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Product Use Scheduler: A Scheduling Module used in EPA’s Human Exposure Model
Citation:
Varghese, A., T. Hong, L. Jessica, H. Hubbard, K. Dionisio, N. Brandon, AND P. Price. Product Use Scheduler: A Scheduling Module used in EPA’s Human Exposure Model. 2017 ISES Annual Meeting, Durham, NC, October 15 - 19, 2017.
Impact/Purpose:
The research presented is a critical component of the LC-HEM software. It allows the prediction of longitudinal patterns in chemical exposure the results from the use of consumer products.
Description:
The scheduling model (SM) was developed for scheduling the use of consumer products in the U.S. EPA’s Human Exposure Model (HEM), an integrated modeling system to estimate human exposure to chemicals in household consumer products. The SM begins with year-long daily activity patterns which are produced by a separate module in HEM. These patterns specify the start times and durations for five macro behaviors: sleep, eat, work/school, commute, and idle time (time not spent in the other activities). The SM schedules the use of more than 300 types of products during idle times. The SM determines which of the product types are used in a household based on the characteristics of the household (e.g., house size and type), the characteristics of individuals living in the house (e.g., gender, age, and work status), and the prevalence of product use. The predictions of product use on a given day are then determined for each product type based on seasonality of product use and estimates of frequency and duration taken from the SHEDS-High throughput model. The SM considers whether products are used to satisfy personal or communal needs (frequency is based on the person or household, respectively) and whether a period of idle time is sufficiently long to allow the use of product, and also clusters products typically used at the same time (e.g., toothpaste and mouthwash, paint primer and paint, car wash and car wax). The SM output is a set of activity patterns that specifies the products used on each day of a year by each individual in a household, the durations of product use, and the mass of product used. These estimates are temporally consistent (individuals do not do two things at once), are consistent with longitudinal predictions of macro behaviors, reflect demographic information, and are consistent with the day of the week and season of the year. The results are used to model human exposure to chemicals in products and the releases of the chemicals to the environment.
