The objective was to develop a computer software package (to be registered as InPest) that runs under Microsoft Excel on a personal computer to help in the risk assessment of indoor-use pesticides for both applicators and indoor occupants for various methods of application including space spraying, electric vaporizing, broadcast spraying, and residual spraying. For space spraying, the movement of the pesticide in a sprayed room including droplet settlement, permeation into the floor, degradation, transference, and discharge by ventilation were described as precisely as possible by various physicochemical equations. The equations thus obtained were then incorporated into the Fugacity model (Level IV).When pesticide information regarding molecular weight, vapor pressure, water solubility, and octanol/water partition coefficient is available, InPest is able to simulate IMPLICATIONS There are several computer models for simulating the indoor behavior of chemicals. However, they are incapable of predicting the movement, and thus the concentration of chemicals in all room media including floor, wall, and ceiling materials as well as aerosol droplets floating in the air. A simulation model (InPest) was developed by the authors based on the Fugacity model, taking into account the generation of aerosol and vapor, settling and horizontal movement of droplets, changes in droplet diameter, and adsorption and dissipation. Using this model, improved and more detailed prediction of movement was achieved. Utilizing the BASIC programming language, user-friendly software that runs under Microsoft-Excel was developed. Called InPest, it can be used as a risk assessment tool to evaluate the safety of an indoor-use pesticide by comparing the mammalian toxicological levels with the estimated exposure to the pesticide of room occupants. The InPest concept can also be applied to simulation of the indoor behavior of other chemicals besides pesticides.the time-dependent concentrations of the pesticide in the air and residual amounts on floor, wall, and ceiling materials under various conditions. Simulation data indicate that the predicted behavior of pesticides fully agrees with the measured data. Based on the predicted concentrations in the air and amounts of residue on the floor, the levels of exposure to room occupants via inhalation, dermal, or oral intake can be computed and compared with the mammalian toxicological data. Thus, InPest is a powerful tool for evaluating the safety of indoor-use pesticides with regard to human health.
INTRODUCTIONIn order to control household flies, mosquitoes and cockroaches, indoor-use pesticides are applied indoors using various methods. For the safety assessment of pesticides on humans, simulation models have been developed for four such methods: space spraying, 1,2 electric vaporizing,
