogens or causes cannot be identified in most cases. Therefore, a well-defined experimental platform needs to characterize the major components, distributions, boundaries, exchangeable rate, and loading between the system and surroundings (Freijer and Bloemen, 2000;Yang and Zhang, 2008;Demou et al, 2009;Kim et al, 2010). The indoor air quality is significantly influenced by infiltration into the building mainly through the ventilation system and to a lesser extent, through windows or cracks .…”

Indoor particulate matter in urban residences of Alexandria, Egypt

“…The filtration effect caused by the air conditioning system and the weak transportation ability of outdoor particulates into the indoor environment through frequently closed windows lead to both low I/O ratio of the particulate level and low air change rate. These arguments have been suggested through models by Tung et al (1999), Freijer and Bloemen (2000), and Chao and Tung (2001).…”