Application residential modeling

The application of pesticides is widespread in agriculture and elsewhere, and the concomitant risks depend on their toxicity, and duration and frequency, as well as the level of exposure (Henderson et al., 1993 Krieger and Ross, 1993). Exposure may be incidental or almost continuous. This is true not only for workers (occupational exposure), but also for the general public and people who may be considered as bystanders, who are not involved in the actual occupational activities with pesticides, but are close enough to get exposed. In this present chapter, only operator exposure will be discussed because agricultural re-entry modelling is discussed in Chapter 2 and residential post-application exposure modelling in Chapter 6 of this book. 

INTRODUCTION 210 STATUS OF RESIDENTIAL MODELS 211 EXPOSURE PHASES IN RESIDENTIAL EXPOSURE 212 Mixing and Loading Phase 212 Application Phase 212 Post-Apphcation Phase 213 MODEL CONCEPTS FRAMEWORKS 214 Mass-Balanced Air Qnality Model 214 Fngacity Model 215 Flnid Dynamics Model 216 MODEL CONCEPTS SOURCES AND SINKS 216 Sonrce Evaporation of Pesticides 216 Vapor-Pressnre-Driven Evaporation 216 Chinn Evaporation 217... 

Compared with the occupational exposnre of applicators and workers following pesticide application in the field, post-application residential exposure to pesticides used in and around the home is lower in level, but encompasses a wider variety of scenarios, such as age distribution, activity patterns and product use. Typically, few data are available on residential exposure, while a large body of data does exist for occupational exposures. Residential exposure assessment and modeling may benefit from the new data requirements under the United States Food Qnality Protection Act of 1996 (Lewis et al, 1994 Hill et al., 1995 Lu and Fenske, 1998 USEPA, 1990 Whitmore et al., 1994). In occupational exposnre assessment, a database approach is favored, while in residential exposure assessment a mechanistic and statistical modeling approach is dominant. 

United States Plug Power is developing a 7 kWe fuel cell system for residential applications. They have tested their system on hydrogen and are planning market introduction of several models which could use hydrogen, propane, or natural gas. 

Because data on non-professional exposure is scarce but exposure assessments are necessary, models have become a main tool in assessing residential exposure. It appears to be easier to obtain good quality data on exposure factors (room sizes, typical amounts used, etc.), which can be used as parameters in models, than to obtain direct exposure measurements. Critics of the modeling process say that the information generated through models is suspect because of the inherent simplifications involved. This criticism may be valid if risk assessors who utilize models do not make the appropriate selections that are needed in their application. They need to ask the following which model should be used which data should be fed into the model why do these two (three) models produce different results, and are the differences significant for risk assessment which data are necessary... 

Maday, J.D., Brouwer, )., and Samudsen, G.S. (2007) Dynamic modeling of hybrid energy storage systems coupled to photovoltaic generation in residential applications. /. Power Sources, 163, 916-925. 

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