Modeling of outdoor/indoor relationships of gas phase pollutants and particulate matter
S.S. Isukapalli, P.G. Georgopoulos (EOHSI, UMDNJ - R.W. Johnson Medical School and Rutgers University)
The physical and chemical interactions between gas phase pollutants and particulate matter (PM) are important factors governing the levels of indoor PM. These interactions are especially significant when emissions from indoor sources such as stoves interact with the ambient air that infiltrates from outdoors, resulting in the formation of secondary PM. Here, the formulation as well as various applications of an integrated modeling environment, the MENTOR framework (Modeling ENvironment for TOtal Risk studies), that can be used to study outdoor/indoor relationships of gas phase pollutants and fine particulate matter (PM) are presented. The MENTOR approach maintains compatibility across different spatial scales (regional, urban, local, and microenvironmental) by modeling the underlying physical and chemical processes in a consistent manner.
Different case studies evaluate the contributions of influx of outdoor air, indoor sources, nonlinear chemistry, new particle formation and deposition, etc., to the levels of pollutants indoors. The modules for indoor air are developed so as to allow direct coupling of these models with local and regional scale air quality models. The indoor air model requires detailed ambient air quality information, such as the chemical composition of PM, which can be only be provided by air quality models. However, this model can make use of detailed information that may be available from advanced monitoring networks.
The results from the case studies indicate the importance of considering all the physico-chemical processes in tandem in the modeling of indoor levels of PM. This mechanistic modeling approach provides tools for improving assessments of human exposure to PM.