Problems and progress in linking outdoor and indoor physics and chemistry of airborne particulate matter
Q. Sun, S. Isukapalli, P.G. Georgopoulos (EOHSI, UMDNJ - R.W. Johnson Medical School and Rutgers University)
MENTOR-OPERAS provide a set of novel mechanistically-based microenvironmental modeling tools that aim to improve the determination of outdoor/indoor relationships of photochemical pollutants and fine particles and, subsequently, of human exposure assessments. These modeling tools are used in conjunction with information from either ambient monitoring networks or from ambient urban and regional scale air quality models that incorporate in their formulation detailed aerosol physics and chemistry coupled with gas phase photochemistry (specifically UAM-AERO,UAM-UDAERO, and MAQSIP-UDAERO). The integration of ambient and microenvironmental information is accomplished using Geographic Information Systems (GIS) tools, to facilitate exposure scenario implementation.
The integrated outdoor/indoor PM modeling system is tested through case studies, to evaluate the contributions of influx of outdoor air, indoor sources of particles and of particle precursors, nonlinear chemical transformations, new particle formation and deposition, etc., to the levels (mass and number concentrations) and attributes (size distribution and size-dependent chemical composition) of particulate matter in the indoor environment. The effects of various uncertainties in model parameters on the calculated indoor concentrations and other attributes are also studied. Furthermore, the impact of different assumptions used to model physical and chemical processes affecting the evolution of indoor aerosol (equilibrium versus transport-limited gas/aerosol coupling, etc.) is examined. One of the main aspects of this modeling approach is the consistency in the description of the various physical and chemical attributes of the particulate matter across the various temporal and spatial scales associated with both outdoor and indoor scale transport, mixing, and transformation processes.