AIR DISPERSION OF CHEMICALS IN INDUSTRIAL FACILITIES

A USER-FRIENDLY SOFTWARE TOOL IS BEING DEVELOPED FOR MODELING THE AIRBORNE CONCENTRATIONS OF HAZARDOUS CHEMICALS IN LARGE INDOOR SPACES IN WHICH POLLUTANTS ARE NOT UNIFORMLY DISTRIBUTED. CURRENT INDOOR AIR POLLUTION MODELS HAVE LIMITED ABILITY TO DEAL WITH SUCH HETEROGENEOUS CONDITIONS. IN THIS RESEARCH, SYSTEM DYNAMICS SOFTWARE IS BEING APPLIED TO SIMULATE AIR DISPERSION IN OPEN INDOOR SETTINGS. THE MODELING APPROACH CONSISTS OF DIVIDING THE INDOOR SPACE INTO AN INTERCONNECTED NETWORK OF SUBVOLUMES. ADJACENT SUBVOLUMES ARE ASSUMED TO EXCHANGE POLLUTANTS. IN ADDITION, A VARIETY OF PHYSICAL PROCESSES ARE MODELED THAT INFLUENCE THE CONCENTRATIONS OF POLLUTANTS IN EACH SUBVOLUME, INCLUDING EMISSIONS, LOCAL AIR SUPPLY OR VENTILATION, AND CHEMICAL REACTIONS. MODELING IS PERFORMED IN AN INTERACTIVE GRAPHICAL ENVIRONMENT THAT CORRESPONDS TO THE PHYSICAL ENVIRONMENT. MODELING ELEMENTS INCLUDE BOTH SUBVOLUMES AND CONNECTORS THAT REPRESENT THE UNDERLYING MATHEMATICAL EQUATIONS, WHICH ARE AUTOMATICALLY SOLVED AS A LINKED SYSTEM OF TIME-DEPENDENT DIFFERENTIAL EQUATIONS. THE USEFULNESS OF THE MODELING APPROACH WILL BE DEMONSTRATED BY APPLYING THE ALGORITHMS TO INDUSTRIAL HYGIENE SURVEYS IN WHICH EMPIRICAL DATA HAVE BEEN COLLECTED.